Fix build warnings without grind_signatures
[rust-lightning] / lightning / src / ln / channelmanager.rs
index 674977faaebc2ecd519682ea8f5edb17589fc81b..7acd99e3eba491baca576de6e9282d2317907385 100644 (file)
@@ -42,7 +42,7 @@ use chain::transaction::{OutPoint, TransactionData};
 // construct one themselves.
 use ln::{PaymentHash, PaymentPreimage, PaymentSecret};
 use ln::channel::{Channel, ChannelError, ChannelUpdateStatus, UpdateFulfillCommitFetch};
-use ln::features::{InitFeatures, NodeFeatures};
+use ln::features::{ChannelTypeFeatures, InitFeatures, NodeFeatures};
 use routing::router::{PaymentParameters, Route, RouteHop, RoutePath, RouteParameters};
 use ln::msgs;
 use ln::msgs::NetAddress;
@@ -53,7 +53,7 @@ use util::config::UserConfig;
 use util::events::{EventHandler, EventsProvider, MessageSendEvent, MessageSendEventsProvider, ClosureReason};
 use util::{byte_utils, events};
 use util::scid_utils::fake_scid;
-use util::ser::{BigSize, FixedLengthReader, Readable, ReadableArgs, MaybeReadable, Writeable, Writer};
+use util::ser::{BigSize, FixedLengthReader, Readable, ReadableArgs, MaybeReadable, Writeable, Writer, VecWriter};
 use util::logger::{Level, Logger};
 use util::errors::APIError;
 
@@ -69,6 +69,7 @@ use core::ops::Deref;
 
 #[cfg(any(test, feature = "std"))]
 use std::time::Instant;
+use util::crypto::sign;
 
 mod inbound_payment {
        use alloc::string::ToString;
@@ -441,6 +442,7 @@ struct ClaimableHTLC {
        cltv_expiry: u32,
        value: u64,
        onion_payload: OnionPayload,
+       timer_ticks: u8,
 }
 
 /// A payment identifier used to uniquely identify a payment to LDK.
@@ -496,6 +498,7 @@ impl core::hash::Hash for HTLCSource {
                }
        }
 }
+#[cfg(not(feature = "grind_signatures"))]
 #[cfg(test)]
 impl HTLCSource {
        pub fn dummy() -> Self {
@@ -660,8 +663,16 @@ pub(super) enum RAACommitmentOrder {
 // Note this is only exposed in cfg(test):
 pub(super) struct ChannelHolder<Signer: Sign> {
        pub(super) by_id: HashMap<[u8; 32], Channel<Signer>>,
+       /// SCIDs (and outbound SCID aliases) to the real channel id. Outbound SCID aliases are added
+       /// here once the channel is available for normal use, with SCIDs being added once the funding
+       /// transaction is confirmed at the channel's required confirmation depth.
        pub(super) short_to_id: HashMap<u64, [u8; 32]>,
-       /// short channel id -> forward infos. Key of 0 means payments received
+       /// SCID/SCID Alias -> forward infos. Key of 0 means payments received.
+       ///
+       /// Note that because we may have an SCID Alias as the key we can have two entries per channel,
+       /// though in practice we probably won't be receiving HTLCs for a channel both via the alias
+       /// and via the classic SCID.
+       ///
        /// 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 PendingHTLCInfo!
@@ -878,6 +889,8 @@ impl PendingOutboundPayment {
 /// issues such as overly long function definitions. Note that the ChannelManager can take any
 /// type that implements KeysInterface for its keys manager, but this type alias chooses the
 /// concrete type of the KeysManager.
+///
+/// (C-not exported) as Arcs don't make sense in bindings
 pub type SimpleArcChannelManager<M, T, F, L> = ChannelManager<InMemorySigner, Arc<M>, Arc<T>, Arc<KeysManager>, Arc<F>, Arc<L>>;
 
 /// SimpleRefChannelManager is a type alias for a ChannelManager reference, and is the reference
@@ -888,6 +901,8 @@ pub type SimpleArcChannelManager<M, T, F, L> = ChannelManager<InMemorySigner, Ar
 /// helps with issues such as long function definitions. Note that the ChannelManager can take any
 /// type that implements KeysInterface for its keys manager, but this type alias chooses the
 /// concrete type of the KeysManager.
+///
+/// (C-not exported) as Arcs don't make sense in bindings
 pub type SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, M, T, F, L> = ChannelManager<InMemorySigner, &'a M, &'b T, &'c KeysManager, &'d F, &'e L>;
 
 /// Manager which keeps track of a number of channels and sends messages to the appropriate
@@ -971,6 +986,12 @@ pub struct ChannelManager<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref,
        /// Locked *after* channel_state.
        pending_outbound_payments: Mutex<HashMap<PaymentId, PendingOutboundPayment>>,
 
+       /// The set of outbound SCID aliases across all our channels, including unconfirmed channels
+       /// and some closed channels which reached a usable state prior to being closed. This is used
+       /// only to avoid duplicates, and is not persisted explicitly to disk, but rebuilt from the
+       /// active channel list on load.
+       outbound_scid_aliases: Mutex<HashSet<u64>>,
+
        our_network_key: SecretKey,
        our_network_pubkey: PublicKey,
 
@@ -1134,6 +1155,9 @@ const CHECK_CLTV_EXPIRY_SANITY_2: u32 = MIN_CLTV_EXPIRY_DELTA as u32 - LATENCY_G
 /// pending HTLCs in flight.
 pub(crate) const PAYMENT_EXPIRY_BLOCKS: u32 = 3;
 
+/// The number of ticks of [`ChannelManager::timer_tick_occurred`] until expiry of incomplete MPPs
+pub(crate) const MPP_TIMEOUT_TICKS: u8 = 3;
+
 /// Information needed for constructing an invoice route hint for this channel.
 #[derive(Clone, Debug, PartialEq)]
 pub struct CounterpartyForwardingInfo {
@@ -1186,9 +1210,29 @@ pub struct ChannelDetails {
        /// Note that, if this has been set, `channel_id` will be equivalent to
        /// `funding_txo.unwrap().to_channel_id()`.
        pub funding_txo: Option<OutPoint>,
+       /// The features which this channel operates with. See individual features for more info.
+       ///
+       /// `None` until negotiation completes and the channel type is finalized.
+       pub channel_type: Option<ChannelTypeFeatures>,
        /// The position of the funding transaction in the chain. None if the funding transaction has
        /// not yet been confirmed and the channel fully opened.
+       ///
+       /// Note that if [`inbound_scid_alias`] is set, it must be used for invoices and inbound
+       /// payments instead of this. See [`get_inbound_payment_scid`].
+       ///
+       /// [`inbound_scid_alias`]: Self::inbound_scid_alias
+       /// [`get_inbound_payment_scid`]: Self::get_inbound_payment_scid
        pub short_channel_id: Option<u64>,
+       /// An optional [`short_channel_id`] alias for this channel, randomly generated by our
+       /// counterparty and usable in place of [`short_channel_id`] in invoice route hints. Our
+       /// counterparty will recognize the alias provided here in place of the [`short_channel_id`]
+       /// when they see a payment to be routed to us.
+       ///
+       /// Our counterparty may choose to rotate this value at any time, though will always recognize
+       /// previous values for inbound payment forwarding.
+       ///
+       /// [`short_channel_id`]: Self::short_channel_id
+       pub inbound_scid_alias: Option<u64>,
        /// The value, in satoshis, of this channel as appears in the funding output
        pub channel_value_satoshis: u64,
        /// The value, in satoshis, that must always be held in the channel for us. This value ensures
@@ -1274,6 +1318,18 @@ pub struct ChannelDetails {
        pub is_public: bool,
 }
 
+impl ChannelDetails {
+       /// Gets the current SCID which should be used to identify this channel for inbound payments.
+       /// This should be used for providing invoice hints or in any other context where our
+       /// counterparty will forward a payment to us.
+       ///
+       /// This is either the [`ChannelDetails::inbound_scid_alias`], if set, or the
+       /// [`ChannelDetails::short_channel_id`]. See those for more information.
+       pub fn get_inbound_payment_scid(&self) -> Option<u64> {
+               self.inbound_scid_alias.or(self.short_channel_id)
+       }
+}
+
 /// If a payment fails to send, it can be in one of several states. This enum is returned as the
 /// Err() type describing which state the payment is in, see the description of individual enum
 /// states for more.
@@ -1322,6 +1378,7 @@ pub enum PaymentSendFailure {
 /// Route hints used in constructing invoices for [phantom node payents].
 ///
 /// [phantom node payments]: crate::chain::keysinterface::PhantomKeysManager
+#[derive(Clone)]
 pub struct PhantomRouteHints {
        /// The list of channels to be included in the invoice route hints.
        pub channels: Vec<ChannelDetails>,
@@ -1382,6 +1439,24 @@ macro_rules! handle_error {
        }
 }
 
+macro_rules! update_maps_on_chan_removal {
+       ($self: expr, $short_to_id: expr, $channel: expr) => {
+               if let Some(short_id) = $channel.get_short_channel_id() {
+                       $short_to_id.remove(&short_id);
+               } else {
+                       // If the channel was never confirmed on-chain prior to its closure, remove the
+                       // outbound SCID alias we used for it from the collision-prevention set. While we
+                       // generally want to avoid ever re-using an outbound SCID alias across all channels, we
+                       // also don't want a counterparty to be able to trivially cause a memory leak by simply
+                       // opening a million channels with us which are closed before we ever reach the funding
+                       // stage.
+                       let alias_removed = $self.outbound_scid_aliases.lock().unwrap().remove(&$channel.outbound_scid_alias());
+                       debug_assert!(alias_removed);
+               }
+               $short_to_id.remove(&$channel.outbound_scid_alias());
+       }
+}
+
 /// Returns (boolean indicating if we should remove the Channel object from memory, a mapped error)
 macro_rules! convert_chan_err {
        ($self: ident, $err: expr, $short_to_id: expr, $channel: expr, $channel_id: expr) => {
@@ -1394,18 +1469,14 @@ macro_rules! convert_chan_err {
                        },
                        ChannelError::Close(msg) => {
                                log_error!($self.logger, "Closing channel {} due to close-required error: {}", log_bytes!($channel_id[..]), msg);
-                               if let Some(short_id) = $channel.get_short_channel_id() {
-                                       $short_to_id.remove(&short_id);
-                               }
+                               update_maps_on_chan_removal!($self, $short_to_id, $channel);
                                let shutdown_res = $channel.force_shutdown(true);
                                (true, MsgHandleErrInternal::from_finish_shutdown(msg, *$channel_id, $channel.get_user_id(),
                                        shutdown_res, $self.get_channel_update_for_broadcast(&$channel).ok()))
                        },
                        ChannelError::CloseDelayBroadcast(msg) => {
                                log_error!($self.logger, "Channel {} need to be shutdown but closing transactions not broadcast due to {}", log_bytes!($channel_id[..]), msg);
-                               if let Some(short_id) = $channel.get_short_channel_id() {
-                                       $short_to_id.remove(&short_id);
-                               }
+                               update_maps_on_chan_removal!($self, $short_to_id, $channel);
                                let shutdown_res = $channel.force_shutdown(false);
                                (true, MsgHandleErrInternal::from_finish_shutdown(msg, *$channel_id, $channel.get_user_id(),
                                        shutdown_res, $self.get_channel_update_for_broadcast(&$channel).ok()))
@@ -1445,28 +1516,21 @@ macro_rules! try_chan_entry {
 }
 
 macro_rules! remove_channel {
-       ($channel_state: expr, $entry: expr) => {
+       ($self: expr, $channel_state: expr, $entry: expr) => {
                {
                        let channel = $entry.remove_entry().1;
-                       if let Some(short_id) = channel.get_short_channel_id() {
-                               $channel_state.short_to_id.remove(&short_id);
-                       }
+                       update_maps_on_chan_removal!($self, $channel_state.short_to_id, channel);
                        channel
                }
        }
 }
 
 macro_rules! handle_monitor_err {
-       ($self: ident, $err: expr, $channel_state: expr, $entry: expr, $action_type: path, $resend_raa: expr, $resend_commitment: expr) => {
-               handle_monitor_err!($self, $err, $channel_state, $entry, $action_type, $resend_raa, $resend_commitment, Vec::new(), Vec::new())
-       };
        ($self: ident, $err: expr, $short_to_id: expr, $chan: expr, $action_type: path, $resend_raa: expr, $resend_commitment: expr, $failed_forwards: expr, $failed_fails: expr, $failed_finalized_fulfills: expr, $chan_id: expr) => {
                match $err {
                        ChannelMonitorUpdateErr::PermanentFailure => {
                                log_error!($self.logger, "Closing channel {} due to monitor update ChannelMonitorUpdateErr::PermanentFailure", log_bytes!($chan_id[..]));
-                               if let Some(short_id) = $chan.get_short_channel_id() {
-                                       $short_to_id.remove(&short_id);
-                               }
+                               update_maps_on_chan_removal!($self, $short_to_id, $chan);
                                // TODO: $failed_fails is dropped here, which will cause other channels to hit the
                                // chain in a confused state! We need to move them into the ChannelMonitor which
                                // will be responsible for failing backwards once things confirm on-chain.
@@ -1512,9 +1576,19 @@ macro_rules! handle_monitor_err {
                }
                res
        } };
+       ($self: ident, $err: expr, $channel_state: expr, $entry: expr, $action_type: path, $chan_id: expr, COMMITMENT_UPDATE_ONLY) => { {
+               debug_assert!($action_type == RAACommitmentOrder::CommitmentFirst);
+               handle_monitor_err!($self, $err, $channel_state, $entry, $action_type, false, true, Vec::new(), Vec::new(), Vec::new(), $chan_id)
+       } };
+       ($self: ident, $err: expr, $channel_state: expr, $entry: expr, $action_type: path, $chan_id: expr, NO_UPDATE) => {
+               handle_monitor_err!($self, $err, $channel_state, $entry, $action_type, false, false, Vec::new(), Vec::new(), Vec::new(), $chan_id)
+       };
+       ($self: ident, $err: expr, $channel_state: expr, $entry: expr, $action_type: path, $resend_raa: expr, $resend_commitment: expr) => {
+               handle_monitor_err!($self, $err, $channel_state, $entry, $action_type, $resend_raa, $resend_commitment, Vec::new(), Vec::new(), Vec::new())
+       };
        ($self: ident, $err: expr, $channel_state: expr, $entry: expr, $action_type: path, $resend_raa: expr, $resend_commitment: expr, $failed_forwards: expr, $failed_fails: expr) => {
                handle_monitor_err!($self, $err, $channel_state, $entry, $action_type, $resend_raa, $resend_commitment, $failed_forwards, $failed_fails, Vec::new())
-       }
+       };
 }
 
 macro_rules! return_monitor_err {
@@ -1538,15 +1612,34 @@ macro_rules! maybe_break_monitor_err {
        }
 }
 
+macro_rules! send_funding_locked {
+       ($short_to_id: expr, $pending_msg_events: expr, $channel: expr, $funding_locked_msg: expr) => {
+               $pending_msg_events.push(events::MessageSendEvent::SendFundingLocked {
+                       node_id: $channel.get_counterparty_node_id(),
+                       msg: $funding_locked_msg,
+               });
+               // Note that we may send a funding locked multiple times for a channel if we reconnect, so
+               // we allow collisions, but we shouldn't ever be updating the channel ID pointed to.
+               let outbound_alias_insert = $short_to_id.insert($channel.outbound_scid_alias(), $channel.channel_id());
+               assert!(outbound_alias_insert.is_none() || outbound_alias_insert.unwrap() == $channel.channel_id(),
+                       "SCIDs should never collide - ensure you weren't behind the chain tip by a full month when creating channels");
+               if let Some(real_scid) = $channel.get_short_channel_id() {
+                       let scid_insert = $short_to_id.insert(real_scid, $channel.channel_id());
+                       assert!(scid_insert.is_none() || scid_insert.unwrap() == $channel.channel_id(),
+                               "SCIDs should never collide - ensure you weren't behind the chain tip by a full month when creating channels");
+               }
+       }
+}
+
 macro_rules! handle_chan_restoration_locked {
        ($self: ident, $channel_lock: expr, $channel_state: expr, $channel_entry: expr,
         $raa: expr, $commitment_update: expr, $order: expr, $chanmon_update: expr,
         $pending_forwards: expr, $funding_broadcastable: expr, $funding_locked: expr, $announcement_sigs: expr) => { {
                let mut htlc_forwards = None;
-               let counterparty_node_id = $channel_entry.get().get_counterparty_node_id();
 
                let chanmon_update: Option<ChannelMonitorUpdate> = $chanmon_update; // Force type-checking to resolve
                let chanmon_update_is_none = chanmon_update.is_none();
+               let counterparty_node_id = $channel_entry.get().get_counterparty_node_id();
                let res = loop {
                        let forwards: Vec<(PendingHTLCInfo, u64)> = $pending_forwards; // Force type-checking to resolve
                        if !forwards.is_empty() {
@@ -1572,11 +1665,7 @@ macro_rules! handle_chan_restoration_locked {
                                // Similar to the above, this implies that we're letting the funding_locked fly
                                // before it should be allowed to.
                                assert!(chanmon_update.is_none());
-                               $channel_state.pending_msg_events.push(events::MessageSendEvent::SendFundingLocked {
-                                       node_id: counterparty_node_id,
-                                       msg,
-                               });
-                               $channel_state.short_to_id.insert($channel_entry.get().get_short_channel_id().unwrap(), $channel_entry.get().channel_id());
+                               send_funding_locked!($channel_state.short_to_id, $channel_state.pending_msg_events, $channel_entry.get(), msg);
                        }
                        if let Some(msg) = $announcement_sigs {
                                $channel_state.pending_msg_events.push(events::MessageSendEvent::SendAnnouncementSignatures {
@@ -1705,6 +1794,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                claimable_htlcs: HashMap::new(),
                                pending_msg_events: Vec::new(),
                        }),
+                       outbound_scid_aliases: Mutex::new(HashSet::new()),
                        pending_inbound_payments: Mutex::new(HashMap::new()),
                        pending_outbound_payments: Mutex::new(HashMap::new()),
 
@@ -1736,6 +1826,25 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                &self.default_configuration
        }
 
+       fn create_and_insert_outbound_scid_alias(&self) -> u64 {
+               let height = self.best_block.read().unwrap().height();
+               let mut outbound_scid_alias = 0;
+               let mut i = 0;
+               loop {
+                       if cfg!(fuzzing) { // fuzzing chacha20 doesn't use the key at all so we always get the same alias
+                               outbound_scid_alias += 1;
+                       } else {
+                               outbound_scid_alias = fake_scid::Namespace::OutboundAlias.get_fake_scid(height, &self.genesis_hash, &self.fake_scid_rand_bytes, &self.keys_manager);
+                       }
+                       if outbound_scid_alias != 0 && self.outbound_scid_aliases.lock().unwrap().insert(outbound_scid_alias) {
+                               break;
+                       }
+                       i += 1;
+                       if i > 1_000_000 { panic!("Your RNG is busted or we ran out of possible outbound SCID aliases (which should never happen before we run out of memory to store channels"); }
+               }
+               outbound_scid_alias
+       }
+
        /// Creates a new outbound channel to the given remote node and with the given value.
        ///
        /// `user_channel_id` will be provided back as in
@@ -1771,11 +1880,20 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                        let per_peer_state = self.per_peer_state.read().unwrap();
                        match per_peer_state.get(&their_network_key) {
                                Some(peer_state) => {
+                                       let outbound_scid_alias = self.create_and_insert_outbound_scid_alias();
                                        let peer_state = peer_state.lock().unwrap();
                                        let their_features = &peer_state.latest_features;
                                        let config = if override_config.is_some() { override_config.as_ref().unwrap() } else { &self.default_configuration };
-                                       Channel::new_outbound(&self.fee_estimator, &self.keys_manager, their_network_key, their_features,
-                                               channel_value_satoshis, push_msat, user_channel_id, config, self.best_block.read().unwrap().height())?
+                                       match Channel::new_outbound(&self.fee_estimator, &self.keys_manager, their_network_key,
+                                               their_features, channel_value_satoshis, push_msat, user_channel_id, config,
+                                               self.best_block.read().unwrap().height(), outbound_scid_alias)
+                                       {
+                                               Ok(res) => res,
+                                               Err(e) => {
+                                                       self.outbound_scid_aliases.lock().unwrap().remove(&outbound_scid_alias);
+                                                       return Err(e);
+                                               },
+                                       }
                                },
                                None => return Err(APIError::ChannelUnavailable { err: format!("Not connected to node: {}", their_network_key) }),
                        }
@@ -1824,7 +1942,11 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                                forwarding_info: channel.counterparty_forwarding_info(),
                                        },
                                        funding_txo: channel.get_funding_txo(),
+                                       // Note that accept_channel (or open_channel) is always the first message, so
+                                       // `have_received_message` indicates that type negotiation has completed.
+                                       channel_type: if channel.have_received_message() { Some(channel.get_channel_type().clone()) } else { None },
                                        short_channel_id: channel.get_short_channel_id(),
+                                       inbound_scid_alias: channel.latest_inbound_scid_alias(),
                                        channel_value_satoshis: channel.get_value_satoshis(),
                                        unspendable_punishment_reserve: to_self_reserve_satoshis,
                                        balance_msat,
@@ -1910,9 +2032,9 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                        if let Some(monitor_update) = monitor_update {
                                                if let Err(e) = self.chain_monitor.update_channel(chan_entry.get().get_funding_txo().unwrap(), monitor_update) {
                                                        let (result, is_permanent) =
-                                                               handle_monitor_err!(self, e, channel_state.short_to_id, chan_entry.get_mut(), RAACommitmentOrder::CommitmentFirst, false, false, Vec::new(), Vec::new(), Vec::new(), chan_entry.key());
+                                                               handle_monitor_err!(self, e, channel_state.short_to_id, chan_entry.get_mut(), RAACommitmentOrder::CommitmentFirst, chan_entry.key(), NO_UPDATE);
                                                        if is_permanent {
-                                                               remove_channel!(channel_state, chan_entry);
+                                                               remove_channel!(self, channel_state, chan_entry);
                                                                break result;
                                                        }
                                                }
@@ -1924,7 +2046,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                        });
 
                                        if chan_entry.get().is_shutdown() {
-                                               let channel = remove_channel!(channel_state, chan_entry);
+                                               let channel = remove_channel!(self, channel_state, chan_entry);
                                                if let Ok(channel_update) = self.get_channel_update_for_broadcast(&channel) {
                                                        channel_state.pending_msg_events.push(events::MessageSendEvent::BroadcastChannelUpdate {
                                                                msg: channel_update
@@ -2018,9 +2140,6 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                                return Err(APIError::ChannelUnavailable{err: "No such channel".to_owned()});
                                        }
                                }
-                               if let Some(short_id) = chan.get().get_short_channel_id() {
-                                       channel_state.short_to_id.remove(&short_id);
-                               }
                                if peer_node_id.is_some() {
                                        if let Some(peer_msg) = peer_msg {
                                                self.issue_channel_close_events(chan.get(),ClosureReason::CounterpartyForceClosed { peer_msg: peer_msg.to_string() });
@@ -2028,7 +2147,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                } else {
                                        self.issue_channel_close_events(chan.get(),ClosureReason::HolderForceClosed);
                                }
-                               chan.remove_entry().1
+                               remove_channel!(self, channel_state, chan)
                        } else {
                                return Err(APIError::ChannelUnavailable{err: "No such channel".to_owned()});
                        }
@@ -2310,15 +2429,19 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                        };
                                        let (chan_update_opt, forwardee_cltv_expiry_delta) = if let Some(forwarding_id) = forwarding_id_opt {
                                                let chan = channel_state.as_mut().unwrap().by_id.get_mut(&forwarding_id).unwrap();
-                                               // Leave channel updates as None for private channels.
-                                               let chan_update_opt = if chan.should_announce() {
-                                                       Some(self.get_channel_update_for_unicast(chan).unwrap()) } else { None };
                                                if !chan.should_announce() && !self.default_configuration.accept_forwards_to_priv_channels {
                                                        // Note that the behavior here should be identical to the above block - we
                                                        // should NOT reveal the existence or non-existence of a private channel if
                                                        // we don't allow forwards outbound over them.
-                                                       break Some(("Don't have available channel for forwarding as requested.", 0x4000 | 10, None));
+                                                       break Some(("Refusing to forward to a private channel based on our config.", 0x4000 | 10, None));
+                                               }
+                                               if chan.get_channel_type().supports_scid_privacy() && *short_channel_id != chan.outbound_scid_alias() {
+                                                       // `option_scid_alias` (referred to in LDK as `scid_privacy`) means
+                                                       // "refuse to forward unless the SCID alias was used", so we pretend
+                                                       // we don't have the channel here.
+                                                       break Some(("Refusing to forward over real channel SCID as our counterparty requested.", 0x4000 | 10, None));
                                                }
+                                               let chan_update_opt = self.get_channel_update_for_onion(*short_channel_id, chan).ok();
 
                                                // Note that we could technically not return an error yet here and just hope
                                                // that the connection is reestablished or monitor updated by the time we get
@@ -2368,21 +2491,22 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                        break None;
                                }
                                {
-                                       let mut res = Vec::with_capacity(8 + 128);
+                                       let mut res = VecWriter(Vec::with_capacity(chan_update.serialized_length() + 8 + 2));
                                        if let Some(chan_update) = chan_update {
                                                if code == 0x1000 | 11 || code == 0x1000 | 12 {
-                                                       res.extend_from_slice(&byte_utils::be64_to_array(msg.amount_msat));
+                                                       msg.amount_msat.write(&mut res).expect("Writes cannot fail");
                                                }
                                                else if code == 0x1000 | 13 {
-                                                       res.extend_from_slice(&byte_utils::be32_to_array(msg.cltv_expiry));
+                                                       msg.cltv_expiry.write(&mut res).expect("Writes cannot fail");
                                                }
                                                else if code == 0x1000 | 20 {
                                                        // TODO: underspecified, follow https://github.com/lightningnetwork/lightning-rfc/issues/791
-                                                       res.extend_from_slice(&byte_utils::be16_to_array(0));
+                                                       0u16.write(&mut res).expect("Writes cannot fail");
                                                }
-                                               res.extend_from_slice(&chan_update.encode_with_len()[..]);
+                                               (chan_update.serialized_length() as u16).write(&mut res).expect("Writes cannot fail");
+                                               chan_update.write(&mut res).expect("Writes cannot fail");
                                        }
-                                       return_err!(err, code, &res[..]);
+                                       return_err!(err, code, &res.0[..]);
                                }
                        }
                }
@@ -2418,6 +2542,10 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                        Some(id) => id,
                };
 
+               self.get_channel_update_for_onion(short_channel_id, chan)
+       }
+       fn get_channel_update_for_onion(&self, short_channel_id: u64, chan: &Channel<Signer>) -> Result<msgs::ChannelUpdate, LightningError> {
+               log_trace!(self.logger, "Generating channel update for channel {}", log_bytes!(chan.channel_id()));
                let were_node_one = PublicKey::from_secret_key(&self.secp_ctx, &self.our_network_key).serialize()[..] < chan.get_counterparty_node_id().serialize()[..];
 
                let unsigned = msgs::UnsignedChannelUpdate {
@@ -2956,7 +3084,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                        excess_data: Vec::new(),
                };
                let msghash = hash_to_message!(&Sha256dHash::hash(&announcement.encode()[..])[..]);
-               let node_announce_sig = self.secp_ctx.sign(&msghash, &self.our_network_key);
+               let node_announce_sig = sign(&self.secp_ctx, &msghash, &self.our_network_key);
 
                let mut channel_state_lock = self.channel_state.lock().unwrap();
                let channel_state = &mut *channel_state_lock;
@@ -3107,9 +3235,9 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                                                                        } else {
                                                                                                panic!("Stated return value requirements in send_htlc() were not met");
                                                                                        }
-                                                                                       let chan_update = self.get_channel_update_for_unicast(chan.get()).unwrap();
+                                                                                       let (failure_code, data) = self.get_htlc_temp_fail_err_and_data(0x1000|7, short_chan_id, chan.get());
                                                                                        failed_forwards.push((htlc_source, payment_hash,
-                                                                                               HTLCFailReason::Reason { failure_code: 0x1000 | 7, data: chan_update.encode_with_len() }
+                                                                                               HTLCFailReason::Reason { failure_code, data }
                                                                                        ));
                                                                                        continue;
                                                                                },
@@ -3175,12 +3303,9 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                                                                }
                                                                                ChannelError::Close(msg) => {
                                                                                        log_trace!(self.logger, "Closing channel {} due to Close-required error: {}", log_bytes!(chan.key()[..]), msg);
-                                                                                       let (channel_id, mut channel) = chan.remove_entry();
-                                                                                       if let Some(short_id) = channel.get_short_channel_id() {
-                                                                                               channel_state.short_to_id.remove(&short_id);
-                                                                                       }
+                                                                                       let mut channel = remove_channel!(self, channel_state, chan);
                                                                                        // ChannelClosed event is generated by handle_error for us.
-                                                                                       Err(MsgHandleErrInternal::from_finish_shutdown(msg, channel_id, channel.get_user_id(), channel.force_shutdown(true), self.get_channel_update_for_broadcast(&channel).ok()))
+                                                                                       Err(MsgHandleErrInternal::from_finish_shutdown(msg, channel.channel_id(), channel.get_user_id(), channel.force_shutdown(true), self.get_channel_update_for_broadcast(&channel).ok()))
                                                                                },
                                                                                ChannelError::CloseDelayBroadcast(_) => { panic!("Wait is only generated on receipt of channel_reestablish, which is handled by try_chan_entry, we don't bother to support it here"); }
                                                                        };
@@ -3233,6 +3358,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                                                                phantom_shared_secret,
                                                                        },
                                                                        value: amt_to_forward,
+                                                                       timer_ticks: 0,
                                                                        cltv_expiry,
                                                                        onion_payload,
                                                                };
@@ -3454,7 +3580,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                let ret_err = match res {
                        Ok(Some((update_fee, commitment_signed, monitor_update))) => {
                                if let Err(e) = self.chain_monitor.update_channel(chan.get_funding_txo().unwrap(), monitor_update) {
-                                       let (res, drop) = handle_monitor_err!(self, e, short_to_id, chan, RAACommitmentOrder::CommitmentFirst, false, true, Vec::new(), Vec::new(), Vec::new(), chan_id);
+                                       let (res, drop) = handle_monitor_err!(self, e, short_to_id, chan, RAACommitmentOrder::CommitmentFirst, chan_id, COMMITMENT_UPDATE_ONLY);
                                        if drop { retain_channel = false; }
                                        res
                                } else {
@@ -3527,6 +3653,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                        let new_feerate = self.fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Normal);
 
                        let mut handle_errors = Vec::new();
+                       let mut timed_out_mpp_htlcs = Vec::new();
                        {
                                let mut channel_state_lock = self.channel_state.lock().unwrap();
                                let channel_state = &mut *channel_state_lock;
@@ -3575,6 +3702,32 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 
                                        true
                                });
+
+                               channel_state.claimable_htlcs.retain(|payment_hash, htlcs| {
+                                       if htlcs.is_empty() {
+                                               // This should be unreachable
+                                               debug_assert!(false);
+                                               return false;
+                                       }
+                                       if let OnionPayload::Invoice(ref final_hop_data) = htlcs[0].onion_payload {
+                                               // Check if we've received all the parts we need for an MPP (the value of the parts adds to total_msat).
+                                               // In this case we're not going to handle any timeouts of the parts here.
+                                               if final_hop_data.total_msat == htlcs.iter().fold(0, |total, htlc| total + htlc.value) {
+                                                       return true;
+                                               } else if htlcs.into_iter().any(|htlc| {
+                                                       htlc.timer_ticks += 1;
+                                                       return htlc.timer_ticks >= MPP_TIMEOUT_TICKS
+                                               }) {
+                                                       timed_out_mpp_htlcs.extend(htlcs.into_iter().map(|htlc| (htlc.prev_hop.clone(), payment_hash.clone())));
+                                                       return false;
+                                               }
+                                       }
+                                       true
+                               });
+                       }
+
+                       for htlc_source in timed_out_mpp_htlcs.drain(..) {
+                               self.fail_htlc_backwards_internal(self.channel_state.lock().unwrap(), HTLCSource::PreviousHopData(htlc_source.0), &htlc_source.1, HTLCFailReason::Reason { failure_code: 23, data: Vec::new() });
                        }
 
                        for (err, counterparty_node_id) in handle_errors.drain(..) {
@@ -3608,6 +3761,51 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                } else { false }
        }
 
+       /// Gets an HTLC onion failure code and error data for an `UPDATE` error, given the error code
+       /// that we want to return and a channel.
+       ///
+       /// This is for failures on the channel on which the HTLC was *received*, not failures
+       /// forwarding
+       fn get_htlc_inbound_temp_fail_err_and_data(&self, desired_err_code: u16, chan: &Channel<Signer>) -> (u16, Vec<u8>) {
+               // We can't be sure what SCID was used when relaying inbound towards us, so we have to
+               // guess somewhat. If its a public channel, we figure best to just use the real SCID (as
+               // we're not leaking that we have a channel with the counterparty), otherwise we try to use
+               // an inbound SCID alias before the real SCID.
+               let scid_pref = if chan.should_announce() {
+                       chan.get_short_channel_id().or(chan.latest_inbound_scid_alias())
+               } else {
+                       chan.latest_inbound_scid_alias().or(chan.get_short_channel_id())
+               };
+               if let Some(scid) = scid_pref {
+                       self.get_htlc_temp_fail_err_and_data(desired_err_code, scid, chan)
+               } else {
+                       (0x4000|10, Vec::new())
+               }
+       }
+
+
+       /// Gets an HTLC onion failure code and error data for an `UPDATE` error, given the error code
+       /// that we want to return and a channel.
+       fn get_htlc_temp_fail_err_and_data(&self, desired_err_code: u16, scid: u64, chan: &Channel<Signer>) -> (u16, Vec<u8>) {
+               debug_assert_eq!(desired_err_code & 0x1000, 0x1000);
+               if let Ok(upd) = self.get_channel_update_for_onion(scid, chan) {
+                       let mut enc = VecWriter(Vec::with_capacity(upd.serialized_length() + 4));
+                       if desired_err_code == 0x1000 | 20 {
+                               // TODO: underspecified, follow https://github.com/lightning/bolts/issues/791
+                               0u16.write(&mut enc).expect("Writes cannot fail");
+                       }
+                       (upd.serialized_length() as u16).write(&mut enc).expect("Writes cannot fail");
+                       upd.write(&mut enc).expect("Writes cannot fail");
+                       (desired_err_code, enc.0)
+               } else {
+                       // If we fail to get a unicast channel_update, it implies we don't yet have an SCID,
+                       // which means we really shouldn't have gotten a payment to be forwarded over this
+                       // channel yet, or if we did it's from a route hint. Either way, returning an error of
+                       // PERM|no_such_channel should be fine.
+                       (0x4000|10, Vec::new())
+               }
+       }
+
        // Fail a list of HTLCs that were just freed from the holding cell. The HTLCs need to be
        // failed backwards or, if they were one of our outgoing HTLCs, then their failure needs to
        // be surfaced to the user.
@@ -3618,11 +3816,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                        let (failure_code, onion_failure_data) =
                                                match self.channel_state.lock().unwrap().by_id.entry(channel_id) {
                                                        hash_map::Entry::Occupied(chan_entry) => {
-                                                               if let Ok(upd) = self.get_channel_update_for_unicast(&chan_entry.get()) {
-                                                                       (0x1000|7, upd.encode_with_len())
-                                                               } else {
-                                                                       (0x4000|10, Vec::new())
-                                                               }
+                                                               self.get_htlc_inbound_temp_fail_err_and_data(0x1000|7, &chan_entry.get())
                                                        },
                                                        hash_map::Entry::Vacant(_) => (0x4000|10, Vec::new())
                                                };
@@ -4135,10 +4329,12 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                // channel_update later through the announcement_signatures process for public
                                // channels, but there's no reason not to just inform our counterparty of our fees
                                // now.
-                               Some(events::MessageSendEvent::SendChannelUpdate {
-                                       node_id: channel.get().get_counterparty_node_id(),
-                                       msg: self.get_channel_update_for_unicast(channel.get()).unwrap(),
-                               })
+                               if let Ok(msg) = self.get_channel_update_for_unicast(channel.get()) {
+                                       Some(events::MessageSendEvent::SendChannelUpdate {
+                                               node_id: channel.get().get_counterparty_node_id(),
+                                               msg,
+                                       })
+                               } else { None }
                        } else { None };
                        chan_restoration_res = handle_chan_restoration_locked!(self, channel_lock, channel_state, channel, updates.raa, updates.commitment_update, updates.order, None, updates.accepted_htlcs, updates.funding_broadcastable, updates.funding_locked, updates.announcement_sigs);
                        if let Some(upd) = channel_update {
@@ -4158,8 +4354,13 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
        ///
        /// The `temporary_channel_id` parameter indicates which inbound channel should be accepted.
        ///
-       /// [`Event::OpenChannelRequest`]: crate::util::events::Event::OpenChannelRequest
-       pub fn accept_inbound_channel(&self, temporary_channel_id: &[u8; 32]) -> Result<(), APIError> {
+       /// For inbound channels, the `user_channel_id` parameter will be provided back in
+       /// [`Event::ChannelClosed::user_channel_id`] to allow tracking of which events correspond
+       /// with which `accept_inbound_channel` call.
+       ///
+       /// [`Event::OpenChannelRequest`]: events::Event::OpenChannelRequest
+       /// [`Event::ChannelClosed::user_channel_id`]: events::Event::ChannelClosed::user_channel_id
+       pub fn accept_inbound_channel(&self, temporary_channel_id: &[u8; 32], user_channel_id: u64) -> Result<(), APIError> {
                let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
 
                let mut channel_state_lock = self.channel_state.lock().unwrap();
@@ -4171,7 +4372,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                }
                                channel_state.pending_msg_events.push(events::MessageSendEvent::SendAcceptChannel {
                                        node_id: channel.get().get_counterparty_node_id(),
-                                       msg: channel.get_mut().accept_inbound_channel(),
+                                       msg: channel.get_mut().accept_inbound_channel(user_channel_id),
                                });
                        }
                        hash_map::Entry::Vacant(_) => {
@@ -4190,18 +4391,29 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                        return Err(MsgHandleErrInternal::send_err_msg_no_close("No inbound channels accepted".to_owned(), msg.temporary_channel_id.clone()));
                }
 
-               let mut channel = Channel::new_from_req(&self.fee_estimator, &self.keys_manager, counterparty_node_id.clone(),
-                               &their_features, msg, 0, &self.default_configuration, self.best_block.read().unwrap().height(), &self.logger)
-                       .map_err(|e| MsgHandleErrInternal::from_chan_no_close(e, msg.temporary_channel_id))?;
+               let outbound_scid_alias = self.create_and_insert_outbound_scid_alias();
+               let mut channel = match Channel::new_from_req(&self.fee_estimator, &self.keys_manager,
+                       counterparty_node_id.clone(), &their_features, msg, 0, &self.default_configuration,
+                       self.best_block.read().unwrap().height(), &self.logger, outbound_scid_alias)
+               {
+                       Err(e) => {
+                               self.outbound_scid_aliases.lock().unwrap().remove(&outbound_scid_alias);
+                               return Err(MsgHandleErrInternal::from_chan_no_close(e, msg.temporary_channel_id));
+                       },
+                       Ok(res) => res
+               };
                let mut channel_state_lock = self.channel_state.lock().unwrap();
                let channel_state = &mut *channel_state_lock;
                match channel_state.by_id.entry(channel.channel_id()) {
-                       hash_map::Entry::Occupied(_) => return Err(MsgHandleErrInternal::send_err_msg_no_close("temporary_channel_id collision!".to_owned(), msg.temporary_channel_id.clone())),
+                       hash_map::Entry::Occupied(_) => {
+                               self.outbound_scid_aliases.lock().unwrap().remove(&outbound_scid_alias);
+                               return Err(MsgHandleErrInternal::send_err_msg_no_close("temporary_channel_id collision!".to_owned(), msg.temporary_channel_id.clone()))
+                       },
                        hash_map::Entry::Vacant(entry) => {
                                if !self.default_configuration.manually_accept_inbound_channels {
                                        channel_state.pending_msg_events.push(events::MessageSendEvent::SendAcceptChannel {
                                                node_id: counterparty_node_id.clone(),
-                                               msg: channel.accept_inbound_channel(),
+                                               msg: channel.accept_inbound_channel(0),
                                        });
                                } else {
                                        let mut pending_events = self.pending_events.lock().unwrap();
@@ -4211,6 +4423,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                                        counterparty_node_id: counterparty_node_id.clone(),
                                                        funding_satoshis: msg.funding_satoshis,
                                                        push_msat: msg.push_msat,
+                                                       channel_type: channel.get_channel_type().clone(),
                                                }
                                        );
                                }
@@ -4362,10 +4575,12 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                        // channel_update here if the channel is not public, i.e. we're not sending an
                                        // announcement_signatures.
                                        log_trace!(self.logger, "Sending private initial channel_update for our counterparty on channel {}", log_bytes!(chan.get().channel_id()));
-                                       channel_state.pending_msg_events.push(events::MessageSendEvent::SendChannelUpdate {
-                                               node_id: counterparty_node_id.clone(),
-                                               msg: self.get_channel_update_for_unicast(chan.get()).unwrap(),
-                                       });
+                                       if let Ok(msg) = self.get_channel_update_for_unicast(chan.get()) {
+                                               channel_state.pending_msg_events.push(events::MessageSendEvent::SendChannelUpdate {
+                                                       node_id: counterparty_node_id.clone(),
+                                                       msg,
+                                               });
+                                       }
                                }
                                Ok(())
                        },
@@ -4398,9 +4613,9 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                        if let Some(monitor_update) = monitor_update {
                                                if let Err(e) = self.chain_monitor.update_channel(chan_entry.get().get_funding_txo().unwrap(), monitor_update) {
                                                        let (result, is_permanent) =
-                                                               handle_monitor_err!(self, e, channel_state.short_to_id, chan_entry.get_mut(), RAACommitmentOrder::CommitmentFirst, false, false, Vec::new(), Vec::new(), Vec::new(), chan_entry.key());
+                                                               handle_monitor_err!(self, e, channel_state.short_to_id, chan_entry.get_mut(), RAACommitmentOrder::CommitmentFirst, chan_entry.key(), NO_UPDATE);
                                                        if is_permanent {
-                                                               remove_channel!(channel_state, chan_entry);
+                                                               remove_channel!(self, channel_state, chan_entry);
                                                                break result;
                                                        }
                                                }
@@ -4448,10 +4663,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                                // also implies there are no pending HTLCs left on the channel, so we can
                                                // fully delete it from tracking (the channel monitor is still around to
                                                // watch for old state broadcasts)!
-                                               if let Some(short_id) = chan_entry.get().get_short_channel_id() {
-                                                       channel_state.short_to_id.remove(&short_id);
-                                               }
-                                               (tx, Some(chan_entry.remove_entry().1))
+                                               (tx, Some(remove_channel!(self, channel_state, chan_entry)))
                                        } else { (tx, None) }
                                },
                                hash_map::Entry::Vacant(_) => return Err(MsgHandleErrInternal::send_err_msg_no_close("Failed to find corresponding channel".to_owned(), msg.channel_id))
@@ -4499,28 +4711,8 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                        match pending_forward_info {
                                                PendingHTLCStatus::Forward(PendingHTLCInfo { ref incoming_shared_secret, .. }) => {
                                                        let reason = if (error_code & 0x1000) != 0 {
-                                                               if let Ok(upd) = self.get_channel_update_for_unicast(chan) {
-                                                                       onion_utils::build_first_hop_failure_packet(incoming_shared_secret, error_code, &{
-                                                                               let mut res = Vec::with_capacity(8 + 128);
-                                                                               // TODO: underspecified, follow https://github.com/lightningnetwork/lightning-rfc/issues/791
-                                                                               if error_code == 0x1000 | 20 {
-                                                                                       res.extend_from_slice(&byte_utils::be16_to_array(0));
-                                                                               }
-                                                                               res.extend_from_slice(&upd.encode_with_len()[..]);
-                                                                               res
-                                                                       }[..])
-                                                               } else {
-                                                                       // The only case where we'd be unable to
-                                                                       // successfully get a channel update is if the
-                                                                       // channel isn't in the fully-funded state yet,
-                                                                       // implying our counterparty is trying to route
-                                                                       // payments over the channel back to themselves
-                                                                       // (because no one else should know the short_id
-                                                                       // is a lightning channel yet). We should have
-                                                                       // no problem just calling this
-                                                                       // unknown_next_peer (0x4000|10).
-                                                                       onion_utils::build_first_hop_failure_packet(incoming_shared_secret, 0x4000|10, &[])
-                                                               }
+                                                               let (real_code, error_data) = self.get_htlc_inbound_temp_fail_err_and_data(error_code, chan);
+                                                               onion_utils::build_first_hop_failure_packet(incoming_shared_secret, real_code, &error_data)
                                                        } else {
                                                                onion_utils::build_first_hop_failure_packet(incoming_shared_secret, error_code, &[])
                                                        };
@@ -4842,10 +5034,12 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                                // If the channel is in a usable state (ie the channel is not being shut
                                                // down), send a unicast channel_update to our counterparty to make sure
                                                // they have the latest channel parameters.
-                                               channel_update = Some(events::MessageSendEvent::SendChannelUpdate {
-                                                       node_id: chan.get().get_counterparty_node_id(),
-                                                       msg: self.get_channel_update_for_unicast(chan.get()).unwrap(),
-                                               });
+                                               if let Ok(msg) = self.get_channel_update_for_unicast(chan.get()) {
+                                                       channel_update = Some(events::MessageSendEvent::SendChannelUpdate {
+                                                               node_id: chan.get().get_counterparty_node_id(),
+                                                               msg,
+                                                       });
+                                               }
                                        }
                                        let need_lnd_workaround = chan.get_mut().workaround_lnd_bug_4006.take();
                                        chan_restoration_res = handle_chan_restoration_locked!(
@@ -4889,12 +5083,9 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                        let mut channel_lock = self.channel_state.lock().unwrap();
                                        let channel_state = &mut *channel_lock;
                                        let by_id = &mut channel_state.by_id;
-                                       let short_to_id = &mut channel_state.short_to_id;
                                        let pending_msg_events = &mut channel_state.pending_msg_events;
-                                       if let Some(mut chan) = by_id.remove(&funding_outpoint.to_channel_id()) {
-                                               if let Some(short_id) = chan.get_short_channel_id() {
-                                                       short_to_id.remove(&short_id);
-                                               }
+                                       if let hash_map::Entry::Occupied(chan_entry) = by_id.entry(funding_outpoint.to_channel_id()) {
+                                               let mut chan = remove_channel!(self, channel_state, chan_entry);
                                                failed_channels.push(chan.force_shutdown(false));
                                                if let Ok(update) = self.get_channel_update_for_broadcast(&chan) {
                                                        pending_msg_events.push(events::MessageSendEvent::BroadcastChannelUpdate {
@@ -4964,7 +5155,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                                if let Some((commitment_update, monitor_update)) = commitment_opt {
                                                        if let Err(e) = self.chain_monitor.update_channel(chan.get_funding_txo().unwrap(), monitor_update) {
                                                                has_monitor_update = true;
-                                                               let (res, close_channel) = handle_monitor_err!(self, e, short_to_id, chan, RAACommitmentOrder::CommitmentFirst, false, true, Vec::new(), Vec::new(), Vec::new(), channel_id);
+                                                               let (res, close_channel) = handle_monitor_err!(self, e, short_to_id, chan, RAACommitmentOrder::CommitmentFirst, channel_id, COMMITMENT_UPDATE_ONLY);
                                                                handle_errors.push((chan.get_counterparty_node_id(), res));
                                                                if close_channel { return false; }
                                                        } else {
@@ -5023,10 +5214,6 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                                if let Some(tx) = tx_opt {
                                                        // We're done with this channel. We got a closing_signed and sent back
                                                        // a closing_signed with a closing transaction to broadcast.
-                                                       if let Some(short_id) = chan.get_short_channel_id() {
-                                                               short_to_id.remove(&short_id);
-                                                       }
-
                                                        if let Ok(update) = self.get_channel_update_for_broadcast(&chan) {
                                                                pending_msg_events.push(events::MessageSendEvent::BroadcastChannelUpdate {
                                                                        msg: update
@@ -5037,6 +5224,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 
                                                        log_info!(self.logger, "Broadcasting {}", log_tx!(tx));
                                                        self.tx_broadcaster.broadcast_transaction(&tx);
+                                                       update_maps_on_chan_removal!(self, short_to_id, chan);
                                                        false
                                                } else { true }
                                        },
@@ -5144,6 +5332,8 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
        /// Legacy version of [`create_inbound_payment`]. Use this method if you wish to share
        /// serialized state with LDK node(s) running 0.0.103 and earlier.
        ///
+       /// May panic if `invoice_expiry_delta_secs` is greater than one year.
+       ///
        /// # Note
        /// This method is deprecated and will be removed soon.
        ///
@@ -5184,8 +5374,6 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
        /// If you need exact expiry semantics, you should enforce them upon receipt of
        /// [`PaymentReceived`].
        ///
-       /// May panic if `invoice_expiry_delta_secs` is greater than one year.
-       ///
        /// Note that invoices generated for inbound payments should have their `min_final_cltv_expiry`
        /// set to at least [`MIN_FINAL_CLTV_EXPIRY`].
        ///
@@ -5208,6 +5396,8 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
        /// Legacy version of [`create_inbound_payment_for_hash`]. Use this method if you wish to share
        /// serialized state with LDK node(s) running 0.0.103 and earlier.
        ///
+       /// May panic if `invoice_expiry_delta_secs` is greater than one year.
+       ///
        /// # Note
        /// This method is deprecated and will be removed soon.
        ///
@@ -5233,7 +5423,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                let mut channel_state = self.channel_state.lock().unwrap();
                let best_block = self.best_block.read().unwrap();
                loop {
-                       let scid_candidate = fake_scid::get_phantom_scid(&self.fake_scid_rand_bytes, best_block.height(), &self.genesis_hash, &self.keys_manager);
+                       let scid_candidate = fake_scid::Namespace::Phantom.get_fake_scid(best_block.height(), &self.genesis_hash, &self.fake_scid_rand_bytes, &self.keys_manager);
                        // Ensure the generated scid doesn't conflict with a real channel.
                        match channel_state.short_to_id.entry(scid_candidate) {
                                hash_map::Entry::Occupied(_) => continue,
@@ -5408,6 +5598,12 @@ where
                let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
                self.do_chain_event(Some(height), |channel| channel.transactions_confirmed(&block_hash, height, txdata, self.genesis_hash.clone(), self.get_our_node_id(), &self.logger)
                        .map(|(a, b)| (a, Vec::new(), b)));
+
+               let last_best_block_height = self.best_block.read().unwrap().height();
+               if height < last_best_block_height {
+                       let timestamp = self.highest_seen_timestamp.load(Ordering::Acquire);
+                       self.do_chain_event(Some(last_best_block_height), |channel| channel.best_block_updated(last_best_block_height, timestamp as u32, self.genesis_hash.clone(), self.get_our_node_id(), &self.logger));
+               }
        }
 
        fn best_block_updated(&self, header: &BlockHeader, height: u32) {
@@ -5514,27 +5710,24 @@ where
                                let res = f(channel);
                                if let Ok((funding_locked_opt, mut timed_out_pending_htlcs, announcement_sigs)) = res {
                                        for (source, payment_hash) in timed_out_pending_htlcs.drain(..) {
-                                               let chan_update = self.get_channel_update_for_unicast(&channel).map(|u| u.encode_with_len()).unwrap(); // Cannot add/recv HTLCs before we have a short_id so unwrap is safe
-                                               timed_out_htlcs.push((source, payment_hash,  HTLCFailReason::Reason {
-                                                       failure_code: 0x1000 | 14, // expiry_too_soon, or at least it is now
-                                                       data: chan_update,
+                                               let (failure_code, data) = self.get_htlc_inbound_temp_fail_err_and_data(0x1000|14 /* expiry_too_soon */, &channel);
+                                               timed_out_htlcs.push((source, payment_hash, HTLCFailReason::Reason {
+                                                       failure_code, data,
                                                }));
                                        }
                                        if let Some(funding_locked) = funding_locked_opt {
-                                               pending_msg_events.push(events::MessageSendEvent::SendFundingLocked {
-                                                       node_id: channel.get_counterparty_node_id(),
-                                                       msg: funding_locked,
-                                               });
+                                               send_funding_locked!(short_to_id, pending_msg_events, channel, funding_locked);
                                                if channel.is_usable() {
                                                        log_trace!(self.logger, "Sending funding_locked with private initial channel_update for our counterparty on channel {}", log_bytes!(channel.channel_id()));
-                                                       pending_msg_events.push(events::MessageSendEvent::SendChannelUpdate {
-                                                               node_id: channel.get_counterparty_node_id(),
-                                                               msg: self.get_channel_update_for_unicast(channel).unwrap(),
-                                                       });
+                                                       if let Ok(msg) = self.get_channel_update_for_unicast(channel) {
+                                                               pending_msg_events.push(events::MessageSendEvent::SendChannelUpdate {
+                                                                       node_id: channel.get_counterparty_node_id(),
+                                                                       msg,
+                                                               });
+                                                       }
                                                } else {
                                                        log_trace!(self.logger, "Sending funding_locked WITHOUT channel_update for {}", log_bytes!(channel.channel_id()));
                                                }
-                                               short_to_id.insert(channel.get_short_channel_id().unwrap(), channel.channel_id());
                                        }
                                        if let Some(announcement_sigs) = announcement_sigs {
                                                log_trace!(self.logger, "Sending announcement_signatures for channel {}", log_bytes!(channel.channel_id()));
@@ -5554,9 +5747,7 @@ where
                                                }
                                        }
                                } else if let Err(reason) = res {
-                                       if let Some(short_id) = channel.get_short_channel_id() {
-                                               short_to_id.remove(&short_id);
-                                       }
+                                       update_maps_on_chan_removal!(self, short_to_id, channel);
                                        // It looks like our counterparty went on-chain or funding transaction was
                                        // reorged out of the main chain. Close the channel.
                                        failed_channels.push(channel.force_shutdown(true));
@@ -5746,15 +5937,13 @@ impl<Signer: Sign, M: Deref , T: Deref , K: Deref , F: Deref , L: Deref >
                {
                        let mut channel_state_lock = self.channel_state.lock().unwrap();
                        let channel_state = &mut *channel_state_lock;
-                       let short_to_id = &mut channel_state.short_to_id;
                        let pending_msg_events = &mut channel_state.pending_msg_events;
+                       let short_to_id = &mut channel_state.short_to_id;
                        if no_connection_possible {
                                log_debug!(self.logger, "Failing all channels with {} due to no_connection_possible", log_pubkey!(counterparty_node_id));
                                channel_state.by_id.retain(|_, chan| {
                                        if chan.get_counterparty_node_id() == *counterparty_node_id {
-                                               if let Some(short_id) = chan.get_short_channel_id() {
-                                                       short_to_id.remove(&short_id);
-                                               }
+                                               update_maps_on_chan_removal!(self, short_to_id, chan);
                                                failed_channels.push(chan.force_shutdown(true));
                                                if let Ok(update) = self.get_channel_update_for_broadcast(&chan) {
                                                        pending_msg_events.push(events::MessageSendEvent::BroadcastChannelUpdate {
@@ -5773,9 +5962,7 @@ impl<Signer: Sign, M: Deref , T: Deref , K: Deref , F: Deref , L: Deref >
                                        if chan.get_counterparty_node_id() == *counterparty_node_id {
                                                chan.remove_uncommitted_htlcs_and_mark_paused(&self.logger);
                                                if chan.is_shutdown() {
-                                                       if let Some(short_id) = chan.get_short_channel_id() {
-                                                               short_to_id.remove(&short_id);
-                                                       }
+                                                       update_maps_on_chan_removal!(self, short_to_id, chan);
                                                        self.issue_channel_close_events(chan, ClosureReason::DisconnectedPeer);
                                                        return false;
                                                } else {
@@ -5806,6 +5993,7 @@ impl<Signer: Sign, M: Deref , T: Deref , K: Deref , F: Deref , L: Deref >
                                        &events::MessageSendEvent::SendChannelRangeQuery { .. } => false,
                                        &events::MessageSendEvent::SendShortIdsQuery { .. } => false,
                                        &events::MessageSendEvent::SendReplyChannelRange { .. } => false,
+                                       &events::MessageSendEvent::SendGossipTimestampFilter { .. } => false,
                                }
                        });
                }
@@ -5871,6 +6059,23 @@ impl<Signer: Sign, M: Deref , T: Deref , K: Deref , F: Deref , L: Deref >
                                }
                        }
                } else {
+                       {
+                               // First check if we can advance the channel type and try again.
+                               let mut channel_state = self.channel_state.lock().unwrap();
+                               if let Some(chan) = channel_state.by_id.get_mut(&msg.channel_id) {
+                                       if chan.get_counterparty_node_id() != *counterparty_node_id {
+                                               return;
+                                       }
+                                       if let Ok(msg) = chan.maybe_handle_error_without_close(self.genesis_hash) {
+                                               channel_state.pending_msg_events.push(events::MessageSendEvent::SendOpenChannel {
+                                                       node_id: *counterparty_node_id,
+                                                       msg,
+                                               });
+                                               return;
+                                       }
+                               }
+                       }
+
                        // Untrusted messages from peer, we throw away the error if id points to a non-existent channel
                        let _ = self.force_close_channel_with_peer(&msg.channel_id, Some(counterparty_node_id), Some(&msg.data));
                }
@@ -5965,7 +6170,9 @@ impl_writeable_tlv_based!(ChannelCounterparty, {
 });
 
 impl_writeable_tlv_based!(ChannelDetails, {
+       (1, inbound_scid_alias, option),
        (2, channel_id, required),
+       (3, channel_type, option),
        (4, counterparty, required),
        (6, funding_txo, option),
        (8, short_channel_id, option),
@@ -6145,6 +6352,7 @@ impl Readable for ClaimableHTLC {
                };
                Ok(Self {
                        prev_hop: prev_hop.0.unwrap(),
+                       timer_ticks: 0,
                        value,
                        onion_payload,
                        cltv_expiry,
@@ -6774,6 +6982,32 @@ impl<'a, Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
                        }
                }
 
+               let mut outbound_scid_aliases = HashSet::new();
+               for (chan_id, chan) in by_id.iter_mut() {
+                       if chan.outbound_scid_alias() == 0 {
+                               let mut outbound_scid_alias;
+                               loop {
+                                       outbound_scid_alias = fake_scid::Namespace::OutboundAlias
+                                               .get_fake_scid(best_block_height, &genesis_hash, fake_scid_rand_bytes.as_ref().unwrap(), &args.keys_manager);
+                                       if outbound_scid_aliases.insert(outbound_scid_alias) { break; }
+                               }
+                               chan.set_outbound_scid_alias(outbound_scid_alias);
+                       } else if !outbound_scid_aliases.insert(chan.outbound_scid_alias()) {
+                               // Note that in rare cases its possible to hit this while reading an older
+                               // channel if we just happened to pick a colliding outbound alias above.
+                               log_error!(args.logger, "Got duplicate outbound SCID alias; {}", chan.outbound_scid_alias());
+                               return Err(DecodeError::InvalidValue);
+                       }
+                       if chan.is_usable() {
+                               if short_to_id.insert(chan.outbound_scid_alias(), *chan_id).is_some() {
+                                       // Note that in rare cases its possible to hit this while reading an older
+                                       // channel if we just happened to pick a colliding outbound alias above.
+                                       log_error!(args.logger, "Got duplicate outbound SCID alias; {}", chan.outbound_scid_alias());
+                                       return Err(DecodeError::InvalidValue);
+                               }
+                       }
+               }
+
                let inbound_pmt_key_material = args.keys_manager.get_inbound_payment_key_material();
                let expanded_inbound_key = inbound_payment::ExpandedKey::new(&inbound_pmt_key_material);
                let channel_manager = ChannelManager {
@@ -6794,6 +7028,8 @@ impl<'a, Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
                        inbound_payment_key: expanded_inbound_key,
                        pending_inbound_payments: Mutex::new(pending_inbound_payments),
                        pending_outbound_payments: Mutex::new(pending_outbound_payments.unwrap()),
+
+                       outbound_scid_aliases: Mutex::new(outbound_scid_aliases),
                        fake_scid_rand_bytes: fake_scid_rand_bytes.unwrap(),
 
                        our_network_key,
@@ -6843,6 +7079,7 @@ mod tests {
        use util::errors::APIError;
        use util::events::{Event, MessageSendEvent, MessageSendEventsProvider};
        use util::test_utils;
+       use chain::keysinterface::KeysInterface;
 
        #[cfg(feature = "std")]
        #[test]
@@ -7096,6 +7333,7 @@ mod tests {
                let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
                create_announced_chan_between_nodes(&nodes, 0, 1, InitFeatures::known(), InitFeatures::known());
                let scorer = test_utils::TestScorer::with_penalty(0);
+               let random_seed_bytes = chanmon_cfgs[1].keys_manager.get_secure_random_bytes();
 
                // To start (1), send a regular payment but don't claim it.
                let expected_route = [&nodes[1]];
@@ -7109,7 +7347,7 @@ mod tests {
                };
                let route = find_route(
                        &nodes[0].node.get_our_node_id(), &route_params, nodes[0].network_graph, None,
-                       nodes[0].logger, &scorer
+                       nodes[0].logger, &scorer, &random_seed_bytes
                ).unwrap();
                nodes[0].node.send_spontaneous_payment(&route, Some(payment_preimage)).unwrap();
                check_added_monitors!(nodes[0], 1);
@@ -7140,7 +7378,7 @@ mod tests {
                let payment_preimage = PaymentPreimage([42; 32]);
                let route = find_route(
                        &nodes[0].node.get_our_node_id(), &route_params, nodes[0].network_graph, None,
-                       nodes[0].logger, &scorer
+                       nodes[0].logger, &scorer, &random_seed_bytes
                ).unwrap();
                let (payment_hash, _) = nodes[0].node.send_spontaneous_payment(&route, Some(payment_preimage)).unwrap();
                check_added_monitors!(nodes[0], 1);
@@ -7189,8 +7427,8 @@ mod tests {
 
                let payer_pubkey = nodes[0].node.get_our_node_id();
                let payee_pubkey = nodes[1].node.get_our_node_id();
-               nodes[0].node.peer_connected(&payee_pubkey, &msgs::Init { features: InitFeatures::known() });
-               nodes[1].node.peer_connected(&payer_pubkey, &msgs::Init { features: InitFeatures::known() });
+               nodes[0].node.peer_connected(&payee_pubkey, &msgs::Init { features: InitFeatures::known(), remote_network_address: None });
+               nodes[1].node.peer_connected(&payer_pubkey, &msgs::Init { features: InitFeatures::known(), remote_network_address: None });
 
                let _chan = create_chan_between_nodes(&nodes[0], &nodes[1], InitFeatures::known(), InitFeatures::known());
                let route_params = RouteParameters {
@@ -7201,9 +7439,10 @@ mod tests {
                let network_graph = nodes[0].network_graph;
                let first_hops = nodes[0].node.list_usable_channels();
                let scorer = test_utils::TestScorer::with_penalty(0);
+               let random_seed_bytes = chanmon_cfgs[1].keys_manager.get_secure_random_bytes();
                let route = find_route(
                        &payer_pubkey, &route_params, network_graph, Some(&first_hops.iter().collect::<Vec<_>>()),
-                       nodes[0].logger, &scorer
+                       nodes[0].logger, &scorer, &random_seed_bytes
                ).unwrap();
 
                let test_preimage = PaymentPreimage([42; 32]);
@@ -7232,8 +7471,8 @@ mod tests {
 
                let payer_pubkey = nodes[0].node.get_our_node_id();
                let payee_pubkey = nodes[1].node.get_our_node_id();
-               nodes[0].node.peer_connected(&payee_pubkey, &msgs::Init { features: InitFeatures::known() });
-               nodes[1].node.peer_connected(&payer_pubkey, &msgs::Init { features: InitFeatures::known() });
+               nodes[0].node.peer_connected(&payee_pubkey, &msgs::Init { features: InitFeatures::known(), remote_network_address: None });
+               nodes[1].node.peer_connected(&payer_pubkey, &msgs::Init { features: InitFeatures::known(), remote_network_address: None });
 
                let _chan = create_chan_between_nodes(&nodes[0], &nodes[1], InitFeatures::known(), InitFeatures::known());
                let route_params = RouteParameters {
@@ -7244,9 +7483,10 @@ mod tests {
                let network_graph = nodes[0].network_graph;
                let first_hops = nodes[0].node.list_usable_channels();
                let scorer = test_utils::TestScorer::with_penalty(0);
+               let random_seed_bytes = chanmon_cfgs[1].keys_manager.get_secure_random_bytes();
                let route = find_route(
                        &payer_pubkey, &route_params, network_graph, Some(&first_hops.iter().collect::<Vec<_>>()),
-                       nodes[0].logger, &scorer
+                       nodes[0].logger, &scorer, &random_seed_bytes
                ).unwrap();
 
                let test_preimage = PaymentPreimage([42; 32]);
@@ -7330,7 +7570,7 @@ mod tests {
 pub mod bench {
        use chain::Listen;
        use chain::chainmonitor::{ChainMonitor, Persist};
-       use chain::keysinterface::{KeysManager, InMemorySigner};
+       use chain::keysinterface::{KeysManager, KeysInterface, InMemorySigner};
        use ln::channelmanager::{BestBlock, ChainParameters, ChannelManager, PaymentHash, PaymentPreimage};
        use ln::features::{InitFeatures, InvoiceFeatures};
        use ln::functional_test_utils::*;
@@ -7339,7 +7579,7 @@ pub mod bench {
        use routing::router::{PaymentParameters, get_route};
        use util::test_utils;
        use util::config::UserConfig;
-       use util::events::{Event, MessageSendEvent, MessageSendEventsProvider, PaymentPurpose};
+       use util::events::{Event, MessageSendEvent, MessageSendEventsProvider};
 
        use bitcoin::hashes::Hash;
        use bitcoin::hashes::sha256::Hash as Sha256;
@@ -7397,8 +7637,8 @@ pub mod bench {
                });
                let node_b_holder = NodeHolder { node: &node_b };
 
-               node_a.peer_connected(&node_b.get_our_node_id(), &Init { features: InitFeatures::known() });
-               node_b.peer_connected(&node_a.get_our_node_id(), &Init { features: InitFeatures::known() });
+               node_a.peer_connected(&node_b.get_our_node_id(), &Init { features: InitFeatures::known(), remote_network_address: None });
+               node_b.peer_connected(&node_a.get_our_node_id(), &Init { features: InitFeatures::known(), remote_network_address: None });
                node_a.create_channel(node_b.get_our_node_id(), 8_000_000, 100_000_000, 42, None).unwrap();
                node_b.handle_open_channel(&node_a.get_our_node_id(), InitFeatures::known(), &get_event_msg!(node_a_holder, MessageSendEvent::SendOpenChannel, node_b.get_our_node_id()));
                node_a.handle_accept_channel(&node_b.get_our_node_id(), InitFeatures::known(), &get_event_msg!(node_b_holder, MessageSendEvent::SendAcceptChannel, node_a.get_our_node_id()));
@@ -7447,8 +7687,11 @@ pub mod bench {
                                let payment_params = PaymentParameters::from_node_id($node_b.get_our_node_id())
                                        .with_features(InvoiceFeatures::known());
                                let scorer = test_utils::TestScorer::with_penalty(0);
-                               let route = get_route(&$node_a.get_our_node_id(), &payment_params, &dummy_graph,
-                                       Some(&usable_channels.iter().map(|r| r).collect::<Vec<_>>()), 10_000, TEST_FINAL_CLTV, &logger_a, &scorer).unwrap();
+                               let seed = [3u8; 32];
+                               let keys_manager = KeysManager::new(&seed, 42, 42);
+                               let random_seed_bytes = keys_manager.get_secure_random_bytes();
+                               let route = get_route(&$node_a.get_our_node_id(), &payment_params, &dummy_graph.read_only(),
+                                       Some(&usable_channels.iter().map(|r| r).collect::<Vec<_>>()), 10_000, TEST_FINAL_CLTV, &logger_a, &scorer, &random_seed_bytes).unwrap();
 
                                let mut payment_preimage = PaymentPreimage([0; 32]);
                                payment_preimage.0[0..8].copy_from_slice(&payment_count.to_le_bytes());