Merge pull request #1078 from TheBlueMatt/2021-09-chan-types
[rust-lightning] / lightning / src / ln / channel.rs
index 4bb549d8f6c59f5b964f5f361ad6f32792082512..e39478bd740c063ce1f29a7dc853238ec75fcf48 100644 (file)
@@ -23,10 +23,10 @@ use bitcoin::secp256k1::{Secp256k1,Signature};
 use bitcoin::secp256k1;
 
 use ln::{PaymentPreimage, PaymentHash};
-use ln::features::{ChannelFeatures, InitFeatures};
+use ln::features::{ChannelFeatures, ChannelTypeFeatures, InitFeatures};
 use ln::msgs;
 use ln::msgs::{DecodeError, OptionalField, DataLossProtect};
-use ln::script::ShutdownScript;
+use ln::script::{self, ShutdownScript};
 use ln::channelmanager::{CounterpartyForwardingInfo, PendingHTLCStatus, HTLCSource, HTLCFailReason, HTLCFailureMsg, PendingHTLCInfo, RAACommitmentOrder, BREAKDOWN_TIMEOUT, MIN_CLTV_EXPIRY_DELTA, MAX_LOCAL_BREAKDOWN_TIMEOUT};
 use ln::chan_utils::{CounterpartyCommitmentSecrets, TxCreationKeys, HTLCOutputInCommitment, HTLC_SUCCESS_TX_WEIGHT, HTLC_TIMEOUT_TX_WEIGHT, make_funding_redeemscript, ChannelPublicKeys, CommitmentTransaction, HolderCommitmentTransaction, ChannelTransactionParameters, CounterpartyChannelTransactionParameters, MAX_HTLCS, get_commitment_transaction_number_obscure_factor, ClosingTransaction};
 use ln::chan_utils;
@@ -44,7 +44,6 @@ use util::scid_utils::scid_from_parts;
 use io;
 use prelude::*;
 use core::{cmp,mem,fmt};
-use core::convert::TryFrom;
 use core::ops::Deref;
 #[cfg(any(test, feature = "fuzztarget", debug_assertions))]
 use sync::Mutex;
@@ -340,6 +339,29 @@ pub enum UpdateFulfillCommitFetch {
        DuplicateClaim {},
 }
 
+/// The return value of `revoke_and_ack` on success, primarily updates to other channels or HTLC
+/// state.
+pub(super) struct RAAUpdates {
+       pub commitment_update: Option<msgs::CommitmentUpdate>,
+       pub accepted_htlcs: Vec<(PendingHTLCInfo, u64)>,
+       pub failed_htlcs: Vec<(HTLCSource, PaymentHash, HTLCFailReason)>,
+       pub finalized_claimed_htlcs: Vec<HTLCSource>,
+       pub monitor_update: ChannelMonitorUpdate,
+       pub holding_cell_failed_htlcs: Vec<(HTLCSource, PaymentHash)>,
+}
+
+/// The return value of `monitor_updating_restored`
+pub(super) struct MonitorRestoreUpdates {
+       pub raa: Option<msgs::RevokeAndACK>,
+       pub commitment_update: Option<msgs::CommitmentUpdate>,
+       pub order: RAACommitmentOrder,
+       pub accepted_htlcs: Vec<(PendingHTLCInfo, u64)>,
+       pub failed_htlcs: Vec<(HTLCSource, PaymentHash, HTLCFailReason)>,
+       pub finalized_claimed_htlcs: Vec<HTLCSource>,
+       pub funding_broadcastable: Option<Transaction>,
+       pub funding_locked: Option<msgs::FundingLocked>,
+}
+
 /// If the majority of the channels funds are to the fundee and the initiator holds only just
 /// enough funds to cover their reserve value, channels are at risk of getting "stuck". Because the
 /// initiator controls the feerate, if they then go to increase the channel fee, they may have no
@@ -407,6 +429,7 @@ pub(super) struct Channel<Signer: Sign> {
        monitor_pending_commitment_signed: bool,
        monitor_pending_forwards: Vec<(PendingHTLCInfo, u64)>,
        monitor_pending_failures: Vec<(HTLCSource, PaymentHash, HTLCFailReason)>,
+       monitor_pending_finalized_fulfills: Vec<HTLCSource>,
 
        // pending_update_fee is filled when sending and receiving update_fee.
        //
@@ -527,6 +550,9 @@ pub(super) struct Channel<Signer: Sign> {
        // is fine, but as a sanity check in our failure to generate the second claim, we check here
        // that the original was a claim, and that we aren't now trying to fulfill a failed HTLC.
        historical_inbound_htlc_fulfills: HashSet<u64>,
+
+       /// This channel's type, as negotiated during channel open
+       channel_type: ChannelTypeFeatures,
 }
 
 #[cfg(any(test, feature = "fuzztarget"))]
@@ -555,21 +581,24 @@ pub const ANCHOR_OUTPUT_VALUE_SATOSHI: u64 = 330;
 /// it's 2^24.
 pub const MAX_FUNDING_SATOSHIS: u64 = 1 << 24;
 
-/// Maximum counterparty `dust_limit_satoshis` allowed. 2 * standard dust threshold on p2wsh output
-/// Scales up on Bitcoin Core's proceeding policy with dust outputs. A typical p2wsh output is 43
-/// bytes to which Core's `GetDustThreshold()` sums up a minimal spend of 67 bytes (even if
-/// a p2wsh witnessScript might be *effectively* smaller), `dustRelayFee` is set to 3000sat/kb, thus
-/// 110 * 3000 / 1000 = 330. Per-protocol rules, all time-sensitive outputs are p2wsh, a value of
-/// 330 sats is the lower bound desired to ensure good propagation of transactions. We give a bit
-/// of margin to our counterparty and pick up 660 satoshis as an accepted `dust_limit_satoshis`
-/// upper bound to avoid negotiation conflicts with other implementations.
-pub const MAX_DUST_LIMIT_SATOSHIS: u64 = 2 * 330;
-
-/// A typical p2wsh output is 43 bytes to which Core's `GetDustThreshold()` sums up a minimal
-/// spend of 67 bytes (even if a p2wsh witnessScript might be *effectively* smaller), `dustRelayFee`
-/// is set to 3000sat/kb, thus 110 * 3000 / 1000 = 330. Per-protocol rules, all time-sensitive outputs
-/// are p2wsh, a value of 330 sats is the lower bound desired to ensure good propagation of transactions.
-pub const MIN_DUST_LIMIT_SATOSHIS: u64 = 330;
+/// The maximum network dust limit for standard script formats. This currently represents the
+/// minimum output value for a P2SH output before Bitcoin Core 22 considers the entire
+/// transaction non-standard and thus refuses to relay it.
+/// We also use this as the maximum counterparty `dust_limit_satoshis` allowed, given many
+/// implementations use this value for their dust limit today.
+pub const MAX_STD_OUTPUT_DUST_LIMIT_SATOSHIS: u64 = 546;
+
+/// The maximum channel dust limit we will accept from our counterparty.
+pub const MAX_CHAN_DUST_LIMIT_SATOSHIS: u64 = MAX_STD_OUTPUT_DUST_LIMIT_SATOSHIS;
+
+/// The dust limit is used for both the commitment transaction outputs as well as the closing
+/// transactions. For cooperative closing transactions, we require segwit outputs, though accept
+/// *any* segwit scripts, which are allowed to be up to 42 bytes in length.
+/// In order to avoid having to concern ourselves with standardness during the closing process, we
+/// simply require our counterparty to use a dust limit which will leave any segwit output
+/// standard.
+/// See https://github.com/lightningnetwork/lightning-rfc/issues/905 for more details.
+pub const MIN_CHAN_DUST_LIMIT_SATOSHIS: u64 = 354;
 
 /// Used to return a simple Error back to ChannelManager. Will get converted to a
 /// msgs::ErrorAction::SendErrorMessage or msgs::ErrorAction::IgnoreError as appropriate with our
@@ -636,7 +665,7 @@ impl<Signer: Sign> Channel<Signer> {
                        return Err(APIError::APIMisuseError {err: format!("Configured with an unreasonable our_to_self_delay ({}) putting user funds at risks", holder_selected_contest_delay)});
                }
                let holder_selected_channel_reserve_satoshis = Channel::<Signer>::get_holder_selected_channel_reserve_satoshis(channel_value_satoshis);
-               if holder_selected_channel_reserve_satoshis < MIN_DUST_LIMIT_SATOSHIS {
+               if holder_selected_channel_reserve_satoshis < MIN_CHAN_DUST_LIMIT_SATOSHIS {
                        return Err(APIError::APIMisuseError { err: format!("Holder selected channel  reserve below implemention limit dust_limit_satoshis {}", holder_selected_channel_reserve_satoshis) });
                }
 
@@ -690,6 +719,7 @@ impl<Signer: Sign> Channel<Signer> {
                        monitor_pending_commitment_signed: false,
                        monitor_pending_forwards: Vec::new(),
                        monitor_pending_failures: Vec::new(),
+                       monitor_pending_finalized_fulfills: Vec::new(),
 
                        #[cfg(debug_assertions)]
                        holder_max_commitment_tx_output: Mutex::new((channel_value_satoshis * 1000 - push_msat, push_msat)),
@@ -707,7 +737,7 @@ impl<Signer: Sign> Channel<Signer> {
 
                        feerate_per_kw: feerate,
                        counterparty_dust_limit_satoshis: 0,
-                       holder_dust_limit_satoshis: MIN_DUST_LIMIT_SATOSHIS,
+                       holder_dust_limit_satoshis: MIN_CHAN_DUST_LIMIT_SATOSHIS,
                        counterparty_max_htlc_value_in_flight_msat: 0,
                        counterparty_selected_channel_reserve_satoshis: None, // Filled in in accept_channel
                        counterparty_htlc_minimum_msat: 0,
@@ -748,6 +778,11 @@ impl<Signer: Sign> Channel<Signer> {
 
                        #[cfg(any(test, feature = "fuzztarget"))]
                        historical_inbound_htlc_fulfills: HashSet::new(),
+
+                       // We currently only actually support one channel type, so don't retry with new types
+                       // on error messages. When we support more we'll need fallback support (assuming we
+                       // want to support old types).
+                       channel_type: ChannelTypeFeatures::only_static_remote_key(),
                })
        }
 
@@ -776,6 +811,23 @@ impl<Signer: Sign> Channel<Signer> {
                where K::Target: KeysInterface<Signer = Signer>,
           F::Target: FeeEstimator
        {
+               // First check the channel type is known, failing before we do anything else if we don't
+               // support this channel type.
+               let channel_type = if let Some(channel_type) = &msg.channel_type {
+                       if channel_type.supports_any_optional_bits() {
+                               return Err(ChannelError::Close("Channel Type field contained optional bits - this is not allowed".to_owned()));
+                       }
+                       if *channel_type != ChannelTypeFeatures::only_static_remote_key() {
+                               return Err(ChannelError::Close("Channel Type was not understood".to_owned()));
+                       }
+                       channel_type.clone()
+               } else {
+                       ChannelTypeFeatures::from_counterparty_init(&their_features)
+               };
+               if !channel_type.supports_static_remote_key() {
+                       return Err(ChannelError::Close("Channel Type was not understood - we require static remote key".to_owned()));
+               }
+
                let holder_signer = keys_provider.get_channel_signer(true, msg.funding_satoshis);
                let pubkeys = holder_signer.pubkeys().clone();
                let counterparty_pubkeys = ChannelPublicKeys {
@@ -841,11 +893,11 @@ impl<Signer: Sign> Channel<Signer> {
                if msg.max_accepted_htlcs < config.peer_channel_config_limits.min_max_accepted_htlcs {
                        return Err(ChannelError::Close(format!("max_accepted_htlcs ({}) is less than the user specified limit ({})", msg.max_accepted_htlcs, config.peer_channel_config_limits.min_max_accepted_htlcs)));
                }
-               if msg.dust_limit_satoshis < MIN_DUST_LIMIT_SATOSHIS {
-                       return Err(ChannelError::Close(format!("dust_limit_satoshis ({}) is less than the implementation limit ({})", msg.dust_limit_satoshis, MIN_DUST_LIMIT_SATOSHIS)));
+               if msg.dust_limit_satoshis < MIN_CHAN_DUST_LIMIT_SATOSHIS {
+                       return Err(ChannelError::Close(format!("dust_limit_satoshis ({}) is less than the implementation limit ({})", msg.dust_limit_satoshis, MIN_CHAN_DUST_LIMIT_SATOSHIS)));
                }
-               if msg.dust_limit_satoshis >  MAX_DUST_LIMIT_SATOSHIS {
-                       return Err(ChannelError::Close(format!("dust_limit_satoshis ({}) is greater than the implementation limit ({})", msg.dust_limit_satoshis, MAX_DUST_LIMIT_SATOSHIS)));
+               if msg.dust_limit_satoshis >  MAX_CHAN_DUST_LIMIT_SATOSHIS {
+                       return Err(ChannelError::Close(format!("dust_limit_satoshis ({}) is greater than the implementation limit ({})", msg.dust_limit_satoshis, MAX_CHAN_DUST_LIMIT_SATOSHIS)));
                }
 
                // Convert things into internal flags and prep our state:
@@ -862,11 +914,11 @@ impl<Signer: Sign> Channel<Signer> {
                let background_feerate = fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Background);
 
                let holder_selected_channel_reserve_satoshis = Channel::<Signer>::get_holder_selected_channel_reserve_satoshis(msg.funding_satoshis);
-               if holder_selected_channel_reserve_satoshis < MIN_DUST_LIMIT_SATOSHIS {
-                       return Err(ChannelError::Close(format!("Suitable channel reserve not found. remote_channel_reserve was ({}). dust_limit_satoshis is ({}).", holder_selected_channel_reserve_satoshis, MIN_DUST_LIMIT_SATOSHIS)));
+               if holder_selected_channel_reserve_satoshis < MIN_CHAN_DUST_LIMIT_SATOSHIS {
+                       return Err(ChannelError::Close(format!("Suitable channel reserve not found. remote_channel_reserve was ({}). dust_limit_satoshis is ({}).", holder_selected_channel_reserve_satoshis, MIN_CHAN_DUST_LIMIT_SATOSHIS)));
                }
-               if msg.channel_reserve_satoshis < MIN_DUST_LIMIT_SATOSHIS {
-                       return Err(ChannelError::Close(format!("channel_reserve_satoshis ({}) is smaller than our dust limit ({})", msg.channel_reserve_satoshis, MIN_DUST_LIMIT_SATOSHIS)));
+               if msg.channel_reserve_satoshis < MIN_CHAN_DUST_LIMIT_SATOSHIS {
+                       return Err(ChannelError::Close(format!("channel_reserve_satoshis ({}) is smaller than our dust limit ({})", msg.channel_reserve_satoshis, MIN_CHAN_DUST_LIMIT_SATOSHIS)));
                }
                if holder_selected_channel_reserve_satoshis < msg.dust_limit_satoshis {
                        return Err(ChannelError::Close(format!("Dust limit ({}) too high for the channel reserve we require the remote to keep ({})", msg.dust_limit_satoshis, holder_selected_channel_reserve_satoshis)));
@@ -893,10 +945,10 @@ impl<Signer: Sign> Channel<Signer> {
                                        if script.len() == 0 {
                                                None
                                        } else {
-                                               match ShutdownScript::try_from((script.clone(), their_features)) {
-                                                       Ok(shutdown_script) => Some(shutdown_script.into_inner()),
-                                                       Err(_) => return Err(ChannelError::Close(format!("Peer is signaling upfront_shutdown but has provided an unacceptable scriptpubkey format: {}", script))),
+                                               if !script::is_bolt2_compliant(&script, their_features) {
+                                                       return Err(ChannelError::Close(format!("Peer is signaling upfront_shutdown but has provided an unacceptable scriptpubkey format: {}", script)))
                                                }
+                                               Some(script.clone())
                                        }
                                },
                                // Peer is signaling upfront shutdown but don't opt-out with correct mechanism (a.k.a 0-length script). Peer looks buggy, we fail the channel
@@ -953,6 +1005,7 @@ impl<Signer: Sign> Channel<Signer> {
                        monitor_pending_commitment_signed: false,
                        monitor_pending_forwards: Vec::new(),
                        monitor_pending_failures: Vec::new(),
+                       monitor_pending_finalized_fulfills: Vec::new(),
 
                        #[cfg(debug_assertions)]
                        holder_max_commitment_tx_output: Mutex::new((msg.push_msat, msg.funding_satoshis * 1000 - msg.push_msat)),
@@ -971,7 +1024,7 @@ impl<Signer: Sign> Channel<Signer> {
                        feerate_per_kw: msg.feerate_per_kw,
                        channel_value_satoshis: msg.funding_satoshis,
                        counterparty_dust_limit_satoshis: msg.dust_limit_satoshis,
-                       holder_dust_limit_satoshis: MIN_DUST_LIMIT_SATOSHIS,
+                       holder_dust_limit_satoshis: MIN_CHAN_DUST_LIMIT_SATOSHIS,
                        counterparty_max_htlc_value_in_flight_msat: cmp::min(msg.max_htlc_value_in_flight_msat, msg.funding_satoshis * 1000),
                        counterparty_selected_channel_reserve_satoshis: Some(msg.channel_reserve_satoshis),
                        counterparty_htlc_minimum_msat: msg.htlc_minimum_msat,
@@ -1015,6 +1068,8 @@ impl<Signer: Sign> Channel<Signer> {
 
                        #[cfg(any(test, feature = "fuzztarget"))]
                        historical_inbound_htlc_fulfills: HashSet::new(),
+
+                       channel_type,
                };
 
                Ok(chan)
@@ -1615,11 +1670,11 @@ impl<Signer: Sign> Channel<Signer> {
                if msg.max_accepted_htlcs < config.peer_channel_config_limits.min_max_accepted_htlcs {
                        return Err(ChannelError::Close(format!("max_accepted_htlcs ({}) is less than the user specified limit ({})", msg.max_accepted_htlcs, config.peer_channel_config_limits.min_max_accepted_htlcs)));
                }
-               if msg.dust_limit_satoshis < MIN_DUST_LIMIT_SATOSHIS {
-                       return Err(ChannelError::Close(format!("dust_limit_satoshis ({}) is less than the implementation limit ({})", msg.dust_limit_satoshis, MIN_DUST_LIMIT_SATOSHIS)));
+               if msg.dust_limit_satoshis < MIN_CHAN_DUST_LIMIT_SATOSHIS {
+                       return Err(ChannelError::Close(format!("dust_limit_satoshis ({}) is less than the implementation limit ({})", msg.dust_limit_satoshis, MIN_CHAN_DUST_LIMIT_SATOSHIS)));
                }
-               if msg.dust_limit_satoshis > MAX_DUST_LIMIT_SATOSHIS {
-                       return Err(ChannelError::Close(format!("dust_limit_satoshis ({}) is greater than the implementation limit ({})", msg.dust_limit_satoshis, MAX_DUST_LIMIT_SATOSHIS)));
+               if msg.dust_limit_satoshis > MAX_CHAN_DUST_LIMIT_SATOSHIS {
+                       return Err(ChannelError::Close(format!("dust_limit_satoshis ({}) is greater than the implementation limit ({})", msg.dust_limit_satoshis, MAX_CHAN_DUST_LIMIT_SATOSHIS)));
                }
                if msg.minimum_depth > config.peer_channel_config_limits.max_minimum_depth {
                        return Err(ChannelError::Close(format!("We consider the minimum depth to be unreasonably large. Expected minimum: ({}). Actual: ({})", config.peer_channel_config_limits.max_minimum_depth, msg.minimum_depth)));
@@ -1638,10 +1693,10 @@ impl<Signer: Sign> Channel<Signer> {
                                        if script.len() == 0 {
                                                None
                                        } else {
-                                               match ShutdownScript::try_from((script.clone(), their_features)) {
-                                                       Ok(shutdown_script) => Some(shutdown_script.into_inner()),
-                                                       Err(_) => return Err(ChannelError::Close(format!("Peer is signaling upfront_shutdown but has provided an unacceptable scriptpubkey format: {}", script))),
+                                               if !script::is_bolt2_compliant(&script, their_features) {
+                                                       return Err(ChannelError::Close(format!("Peer is signaling upfront_shutdown but has provided an unacceptable scriptpubkey format: {}", script)));
                                                }
+                                               Some(script.clone())
                                        }
                                },
                                // Peer is signaling upfront shutdown but don't opt-out with correct mechanism (a.k.a 0-length script). Peer looks buggy, we fail the channel
@@ -1901,6 +1956,15 @@ impl<Signer: Sign> Channel<Signer> {
                Ok(())
        }
 
+       /// Returns transaction if there is pending funding transaction that is yet to broadcast
+       pub fn unbroadcasted_funding(&self) -> Option<Transaction> {
+                if self.channel_state & (ChannelState::FundingCreated as u32) != 0 {
+                        self.funding_transaction.clone()
+                } else {
+                        None
+                }
+       }
+
        /// Returns a HTLCStats about inbound pending htlcs
        fn get_inbound_pending_htlc_stats(&self) -> HTLCStats {
                let mut stats = HTLCStats {
@@ -2700,7 +2764,7 @@ impl<Signer: Sign> Channel<Signer> {
        /// waiting on this revoke_and_ack. The generation of this new commitment_signed may also fail,
        /// generating an appropriate error *after* the channel state has been updated based on the
        /// revoke_and_ack message.
-       pub fn revoke_and_ack<L: Deref>(&mut self, msg: &msgs::RevokeAndACK, logger: &L) -> Result<(Option<msgs::CommitmentUpdate>, Vec<(PendingHTLCInfo, u64)>, Vec<(HTLCSource, PaymentHash, HTLCFailReason)>, ChannelMonitorUpdate, Vec<(HTLCSource, PaymentHash)>), ChannelError>
+       pub fn revoke_and_ack<L: Deref>(&mut self, msg: &msgs::RevokeAndACK, logger: &L) -> Result<RAAUpdates, ChannelError>
                where L::Target: Logger,
        {
                if (self.channel_state & (ChannelState::ChannelFunded as u32)) != (ChannelState::ChannelFunded as u32) {
@@ -2766,6 +2830,7 @@ impl<Signer: Sign> Channel<Signer> {
                log_trace!(logger, "Updating HTLCs on receipt of RAA in channel {}...", log_bytes!(self.channel_id()));
                let mut to_forward_infos = Vec::new();
                let mut revoked_htlcs = Vec::new();
+               let mut finalized_claimed_htlcs = Vec::new();
                let mut update_fail_htlcs = Vec::new();
                let mut update_fail_malformed_htlcs = Vec::new();
                let mut require_commitment = false;
@@ -2792,6 +2857,7 @@ impl<Signer: Sign> Channel<Signer> {
                                        if let Some(reason) = fail_reason.clone() { // We really want take() here, but, again, non-mut ref :(
                                                revoked_htlcs.push((htlc.source.clone(), htlc.payment_hash, reason));
                                        } else {
+                                               finalized_claimed_htlcs.push(htlc.source.clone());
                                                // They fulfilled, so we sent them money
                                                value_to_self_msat_diff -= htlc.amount_msat as i64;
                                        }
@@ -2888,8 +2954,14 @@ impl<Signer: Sign> Channel<Signer> {
                        }
                        self.monitor_pending_forwards.append(&mut to_forward_infos);
                        self.monitor_pending_failures.append(&mut revoked_htlcs);
+                       self.monitor_pending_finalized_fulfills.append(&mut finalized_claimed_htlcs);
                        log_debug!(logger, "Received a valid revoke_and_ack for channel {} but awaiting a monitor update resolution to reply.", log_bytes!(self.channel_id()));
-                       return Ok((None, Vec::new(), Vec::new(), monitor_update, Vec::new()))
+                       return Ok(RAAUpdates {
+                               commitment_update: None, finalized_claimed_htlcs: Vec::new(),
+                               accepted_htlcs: Vec::new(), failed_htlcs: Vec::new(),
+                               monitor_update,
+                               holding_cell_failed_htlcs: Vec::new()
+                       });
                }
 
                match self.free_holding_cell_htlcs(logger)? {
@@ -2908,7 +2980,14 @@ impl<Signer: Sign> Channel<Signer> {
                                self.latest_monitor_update_id = monitor_update.update_id;
                                monitor_update.updates.append(&mut additional_update.updates);
 
-                               Ok((Some(commitment_update), to_forward_infos, revoked_htlcs, monitor_update, htlcs_to_fail))
+                               Ok(RAAUpdates {
+                                       commitment_update: Some(commitment_update),
+                                       finalized_claimed_htlcs,
+                                       accepted_htlcs: to_forward_infos,
+                                       failed_htlcs: revoked_htlcs,
+                                       monitor_update,
+                                       holding_cell_failed_htlcs: htlcs_to_fail
+                               })
                        },
                        (None, htlcs_to_fail) => {
                                if require_commitment {
@@ -2921,17 +3000,27 @@ impl<Signer: Sign> Channel<Signer> {
 
                                        log_debug!(logger, "Received a valid revoke_and_ack for channel {}. Responding with a commitment update with {} HTLCs failed.",
                                                log_bytes!(self.channel_id()), update_fail_htlcs.len() + update_fail_malformed_htlcs.len());
-                                       Ok((Some(msgs::CommitmentUpdate {
-                                               update_add_htlcs: Vec::new(),
-                                               update_fulfill_htlcs: Vec::new(),
-                                               update_fail_htlcs,
-                                               update_fail_malformed_htlcs,
-                                               update_fee: None,
-                                               commitment_signed
-                                       }), to_forward_infos, revoked_htlcs, monitor_update, htlcs_to_fail))
+                                       Ok(RAAUpdates {
+                                               commitment_update: Some(msgs::CommitmentUpdate {
+                                                       update_add_htlcs: Vec::new(),
+                                                       update_fulfill_htlcs: Vec::new(),
+                                                       update_fail_htlcs,
+                                                       update_fail_malformed_htlcs,
+                                                       update_fee: None,
+                                                       commitment_signed
+                                               }),
+                                               finalized_claimed_htlcs,
+                                               accepted_htlcs: to_forward_infos, failed_htlcs: revoked_htlcs,
+                                               monitor_update, holding_cell_failed_htlcs: htlcs_to_fail
+                                       })
                                } else {
                                        log_debug!(logger, "Received a valid revoke_and_ack for channel {} with no reply necessary.", log_bytes!(self.channel_id()));
-                                       Ok((None, to_forward_infos, revoked_htlcs, monitor_update, htlcs_to_fail))
+                                       Ok(RAAUpdates {
+                                               commitment_update: None,
+                                               finalized_claimed_htlcs,
+                                               accepted_htlcs: to_forward_infos, failed_htlcs: revoked_htlcs,
+                                               monitor_update, holding_cell_failed_htlcs: htlcs_to_fail
+                                       })
                                }
                        }
                }
@@ -3046,18 +3135,23 @@ impl<Signer: Sign> Channel<Signer> {
        /// which failed. The messages which were generated from that call which generated the
        /// monitor update failure must *not* have been sent to the remote end, and must instead
        /// have been dropped. They will be regenerated when monitor_updating_restored is called.
-       pub fn monitor_update_failed(&mut self, resend_raa: bool, resend_commitment: bool, mut pending_forwards: Vec<(PendingHTLCInfo, u64)>, mut pending_fails: Vec<(HTLCSource, PaymentHash, HTLCFailReason)>) {
+       pub fn monitor_update_failed(&mut self, resend_raa: bool, resend_commitment: bool,
+               mut pending_forwards: Vec<(PendingHTLCInfo, u64)>,
+               mut pending_fails: Vec<(HTLCSource, PaymentHash, HTLCFailReason)>,
+               mut pending_finalized_claimed_htlcs: Vec<HTLCSource>
+       ) {
                self.monitor_pending_revoke_and_ack |= resend_raa;
                self.monitor_pending_commitment_signed |= resend_commitment;
                self.monitor_pending_forwards.append(&mut pending_forwards);
                self.monitor_pending_failures.append(&mut pending_fails);
+               self.monitor_pending_finalized_fulfills.append(&mut pending_finalized_claimed_htlcs);
                self.channel_state |= ChannelState::MonitorUpdateFailed as u32;
        }
 
        /// Indicates that the latest ChannelMonitor update has been committed by the client
        /// successfully and we should restore normal operation. Returns messages which should be sent
        /// to the remote side.
-       pub fn monitor_updating_restored<L: Deref>(&mut self, logger: &L) -> (Option<msgs::RevokeAndACK>, Option<msgs::CommitmentUpdate>, RAACommitmentOrder, Vec<(PendingHTLCInfo, u64)>, Vec<(HTLCSource, PaymentHash, HTLCFailReason)>, Option<Transaction>, Option<msgs::FundingLocked>) where L::Target: Logger {
+       pub fn monitor_updating_restored<L: Deref>(&mut self, logger: &L) -> MonitorRestoreUpdates where L::Target: Logger {
                assert_eq!(self.channel_state & ChannelState::MonitorUpdateFailed as u32, ChannelState::MonitorUpdateFailed as u32);
                self.channel_state &= !(ChannelState::MonitorUpdateFailed as u32);
 
@@ -3080,15 +3174,20 @@ impl<Signer: Sign> Channel<Signer> {
                        })
                } else { None };
 
-               let mut forwards = Vec::new();
-               mem::swap(&mut forwards, &mut self.monitor_pending_forwards);
-               let mut failures = Vec::new();
-               mem::swap(&mut failures, &mut self.monitor_pending_failures);
+               let mut accepted_htlcs = Vec::new();
+               mem::swap(&mut accepted_htlcs, &mut self.monitor_pending_forwards);
+               let mut failed_htlcs = Vec::new();
+               mem::swap(&mut failed_htlcs, &mut self.monitor_pending_failures);
+               let mut finalized_claimed_htlcs = Vec::new();
+               mem::swap(&mut finalized_claimed_htlcs, &mut self.monitor_pending_finalized_fulfills);
 
                if self.channel_state & (ChannelState::PeerDisconnected as u32) != 0 {
                        self.monitor_pending_revoke_and_ack = false;
                        self.monitor_pending_commitment_signed = false;
-                       return (None, None, RAACommitmentOrder::RevokeAndACKFirst, forwards, failures, funding_broadcastable, funding_locked);
+                       return MonitorRestoreUpdates {
+                               raa: None, commitment_update: None, order: RAACommitmentOrder::RevokeAndACKFirst,
+                               accepted_htlcs, failed_htlcs, finalized_claimed_htlcs, funding_broadcastable, funding_locked
+                       };
                }
 
                let raa = if self.monitor_pending_revoke_and_ack {
@@ -3105,7 +3204,9 @@ impl<Signer: Sign> Channel<Signer> {
                        log_bytes!(self.channel_id()), if funding_broadcastable.is_some() { "a funding broadcastable, " } else { "" },
                        if commitment_update.is_some() { "a" } else { "no" }, if raa.is_some() { "an" } else { "no" },
                        match order { RAACommitmentOrder::CommitmentFirst => "commitment", RAACommitmentOrder::RevokeAndACKFirst => "RAA"});
-               (raa, commitment_update, order, forwards, failures, funding_broadcastable, funding_locked)
+               MonitorRestoreUpdates {
+                       raa, commitment_update, order, accepted_htlcs, failed_htlcs, finalized_claimed_htlcs, funding_broadcastable, funding_locked
+               }
        }
 
        pub fn update_fee<F: Deref>(&mut self, fee_estimator: &F, msg: &msgs::UpdateFee) -> Result<(), ChannelError>
@@ -3491,17 +3592,16 @@ impl<Signer: Sign> Channel<Signer> {
                }
                assert_eq!(self.channel_state & ChannelState::ShutdownComplete as u32, 0);
 
-               let shutdown_scriptpubkey = match ShutdownScript::try_from((msg.scriptpubkey.clone(), their_features)) {
-                       Ok(script) => script.into_inner(),
-                       Err(_) => return Err(ChannelError::Close(format!("Got a nonstandard scriptpubkey ({}) from remote peer", msg.scriptpubkey.to_bytes().to_hex()))),
-               };
+               if !script::is_bolt2_compliant(&msg.scriptpubkey, their_features) {
+                       return Err(ChannelError::Close(format!("Got a nonstandard scriptpubkey ({}) from remote peer", msg.scriptpubkey.to_bytes().to_hex())));
+               }
 
                if self.counterparty_shutdown_scriptpubkey.is_some() {
-                       if Some(&shutdown_scriptpubkey) != self.counterparty_shutdown_scriptpubkey.as_ref() {
-                               return Err(ChannelError::Close(format!("Got shutdown request with a scriptpubkey ({}) which did not match their previous scriptpubkey.", shutdown_scriptpubkey.to_bytes().to_hex())));
+                       if Some(&msg.scriptpubkey) != self.counterparty_shutdown_scriptpubkey.as_ref() {
+                               return Err(ChannelError::Close(format!("Got shutdown request with a scriptpubkey ({}) which did not match their previous scriptpubkey.", msg.scriptpubkey.to_bytes().to_hex())));
                        }
                } else {
-                       self.counterparty_shutdown_scriptpubkey = Some(shutdown_scriptpubkey);
+                       self.counterparty_shutdown_scriptpubkey = Some(msg.scriptpubkey.clone());
                }
 
                // If we have any LocalAnnounced updates we'll probably just get back an update_fail_htlc
@@ -3628,6 +3728,12 @@ impl<Signer: Sign> Channel<Signer> {
                        },
                };
 
+               for outp in closing_tx.trust().built_transaction().output.iter() {
+                       if !outp.script_pubkey.is_witness_program() && outp.value < MAX_STD_OUTPUT_DUST_LIMIT_SATOSHIS {
+                               return Err(ChannelError::Close("Remote sent us a closing_signed with a dust output. Always use segwit closing scripts!".to_owned()));
+                       }
+               }
+
                assert!(self.shutdown_scriptpubkey.is_some());
                if let Some((last_fee, sig)) = self.last_sent_closing_fee {
                        if last_fee == msg.fee_satoshis {
@@ -4204,6 +4310,7 @@ impl<Signer: Sign> Channel<Signer> {
                                Some(script) => script.clone().into_inner(),
                                None => Builder::new().into_script(),
                        }),
+                       channel_type: Some(self.channel_type.clone()),
                }
        }
 
@@ -5160,6 +5267,8 @@ impl<Signer: Sign> Writeable for Channel<Signer> {
                        (5, self.config, required),
                        (7, self.shutdown_scriptpubkey, option),
                        (9, self.target_closing_feerate_sats_per_kw, option),
+                       (11, self.monitor_pending_finalized_fulfills, vec_type),
+                       (13, self.channel_type, required),
                });
 
                Ok(())
@@ -5393,6 +5502,10 @@ impl<'a, Signer: Sign, K: Deref> ReadableArgs<&'a K> for Channel<Signer>
 
                let mut announcement_sigs = None;
                let mut target_closing_feerate_sats_per_kw = None;
+               let mut monitor_pending_finalized_fulfills = Some(Vec::new());
+               // Prior to supporting channel type negotiation, all of our channels were static_remotekey
+               // only, so we default to that if none was written.
+               let mut channel_type = Some(ChannelTypeFeatures::only_static_remote_key());
                read_tlv_fields!(reader, {
                        (0, announcement_sigs, option),
                        (1, minimum_depth, option),
@@ -5400,8 +5513,17 @@ impl<'a, Signer: Sign, K: Deref> ReadableArgs<&'a K> for Channel<Signer>
                        (5, config, option), // Note that if none is provided we will *not* overwrite the existing one.
                        (7, shutdown_scriptpubkey, option),
                        (9, target_closing_feerate_sats_per_kw, option),
+                       (11, monitor_pending_finalized_fulfills, vec_type),
+                       (13, channel_type, option),
                });
 
+               let chan_features = channel_type.as_ref().unwrap();
+               if chan_features.supports_unknown_bits() || chan_features.requires_unknown_bits() {
+                       // If the channel was written by a new version and negotiated with features we don't
+                       // understand yet, refuse to read it.
+                       return Err(DecodeError::UnknownRequiredFeature);
+               }
+
                let mut secp_ctx = Secp256k1::new();
                secp_ctx.seeded_randomize(&keys_source.get_secure_random_bytes());
 
@@ -5435,6 +5557,7 @@ impl<'a, Signer: Sign, K: Deref> ReadableArgs<&'a K> for Channel<Signer>
                        monitor_pending_commitment_signed,
                        monitor_pending_forwards,
                        monitor_pending_failures,
+                       monitor_pending_finalized_fulfills: monitor_pending_finalized_fulfills.unwrap(),
 
                        pending_update_fee,
                        holding_cell_update_fee,
@@ -5493,6 +5616,8 @@ impl<'a, Signer: Sign, K: Deref> ReadableArgs<&'a K> for Channel<Signer>
 
                        #[cfg(any(test, feature = "fuzztarget"))]
                        historical_inbound_htlc_fulfills,
+
+                       channel_type: channel_type.unwrap(),
                })
        }
 }
@@ -5684,6 +5809,8 @@ mod tests {
                                session_priv: SecretKey::from_slice(&hex::decode("0fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff").unwrap()[..]).unwrap(),
                                first_hop_htlc_msat: 548,
                                payment_id: PaymentId([42; 32]),
+                               payment_secret: None,
+                               payee: None,
                        }
                });