Merge pull request #838 from TheBlueMatt/2021-03-skip-blocks
[rust-lightning] / lightning / src / ln / channelmanager.rs
index 43bee89dc2867a208a76ce67f534c451bee0c09b..efb2fe9c37bd9a8ec2c9a36d9a521072a6f8c6f3 100644 (file)
@@ -39,6 +39,9 @@ use chain::Watch;
 use chain::chaininterface::{BroadcasterInterface, FeeEstimator};
 use chain::channelmonitor::{ChannelMonitor, ChannelMonitorUpdate, ChannelMonitorUpdateStep, ChannelMonitorUpdateErr, HTLC_FAIL_BACK_BUFFER, CLTV_CLAIM_BUFFER, LATENCY_GRACE_PERIOD_BLOCKS, ANTI_REORG_DELAY, MonitorEvent, CLOSED_CHANNEL_UPDATE_ID};
 use chain::transaction::{OutPoint, TransactionData};
+// Since this struct is returned in `list_channels` methods, expose it here in case users want to
+// construct one themselves.
+pub use ln::channel::CounterpartyForwardingInfo;
 use ln::channel::{Channel, ChannelError};
 use ln::features::{InitFeatures, NodeFeatures};
 use routing::router::{Route, RouteHop};
@@ -423,7 +426,7 @@ pub struct ChannelManager<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref,
        pub(super) latest_block_height: AtomicUsize,
        #[cfg(not(test))]
        latest_block_height: AtomicUsize,
-       last_block_hash: Mutex<BlockHash>,
+       last_block_hash: RwLock<BlockHash>,
        secp_ctx: Secp256k1<secp256k1::All>,
 
        #[cfg(any(test, feature = "_test_utils"))]
@@ -431,6 +434,7 @@ pub struct ChannelManager<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref,
        #[cfg(not(any(test, feature = "_test_utils")))]
        channel_state: Mutex<ChannelHolder<Signer>>,
        our_network_key: SecretKey,
+       our_network_pubkey: PublicKey,
 
        /// Used to track the last value sent in a node_announcement "timestamp" field. We ensure this
        /// value increases strictly since we don't assume access to a time source.
@@ -461,11 +465,30 @@ pub struct ChannelManager<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref,
        logger: L,
 }
 
+/// Chain-related parameters used to construct a new `ChannelManager`.
+///
+/// Typically, the block-specific parameters are derived from the best block hash for the network,
+/// as a newly constructed `ChannelManager` will not have created any channels yet. These parameters
+/// are not needed when deserializing a previously constructed `ChannelManager`.
+pub struct ChainParameters {
+       /// The network for determining the `chain_hash` in Lightning messages.
+       pub network: Network,
+
+       /// The hash of the latest block successfully connected.
+       pub latest_hash: BlockHash,
+
+       /// The height of the latest block successfully connected.
+       ///
+       /// Used to track on-chain channel funding outputs and send payments with reliable timelocks.
+       pub latest_height: usize,
+}
+
 /// Whenever we release the `ChannelManager`'s `total_consistency_lock`, from read mode, it is
-/// desirable to notify any listeners on `wait_timeout`/`wait` that new updates are available for
-/// persistence. Therefore, this struct is responsible for locking the total consistency lock and,
-/// upon going out of scope, sending the aforementioned notification (since the lock being released
-/// indicates that the updates are ready for persistence).
+/// desirable to notify any listeners on `await_persistable_update_timeout`/
+/// `await_persistable_update` that new updates are available for persistence. Therefore, this
+/// struct is responsible for locking the total consistency lock and, upon going out of scope,
+/// sending the aforementioned notification (since the lock being released indicates that the
+/// updates are ready for persistence).
 struct PersistenceNotifierGuard<'a> {
        persistence_notifier: &'a PersistenceNotifier,
        // We hold onto this result so the lock doesn't get released immediately.
@@ -489,18 +512,28 @@ impl<'a> Drop for PersistenceNotifierGuard<'a> {
        }
 }
 
-/// The amount of time we require our counterparty wait to claim their money (ie time between when
-/// we, or our watchtower, must check for them having broadcast a theft transaction).
-pub(crate) const BREAKDOWN_TIMEOUT: u16 = 6 * 24;
-/// The amount of time we're willing to wait to claim money back to us
-pub(crate) const MAX_LOCAL_BREAKDOWN_TIMEOUT: u16 = 6 * 24 * 7;
+/// The amount of time in blocks we require our counterparty wait to claim their money (ie time
+/// between when we, or our watchtower, must check for them having broadcast a theft transaction).
+///
+/// This can be increased (but not decreased) through [`ChannelHandshakeConfig::our_to_self_delay`]
+///
+/// [`ChannelHandshakeConfig::our_to_self_delay`]: crate::util::config::ChannelHandshakeConfig::our_to_self_delay
+pub const BREAKDOWN_TIMEOUT: u16 = 6 * 24;
+/// The amount of time in blocks we're willing to wait to claim money back to us. This matches
+/// the maximum required amount in lnd as of March 2021.
+pub(crate) const MAX_LOCAL_BREAKDOWN_TIMEOUT: u16 = 2 * 6 * 24 * 7;
 
 /// The minimum number of blocks between an inbound HTLC's CLTV and the corresponding outbound
-/// HTLC's CLTV. This should always be a few blocks greater than channelmonitor::CLTV_CLAIM_BUFFER,
-/// ie the node we forwarded the payment on to should always have enough room to reliably time out
-/// the HTLC via a full update_fail_htlc/commitment_signed dance before we hit the
-/// CLTV_CLAIM_BUFFER point (we static assert that it's at least 3 blocks more).
-const CLTV_EXPIRY_DELTA: u16 = 6 * 12; //TODO?
+/// HTLC's CLTV. The current default represents roughly six hours of blocks at six blocks/hour.
+///
+/// This can be increased (but not decreased) through [`ChannelConfig::cltv_expiry_delta`]
+///
+/// [`ChannelConfig::cltv_expiry_delta`]: crate::util::config::ChannelConfig::cltv_expiry_delta
+// This should always be a few blocks greater than channelmonitor::CLTV_CLAIM_BUFFER,
+// i.e. the node we forwarded the payment on to should always have enough room to reliably time out
+// the HTLC via a full update_fail_htlc/commitment_signed dance before we hit the
+// CLTV_CLAIM_BUFFER point (we static assert that it's at least 3 blocks more).
+pub const MIN_CLTV_EXPIRY_DELTA: u16 = 6 * 6;
 pub(super) const CLTV_FAR_FAR_AWAY: u32 = 6 * 24 * 7; //TODO?
 
 // Check that our CLTV_EXPIRY is at least CLTV_CLAIM_BUFFER + ANTI_REORG_DELAY + LATENCY_GRACE_PERIOD_BLOCKS,
@@ -511,13 +544,13 @@ pub(super) const CLTV_FAR_FAR_AWAY: u32 = 6 * 24 * 7; //TODO?
 // LATENCY_GRACE_PERIOD_BLOCKS.
 #[deny(const_err)]
 #[allow(dead_code)]
-const CHECK_CLTV_EXPIRY_SANITY: u32 = CLTV_EXPIRY_DELTA as u32 - LATENCY_GRACE_PERIOD_BLOCKS - CLTV_CLAIM_BUFFER - ANTI_REORG_DELAY - LATENCY_GRACE_PERIOD_BLOCKS;
+const CHECK_CLTV_EXPIRY_SANITY: u32 = MIN_CLTV_EXPIRY_DELTA as u32 - LATENCY_GRACE_PERIOD_BLOCKS - CLTV_CLAIM_BUFFER - ANTI_REORG_DELAY - LATENCY_GRACE_PERIOD_BLOCKS;
 
 // Check for ability of an attacker to make us fail on-chain by delaying inbound claim. See
 // ChannelMontior::would_broadcast_at_height for a description of why this is needed.
 #[deny(const_err)]
 #[allow(dead_code)]
-const CHECK_CLTV_EXPIRY_SANITY_2: u32 = CLTV_EXPIRY_DELTA as u32 - LATENCY_GRACE_PERIOD_BLOCKS - 2*CLTV_CLAIM_BUFFER;
+const CHECK_CLTV_EXPIRY_SANITY_2: u32 = MIN_CLTV_EXPIRY_DELTA as u32 - LATENCY_GRACE_PERIOD_BLOCKS - 2*CLTV_CLAIM_BUFFER;
 
 /// Details of a channel, as returned by ChannelManager::list_channels and ChannelManager::list_usable_channels
 #[derive(Clone)]
@@ -554,6 +587,10 @@ pub struct ChannelDetails {
        /// True if the channel is (a) confirmed and funding_locked messages have been exchanged, (b)
        /// the peer is connected, and (c) no monitor update failure is pending resolution.
        pub is_live: bool,
+
+       /// Information on the fees and requirements that the counterparty requires when forwarding
+       /// payments to us through this channel.
+       pub counterparty_forwarding_info: Option<CounterpartyForwardingInfo>,
 }
 
 /// If a payment fails to send, it can be in one of several states. This enum is returned as the
@@ -770,25 +807,22 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
        ///
        /// panics if channel_value_satoshis is >= `MAX_FUNDING_SATOSHIS`!
        ///
-       /// Users must provide the current blockchain height from which to track onchain channel
-       /// funding outpoints and send payments with reliable timelocks.
-       ///
        /// Users need to notify the new ChannelManager when a new block is connected or
-       /// disconnected using its `block_connected` and `block_disconnected` methods.
-       pub fn new(network: Network, fee_est: F, chain_monitor: M, tx_broadcaster: T, logger: L, keys_manager: K, config: UserConfig, current_blockchain_height: usize) -> Self {
+       /// disconnected using its `block_connected` and `block_disconnected` methods, starting
+       /// from after `params.latest_hash`.
+       pub fn new(fee_est: F, chain_monitor: M, tx_broadcaster: T, logger: L, keys_manager: K, config: UserConfig, params: ChainParameters) -> Self {
                let mut secp_ctx = Secp256k1::new();
                secp_ctx.seeded_randomize(&keys_manager.get_secure_random_bytes());
 
                ChannelManager {
                        default_configuration: config.clone(),
-                       genesis_hash: genesis_block(network).header.block_hash(),
+                       genesis_hash: genesis_block(params.network).header.block_hash(),
                        fee_estimator: fee_est,
                        chain_monitor,
                        tx_broadcaster,
 
-                       latest_block_height: AtomicUsize::new(current_blockchain_height),
-                       last_block_hash: Mutex::new(Default::default()),
-                       secp_ctx,
+                       latest_block_height: AtomicUsize::new(params.latest_height),
+                       last_block_hash: RwLock::new(params.latest_hash),
 
                        channel_state: Mutex::new(ChannelHolder{
                                by_id: HashMap::new(),
@@ -798,6 +832,8 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                pending_msg_events: Vec::new(),
                        }),
                        our_network_key: keys_manager.get_node_secret(),
+                       our_network_pubkey: PublicKey::from_secret_key(&secp_ctx, &keys_manager.get_node_secret()),
+                       secp_ctx,
 
                        last_node_announcement_serial: AtomicUsize::new(0),
 
@@ -874,6 +910,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                        outbound_capacity_msat,
                                        user_id: channel.get_user_id(),
                                        is_live: channel.is_live(),
+                                       counterparty_forwarding_info: channel.counterparty_forwarding_info(),
                                });
                        }
                }
@@ -967,16 +1004,14 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                }
        }
 
-       fn force_close_channel_with_peer(&self, channel_id: &[u8; 32], peer_node_id: Option<&PublicKey>) -> Result<(), APIError> {
+       fn force_close_channel_with_peer(&self, channel_id: &[u8; 32], peer_node_id: Option<&PublicKey>) -> Result<PublicKey, APIError> {
                let mut chan = {
                        let mut channel_state_lock = self.channel_state.lock().unwrap();
                        let channel_state = &mut *channel_state_lock;
                        if let hash_map::Entry::Occupied(chan) = channel_state.by_id.entry(channel_id.clone()) {
                                if let Some(node_id) = peer_node_id {
                                        if chan.get().get_counterparty_node_id() != *node_id {
-                                               // Error or Ok here doesn't matter - the result is only exposed publicly
-                                               // when peer_node_id is None anyway.
-                                               return Ok(());
+                                               return Err(APIError::ChannelUnavailable{err: "No such channel".to_owned()});
                                        }
                                }
                                if let Some(short_id) = chan.get().get_short_channel_id() {
@@ -996,14 +1031,27 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                        });
                }
 
-               Ok(())
+               Ok(chan.get_counterparty_node_id())
        }
 
        /// Force closes a channel, immediately broadcasting the latest local commitment transaction to
        /// the chain and rejecting new HTLCs on the given channel. Fails if channel_id is unknown to the manager.
        pub fn force_close_channel(&self, channel_id: &[u8; 32]) -> Result<(), APIError> {
                let _persistence_guard = PersistenceNotifierGuard::new(&self.total_consistency_lock, &self.persistence_notifier);
-               self.force_close_channel_with_peer(channel_id, None)
+               match self.force_close_channel_with_peer(channel_id, None) {
+                       Ok(counterparty_node_id) => {
+                               self.channel_state.lock().unwrap().pending_msg_events.push(
+                                       events::MessageSendEvent::HandleError {
+                                               node_id: counterparty_node_id,
+                                               action: msgs::ErrorAction::SendErrorMessage {
+                                                       msg: msgs::ErrorMessage { channel_id: *channel_id, data: "Channel force-closed".to_owned() }
+                                               },
+                                       }
+                               );
+                               Ok(())
+                       },
+                       Err(e) => Err(e)
+               }
        }
 
        /// Force close all channels, immediately broadcasting the latest local commitment transaction
@@ -1241,7 +1289,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                        if fee.is_none() || msg.amount_msat < fee.unwrap() || (msg.amount_msat - fee.unwrap()) < *amt_to_forward { // fee_insufficient
                                                break Some(("Prior hop has deviated from specified fees parameters or origin node has obsolete ones", 0x1000 | 12, Some(self.get_channel_update(chan).unwrap())));
                                        }
-                                       if (msg.cltv_expiry as u64) < (*outgoing_cltv_value) as u64 + CLTV_EXPIRY_DELTA as u64 { // incorrect_cltv_expiry
+                                       if (msg.cltv_expiry as u64) < (*outgoing_cltv_value) as u64 + chan.get_cltv_expiry_delta() as u64 { // incorrect_cltv_expiry
                                                break Some(("Forwarding node has tampered with the intended HTLC values or origin node has an obsolete cltv_expiry_delta", 0x1000 | 13, Some(self.get_channel_update(chan).unwrap())));
                                        }
                                        let cur_height = self.latest_block_height.load(Ordering::Acquire) as u32 + 1;
@@ -1299,7 +1347,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                        short_channel_id,
                        timestamp: chan.get_update_time_counter(),
                        flags: (!were_node_one) as u8 | ((!chan.is_live() as u8) << 1),
-                       cltv_expiry_delta: CLTV_EXPIRY_DELTA,
+                       cltv_expiry_delta: chan.get_cltv_expiry_delta(),
                        htlc_minimum_msat: chan.get_counterparty_htlc_minimum_msat(),
                        htlc_maximum_msat: OptionalField::Present(chan.get_announced_htlc_max_msat()),
                        fee_base_msat: chan.get_holder_fee_base_msat(&self.fee_estimator),
@@ -2280,7 +2328,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 
        /// Gets the node_id held by this ChannelManager
        pub fn get_our_node_id(&self) -> PublicKey {
-               PublicKey::from_secret_key(&self.secp_ctx, &self.our_network_key)
+               self.our_network_pubkey.clone()
        }
 
        /// Restores a single, given channel to normal operation after a
@@ -2438,6 +2486,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 
        fn internal_funding_created(&self, counterparty_node_id: &PublicKey, msg: &msgs::FundingCreated) -> Result<(), MsgHandleErrInternal> {
                let ((funding_msg, monitor), mut chan) = {
+                       let last_block_hash = *self.last_block_hash.read().unwrap();
                        let mut channel_lock = self.channel_state.lock().unwrap();
                        let channel_state = &mut *channel_lock;
                        match channel_state.by_id.entry(msg.temporary_channel_id.clone()) {
@@ -2445,7 +2494,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                        if chan.get().get_counterparty_node_id() != *counterparty_node_id {
                                                return Err(MsgHandleErrInternal::send_err_msg_no_close("Got a message for a channel from the wrong node!".to_owned(), msg.temporary_channel_id));
                                        }
-                                       (try_chan_entry!(self, chan.get_mut().funding_created(msg, &self.logger), channel_state, chan), chan.remove())
+                                       (try_chan_entry!(self, chan.get_mut().funding_created(msg, last_block_hash, &self.logger), channel_state, chan), chan.remove())
                                },
                                hash_map::Entry::Vacant(_) => return Err(MsgHandleErrInternal::send_err_msg_no_close("Failed to find corresponding channel".to_owned(), msg.temporary_channel_id))
                        }
@@ -2494,6 +2543,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 
        fn internal_funding_signed(&self, counterparty_node_id: &PublicKey, msg: &msgs::FundingSigned) -> Result<(), MsgHandleErrInternal> {
                let (funding_txo, user_id) = {
+                       let last_block_hash = *self.last_block_hash.read().unwrap();
                        let mut channel_lock = self.channel_state.lock().unwrap();
                        let channel_state = &mut *channel_lock;
                        match channel_state.by_id.entry(msg.channel_id) {
@@ -2501,7 +2551,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                        if chan.get().get_counterparty_node_id() != *counterparty_node_id {
                                                return Err(MsgHandleErrInternal::send_err_msg_no_close("Got a message for a channel from the wrong node!".to_owned(), msg.channel_id));
                                        }
-                                       let monitor = match chan.get_mut().funding_signed(&msg, &self.logger) {
+                                       let monitor = match chan.get_mut().funding_signed(&msg, last_block_hash, &self.logger) {
                                                Ok(update) => update,
                                                Err(e) => try_chan_entry!(self, Err(e), channel_state, chan),
                                        };
@@ -2974,6 +3024,29 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                Ok(())
        }
 
+       fn internal_channel_update(&self, counterparty_node_id: &PublicKey, msg: &msgs::ChannelUpdate) -> Result<(), MsgHandleErrInternal> {
+               let mut channel_state_lock = self.channel_state.lock().unwrap();
+               let channel_state = &mut *channel_state_lock;
+               let chan_id = match channel_state.short_to_id.get(&msg.contents.short_channel_id) {
+                       Some(chan_id) => chan_id.clone(),
+                       None => {
+                               // It's not a local channel
+                               return Ok(())
+                       }
+               };
+               match channel_state.by_id.entry(chan_id) {
+                       hash_map::Entry::Occupied(mut chan) => {
+                               if chan.get().get_counterparty_node_id() != *counterparty_node_id {
+                                       // TODO: see issue #153, need a consistent behavior on obnoxious behavior from random node
+                                       return Err(MsgHandleErrInternal::send_err_msg_no_close("Got a message for a channel from the wrong node!".to_owned(), chan_id));
+                               }
+                               try_chan_entry!(self, chan.get_mut().channel_update(&msg), channel_state, chan);
+                       },
+                       hash_map::Entry::Vacant(_) => unreachable!()
+               }
+               Ok(())
+       }
+
        fn internal_channel_reestablish(&self, counterparty_node_id: &PublicKey, msg: &msgs::ChannelReestablish) -> Result<(), MsgHandleErrInternal> {
                let mut channel_state_lock = self.channel_state.lock().unwrap();
                let channel_state = &mut *channel_state_lock;
@@ -3134,6 +3207,12 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                                                        msg: update
                                                                });
                                                        }
+                                                       pending_msg_events.push(events::MessageSendEvent::HandleError {
+                                                               node_id: chan.get_counterparty_node_id(),
+                                                               action: msgs::ErrorAction::SendErrorMessage {
+                                                                       msg: msgs::ErrorMessage { channel_id: chan.channel_id(), data: "Channel force-closed".to_owned() }
+                                                               },
+                                                       });
                                                }
                                        },
                                }
@@ -3216,12 +3295,26 @@ where
        L::Target: Logger,
 {
        fn block_connected(&self, block: &Block, height: u32) {
+               assert_eq!(*self.last_block_hash.read().unwrap(), block.header.prev_blockhash,
+                       "Blocks must be connected in chain-order - the connected header must build on the last connected header");
+               assert_eq!(self.latest_block_height.load(Ordering::Acquire) as u64, height as u64 - 1,
+                       "Blocks must be connected in chain-order - the connected block height must be one greater than the previous height");
                let txdata: Vec<_> = block.txdata.iter().enumerate().collect();
-               ChannelManager::block_connected(self, &block.header, &txdata, height);
+               self.transactions_confirmed(&block.header, height, &txdata);
+               self.update_best_block(&block.header, height);
        }
 
-       fn block_disconnected(&self, header: &BlockHeader, _height: u32) {
-               ChannelManager::block_disconnected(self, header);
+       fn block_disconnected(&self, header: &BlockHeader, height: u32) {
+               assert_eq!(*self.last_block_hash.read().unwrap(), header.block_hash(),
+                       "Blocks must be disconnected in chain-order - the disconnected header must be the last connected header");
+
+               let _persistence_guard = PersistenceNotifierGuard::new(&self.total_consistency_lock, &self.persistence_notifier);
+               let new_height = self.latest_block_height.fetch_sub(1, Ordering::AcqRel) as u32 - 1;
+               assert_eq!(new_height, height - 1,
+                       "Blocks must be disconnected in chain-order - the disconnected block must have the correct height");
+               *self.last_block_hash.write().unwrap() = header.prev_blockhash;
+
+               self.do_chain_event(new_height, |channel| channel.update_best_block(new_height, header.time));
        }
 }
 
@@ -3232,14 +3325,12 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
         F::Target: FeeEstimator,
         L::Target: Logger,
 {
-       /// Updates channel state based on transactions seen in a connected block.
-       pub fn block_connected(&self, header: &BlockHeader, txdata: &TransactionData, height: u32) {
+       fn do_chain_event<FN: Fn(&mut Channel<Signer>) -> Result<(Option<msgs::FundingLocked>, Vec<(HTLCSource, PaymentHash)>), msgs::ErrorMessage>>
+                       (&self, height: u32, f: FN) {
                // Note that we MUST NOT end up calling methods on self.chain_monitor here - we're called
                // during initialization prior to the chain_monitor being fully configured in some cases.
                // See the docs for `ChannelManagerReadArgs` for more.
-               let header_hash = header.block_hash();
-               log_trace!(self.logger, "Block {} at height {} connected", header_hash, height);
-               let _persistence_guard = PersistenceNotifierGuard::new(&self.total_consistency_lock, &self.persistence_notifier);
+
                let mut failed_channels = Vec::new();
                let mut timed_out_htlcs = Vec::new();
                {
@@ -3248,7 +3339,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                        let short_to_id = &mut channel_state.short_to_id;
                        let pending_msg_events = &mut channel_state.pending_msg_events;
                        channel_state.by_id.retain(|_, channel| {
-                               let res = channel.block_connected(header, txdata, height);
+                               let res = f(channel);
                                if let Ok((chan_res, mut timed_out_pending_htlcs)) = res {
                                        for (source, payment_hash) in timed_out_pending_htlcs.drain(..) {
                                                let chan_update = self.get_channel_update(&channel).map(|u| u.encode_with_len()).unwrap(); // Cannot add/recv HTLCs before we have a short_id so unwrap is safe
@@ -3274,32 +3365,23 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                                                short_to_id.insert(channel.get_short_channel_id().unwrap(), channel.channel_id());
                                        }
                                } else if let Err(e) = res {
+                                       if let Some(short_id) = channel.get_short_channel_id() {
+                                               short_to_id.remove(&short_id);
+                                       }
+                                       // 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));
+                                       if let Ok(update) = self.get_channel_update(&channel) {
+                                               pending_msg_events.push(events::MessageSendEvent::BroadcastChannelUpdate {
+                                                       msg: update
+                                               });
+                                       }
                                        pending_msg_events.push(events::MessageSendEvent::HandleError {
                                                node_id: channel.get_counterparty_node_id(),
                                                action: msgs::ErrorAction::SendErrorMessage { msg: e },
                                        });
                                        return false;
                                }
-                               if let Some(funding_txo) = channel.get_funding_txo() {
-                                       for &(_, tx) in txdata.iter() {
-                                               for inp in tx.input.iter() {
-                                                       if inp.previous_output == funding_txo.into_bitcoin_outpoint() {
-                                                               log_trace!(self.logger, "Detected channel-closing tx {} spending {}:{}, closing channel {}", tx.txid(), inp.previous_output.txid, inp.previous_output.vout, log_bytes!(channel.channel_id()));
-                                                               if let Some(short_id) = channel.get_short_channel_id() {
-                                                                       short_to_id.remove(&short_id);
-                                                               }
-                                                               // It looks like our counterparty went on-chain. Close the channel.
-                                                               failed_channels.push(channel.force_shutdown(true));
-                                                               if let Ok(update) = self.get_channel_update(&channel) {
-                                                                       pending_msg_events.push(events::MessageSendEvent::BroadcastChannelUpdate {
-                                                                               msg: update
-                                                                       });
-                                                               }
-                                                               return false;
-                                                       }
-                                               }
-                                       }
-                               }
                                true
                        });
 
@@ -3328,8 +3410,65 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                for (source, payment_hash, reason) in timed_out_htlcs.drain(..) {
                        self.fail_htlc_backwards_internal(self.channel_state.lock().unwrap(), source, &payment_hash, reason);
                }
+       }
+
+       /// Updates channel state to take note of transactions which were confirmed in the given block
+       /// at the given height.
+       ///
+       /// Note that you must still call (or have called) [`update_best_block`] with the block
+       /// information which is included here.
+       ///
+       /// This method may be called before or after [`update_best_block`] for a given block's
+       /// transaction data and may be called multiple times with additional transaction data for a
+       /// given block.
+       ///
+       /// This method may be called for a previous block after an [`update_best_block`] call has
+       /// been made for a later block, however it must *not* be called with transaction data from a
+       /// block which is no longer in the best chain (ie where [`update_best_block`] has already
+       /// been informed about a blockchain reorganization which no longer includes the block which
+       /// corresponds to `header`).
+       ///
+       /// [`update_best_block`]: `Self::update_best_block`
+       pub fn transactions_confirmed(&self, header: &BlockHeader, height: u32, txdata: &TransactionData) {
+               // Note that we MUST NOT end up calling methods on self.chain_monitor here - we're called
+               // during initialization prior to the chain_monitor being fully configured in some cases.
+               // See the docs for `ChannelManagerReadArgs` for more.
+
+               let block_hash = header.block_hash();
+               log_trace!(self.logger, "{} transactions included in block {} at height {} provided", txdata.len(), block_hash, height);
+
+               let _persistence_guard = PersistenceNotifierGuard::new(&self.total_consistency_lock, &self.persistence_notifier);
+               self.do_chain_event(height, |channel| channel.transactions_confirmed(&block_hash, height, txdata, &self.logger).map(|a| (a, Vec::new())));
+       }
+
+       /// Updates channel state with the current best blockchain tip. You should attempt to call this
+       /// quickly after a new block becomes available, however if multiple new blocks become
+       /// available at the same time, only a single `update_best_block()` call needs to be made.
+       ///
+       /// This method should also be called immediately after any block disconnections, once at the
+       /// reorganization fork point, and once with the new chain tip. Calling this method at the
+       /// blockchain reorganization fork point ensures we learn when a funding transaction which was
+       /// previously confirmed is reorganized out of the blockchain, ensuring we do not continue to
+       /// accept payments which cannot be enforced on-chain.
+       ///
+       /// In both the block-connection and block-disconnection case, this method may be called either
+       /// once per block connected or disconnected, or simply at the fork point and new tip(s),
+       /// skipping any intermediary blocks.
+       pub fn update_best_block(&self, header: &BlockHeader, height: u32) {
+               // Note that we MUST NOT end up calling methods on self.chain_monitor here - we're called
+               // during initialization prior to the chain_monitor being fully configured in some cases.
+               // See the docs for `ChannelManagerReadArgs` for more.
+
+               let block_hash = header.block_hash();
+               log_trace!(self.logger, "New best block: {} at height {}", block_hash, height);
+
+               let _persistence_guard = PersistenceNotifierGuard::new(&self.total_consistency_lock, &self.persistence_notifier);
+
                self.latest_block_height.store(height as usize, Ordering::Release);
-               *self.last_block_hash.try_lock().expect("block_(dis)connected must not be called in parallel") = header_hash;
+               *self.last_block_hash.write().unwrap() = block_hash;
+
+               self.do_chain_event(height, |channel| channel.update_best_block(height, header.time));
+
                loop {
                        // Update last_node_announcement_serial to be the max of its current value and the
                        // block timestamp. This should keep us close to the current time without relying on
@@ -3344,55 +3483,20 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
                }
        }
 
-       /// Updates channel state based on a disconnected block.
-       ///
-       /// If necessary, the channel may be force-closed without letting the counterparty participate
-       /// in the shutdown.
-       pub fn block_disconnected(&self, header: &BlockHeader) {
-               // Note that we MUST NOT end up calling methods on self.chain_monitor here - we're called
-               // during initialization prior to the chain_monitor being fully configured in some cases.
-               // See the docs for `ChannelManagerReadArgs` for more.
-               let _persistence_guard = PersistenceNotifierGuard::new(&self.total_consistency_lock, &self.persistence_notifier);
-               let mut failed_channels = 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;
-                       channel_state.by_id.retain(|_,  v| {
-                               if v.block_disconnected(header) {
-                                       if let Some(short_id) = v.get_short_channel_id() {
-                                               short_to_id.remove(&short_id);
-                                       }
-                                       failed_channels.push(v.force_shutdown(true));
-                                       if let Ok(update) = self.get_channel_update(&v) {
-                                               pending_msg_events.push(events::MessageSendEvent::BroadcastChannelUpdate {
-                                                       msg: update
-                                               });
-                                       }
-                                       false
-                               } else {
-                                       true
-                               }
-                       });
-               }
-               self.handle_init_event_channel_failures(failed_channels);
-               self.latest_block_height.fetch_sub(1, Ordering::AcqRel);
-               *self.last_block_hash.try_lock().expect("block_(dis)connected must not be called in parallel") = header.block_hash();
-       }
-
        /// Blocks until ChannelManager needs to be persisted or a timeout is reached. It returns a bool
-       /// indicating whether persistence is necessary. Only one listener on `wait_timeout` is
-       /// guaranteed to be woken up.
+       /// indicating whether persistence is necessary. Only one listener on
+       /// `await_persistable_update` or `await_persistable_update_timeout` is guaranteed to be woken
+       /// up.
        /// Note that the feature `allow_wallclock_use` must be enabled to use this function.
        #[cfg(any(test, feature = "allow_wallclock_use"))]
-       pub fn wait_timeout(&self, max_wait: Duration) -> bool {
+       pub fn await_persistable_update_timeout(&self, max_wait: Duration) -> bool {
                self.persistence_notifier.wait_timeout(max_wait)
        }
 
-       /// Blocks until ChannelManager needs to be persisted. Only one listener on `wait` is
-       /// guaranteed to be woken up.
-       pub fn wait(&self) {
+       /// Blocks until ChannelManager needs to be persisted. Only one listener on
+       /// `await_persistable_update` or `await_persistable_update_timeout` is guaranteed to be woken
+       /// up.
+       pub fn await_persistable_update(&self) {
                self.persistence_notifier.wait()
        }
 
@@ -3488,6 +3592,11 @@ impl<Signer: Sign, M: Deref + Sync + Send, T: Deref + Sync + Send, K: Deref + Sy
                let _ = handle_error!(self, self.internal_announcement_signatures(counterparty_node_id, msg), *counterparty_node_id);
        }
 
+       fn handle_channel_update(&self, counterparty_node_id: &PublicKey, msg: &msgs::ChannelUpdate) {
+               let _persistence_guard = PersistenceNotifierGuard::new(&self.total_consistency_lock, &self.persistence_notifier);
+               let _ = handle_error!(self, self.internal_channel_update(counterparty_node_id, msg), *counterparty_node_id);
+       }
+
        fn handle_channel_reestablish(&self, counterparty_node_id: &PublicKey, msg: &msgs::ChannelReestablish) {
                let _persistence_guard = PersistenceNotifierGuard::new(&self.total_consistency_lock, &self.persistence_notifier);
                let _ = handle_error!(self, self.internal_channel_reestablish(counterparty_node_id, msg), *counterparty_node_id);
@@ -3567,6 +3676,7 @@ impl<Signer: Sign, M: Deref + Sync + Send, T: Deref + Sync + Send, K: Deref + Sy
                                        &events::MessageSendEvent::PaymentFailureNetworkUpdate { .. } => true,
                                        &events::MessageSendEvent::SendChannelRangeQuery { .. } => false,
                                        &events::MessageSendEvent::SendShortIdsQuery { .. } => false,
+                                       &events::MessageSendEvent::SendReplyChannelRange { .. } => false,
                                }
                        });
                }
@@ -3644,7 +3754,7 @@ impl<Signer: Sign, M: Deref + Sync + Send, T: Deref + Sync + Send, K: Deref + Sy
 }
 
 /// Used to signal to the ChannelManager persister that the manager needs to be re-persisted to
-/// disk/backups, through `wait_timeout` and `wait`.
+/// disk/backups, through `await_persistable_update_timeout` and `await_persistable_update`.
 struct PersistenceNotifier {
        /// Users won't access the persistence_lock directly, but rather wait on its bool using
        /// `wait_timeout` and `wait`.
@@ -3934,7 +4044,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> Writeable f
 
                self.genesis_hash.write(writer)?;
                (self.latest_block_height.load(Ordering::Acquire) as u32).write(writer)?;
-               self.last_block_hash.lock().unwrap().write(writer)?;
+               self.last_block_hash.read().unwrap().write(writer)?;
 
                let channel_state = self.channel_state.lock().unwrap();
                let mut unfunded_channels = 0;
@@ -4137,10 +4247,6 @@ impl<'a, Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
                let mut short_to_id = HashMap::with_capacity(cmp::min(channel_count as usize, 128));
                for _ in 0..channel_count {
                        let mut channel: Channel<Signer> = Channel::read(reader, &args.keys_manager)?;
-                       if channel.last_block_connected != Default::default() && channel.last_block_connected != last_block_hash {
-                               return Err(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) {
@@ -4240,8 +4346,7 @@ impl<'a, Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
                        tx_broadcaster: args.tx_broadcaster,
 
                        latest_block_height: AtomicUsize::new(latest_block_height as usize),
-                       last_block_hash: Mutex::new(last_block_hash),
-                       secp_ctx,
+                       last_block_hash: RwLock::new(last_block_hash),
 
                        channel_state: Mutex::new(ChannelHolder {
                                by_id,
@@ -4251,6 +4356,8 @@ impl<'a, Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
                                pending_msg_events: Vec::new(),
                        }),
                        our_network_key: args.keys_manager.get_node_secret(),
+                       our_network_pubkey: PublicKey::from_secret_key(&secp_ctx, &args.keys_manager.get_node_secret()),
+                       secp_ctx,
 
                        last_node_announcement_serial: AtomicUsize::new(last_node_announcement_serial as usize),
 
@@ -4327,3 +4434,154 @@ mod tests {
                }
        }
 }
+
+#[cfg(all(any(test, feature = "_test_utils"), feature = "unstable"))]
+pub mod bench {
+       use chain::Listen;
+       use chain::chainmonitor::ChainMonitor;
+       use chain::channelmonitor::Persist;
+       use chain::keysinterface::{KeysManager, InMemorySigner};
+       use chain::transaction::OutPoint;
+       use ln::channelmanager::{ChainParameters, ChannelManager, PaymentHash, PaymentPreimage};
+       use ln::features::InitFeatures;
+       use ln::functional_test_utils::*;
+       use ln::msgs::ChannelMessageHandler;
+       use routing::network_graph::NetworkGraph;
+       use routing::router::get_route;
+       use util::test_utils;
+       use util::config::UserConfig;
+       use util::events::{Event, EventsProvider, MessageSendEvent, MessageSendEventsProvider};
+
+       use bitcoin::hashes::Hash;
+       use bitcoin::hashes::sha256::Hash as Sha256;
+       use bitcoin::{Block, BlockHeader, Transaction, TxOut};
+
+       use std::sync::Mutex;
+
+       use test::Bencher;
+
+       struct NodeHolder<'a, P: Persist<InMemorySigner>> {
+               node: &'a ChannelManager<InMemorySigner,
+                       &'a ChainMonitor<InMemorySigner, &'a test_utils::TestChainSource,
+                               &'a test_utils::TestBroadcaster, &'a test_utils::TestFeeEstimator,
+                               &'a test_utils::TestLogger, &'a P>,
+                       &'a test_utils::TestBroadcaster, &'a KeysManager,
+                       &'a test_utils::TestFeeEstimator, &'a test_utils::TestLogger>
+       }
+
+       #[cfg(test)]
+       #[bench]
+       fn bench_sends(bench: &mut Bencher) {
+               bench_two_sends(bench, test_utils::TestPersister::new(), test_utils::TestPersister::new());
+       }
+
+       pub fn bench_two_sends<P: Persist<InMemorySigner>>(bench: &mut Bencher, persister_a: P, persister_b: P) {
+               // Do a simple benchmark of sending a payment back and forth between two nodes.
+               // Note that this is unrealistic as each payment send will require at least two fsync
+               // calls per node.
+               let network = bitcoin::Network::Testnet;
+               let genesis_hash = bitcoin::blockdata::constants::genesis_block(network).header.block_hash();
+
+               let tx_broadcaster = test_utils::TestBroadcaster{txn_broadcasted: Mutex::new(Vec::new())};
+               let fee_estimator = test_utils::TestFeeEstimator { sat_per_kw: 253 };
+
+               let mut config: UserConfig = Default::default();
+               config.own_channel_config.minimum_depth = 1;
+
+               let logger_a = test_utils::TestLogger::with_id("node a".to_owned());
+               let chain_monitor_a = ChainMonitor::new(None, &tx_broadcaster, &logger_a, &fee_estimator, &persister_a);
+               let seed_a = [1u8; 32];
+               let keys_manager_a = KeysManager::new(&seed_a, 42, 42);
+               let node_a = ChannelManager::new(&fee_estimator, &chain_monitor_a, &tx_broadcaster, &logger_a, &keys_manager_a, config.clone(), ChainParameters {
+                       network,
+                       latest_hash: genesis_hash,
+                       latest_height: 0,
+               });
+               let node_a_holder = NodeHolder { node: &node_a };
+
+               let logger_b = test_utils::TestLogger::with_id("node a".to_owned());
+               let chain_monitor_b = ChainMonitor::new(None, &tx_broadcaster, &logger_a, &fee_estimator, &persister_b);
+               let seed_b = [2u8; 32];
+               let keys_manager_b = KeysManager::new(&seed_b, 42, 42);
+               let node_b = ChannelManager::new(&fee_estimator, &chain_monitor_b, &tx_broadcaster, &logger_b, &keys_manager_b, config.clone(), ChainParameters {
+                       network,
+                       latest_hash: genesis_hash,
+                       latest_height: 0,
+               });
+               let node_b_holder = NodeHolder { node: &node_b };
+
+               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()));
+
+               let tx;
+               if let Event::FundingGenerationReady { temporary_channel_id, output_script, .. } = get_event!(node_a_holder, Event::FundingGenerationReady) {
+                       tx = Transaction { version: 2, lock_time: 0, input: Vec::new(), output: vec![TxOut {
+                               value: 8_000_000, script_pubkey: output_script,
+                       }]};
+                       let funding_outpoint = OutPoint { txid: tx.txid(), index: 0 };
+                       node_a.funding_transaction_generated(&temporary_channel_id, funding_outpoint);
+               } else { panic!(); }
+
+               node_b.handle_funding_created(&node_a.get_our_node_id(), &get_event_msg!(node_a_holder, MessageSendEvent::SendFundingCreated, node_b.get_our_node_id()));
+               node_a.handle_funding_signed(&node_b.get_our_node_id(), &get_event_msg!(node_b_holder, MessageSendEvent::SendFundingSigned, node_a.get_our_node_id()));
+
+               get_event!(node_a_holder, Event::FundingBroadcastSafe);
+
+               let block = Block {
+                       header: BlockHeader { version: 0x20000000, prev_blockhash: genesis_hash, merkle_root: Default::default(), time: 42, bits: 42, nonce: 42 },
+                       txdata: vec![tx],
+               };
+               Listen::block_connected(&node_a, &block, 1);
+               Listen::block_connected(&node_b, &block, 1);
+
+               node_a.handle_funding_locked(&node_b.get_our_node_id(), &get_event_msg!(node_b_holder, MessageSendEvent::SendFundingLocked, node_a.get_our_node_id()));
+               node_b.handle_funding_locked(&node_a.get_our_node_id(), &get_event_msg!(node_a_holder, MessageSendEvent::SendFundingLocked, node_b.get_our_node_id()));
+
+               let dummy_graph = NetworkGraph::new(genesis_hash);
+
+               macro_rules! send_payment {
+                       ($node_a: expr, $node_b: expr) => {
+                               let usable_channels = $node_a.list_usable_channels();
+                               let route = get_route(&$node_a.get_our_node_id(), &dummy_graph, &$node_b.get_our_node_id(), None, Some(&usable_channels.iter().map(|r| r).collect::<Vec<_>>()), &[], 10_000, TEST_FINAL_CLTV, &logger_a).unwrap();
+
+                               let payment_preimage = PaymentPreimage([0; 32]);
+                               let payment_hash = PaymentHash(Sha256::hash(&payment_preimage.0[..]).into_inner());
+
+                               $node_a.send_payment(&route, payment_hash, &None).unwrap();
+                               let payment_event = SendEvent::from_event($node_a.get_and_clear_pending_msg_events().pop().unwrap());
+                               $node_b.handle_update_add_htlc(&$node_a.get_our_node_id(), &payment_event.msgs[0]);
+                               $node_b.handle_commitment_signed(&$node_a.get_our_node_id(), &payment_event.commitment_msg);
+                               let (raa, cs) = get_revoke_commit_msgs!(NodeHolder { node: &$node_b }, $node_a.get_our_node_id());
+                               $node_a.handle_revoke_and_ack(&$node_b.get_our_node_id(), &raa);
+                               $node_a.handle_commitment_signed(&$node_b.get_our_node_id(), &cs);
+                               $node_b.handle_revoke_and_ack(&$node_a.get_our_node_id(), &get_event_msg!(NodeHolder { node: &$node_a }, MessageSendEvent::SendRevokeAndACK, $node_b.get_our_node_id()));
+
+                               expect_pending_htlcs_forwardable!(NodeHolder { node: &$node_b });
+                               expect_payment_received!(NodeHolder { node: &$node_b }, payment_hash, 10_000);
+                               assert!($node_b.claim_funds(payment_preimage, &None, 10_000));
+
+                               match $node_b.get_and_clear_pending_msg_events().pop().unwrap() {
+                                       MessageSendEvent::UpdateHTLCs { node_id, updates } => {
+                                               assert_eq!(node_id, $node_a.get_our_node_id());
+                                               $node_a.handle_update_fulfill_htlc(&$node_b.get_our_node_id(), &updates.update_fulfill_htlcs[0]);
+                                               $node_a.handle_commitment_signed(&$node_b.get_our_node_id(), &updates.commitment_signed);
+                                       },
+                                       _ => panic!("Failed to generate claim event"),
+                               }
+
+                               let (raa, cs) = get_revoke_commit_msgs!(NodeHolder { node: &$node_a }, $node_b.get_our_node_id());
+                               $node_b.handle_revoke_and_ack(&$node_a.get_our_node_id(), &raa);
+                               $node_b.handle_commitment_signed(&$node_a.get_our_node_id(), &cs);
+                               $node_a.handle_revoke_and_ack(&$node_b.get_our_node_id(), &get_event_msg!(NodeHolder { node: &$node_b }, MessageSendEvent::SendRevokeAndACK, $node_a.get_our_node_id()));
+
+                               expect_payment_sent!(NodeHolder { node: &$node_a }, payment_preimage);
+                       }
+               }
+
+               bench.iter(|| {
+                       send_payment!(node_a, node_b);
+                       send_payment!(node_b, node_a);
+               });
+       }
+}