Use ChannelMonitorUpdates in commitment signing fns in Channel
[rust-lightning] / lightning / src / ln / channelmanager.rs
index 60fe1c4586eb89471113ffe0c8ed6ae97fb90897..b489305c9808e640203b3c5aa85fed2611ec6017 100644 (file)
@@ -34,22 +34,22 @@ use ln::features::InitFeatures;
 use ln::msgs;
 use ln::onion_utils;
 use ln::msgs::{ChannelMessageHandler, DecodeError, LightningError};
-use chain::keysinterface::{ChannelKeys, KeysInterface};
+use chain::keysinterface::{ChannelKeys, KeysInterface, InMemoryChannelKeys};
 use util::config::UserConfig;
 use util::{byte_utils, events};
 use util::ser::{Readable, ReadableArgs, Writeable, Writer};
-use util::chacha20::ChaCha20;
+use util::chacha20::{ChaCha20, ChaChaReader};
 use util::logger::Logger;
 use util::errors::APIError;
 
 use std::{cmp, mem};
 use std::collections::{HashMap, hash_map, HashSet};
-use std::io::Cursor;
+use std::io::{Cursor, Read};
 use std::sync::{Arc, Mutex, MutexGuard, RwLock};
 use std::sync::atomic::{AtomicUsize, Ordering};
 use std::time::Duration;
-
-const SIXTY_FIVE_ZEROS: [u8; 65] = [0; 65];
+use std::marker::{Sync, Send};
+use std::ops::Deref;
 
 // We hold various information about HTLC relay in the HTLC objects in Channel itself:
 //
@@ -57,15 +57,19 @@ const SIXTY_FIVE_ZEROS: [u8; 65] = [0; 65];
 // forward the HTLC with information it will give back to us when it does so, or if it should Fail
 // the HTLC with the relevant message for the Channel to handle giving to the remote peer.
 //
-// When a Channel forwards an HTLC to its peer, it will give us back the PendingForwardHTLCInfo
-// which we will use to construct an outbound HTLC, with a relevant HTLCSource::PreviousHopData
-// filled in to indicate where it came from (which we can use to either fail-backwards or fulfill
-// the HTLC backwards along the relevant path).
+// Once said HTLC is committed in the Channel, if the PendingHTLCStatus indicated Forward, the
+// Channel will return the PendingHTLCInfo back to us, and we will create an HTLCForwardInfo
+// with it to track where it came from (in case of onwards-forward error), waiting a random delay
+// before we forward it.
+//
+// We will then use HTLCForwardInfo's PendingHTLCInfo to construct an outbound HTLC, with a
+// relevant HTLCSource::PreviousHopData filled in to indicate where it came from (which we can use
+// to either fail-backwards or fulfill the HTLC backwards along the relevant path).
 // Alternatively, we can fill an outbound HTLC with a HTLCSource::OutboundRoute indicating this is
 // our payment, which we can use to decode errors or inform the user that the payment was sent.
-/// Stores the info we will need to send when we want to forward an HTLC onwards
+
 #[derive(Clone)] // See Channel::revoke_and_ack for why, tl;dr: Rust bug
-pub(super) struct PendingForwardHTLCInfo {
+pub(super) struct PendingHTLCInfo {
        onion_packet: Option<msgs::OnionPacket>,
        incoming_shared_secret: [u8; 32],
        payment_hash: PaymentHash,
@@ -83,10 +87,22 @@ pub(super) enum HTLCFailureMsg {
 /// Stores whether we can't forward an HTLC or relevant forwarding info
 #[derive(Clone)] // See Channel::revoke_and_ack for why, tl;dr: Rust bug
 pub(super) enum PendingHTLCStatus {
-       Forward(PendingForwardHTLCInfo),
+       Forward(PendingHTLCInfo),
        Fail(HTLCFailureMsg),
 }
 
+pub(super) enum HTLCForwardInfo {
+       AddHTLC {
+               prev_short_channel_id: u64,
+               prev_htlc_id: u64,
+               forward_info: PendingHTLCInfo,
+       },
+       FailHTLC {
+               htlc_id: u64,
+               err_packet: msgs::OnionErrorPacket,
+       },
+}
+
 /// Tracks the inbound corresponding to an outbound HTLC
 #[derive(Clone, PartialEq)]
 pub(super) struct HTLCPreviousHopData {
@@ -194,7 +210,7 @@ impl MsgHandleErrInternal {
                }
        }
        #[inline]
-       fn from_chan_no_close(err: ChannelError, channel_id: [u8; 32]) -> Self {
+       fn from_chan_no_close<ChanSigner: ChannelKeys>(err: ChannelError<ChanSigner>, channel_id: [u8; 32]) -> Self {
                Self {
                        err: match err {
                                ChannelError::Ignore(msg) => LightningError {
@@ -231,18 +247,6 @@ impl MsgHandleErrInternal {
 /// second to 30 seconds, but people expect lightning to be, you know, kinda fast, sadly.
 const MIN_HTLC_RELAY_HOLDING_CELL_MILLIS: u64 = 100;
 
-pub(super) enum HTLCForwardInfo {
-       AddHTLC {
-               prev_short_channel_id: u64,
-               prev_htlc_id: u64,
-               forward_info: PendingForwardHTLCInfo,
-       },
-       FailHTLC {
-               htlc_id: u64,
-               err_packet: msgs::OnionErrorPacket,
-       },
-}
-
 /// For events which result in both a RevokeAndACK and a CommitmentUpdate, by default they should
 /// be sent in the order they appear in the return value, however sometimes the order needs to be
 /// variable at runtime (eg Channel::channel_reestablish needs to re-send messages in the order
@@ -262,7 +266,7 @@ pub(super) struct ChannelHolder<ChanSigner: ChannelKeys> {
        /// short channel id -> forward infos. Key of 0 means payments received
        /// Note that while this is held in the same mutex as the channels themselves, no consistency
        /// guarantees are made about the existence of a channel with the short id here, nor the short
-       /// ids in the PendingForwardHTLCInfo!
+       /// ids in the PendingHTLCInfo!
        pub(super) forward_htlcs: HashMap<u64, Vec<HTLCForwardInfo>>,
        /// payment_hash -> Vec<(amount_received, htlc_source)> for tracking things that were to us and
        /// can be failed/claimed by the user
@@ -275,9 +279,30 @@ pub(super) struct ChannelHolder<ChanSigner: ChannelKeys> {
        pub(super) pending_msg_events: Vec<events::MessageSendEvent>,
 }
 
+/// State we hold per-peer. In the future we should put channels in here, but for now we only hold
+/// the latest Init features we heard from the peer.
+struct PeerState {
+       latest_features: InitFeatures,
+}
+
 #[cfg(not(any(target_pointer_width = "32", target_pointer_width = "64")))]
 const ERR: () = "You need at least 32 bit pointers (well, usize, but we'll assume they're the same) for ChannelManager::latest_block_height";
 
+/// SimpleArcChannelManager is useful when you need a ChannelManager with a static lifetime, e.g.
+/// when you're using lightning-net-tokio (since tokio::spawn requires parameters with static
+/// lifetimes). Other times you can afford a reference, which is more efficient, in which case
+/// SimpleRefChannelManager is the more appropriate type. Defining these type aliases prevents
+/// issues such as overly long function definitions.
+pub type SimpleArcChannelManager<M, T> = Arc<ChannelManager<InMemoryChannelKeys, Arc<M>, Arc<T>>>;
+
+/// SimpleRefChannelManager is a type alias for a ChannelManager reference, and is the reference
+/// counterpart to the SimpleArcChannelManager type alias. Use this type by default when you don't
+/// need a ChannelManager with a static lifetime. You'll need a static lifetime in cases such as
+/// usage of lightning-net-tokio (since tokio::spawn requires parameters with static lifetimes).
+/// But if this is not necessary, using a reference is more efficient. Defining these type aliases
+/// helps with issues such as long function definitions.
+pub type SimpleRefChannelManager<'a, 'b, M, T> = ChannelManager<InMemoryChannelKeys, &'a M, &'b T>;
+
 /// Manager which keeps track of a number of channels and sends messages to the appropriate
 /// channel, also tracking HTLC preimages and forwarding onion packets appropriately.
 ///
@@ -307,13 +332,22 @@ const ERR: () = "You need at least 32 bit pointers (well, usize, but we'll assum
 /// ChannelUpdate messages informing peers that the channel is temporarily disabled. To avoid
 /// spam due to quick disconnection/reconnection, updates are not sent until the channel has been
 /// offline for a full minute. In order to track this, you must call
-/// timer_chan_freshness_every_min roughly once per minute, though it doesn't have to be perfec.
-pub struct ChannelManager<ChanSigner: ChannelKeys> {
+/// timer_chan_freshness_every_min roughly once per minute, though it doesn't have to be perfect.
+///
+/// Rather than using a plain ChannelManager, it is preferable to use either a SimpleArcChannelManager
+/// a SimpleRefChannelManager, for conciseness. See their documentation for more details, but
+/// essentially you should default to using a SimpleRefChannelManager, and use a
+/// 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>
+       where M::Target: ManyChannelMonitor<ChanSigner>,
+        T::Target: BroadcasterInterface,
+{
        default_configuration: UserConfig,
        genesis_hash: Sha256dHash,
        fee_estimator: Arc<FeeEstimator>,
-       monitor: Arc<ManyChannelMonitor>,
-       tx_broadcaster: Arc<BroadcasterInterface>,
+       monitor: M,
+       tx_broadcaster: T,
 
        #[cfg(test)]
        pub(super) latest_block_height: AtomicUsize,
@@ -328,6 +362,14 @@ pub struct ChannelManager<ChanSigner: ChannelKeys> {
        channel_state: Mutex<ChannelHolder<ChanSigner>>,
        our_network_key: SecretKey,
 
+       /// The bulk of our storage will eventually be here (channels and message queues and the like).
+       /// If we are connected to a peer we always at least have an entry here, even if no channels
+       /// are currently open with that peer.
+       /// Because adding or removing an entry is rare, we usually take an outer read lock and then
+       /// operate on the inner value freely. Sadly, this prevents parallel operation when opening a
+       /// new channel.
+       per_peer_state: RwLock<HashMap<PublicKey, Mutex<PeerState>>>,
+
        pending_events: Mutex<Vec<events::Event>>,
        /// Used when we have to take a BIG lock to make sure everything is self-consistent.
        /// Essentially just when we're serializing ourselves out.
@@ -390,6 +432,10 @@ pub struct ChannelDetails {
        pub short_channel_id: Option<u64>,
        /// The node_id of our counterparty
        pub remote_network_id: PublicKey,
+       /// The Features the channel counterparty provided upon last connection.
+       /// Useful for routing as it is the most up-to-date copy of the counterparty's features and
+       /// many routing-relevant features are present in the init context.
+       pub counterparty_features: InitFeatures,
        /// The value, in satoshis, of this channel as appears in the funding output
        pub channel_value_satoshis: u64,
        /// The user_id passed in to create_channel, or 0 if the channel was inbound.
@@ -438,7 +484,7 @@ macro_rules! break_chan_entry {
                match $res {
                        Ok(res) => res,
                        Err(ChannelError::Ignore(msg)) => {
-                               break Err(MsgHandleErrInternal::from_chan_no_close(ChannelError::Ignore(msg), $entry.key().clone()))
+                               break Err(MsgHandleErrInternal::from_chan_no_close::<ChanSigner>(ChannelError::Ignore(msg), $entry.key().clone()))
                        },
                        Err(ChannelError::Close(msg)) => {
                                log_trace!($self, "Closing channel {} due to Close-required error: {}", log_bytes!($entry.key()[..]), msg);
@@ -458,7 +504,7 @@ macro_rules! try_chan_entry {
                match $res {
                        Ok(res) => res,
                        Err(ChannelError::Ignore(msg)) => {
-                               return Err(MsgHandleErrInternal::from_chan_no_close(ChannelError::Ignore(msg), $entry.key().clone()))
+                               return Err(MsgHandleErrInternal::from_chan_no_close::<ChanSigner>(ChannelError::Ignore(msg), $entry.key().clone()))
                        },
                        Err(ChannelError::Close(msg)) => {
                                log_trace!($self, "Closing channel {} due to Close-required error: {}", log_bytes!($entry.key()[..]), msg);
@@ -475,7 +521,7 @@ macro_rules! try_chan_entry {
                                        $channel_state.short_to_id.remove(&short_id);
                                }
                                if let Some(update) = update {
-                                       if let Err(e) = $self.monitor.add_update_monitor(update.get_funding_txo().unwrap(), update) {
+                                       if let Err(e) = $self.monitor.add_update_monitor(update.get_funding_txo().unwrap(), update.clone()) {
                                                match e {
                                                        // Upstream channel is dead, but we want at least to fail backward HTLCs to save
                                                        // downstream channels. In case of PermanentFailure, we are not going to be able
@@ -532,7 +578,7 @@ macro_rules! handle_monitor_err {
                                                        } else if $resend_commitment { "commitment" }
                                                        else if $resend_raa { "RAA" }
                                                        else { "nothing" },
-                                               (&$failed_forwards as &Vec<(PendingForwardHTLCInfo, u64)>).len(),
+                                               (&$failed_forwards as &Vec<(PendingHTLCInfo, u64)>).len(),
                                                (&$failed_fails as &Vec<(HTLCSource, PaymentHash, HTLCFailReason)>).len());
                                if !$resend_commitment {
                                        debug_assert!($action_type == RAACommitmentOrder::RevokeAndACKFirst || !$resend_raa);
@@ -541,7 +587,7 @@ macro_rules! handle_monitor_err {
                                        debug_assert!($action_type == RAACommitmentOrder::CommitmentFirst || !$resend_commitment);
                                }
                                $entry.get_mut().monitor_update_failed($resend_raa, $resend_commitment, $failed_forwards, $failed_fails);
-                               Err(MsgHandleErrInternal::from_chan_no_close(ChannelError::Ignore("Failed to update ChannelMonitor"), *$entry.key()))
+                               Err(MsgHandleErrInternal::from_chan_no_close::<ChanSigner>(ChannelError::Ignore("Failed to update ChannelMonitor"), *$entry.key()))
                        },
                }
        }
@@ -568,7 +614,10 @@ macro_rules! maybe_break_monitor_err {
        }
 }
 
-impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
+impl<ChanSigner: ChannelKeys, M: Deref, T: Deref> ChannelManager<ChanSigner, M, T>
+       where M::Target: ManyChannelMonitor<ChanSigner>,
+        T::Target: BroadcasterInterface,
+{
        /// Constructs a new ChannelManager to hold several channels and route between them.
        ///
        /// This is the main "logic hub" for all channel-related actions, and implements
@@ -587,14 +636,14 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
        /// 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, feeest: Arc<FeeEstimator>, monitor: Arc<ManyChannelMonitor>, tx_broadcaster: Arc<BroadcasterInterface>, logger: Arc<Logger>,keys_manager: Arc<KeysInterface<ChanKeySigner = ChanSigner>>, config: UserConfig, current_blockchain_height: usize) -> Result<Arc<ChannelManager<ChanSigner>>, secp256k1::Error> {
+       pub fn new(network: Network, feeest: Arc<FeeEstimator>, monitor: M, tx_broadcaster: T, logger: Arc<Logger>,keys_manager: Arc<KeysInterface<ChanKeySigner = ChanSigner>>, config: UserConfig, current_blockchain_height: usize) -> Result<ChannelManager<ChanSigner, M, T>, secp256k1::Error> {
                let secp_ctx = Secp256k1::new();
 
-               let res = Arc::new(ChannelManager {
+               let res = ChannelManager {
                        default_configuration: config.clone(),
                        genesis_hash: genesis_block(network).header.bitcoin_hash(),
                        fee_estimator: feeest.clone(),
-                       monitor: monitor.clone(),
+                       monitor,
                        tx_broadcaster,
 
                        latest_block_height: AtomicUsize::new(current_blockchain_height),
@@ -610,13 +659,15 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                        }),
                        our_network_key: keys_manager.get_node_secret(),
 
+                       per_peer_state: RwLock::new(HashMap::new()),
+
                        pending_events: Mutex::new(Vec::new()),
                        total_consistency_lock: RwLock::new(()),
 
                        keys_manager,
 
                        logger,
-               });
+               };
 
                Ok(res)
        }
@@ -660,56 +711,53 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                Ok(())
        }
 
-       /// Gets the list of open channels, in random order. See ChannelDetail field documentation for
-       /// more information.
-       pub fn list_channels(&self) -> Vec<ChannelDetails> {
-               let channel_state = self.channel_state.lock().unwrap();
-               let mut res = Vec::with_capacity(channel_state.by_id.len());
-               for (channel_id, channel) in channel_state.by_id.iter() {
-                       let (inbound_capacity_msat, outbound_capacity_msat) = channel.get_inbound_outbound_available_balance_msat();
-                       res.push(ChannelDetails {
-                               channel_id: (*channel_id).clone(),
-                               short_channel_id: channel.get_short_channel_id(),
-                               remote_network_id: channel.get_their_node_id(),
-                               channel_value_satoshis: channel.get_value_satoshis(),
-                               inbound_capacity_msat,
-                               outbound_capacity_msat,
-                               user_id: channel.get_user_id(),
-                               is_live: channel.is_live(),
-                       });
-               }
-               res
-       }
-
-       /// Gets the list of usable channels, in random order. Useful as an argument to
-       /// Router::get_route to ensure non-announced channels are used.
-       ///
-       /// These are guaranteed to have their is_live value set to true, see the documentation for
-       /// ChannelDetails::is_live for more info on exactly what the criteria are.
-       pub fn list_usable_channels(&self) -> Vec<ChannelDetails> {
-               let channel_state = self.channel_state.lock().unwrap();
-               let mut res = Vec::with_capacity(channel_state.by_id.len());
-               for (channel_id, channel) in channel_state.by_id.iter() {
-                       // Note we use is_live here instead of usable which leads to somewhat confused
-                       // internal/external nomenclature, but that's ok cause that's probably what the user
-                       // really wanted anyway.
-                       if channel.is_live() {
+       fn list_channels_with_filter<F: FnMut(&(&[u8; 32], &Channel<ChanSigner>)) -> bool>(&self, f: F) -> Vec<ChannelDetails> {
+               let mut res = Vec::new();
+               {
+                       let channel_state = self.channel_state.lock().unwrap();
+                       res.reserve(channel_state.by_id.len());
+                       for (channel_id, channel) in channel_state.by_id.iter().filter(f) {
                                let (inbound_capacity_msat, outbound_capacity_msat) = channel.get_inbound_outbound_available_balance_msat();
                                res.push(ChannelDetails {
                                        channel_id: (*channel_id).clone(),
                                        short_channel_id: channel.get_short_channel_id(),
                                        remote_network_id: channel.get_their_node_id(),
+                                       counterparty_features: InitFeatures::empty(),
                                        channel_value_satoshis: channel.get_value_satoshis(),
                                        inbound_capacity_msat,
                                        outbound_capacity_msat,
                                        user_id: channel.get_user_id(),
-                                       is_live: true,
+                                       is_live: channel.is_live(),
                                });
                        }
                }
+               let per_peer_state = self.per_peer_state.read().unwrap();
+               for chan in res.iter_mut() {
+                       if let Some(peer_state) = per_peer_state.get(&chan.remote_network_id) {
+                               chan.counterparty_features = peer_state.lock().unwrap().latest_features.clone();
+                       }
+               }
                res
        }
 
+       /// Gets the list of open channels, in random order. See ChannelDetail field documentation for
+       /// more information.
+       pub fn list_channels(&self) -> Vec<ChannelDetails> {
+               self.list_channels_with_filter(|_| true)
+       }
+
+       /// Gets the list of usable channels, in random order. Useful as an argument to
+       /// Router::get_route to ensure non-announced channels are used.
+       ///
+       /// These are guaranteed to have their is_live value set to true, see the documentation for
+       /// ChannelDetails::is_live for more info on exactly what the criteria are.
+       pub fn list_usable_channels(&self) -> Vec<ChannelDetails> {
+               // Note we use is_live here instead of usable which leads to somewhat confused
+               // internal/external nomenclature, but that's ok cause that's probably what the user
+               // really wanted anyway.
+               self.list_channels_with_filter(|&(_, ref channel)| channel.is_live())
+       }
+
        /// Begins the process of closing a channel. After this call (plus some timeout), no new HTLCs
        /// will be accepted on the given channel, and after additional timeout/the closing of all
        /// pending HTLCs, the channel will be closed on chain.
@@ -866,22 +914,30 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                }
 
                let mut chacha = ChaCha20::new(&rho, &[0u8; 8]);
-               let next_hop_data = {
-                       let mut decoded = [0; 65];
-                       chacha.process(&msg.onion_routing_packet.hop_data[0..65], &mut decoded);
-                       match msgs::OnionHopData::read(&mut Cursor::new(&decoded[..])) {
+               let mut chacha_stream = ChaChaReader { chacha: &mut chacha, read: Cursor::new(&msg.onion_routing_packet.hop_data[..]) };
+               let (next_hop_data, next_hop_hmac) = {
+                       match msgs::OnionHopData::read(&mut chacha_stream) {
                                Err(err) => {
                                        let error_code = match err {
                                                msgs::DecodeError::UnknownVersion => 0x4000 | 1, // unknown realm byte
+                                               msgs::DecodeError::UnknownRequiredFeature|
+                                               msgs::DecodeError::InvalidValue|
+                                               msgs::DecodeError::ShortRead => 0x4000 | 22, // invalid_onion_payload
                                                _ => 0x2000 | 2, // Should never happen
                                        };
                                        return_err!("Unable to decode our hop data", error_code, &[0;0]);
                                },
-                               Ok(msg) => msg
+                               Ok(msg) => {
+                                       let mut hmac = [0; 32];
+                                       if let Err(_) = chacha_stream.read_exact(&mut hmac[..]) {
+                                               return_err!("Unable to decode hop data", 0x4000 | 22, &[0;0]);
+                                       }
+                                       (msg, hmac)
+                               },
                        }
                };
 
-               let pending_forward_info = if next_hop_data.hmac == [0; 32] {
+               let pending_forward_info = if next_hop_hmac == [0; 32] {
                                #[cfg(test)]
                                {
                                        // In tests, make sure that the initial onion pcket data is, at least, non-0.
@@ -891,10 +947,11 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                                        // as-is (and were originally 0s).
                                        // Of course reverse path calculation is still pretty easy given naive routing
                                        // algorithms, but this fixes the most-obvious case.
-                                       let mut new_packet_data = [0; 19*65];
-                                       chacha.process(&msg.onion_routing_packet.hop_data[65..], &mut new_packet_data[0..19*65]);
-                                       assert_ne!(new_packet_data[0..65], [0; 65][..]);
-                                       assert_ne!(new_packet_data[..], [0; 19*65][..]);
+                                       let mut next_bytes = [0; 32];
+                                       chacha_stream.read_exact(&mut next_bytes).unwrap();
+                                       assert_ne!(next_bytes[..], [0; 32][..]);
+                                       chacha_stream.read_exact(&mut next_bytes).unwrap();
+                                       assert_ne!(next_bytes[..], [0; 32][..]);
                                }
 
                                // OUR PAYMENT!
@@ -903,11 +960,11 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                                        return_err!("The final CLTV expiry is too soon to handle", 17, &[0;0]);
                                }
                                // final_incorrect_htlc_amount
-                               if next_hop_data.data.amt_to_forward > msg.amount_msat {
+                               if next_hop_data.amt_to_forward > msg.amount_msat {
                                        return_err!("Upstream node sent less than we were supposed to receive in payment", 19, &byte_utils::be64_to_array(msg.amount_msat));
                                }
                                // final_incorrect_cltv_expiry
-                               if next_hop_data.data.outgoing_cltv_value != msg.cltv_expiry {
+                               if next_hop_data.outgoing_cltv_value != msg.cltv_expiry {
                                        return_err!("Upstream node set CLTV to the wrong value", 18, &byte_utils::be32_to_array(msg.cltv_expiry));
                                }
 
@@ -916,18 +973,29 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                                // instead we stay symmetric with the forwarding case, only responding (after a
                                // delay) once they've send us a commitment_signed!
 
-                               PendingHTLCStatus::Forward(PendingForwardHTLCInfo {
+                               PendingHTLCStatus::Forward(PendingHTLCInfo {
                                        onion_packet: None,
                                        payment_hash: msg.payment_hash.clone(),
                                        short_channel_id: 0,
                                        incoming_shared_secret: shared_secret,
-                                       amt_to_forward: next_hop_data.data.amt_to_forward,
-                                       outgoing_cltv_value: next_hop_data.data.outgoing_cltv_value,
+                                       amt_to_forward: next_hop_data.amt_to_forward,
+                                       outgoing_cltv_value: next_hop_data.outgoing_cltv_value,
                                })
                        } else {
                                let mut new_packet_data = [0; 20*65];
-                               chacha.process(&msg.onion_routing_packet.hop_data[65..], &mut new_packet_data[0..19*65]);
-                               chacha.process(&SIXTY_FIVE_ZEROS[..], &mut new_packet_data[19*65..]);
+                               let read_pos = chacha_stream.read(&mut new_packet_data).unwrap();
+                               #[cfg(debug_assertions)]
+                               {
+                                       // Check two things:
+                                       // a) that the behavior of our stream here will return Ok(0) even if the TLV
+                                       //    read above emptied out our buffer and the unwrap() wont needlessly panic
+                                       // b) that we didn't somehow magically end up with extra data.
+                                       let mut t = [0; 1];
+                                       debug_assert!(chacha_stream.read(&mut t).unwrap() == 0);
+                               }
+                               // Once we've emptied the set of bytes our peer gave us, encrypt 0 bytes until we
+                               // fill the onion hop data we'll forward to our next-hop peer.
+                               chacha_stream.chacha.process_in_place(&mut new_packet_data[read_pos..]);
 
                                let mut new_pubkey = msg.onion_routing_packet.public_key.unwrap();
 
@@ -946,21 +1014,29 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                                        version: 0,
                                        public_key,
                                        hop_data: new_packet_data,
-                                       hmac: next_hop_data.hmac.clone(),
+                                       hmac: next_hop_hmac.clone(),
                                };
 
-                               PendingHTLCStatus::Forward(PendingForwardHTLCInfo {
+                               let short_channel_id = match next_hop_data.format {
+                                       msgs::OnionHopDataFormat::Legacy { short_channel_id } => short_channel_id,
+                                       msgs::OnionHopDataFormat::NonFinalNode { short_channel_id } => short_channel_id,
+                                       msgs::OnionHopDataFormat::FinalNode => {
+                                               return_err!("Final Node OnionHopData provided for us as an intermediary node", 0x4000 | 22, &[0;0]);
+                                       },
+                               };
+
+                               PendingHTLCStatus::Forward(PendingHTLCInfo {
                                        onion_packet: Some(outgoing_packet),
                                        payment_hash: msg.payment_hash.clone(),
-                                       short_channel_id: next_hop_data.data.short_channel_id,
+                                       short_channel_id: short_channel_id,
                                        incoming_shared_secret: shared_secret,
-                                       amt_to_forward: next_hop_data.data.amt_to_forward,
-                                       outgoing_cltv_value: next_hop_data.data.outgoing_cltv_value,
+                                       amt_to_forward: next_hop_data.amt_to_forward,
+                                       outgoing_cltv_value: next_hop_data.outgoing_cltv_value,
                                })
                        };
 
                channel_state = Some(self.channel_state.lock().unwrap());
-               if let &PendingHTLCStatus::Forward(PendingForwardHTLCInfo { ref onion_packet, ref short_channel_id, ref amt_to_forward, ref outgoing_cltv_value, .. }) = &pending_forward_info {
+               if let &PendingHTLCStatus::Forward(PendingHTLCInfo { ref onion_packet, ref short_channel_id, ref amt_to_forward, ref outgoing_cltv_value, .. }) = &pending_forward_info {
                        if onion_packet.is_some() { // If short_channel_id is 0 here, we'll reject them in the body here
                                let id_option = channel_state.as_ref().unwrap().short_to_id.get(&short_channel_id).cloned();
                                let forwarding_id = match id_option {
@@ -1097,6 +1173,9 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                let onion_keys = secp_call!(onion_utils::construct_onion_keys(&self.secp_ctx, &route, &session_priv),
                                APIError::RouteError{err: "Pubkey along hop was maliciously selected"});
                let (onion_payloads, htlc_msat, htlc_cltv) = onion_utils::build_onion_payloads(&route, cur_height)?;
+               if onion_utils::route_size_insane(&onion_payloads) {
+                       return Err(APIError::RouteError{err: "Route size too large considering onion data"});
+               }
                let onion_packet = onion_utils::construct_onion_packet(onion_payloads, onion_keys, prng_seed, &payment_hash);
 
                let _ = self.total_consistency_lock.read().unwrap();
@@ -1124,8 +1203,8 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                                                first_hop_htlc_msat: htlc_msat,
                                        }, onion_packet), channel_state, chan)
                                } {
-                                       Some((update_add, commitment_signed, chan_monitor)) => {
-                                               if let Err(e) = self.monitor.add_update_monitor(chan_monitor.get_funding_txo().unwrap(), chan_monitor) {
+                                       Some((update_add, commitment_signed, monitor_update)) => {
+                                               if let Err(e) = self.monitor.update_monitor(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 resent the commitment update once we unfree monitor
@@ -1228,7 +1307,10 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
        }
 
        fn get_announcement_sigs(&self, chan: &Channel<ChanSigner>) -> Option<msgs::AnnouncementSignatures> {
-               if !chan.should_announce() { return None }
+               if !chan.should_announce() {
+                       log_trace!(self, "Can't send announcement_signatures for private channel {}", log_bytes!(chan.channel_id()));
+                       return None
+               }
 
                let (announcement, our_bitcoin_sig) = match chan.get_channel_announcement(self.get_our_node_id(), self.genesis_hash.clone()) {
                        Ok(res) => res,
@@ -1356,7 +1438,7 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                                                }
 
                                                if !add_htlc_msgs.is_empty() || !fail_htlc_msgs.is_empty() {
-                                                       let (commitment_msg, monitor) = match chan.get_mut().send_commitment() {
+                                                       let (commitment_msg, monitor_update) = match chan.get_mut().send_commitment() {
                                                                Ok(res) => res,
                                                                Err(e) => {
                                                                        // We surely failed send_commitment due to bad keys, in that case
@@ -1382,7 +1464,7 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                                                                        }
                                                                }
                                                        };
-                                                       if let Err(e) = self.monitor.add_update_monitor(monitor.get_funding_txo().unwrap(), monitor) {
+                                                       if let Err(e) = self.monitor.update_monitor(chan.get().get_funding_txo().unwrap(), monitor_update) {
                                                                handle_errors.push((chan.get().get_their_node_id(), handle_monitor_err!(self, e, channel_state, chan, RAACommitmentOrder::CommitmentFirst, false, true)));
                                                                continue;
                                                        }
@@ -1655,8 +1737,8 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                                                let was_frozen_for_monitor = chan.get().is_awaiting_monitor_update();
                                                match chan.get_mut().get_update_fulfill_htlc_and_commit(htlc_id, payment_preimage) {
                                                        Ok((msgs, monitor_option)) => {
-                                                               if let Some(chan_monitor) = monitor_option {
-                                                                       if let Err(e) = self.monitor.add_update_monitor(chan_monitor.get_funding_txo().unwrap(), chan_monitor) {
+                                                               if let Some(monitor_update) = monitor_option {
+                                                                       if let Err(e) = self.monitor.update_monitor(chan.get().get_funding_txo().unwrap(), monitor_update) {
                                                                                if was_frozen_for_monitor {
                                                                                        assert!(msgs.is_none());
                                                                                } else {
@@ -1699,6 +1781,112 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                PublicKey::from_secret_key(&self.secp_ctx, &self.our_network_key)
        }
 
+       /// Restores a single, given channel to normal operation after a
+       /// ChannelMonitorUpdateErr::TemporaryFailure was returned from a channel monitor update
+       /// operation.
+       ///
+       /// All ChannelMonitor updates up to and including highest_applied_update_id must have been
+       /// fully committed in every copy of the given channels' ChannelMonitors.
+       ///
+       /// Note that there is no effect to calling with a highest_applied_update_id other than the
+       /// current latest ChannelMonitorUpdate and one call to this function after multiple
+       /// ChannelMonitorUpdateErr::TemporaryFailures is fine. The highest_applied_update_id field
+       /// 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,
+       ///  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,
+       ///  3) update(s) are applied to each remote copy of a ChannelMonitor,
+       ///  4) once all remote copies are updated, you call this function with the update_id that
+       ///     completed, and once it is the latest the Channel will be re-enabled.
+       pub fn channel_monitor_updated(&self, funding_txo: &OutPoint, highest_applied_update_id: u64) {
+               let _ = self.total_consistency_lock.read().unwrap();
+
+               let mut close_results = Vec::new();
+               let mut htlc_forwards = Vec::new();
+               let mut htlc_failures = Vec::new();
+               let mut pending_events = Vec::new();
+
+               {
+                       let mut channel_lock = self.channel_state.lock().unwrap();
+                       let channel_state = &mut *channel_lock;
+                       let short_to_id = &mut channel_state.short_to_id;
+                       let pending_msg_events = &mut channel_state.pending_msg_events;
+                       let channel = match channel_state.by_id.get_mut(&funding_txo.to_channel_id()) {
+                               Some(chan) => chan,
+                               None => return,
+                       };
+                       if !channel.is_awaiting_monitor_update() || channel.get_latest_monitor_update_id() != highest_applied_update_id {
+                               return;
+                       }
+
+                       let (raa, commitment_update, order, pending_forwards, mut pending_failures, needs_broadcast_safe, funding_locked) = channel.monitor_updating_restored();
+                       if !pending_forwards.is_empty() {
+                               htlc_forwards.push((channel.get_short_channel_id().expect("We can't have pending forwards before funding confirmation"), pending_forwards));
+                       }
+                       htlc_failures.append(&mut pending_failures);
+
+                       macro_rules! handle_cs { () => {
+                               if let Some(update) = commitment_update {
+                                       pending_msg_events.push(events::MessageSendEvent::UpdateHTLCs {
+                                               node_id: channel.get_their_node_id(),
+                                               updates: update,
+                                       });
+                               }
+                       } }
+                       macro_rules! handle_raa { () => {
+                               if let Some(revoke_and_ack) = raa {
+                                       pending_msg_events.push(events::MessageSendEvent::SendRevokeAndACK {
+                                               node_id: channel.get_their_node_id(),
+                                               msg: revoke_and_ack,
+                                       });
+                               }
+                       } }
+                       match order {
+                               RAACommitmentOrder::CommitmentFirst => {
+                                       handle_cs!();
+                                       handle_raa!();
+                               },
+                               RAACommitmentOrder::RevokeAndACKFirst => {
+                                       handle_raa!();
+                                       handle_cs!();
+                               },
+                       }
+                       if needs_broadcast_safe {
+                               pending_events.push(events::Event::FundingBroadcastSafe {
+                                       funding_txo: channel.get_funding_txo().unwrap(),
+                                       user_channel_id: channel.get_user_id(),
+                               });
+                       }
+                       if let Some(msg) = funding_locked {
+                               pending_msg_events.push(events::MessageSendEvent::SendFundingLocked {
+                                       node_id: channel.get_their_node_id(),
+                                       msg,
+                               });
+                               if let Some(announcement_sigs) = self.get_announcement_sigs(channel) {
+                                       pending_msg_events.push(events::MessageSendEvent::SendAnnouncementSignatures {
+                                               node_id: channel.get_their_node_id(),
+                                               msg: announcement_sigs,
+                                       });
+                               }
+                               short_to_id.insert(channel.get_short_channel_id().unwrap(), channel.channel_id());
+                       }
+               }
+
+               self.pending_events.lock().unwrap().append(&mut pending_events);
+
+               for failure in htlc_failures.drain(..) {
+                       self.fail_htlc_backwards_internal(self.channel_state.lock().unwrap(), failure.0, &failure.1, failure.2);
+               }
+               self.forward_htlcs(&mut htlc_forwards[..]);
+
+               for res in close_results.drain(..) {
+                       self.finish_force_close_channel(res);
+               }
+       }
+
        /// Used to restore channels to normal operation after a
        /// ChannelMonitorUpdateErr::TemporaryFailure was returned from a channel monitor update
        /// operation.
@@ -1917,8 +2105,17 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                                        if chan.get().get_their_node_id() != *their_node_id {
                                                return Err(MsgHandleErrInternal::send_err_msg_no_close("Got a message for a channel from the wrong node!", msg.channel_id));
                                        }
-                                       let chan_monitor = try_chan_entry!(self, chan.get_mut().funding_signed(&msg), channel_state, chan);
-                                       if let Err(e) = self.monitor.add_update_monitor(chan_monitor.get_funding_txo().unwrap(), chan_monitor) {
+                                       let monitor_update = match chan.get_mut().funding_signed(&msg) {
+                                               Err((None, e)) => try_chan_entry!(self, Err(e), channel_state, chan),
+                                               Err((Some(monitor_update), e)) => {
+                                                       assert!(chan.get().is_awaiting_monitor_update());
+                                                       let _ = self.monitor.update_monitor(chan.get().get_funding_txo().unwrap(), monitor_update);
+                                                       try_chan_entry!(self, Err(e), channel_state, chan);
+                                                       unreachable!();
+                                               },
+                                               Ok(update) => update,
+                                       };
+                                       if let Err(e) = self.monitor.update_monitor(chan.get().get_funding_txo().unwrap(), monitor_update) {
                                                return_monitor_err!(self, e, channel_state, chan, RAACommitmentOrder::RevokeAndACKFirst, false, false);
                                        }
                                        (chan.get().get_funding_txo().unwrap(), chan.get().get_user_id())
@@ -1944,6 +2141,7 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                                }
                                try_chan_entry!(self, chan.get_mut().funding_locked(&msg), channel_state, chan);
                                if let Some(announcement_sigs) = self.get_announcement_sigs(chan.get()) {
+                                       log_trace!(self, "Sending announcement_signatures for {} in response to funding_locked", log_bytes!(chan.get().channel_id()));
                                        // If we see locking block before receiving remote funding_locked, we broadcast our
                                        // announcement_sigs at remote funding_locked reception. If we receive remote
                                        // funding_locked before seeing locking block, we broadcast our announcement_sigs at locking
@@ -2079,7 +2277,7 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                                        // If the update_add is completely bogus, the call will Err and we will close,
                                        // but if we've sent a shutdown and they haven't acknowledged it yet, we just
                                        // want to reject the new HTLC and fail it backwards instead of forwarding.
-                                       if let PendingHTLCStatus::Forward(PendingForwardHTLCInfo { incoming_shared_secret, .. }) = pending_forward_info {
+                                       if let PendingHTLCStatus::Forward(PendingHTLCInfo { incoming_shared_secret, .. }) = pending_forward_info {
                                                let chan_update = self.get_channel_update(chan.get());
                                                pending_forward_info = PendingHTLCStatus::Fail(HTLCFailureMsg::Relay(msgs::UpdateFailHTLC {
                                                        channel_id: msg.channel_id,
@@ -2156,7 +2354,8 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                                        return Err(MsgHandleErrInternal::send_err_msg_no_close("Got a message for a channel from the wrong node!", msg.channel_id));
                                }
                                if (msg.failure_code & 0x8000) == 0 {
-                                       try_chan_entry!(self, Err(ChannelError::Close("Got update_fail_malformed_htlc with BADONION not set")), channel_state, chan);
+                                       let chan_err: ChannelError<ChanSigner> = ChannelError::Close("Got update_fail_malformed_htlc with BADONION not set");
+                                       try_chan_entry!(self, Err(chan_err), channel_state, chan);
                                }
                                try_chan_entry!(self, chan.get_mut().update_fail_malformed_htlc(&msg, HTLCFailReason::Reason { failure_code: msg.failure_code, data: Vec::new() }), channel_state, chan);
                                Ok(())
@@ -2173,9 +2372,18 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                                if chan.get().get_their_node_id() != *their_node_id {
                                        return Err(MsgHandleErrInternal::send_err_msg_no_close("Got a message for a channel from the wrong node!", msg.channel_id));
                                }
-                               let (revoke_and_ack, commitment_signed, closing_signed, chan_monitor) =
-                                       try_chan_entry!(self, chan.get_mut().commitment_signed(&msg, &*self.fee_estimator), channel_state, chan);
-                               if let Err(e) = self.monitor.add_update_monitor(chan_monitor.get_funding_txo().unwrap(), chan_monitor) {
+                               let (revoke_and_ack, commitment_signed, closing_signed, monitor_update) =
+                                               match chan.get_mut().commitment_signed(&msg, &*self.fee_estimator) {
+                                       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);
+                                               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) {
                                        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
                                }
@@ -2209,7 +2417,7 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
        }
 
        #[inline]
-       fn forward_htlcs(&self, per_source_pending_forwards: &mut [(u64, Vec<(PendingForwardHTLCInfo, u64)>)]) {
+       fn forward_htlcs(&self, per_source_pending_forwards: &mut [(u64, Vec<(PendingHTLCInfo, u64)>)]) {
                for &mut (prev_short_channel_id, ref mut pending_forwards) in per_source_pending_forwards {
                        let mut forward_event = None;
                        if !pending_forwards.is_empty() {
@@ -2250,9 +2458,9 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                                                return Err(MsgHandleErrInternal::send_err_msg_no_close("Got a message for a channel from the wrong node!", msg.channel_id));
                                        }
                                        let was_frozen_for_monitor = chan.get().is_awaiting_monitor_update();
-                                       let (commitment_update, pending_forwards, pending_failures, closing_signed, chan_monitor) =
+                                       let (commitment_update, pending_forwards, pending_failures, closing_signed, monitor_update) =
                                                try_chan_entry!(self, chan.get_mut().revoke_and_ack(&msg, &*self.fee_estimator), channel_state, chan);
-                                       if let Err(e) = self.monitor.add_update_monitor(chan_monitor.get_funding_txo().unwrap(), chan_monitor) {
+                                       if let Err(e) = self.monitor.update_monitor(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());
                                                        return Err(MsgHandleErrInternal::ignore_no_close("Previous monitor update failure prevented responses to RAA"));
@@ -2321,7 +2529,8 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                                let msghash = hash_to_message!(&Sha256dHash::hash(&announcement.encode()[..])[..]);
                                if self.secp_ctx.verify(&msghash, &msg.node_signature, if were_node_one { &announcement.node_id_2 } else { &announcement.node_id_1 }).is_err() ||
                                                self.secp_ctx.verify(&msghash, &msg.bitcoin_signature, if were_node_one { &announcement.bitcoin_key_2 } else { &announcement.bitcoin_key_1 }).is_err() {
-                                       try_chan_entry!(self, Err(ChannelError::Close("Bad announcement_signatures node_signature")), channel_state, chan);
+                                       let chan_err: ChannelError<ChanSigner> = ChannelError::Close("Bad announcement_signatures node_signature");
+                                       try_chan_entry!(self, Err(chan_err), channel_state, chan);
                                }
 
                                let our_node_sig = self.secp_ctx.sign(&msghash, &self.our_network_key);
@@ -2351,10 +2560,10 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                                if chan.get().get_their_node_id() != *their_node_id {
                                        return Err(MsgHandleErrInternal::send_err_msg_no_close("Got a message for a channel from the wrong node!", msg.channel_id));
                                }
-                               let (funding_locked, revoke_and_ack, commitment_update, channel_monitor, mut order, shutdown) =
+                               let (funding_locked, revoke_and_ack, commitment_update, monitor_update_opt, mut order, shutdown) =
                                        try_chan_entry!(self, chan.get_mut().channel_reestablish(msg), channel_state, chan);
-                               if let Some(monitor) = channel_monitor {
-                                       if let Err(e) = self.monitor.add_update_monitor(monitor.get_funding_txo().unwrap(), monitor) {
+                               if let Some(monitor_update) = monitor_update_opt {
+                                       if let Err(e) = self.monitor.update_monitor(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.
@@ -2437,10 +2646,10 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
                                                return Err(APIError::ChannelUnavailable{err: "Channel is either not yet fully established or peer is currently disconnected"});
                                        }
                                        their_node_id = chan.get().get_their_node_id();
-                                       if let Some((update_fee, commitment_signed, chan_monitor)) =
+                                       if let Some((update_fee, commitment_signed, monitor_update)) =
                                                        break_chan_entry!(self, chan.get_mut().send_update_fee_and_commit(feerate_per_kw), channel_state, chan)
                                        {
-                                               if let Err(_e) = self.monitor.add_update_monitor(chan_monitor.get_funding_txo().unwrap(), chan_monitor) {
+                                               if let Err(_e) = self.monitor.update_monitor(chan.get().get_funding_txo().unwrap(), monitor_update) {
                                                        unimplemented!();
                                                }
                                                channel_state.pending_msg_events.push(events::MessageSendEvent::UpdateHTLCs {
@@ -2467,14 +2676,17 @@ impl<ChanSigner: ChannelKeys> ChannelManager<ChanSigner> {
        }
 }
 
-impl<ChanSigner: ChannelKeys> events::MessageSendEventsProvider for ChannelManager<ChanSigner> {
+impl<ChanSigner: ChannelKeys, M: Deref, T: Deref> events::MessageSendEventsProvider for ChannelManager<ChanSigner, M, T>
+       where M::Target: ManyChannelMonitor<ChanSigner>,
+        T::Target: BroadcasterInterface,
+{
        fn get_and_clear_pending_msg_events(&self) -> Vec<events::MessageSendEvent> {
                // TODO: Event release to users and serialization is currently race-y: it's very easy for a
                // user to serialize a ChannelManager with pending events in it and lose those events on
                // restart. This is doubly true for the fail/fulfill-backs from monitor events!
                {
                        //TODO: This behavior should be documented.
-                       for htlc_update in self.monitor.fetch_pending_htlc_updated() {
+                       for htlc_update in self.monitor.get_and_clear_pending_htlcs_updated() {
                                if let Some(preimage) = htlc_update.payment_preimage {
                                        log_trace!(self, "Claiming HTLC with preimage {} from our monitor", log_bytes!(preimage.0));
                                        self.claim_funds_internal(self.channel_state.lock().unwrap(), htlc_update.source, preimage);
@@ -2492,14 +2704,17 @@ impl<ChanSigner: ChannelKeys> events::MessageSendEventsProvider for ChannelManag
        }
 }
 
-impl<ChanSigner: ChannelKeys> events::EventsProvider for ChannelManager<ChanSigner> {
+impl<ChanSigner: ChannelKeys, M: Deref, T: Deref> events::EventsProvider for ChannelManager<ChanSigner, M, T>
+       where M::Target: ManyChannelMonitor<ChanSigner>,
+        T::Target: BroadcasterInterface,
+{
        fn get_and_clear_pending_events(&self) -> Vec<events::Event> {
                // TODO: Event release to users and serialization is currently race-y: it's very easy for a
                // user to serialize a ChannelManager with pending events in it and lose those events on
                // restart. This is doubly true for the fail/fulfill-backs from monitor events!
                {
                        //TODO: This behavior should be documented.
-                       for htlc_update in self.monitor.fetch_pending_htlc_updated() {
+                       for htlc_update in self.monitor.get_and_clear_pending_htlcs_updated() {
                                if let Some(preimage) = htlc_update.payment_preimage {
                                        log_trace!(self, "Claiming HTLC with preimage {} from our monitor", log_bytes!(preimage.0));
                                        self.claim_funds_internal(self.channel_state.lock().unwrap(), htlc_update.source, preimage);
@@ -2517,7 +2732,10 @@ impl<ChanSigner: ChannelKeys> events::EventsProvider for ChannelManager<ChanSign
        }
 }
 
-impl<ChanSigner: ChannelKeys> ChainListener for ChannelManager<ChanSigner> {
+impl<ChanSigner: ChannelKeys, M: Deref + Sync + Send, T: Deref + Sync + Send> ChainListener for ChannelManager<ChanSigner, M, T>
+       where M::Target: ManyChannelMonitor<ChanSigner>,
+        T::Target: BroadcasterInterface,
+{
        fn block_connected(&self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[u32]) {
                let header_hash = header.bitcoin_hash();
                log_trace!(self, "Block {} at height {} connected with {} txn matched", header_hash, height, txn_matched.len());
@@ -2536,10 +2754,13 @@ impl<ChanSigner: ChannelKeys> ChainListener for ChannelManager<ChanSigner> {
                                                msg: funding_locked,
                                        });
                                        if let Some(announcement_sigs) = self.get_announcement_sigs(channel) {
+                                               log_trace!(self, "Sending funding_locked and announcement_signatures for {}", log_bytes!(channel.channel_id()));
                                                pending_msg_events.push(events::MessageSendEvent::SendAnnouncementSignatures {
                                                        node_id: channel.get_their_node_id(),
                                                        msg: announcement_sigs,
                                                });
+                                       } else {
+                                               log_trace!(self, "Sending funding_locked WITHOUT announcement_signatures for {}", log_bytes!(channel.channel_id()));
                                        }
                                        short_to_id.insert(channel.get_short_channel_id().unwrap(), channel.channel_id());
                                } else if let Err(e) = chan_res {
@@ -2631,7 +2852,10 @@ impl<ChanSigner: ChannelKeys> ChainListener for ChannelManager<ChanSigner> {
        }
 }
 
-impl<ChanSigner: ChannelKeys> ChannelMessageHandler for ChannelManager<ChanSigner> {
+impl<ChanSigner: ChannelKeys, M: Deref + Sync + Send, T: Deref + Sync + Send> ChannelMessageHandler for ChannelManager<ChanSigner, M, T>
+       where M::Target: ManyChannelMonitor<ChanSigner>,
+        T::Target: BroadcasterInterface,
+{
        fn handle_open_channel(&self, their_node_id: &PublicKey, their_features: InitFeatures, msg: &msgs::OpenChannel) {
                let _ = self.total_consistency_lock.read().unwrap();
                let res = self.internal_open_channel(their_node_id, their_features, msg);
@@ -2780,6 +3004,7 @@ impl<ChanSigner: ChannelKeys> ChannelMessageHandler for ChannelManager<ChanSigne
                let _ = self.total_consistency_lock.read().unwrap();
                let mut failed_channels = Vec::new();
                let mut failed_payments = Vec::new();
+               let mut no_channels_remain = true;
                {
                        let mut channel_state_lock = self.channel_state.lock().unwrap();
                        let channel_state = &mut *channel_state_lock;
@@ -2818,6 +3043,8 @@ impl<ChanSigner: ChannelKeys> ChannelMessageHandler for ChannelManager<ChanSigne
                                                                short_to_id.remove(&short_id);
                                                        }
                                                        return false;
+                                               } else {
+                                                       no_channels_remain = false;
                                                }
                                        }
                                        true
@@ -2843,6 +3070,10 @@ impl<ChanSigner: ChannelKeys> ChannelMessageHandler for ChannelManager<ChanSigne
                                }
                        });
                }
+               if no_channels_remain {
+                       self.per_peer_state.write().unwrap().remove(their_node_id);
+               }
+
                for failure in failed_channels.drain(..) {
                        self.finish_force_close_channel(failure);
                }
@@ -2853,10 +3084,25 @@ impl<ChanSigner: ChannelKeys> ChannelMessageHandler for ChannelManager<ChanSigne
                }
        }
 
-       fn peer_connected(&self, their_node_id: &PublicKey) {
+       fn peer_connected(&self, their_node_id: &PublicKey, init_msg: &msgs::Init) {
                log_debug!(self, "Generating channel_reestablish events for {}", log_pubkey!(their_node_id));
 
                let _ = self.total_consistency_lock.read().unwrap();
+
+               {
+                       let mut peer_state_lock = self.per_peer_state.write().unwrap();
+                       match peer_state_lock.entry(their_node_id.clone()) {
+                               hash_map::Entry::Vacant(e) => {
+                                       e.insert(Mutex::new(PeerState {
+                                               latest_features: init_msg.features.clone(),
+                                       }));
+                               },
+                               hash_map::Entry::Occupied(e) => {
+                                       e.get().lock().unwrap().latest_features = init_msg.features.clone();
+                               },
+                       }
+               }
+
                let mut channel_state_lock = self.channel_state.lock().unwrap();
                let channel_state = &mut *channel_state_lock;
                let pending_msg_events = &mut channel_state.pending_msg_events;
@@ -2898,7 +3144,7 @@ impl<ChanSigner: ChannelKeys> ChannelMessageHandler for ChannelManager<ChanSigne
 const SERIALIZATION_VERSION: u8 = 1;
 const MIN_SERIALIZATION_VERSION: u8 = 1;
 
-impl Writeable for PendingForwardHTLCInfo {
+impl Writeable for PendingHTLCInfo {
        fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
                self.onion_packet.write(writer)?;
                self.incoming_shared_secret.write(writer)?;
@@ -2910,9 +3156,9 @@ impl Writeable for PendingForwardHTLCInfo {
        }
 }
 
-impl<R: ::std::io::Read> Readable<R> for PendingForwardHTLCInfo {
-       fn read(reader: &mut R) -> Result<PendingForwardHTLCInfo, DecodeError> {
-               Ok(PendingForwardHTLCInfo {
+impl<R: ::std::io::Read> Readable<R> for PendingHTLCInfo {
+       fn read(reader: &mut R) -> Result<PendingHTLCInfo, DecodeError> {
+               Ok(PendingHTLCInfo {
                        onion_packet: Readable::read(reader)?,
                        incoming_shared_secret: Readable::read(reader)?,
                        payment_hash: Readable::read(reader)?,
@@ -3079,7 +3325,10 @@ impl<R: ::std::io::Read> Readable<R> for HTLCForwardInfo {
        }
 }
 
-impl<ChanSigner: ChannelKeys + Writeable> Writeable for ChannelManager<ChanSigner> {
+impl<ChanSigner: ChannelKeys + Writeable, M: Deref, T: Deref> Writeable for ChannelManager<ChanSigner, M, T>
+       where M::Target: ManyChannelMonitor<ChanSigner>,
+        T::Target: BroadcasterInterface,
+{
        fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
                let _ = self.total_consistency_lock.write().unwrap();
 
@@ -3123,6 +3372,14 @@ impl<ChanSigner: ChannelKeys + Writeable> Writeable for ChannelManager<ChanSigne
                        }
                }
 
+               let per_peer_state = self.per_peer_state.write().unwrap();
+               (per_peer_state.len() as u64).write(writer)?;
+               for (peer_pubkey, peer_state_mutex) in per_peer_state.iter() {
+                       peer_pubkey.write(writer)?;
+                       let peer_state = peer_state_mutex.lock().unwrap();
+                       peer_state.latest_features.write(writer)?;
+               }
+
                Ok(())
        }
 }
@@ -3142,7 +3399,11 @@ impl<ChanSigner: ChannelKeys + Writeable> Writeable for ChannelManager<ChanSigne
 /// 5) Move the ChannelMonitors into your local ManyChannelMonitor.
 /// 6) Disconnect/connect blocks on the ChannelManager.
 /// 7) Register the new ChannelManager with your ChainWatchInterface.
-pub struct ChannelManagerReadArgs<'a, ChanSigner: ChannelKeys> {
+pub struct ChannelManagerReadArgs<'a, ChanSigner: 'a + ChannelKeys, M: Deref, T: Deref>
+       where M::Target: ManyChannelMonitor<ChanSigner>,
+        T::Target: BroadcasterInterface,
+{
+
        /// The keys provider which will give us relevant keys. Some keys will be loaded during
        /// deserialization.
        pub keys_manager: Arc<KeysInterface<ChanKeySigner = ChanSigner>>,
@@ -3156,12 +3417,12 @@ pub struct ChannelManagerReadArgs<'a, ChanSigner: ChannelKeys> {
        /// No calls to the ManyChannelMonitor 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: Arc<ManyChannelMonitor>,
+       pub 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
        /// force-closed during deserialization.
-       pub tx_broadcaster: Arc<BroadcasterInterface>,
+       pub tx_broadcaster: T,
        /// The Logger for use in the ChannelManager and which may be used to log information during
        /// deserialization.
        pub logger: Arc<Logger>,
@@ -3179,11 +3440,14 @@ pub struct ChannelManagerReadArgs<'a, ChanSigner: ChannelKeys> {
        ///
        /// In such cases the latest local transactions will be sent to the tx_broadcaster included in
        /// this struct.
-       pub channel_monitors: &'a mut HashMap<OutPoint, &'a mut ChannelMonitor>,
+       pub channel_monitors: &'a mut HashMap<OutPoint, &'a mut ChannelMonitor<ChanSigner>>,
 }
 
-impl<'a, R : ::std::io::Read, ChanSigner: ChannelKeys + Readable<R>> ReadableArgs<R, ChannelManagerReadArgs<'a, ChanSigner>> for (Sha256dHash, ChannelManager<ChanSigner>) {
-       fn read(reader: &mut R, args: ChannelManagerReadArgs<'a, ChanSigner>) -> Result<Self, DecodeError> {
+impl<'a, R : ::std::io::Read, ChanSigner: ChannelKeys + Readable<R>, M: Deref, T: Deref> ReadableArgs<R, ChannelManagerReadArgs<'a, ChanSigner, M, T>> for (Sha256dHash, ChannelManager<ChanSigner, M, T>)
+       where M::Target: ManyChannelMonitor<ChanSigner>,
+        T::Target: BroadcasterInterface,
+{
+       fn read(reader: &mut R, args: ChannelManagerReadArgs<'a, ChanSigner, M, T>) -> Result<Self, DecodeError> {
                let _ver: u8 = Readable::read(reader)?;
                let min_ver: u8 = Readable::read(reader)?;
                if min_ver > SERIALIZATION_VERSION {
@@ -3202,16 +3466,17 @@ impl<'a, R : ::std::io::Read, ChanSigner: ChannelKeys + Readable<R>> ReadableArg
                let mut short_to_id = HashMap::with_capacity(cmp::min(channel_count as usize, 128));
                for _ in 0..channel_count {
                        let mut channel: Channel<ChanSigner> = ReadableArgs::read(reader, args.logger.clone())?;
-                       if channel.last_block_connected != last_block_hash {
+                       if channel.last_block_connected != Default::default() && channel.last_block_connected != last_block_hash {
                                return Err(DecodeError::InvalidValue);
                        }
 
-                       let funding_txo = channel.channel_monitor().get_funding_txo().ok_or(DecodeError::InvalidValue)?;
+                       let funding_txo = channel.get_funding_txo().ok_or(DecodeError::InvalidValue)?;
                        funding_txo_set.insert(funding_txo.clone());
                        if let Some(ref mut monitor) = args.channel_monitors.get_mut(&funding_txo) {
                                if channel.get_cur_local_commitment_transaction_number() != monitor.get_cur_local_commitment_number() ||
                                                channel.get_revoked_remote_commitment_transaction_number() != monitor.get_min_seen_secret() ||
-                                               channel.get_cur_remote_commitment_transaction_number() != monitor.get_cur_remote_commitment_number() {
+                                               channel.get_cur_remote_commitment_transaction_number() != monitor.get_cur_remote_commitment_number() ||
+                                               channel.get_latest_monitor_update_id() != monitor.get_latest_update_id() {
                                        let mut force_close_res = channel.force_shutdown();
                                        force_close_res.0 = monitor.get_latest_local_commitment_txn();
                                        closed_channels.push(force_close_res);
@@ -3256,6 +3521,16 @@ impl<'a, R : ::std::io::Read, ChanSigner: ChannelKeys + Readable<R>> ReadableArg
                        claimable_htlcs.insert(payment_hash, previous_hops);
                }
 
+               let peer_count: u64 = Readable::read(reader)?;
+               let mut per_peer_state = HashMap::with_capacity(cmp::min(peer_count as usize, 128));
+               for _ in 0..peer_count {
+                       let peer_pubkey = Readable::read(reader)?;
+                       let peer_state = PeerState {
+                               latest_features: Readable::read(reader)?,
+                       };
+                       per_peer_state.insert(peer_pubkey, Mutex::new(peer_state));
+               }
+
                let channel_manager = ChannelManager {
                        genesis_hash,
                        fee_estimator: args.fee_estimator,
@@ -3275,6 +3550,8 @@ impl<'a, R : ::std::io::Read, ChanSigner: ChannelKeys + Readable<R>> ReadableArg
                        }),
                        our_network_key: args.keys_manager.get_node_secret(),
 
+                       per_peer_state: RwLock::new(per_peer_state),
+
                        pending_events: Mutex::new(Vec::new()),
                        total_consistency_lock: RwLock::new(()),
                        keys_manager: args.keys_manager,