Merge pull request #3086 from alecchendev/2024-05-holder-commitment
[rust-lightning] / lightning / src / ln / channel.rs
index 2d72082432443cbe35ab1b7003b8e80d708c4c78..d6ab1876ae0a31af8dfacc5bac01e35ed438e008 100644 (file)
@@ -7,6 +7,7 @@
 // You may not use this file except in accordance with one or both of these
 // licenses.
 
+use bitcoin::amount::Amount;
 use bitcoin::blockdata::constants::ChainHash;
 use bitcoin::blockdata::script::{Script, ScriptBuf, Builder};
 use bitcoin::blockdata::transaction::Transaction;
@@ -24,12 +25,13 @@ use bitcoin::secp256k1::{PublicKey,SecretKey};
 use bitcoin::secp256k1::{Secp256k1,ecdsa::Signature};
 use bitcoin::secp256k1;
 
-use crate::ln::{ChannelId, PaymentPreimage, PaymentHash};
+use crate::ln::types::{ChannelId, PaymentPreimage, PaymentHash};
 use crate::ln::features::{ChannelTypeFeatures, InitFeatures};
 use crate::ln::msgs;
 use crate::ln::msgs::DecodeError;
 use crate::ln::script::{self, ShutdownScript};
-use crate::ln::channelmanager::{self, CounterpartyForwardingInfo, PendingHTLCStatus, HTLCSource, SentHTLCId, HTLCFailureMsg, PendingHTLCInfo, RAACommitmentOrder, BREAKDOWN_TIMEOUT, MIN_CLTV_EXPIRY_DELTA, MAX_LOCAL_BREAKDOWN_TIMEOUT, ChannelShutdownState};
+use crate::ln::channel_state::{ChannelShutdownState, CounterpartyForwardingInfo, InboundHTLCDetails, InboundHTLCStateDetails, OutboundHTLCDetails, OutboundHTLCStateDetails};
+use crate::ln::channelmanager::{self, PendingHTLCStatus, HTLCSource, SentHTLCId, HTLCFailureMsg, PendingHTLCInfo, RAACommitmentOrder, BREAKDOWN_TIMEOUT, MIN_CLTV_EXPIRY_DELTA, MAX_LOCAL_BREAKDOWN_TIMEOUT};
 use crate::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 crate::ln::chan_utils;
 use crate::ln::onion_utils::HTLCFailReason;
@@ -37,7 +39,7 @@ use crate::chain::BestBlock;
 use crate::chain::chaininterface::{FeeEstimator, ConfirmationTarget, LowerBoundedFeeEstimator};
 use crate::chain::channelmonitor::{ChannelMonitor, ChannelMonitorUpdate, ChannelMonitorUpdateStep, LATENCY_GRACE_PERIOD_BLOCKS, CLOSED_CHANNEL_UPDATE_ID};
 use crate::chain::transaction::{OutPoint, TransactionData};
-use crate::sign::ecdsa::{EcdsaChannelSigner, WriteableEcdsaChannelSigner};
+use crate::sign::ecdsa::EcdsaChannelSigner;
 use crate::sign::{EntropySource, ChannelSigner, SignerProvider, NodeSigner, Recipient};
 use crate::events::ClosureReason;
 use crate::routing::gossip::NodeId;
@@ -50,7 +52,6 @@ use crate::util::scid_utils::scid_from_parts;
 use crate::io;
 use crate::prelude::*;
 use core::{cmp,mem,fmt};
-use core::convert::TryInto;
 use core::ops::Deref;
 #[cfg(any(test, fuzzing, debug_assertions))]
 use crate::sync::Mutex;
@@ -104,10 +105,38 @@ enum InboundHTLCRemovalReason {
        Fulfill(PaymentPreimage),
 }
 
+/// Represents the resolution status of an inbound HTLC.
+#[derive(Clone)]
+enum InboundHTLCResolution {
+       /// Resolved implies the action we must take with the inbound HTLC has already been determined,
+       /// i.e., we already know whether it must be failed back or forwarded.
+       //
+       // TODO: Once this variant is removed, we should also clean up
+       // [`MonitorRestoreUpdates::accepted_htlcs`] as the path will be unreachable.
+       Resolved {
+               pending_htlc_status: PendingHTLCStatus,
+       },
+       /// Pending implies we will attempt to resolve the inbound HTLC once it has been fully committed
+       /// to by both sides of the channel, i.e., once a `revoke_and_ack` has been processed by both
+       /// nodes for the state update in which it was proposed.
+       Pending {
+               update_add_htlc: msgs::UpdateAddHTLC,
+       },
+}
+
+impl_writeable_tlv_based_enum!(InboundHTLCResolution,
+       (0, Resolved) => {
+               (0, pending_htlc_status, required),
+       },
+       (2, Pending) => {
+               (0, update_add_htlc, required),
+       };
+);
+
 enum InboundHTLCState {
        /// Offered by remote, to be included in next local commitment tx. I.e., the remote sent an
        /// update_add_htlc message for this HTLC.
-       RemoteAnnounced(PendingHTLCStatus),
+       RemoteAnnounced(InboundHTLCResolution),
        /// Included in a received commitment_signed message (implying we've
        /// revoke_and_ack'd it), but the remote hasn't yet revoked their previous
        /// state (see the example below). We have not yet included this HTLC in a
@@ -137,13 +166,13 @@ enum InboundHTLCState {
        /// Implies AwaitingRemoteRevoke.
        ///
        /// [BOLT #2]: https://github.com/lightning/bolts/blob/master/02-peer-protocol.md
-       AwaitingRemoteRevokeToAnnounce(PendingHTLCStatus),
+       AwaitingRemoteRevokeToAnnounce(InboundHTLCResolution),
        /// Included in a received commitment_signed message (implying we've revoke_and_ack'd it).
        /// We have also included this HTLC in our latest commitment_signed and are now just waiting
        /// on the remote's revoke_and_ack to make this HTLC an irrevocable part of the state of the
        /// channel (before it can then get forwarded and/or removed).
        /// Implies AwaitingRemoteRevoke.
-       AwaitingAnnouncedRemoteRevoke(PendingHTLCStatus),
+       AwaitingAnnouncedRemoteRevoke(InboundHTLCResolution),
        Committed,
        /// Removed by us and a new commitment_signed was sent (if we were AwaitingRemoteRevoke when we
        /// created it we would have put it in the holding cell instead). When they next revoke_and_ack
@@ -158,45 +187,6 @@ enum InboundHTLCState {
        LocalRemoved(InboundHTLCRemovalReason),
 }
 
-/// Exposes the state of pending inbound HTLCs.
-///
-/// At a high level, an HTLC being forwarded from one Lightning node to another Lightning node goes
-/// through the following states in the state machine:
-/// - Announced for addition by the originating node through the update_add_htlc message.
-/// - Added to the commitment transaction of the receiving node and originating node in turn
-///   through the exchange of commitment_signed and revoke_and_ack messages.
-/// - Announced for resolution (fulfillment or failure) by the receiving node through either one of
-///   the update_fulfill_htlc, update_fail_htlc, and update_fail_malformed_htlc messages.
-/// - Removed from the commitment transaction of the originating node and receiving node in turn
-///   through the exchange of commitment_signed and revoke_and_ack messages.
-///
-/// This can be used to inspect what next message an HTLC is waiting for to advance its state.
-#[derive(Clone, Debug, PartialEq)]
-pub enum InboundHTLCStateDetails {
-       /// We have added this HTLC in our commitment transaction by receiving commitment_signed and
-       /// returning revoke_and_ack. We are awaiting the appropriate revoke_and_ack's from the remote
-       /// before this HTLC is included on the remote commitment transaction.
-       AwaitingRemoteRevokeToAdd,
-       /// This HTLC has been included in the commitment_signed and revoke_and_ack messages on both sides
-       /// and is included in both commitment transactions.
-       ///
-       /// This HTLC is now safe to either forward or be claimed as a payment by us. The HTLC will
-       /// remain in this state until the forwarded upstream HTLC has been resolved and we resolve this
-       /// HTLC correspondingly, or until we claim it as a payment. If it is part of a multipart
-       /// payment, it will only be claimed together with other required parts.
-       Committed,
-       /// We have received the preimage for this HTLC and it is being removed by fulfilling it with
-       /// update_fulfill_htlc. This HTLC is still on both commitment transactions, but we are awaiting
-       /// the appropriate revoke_and_ack's from the remote before this HTLC is removed from the remote
-       /// commitment transaction after update_fulfill_htlc.
-       AwaitingRemoteRevokeToRemoveFulfill,
-       /// The HTLC is being removed by failing it with update_fail_htlc or update_fail_malformed_htlc.
-       /// This HTLC is still on both commitment transactions, but we are awaiting the appropriate
-       /// revoke_and_ack's from the remote before this HTLC is removed from the remote commitment
-       /// transaction.
-       AwaitingRemoteRevokeToRemoveFail,
-}
-
 impl From<&InboundHTLCState> for Option<InboundHTLCStateDetails> {
        fn from(state: &InboundHTLCState) -> Option<InboundHTLCStateDetails> {
                match state {
@@ -217,13 +207,6 @@ impl From<&InboundHTLCState> for Option<InboundHTLCStateDetails> {
        }
 }
 
-impl_writeable_tlv_based_enum_upgradable!(InboundHTLCStateDetails,
-       (0, AwaitingRemoteRevokeToAdd) => {},
-       (2, Committed) => {},
-       (4, AwaitingRemoteRevokeToRemoveFulfill) => {},
-       (6, AwaitingRemoteRevokeToRemoveFail) => {};
-);
-
 struct InboundHTLCOutput {
        htlc_id: u64,
        amount_msat: u64,
@@ -232,53 +215,6 @@ struct InboundHTLCOutput {
        state: InboundHTLCState,
 }
 
-/// Exposes details around pending inbound HTLCs.
-#[derive(Clone, Debug, PartialEq)]
-pub struct InboundHTLCDetails {
-       /// The HTLC ID.
-       /// The IDs are incremented by 1 starting from 0 for each offered HTLC.
-       /// They are unique per channel and inbound/outbound direction, unless an HTLC was only announced
-       /// and not part of any commitment transaction.
-       pub htlc_id: u64,
-       /// The amount in msat.
-       pub amount_msat: u64,
-       /// The block height at which this HTLC expires.
-       pub cltv_expiry: u32,
-       /// The payment hash.
-       pub payment_hash: PaymentHash,
-       /// The state of the HTLC in the state machine.
-       ///
-       /// Determines on which commitment transactions the HTLC is included and what message the HTLC is
-       /// waiting for to advance to the next state.
-       ///
-       /// See [`InboundHTLCStateDetails`] for information on the specific states.
-       ///
-       /// LDK will always fill this field in, but when downgrading to prior versions of LDK, new
-       /// states may result in `None` here.
-       pub state: Option<InboundHTLCStateDetails>,
-       /// Whether the HTLC has an output below the local dust limit. If so, the output will be trimmed
-       /// from the local commitment transaction and added to the commitment transaction fee.
-       /// For non-anchor channels, this takes into account the cost of the second-stage HTLC
-       /// transactions as well.
-       ///
-       /// When the local commitment transaction is broadcasted as part of a unilateral closure,
-       /// the value of this HTLC will therefore not be claimable but instead burned as a transaction
-       /// fee.
-       ///
-       /// Note that dust limits are specific to each party. An HTLC can be dust for the local
-       /// commitment transaction but not for the counterparty's commitment transaction and vice versa.
-       pub is_dust: bool,
-}
-
-impl_writeable_tlv_based!(InboundHTLCDetails, {
-       (0, htlc_id, required),
-       (2, amount_msat, required),
-       (4, cltv_expiry, required),
-       (6, payment_hash, required),
-       (7, state, upgradable_option),
-       (8, is_dust, required),
-});
-
 #[cfg_attr(test, derive(Clone, Debug, PartialEq))]
 enum OutboundHTLCState {
        /// Added by us and included in a commitment_signed (if we were AwaitingRemoteRevoke when we
@@ -312,42 +248,6 @@ enum OutboundHTLCState {
        AwaitingRemovedRemoteRevoke(OutboundHTLCOutcome),
 }
 
-/// Exposes the state of pending outbound HTLCs.
-///
-/// At a high level, an HTLC being forwarded from one Lightning node to another Lightning node goes
-/// through the following states in the state machine:
-/// - Announced for addition by the originating node through the update_add_htlc message.
-/// - Added to the commitment transaction of the receiving node and originating node in turn
-///   through the exchange of commitment_signed and revoke_and_ack messages.
-/// - Announced for resolution (fulfillment or failure) by the receiving node through either one of
-///   the update_fulfill_htlc, update_fail_htlc, and update_fail_malformed_htlc messages.
-/// - Removed from the commitment transaction of the originating node and receiving node in turn
-///   through the exchange of commitment_signed and revoke_and_ack messages.
-///
-/// This can be used to inspect what next message an HTLC is waiting for to advance its state.
-#[derive(Clone, Debug, PartialEq)]
-pub enum OutboundHTLCStateDetails {
-       /// We are awaiting the appropriate revoke_and_ack's from the remote before the HTLC is added
-       /// on the remote's commitment transaction after update_add_htlc.
-       AwaitingRemoteRevokeToAdd,
-       /// The HTLC has been added to the remote's commitment transaction by sending commitment_signed
-       /// and receiving revoke_and_ack in return.
-       ///
-       /// The HTLC will remain in this state until the remote node resolves the HTLC, or until we
-       /// unilaterally close the channel due to a timeout with an uncooperative remote node.
-       Committed,
-       /// The HTLC has been fulfilled successfully by the remote with a preimage in update_fulfill_htlc,
-       /// and we removed the HTLC from our commitment transaction by receiving commitment_signed and
-       /// returning revoke_and_ack. We are awaiting the appropriate revoke_and_ack's from the remote
-       /// for the removal from its commitment transaction.
-       AwaitingRemoteRevokeToRemoveSuccess,
-       /// The HTLC has been failed by the remote with update_fail_htlc or update_fail_malformed_htlc,
-       /// and we removed the HTLC from our commitment transaction by receiving commitment_signed and
-       /// returning revoke_and_ack. We are awaiting the appropriate revoke_and_ack's from the remote
-       /// for the removal from its commitment transaction.
-       AwaitingRemoteRevokeToRemoveFailure,
-}
-
 impl From<&OutboundHTLCState> for OutboundHTLCStateDetails {
        fn from(state: &OutboundHTLCState) -> OutboundHTLCStateDetails {
                match state {
@@ -371,13 +271,6 @@ impl From<&OutboundHTLCState> for OutboundHTLCStateDetails {
        }
 }
 
-impl_writeable_tlv_based_enum_upgradable!(OutboundHTLCStateDetails,
-       (0, AwaitingRemoteRevokeToAdd) => {},
-       (2, Committed) => {},
-       (4, AwaitingRemoteRevokeToRemoveSuccess) => {},
-       (6, AwaitingRemoteRevokeToRemoveFailure) => {};
-);
-
 #[derive(Clone)]
 #[cfg_attr(test, derive(Debug, PartialEq))]
 enum OutboundHTLCOutcome {
@@ -416,58 +309,6 @@ struct OutboundHTLCOutput {
        skimmed_fee_msat: Option<u64>,
 }
 
-/// Exposes details around pending outbound HTLCs.
-#[derive(Clone, Debug, PartialEq)]
-pub struct OutboundHTLCDetails {
-       /// The HTLC ID.
-       /// The IDs are incremented by 1 starting from 0 for each offered HTLC.
-       /// They are unique per channel and inbound/outbound direction, unless an HTLC was only announced
-       /// and not part of any commitment transaction.
-       ///
-       /// Not present when we are awaiting a remote revocation and the HTLC is not added yet.
-       pub htlc_id: Option<u64>,
-       /// The amount in msat.
-       pub amount_msat: u64,
-       /// The block height at which this HTLC expires.
-       pub cltv_expiry: u32,
-       /// The payment hash.
-       pub payment_hash: PaymentHash,
-       /// The state of the HTLC in the state machine.
-       ///
-       /// Determines on which commitment transactions the HTLC is included and what message the HTLC is
-       /// waiting for to advance to the next state.
-       ///
-       /// See [`OutboundHTLCStateDetails`] for information on the specific states.
-       ///
-       /// LDK will always fill this field in, but when downgrading to prior versions of LDK, new
-       /// states may result in `None` here.
-       pub state: Option<OutboundHTLCStateDetails>,
-       /// The extra fee being skimmed off the top of this HTLC.
-       pub skimmed_fee_msat: Option<u64>,
-       /// Whether the HTLC has an output below the local dust limit. If so, the output will be trimmed
-       /// from the local commitment transaction and added to the commitment transaction fee.
-       /// For non-anchor channels, this takes into account the cost of the second-stage HTLC
-       /// transactions as well.
-       ///
-       /// When the local commitment transaction is broadcasted as part of a unilateral closure,
-       /// the value of this HTLC will therefore not be claimable but instead burned as a transaction
-       /// fee.
-       ///
-       /// Note that dust limits are specific to each party. An HTLC can be dust for the local
-       /// commitment transaction but not for the counterparty's commitment transaction and vice versa.
-       pub is_dust: bool,
-}
-
-impl_writeable_tlv_based!(OutboundHTLCDetails, {
-       (0, htlc_id, required),
-       (2, amount_msat, required),
-       (4, cltv_expiry, required),
-       (6, payment_hash, required),
-       (7, state, upgradable_option),
-       (8, skimmed_fee_msat, required),
-       (10, is_dust, required),
-});
-
 /// See AwaitingRemoteRevoke ChannelState for more info
 #[cfg_attr(test, derive(Clone, Debug, PartialEq))]
 enum HTLCUpdateAwaitingACK {
@@ -896,25 +737,28 @@ pub(super) struct WithChannelContext<'a, L: Deref> where L::Target: Logger {
        pub logger: &'a L,
        pub peer_id: Option<PublicKey>,
        pub channel_id: Option<ChannelId>,
+       pub payment_hash: Option<PaymentHash>,
 }
 
 impl<'a, L: Deref> Logger for WithChannelContext<'a, L> where L::Target: Logger {
        fn log(&self, mut record: Record) {
                record.peer_id = self.peer_id;
                record.channel_id = self.channel_id;
+               record.payment_hash = self.payment_hash;
                self.logger.log(record)
        }
 }
 
 impl<'a, 'b, L: Deref> WithChannelContext<'a, L>
 where L::Target: Logger {
-       pub(super) fn from<S: Deref>(logger: &'a L, context: &'b ChannelContext<S>) -> Self
+       pub(super) fn from<S: Deref>(logger: &'a L, context: &'b ChannelContext<S>, payment_hash: Option<PaymentHash>) -> Self
        where S::Target: SignerProvider
        {
                WithChannelContext {
                        logger,
                        peer_id: Some(context.counterparty_node_id),
                        channel_id: Some(context.channel_id),
+                       payment_hash
                }
        }
 }
@@ -971,14 +815,16 @@ enum HTLCInitiator {
        RemoteOffered,
 }
 
-/// An enum gathering stats on pending HTLCs, either inbound or outbound side.
+/// Current counts of various HTLCs, useful for calculating current balances available exactly.
 struct HTLCStats {
-       pending_htlcs: u32,
-       pending_htlcs_value_msat: u64,
+       pending_inbound_htlcs: usize,
+       pending_outbound_htlcs: usize,
+       pending_inbound_htlcs_value_msat: u64,
+       pending_outbound_htlcs_value_msat: u64,
        on_counterparty_tx_dust_exposure_msat: u64,
        on_holder_tx_dust_exposure_msat: u64,
-       holding_cell_msat: u64,
-       on_holder_tx_holding_cell_htlcs_count: u32, // dust HTLCs *non*-included
+       outbound_holding_cell_msat: u64,
+       on_holder_tx_outbound_holding_cell_htlcs_count: u32, // dust HTLCs *non*-included
 }
 
 /// An enum gathering stats on commitment transaction, either local or remote.
@@ -1044,6 +890,7 @@ pub(super) struct MonitorRestoreUpdates {
        pub accepted_htlcs: Vec<(PendingHTLCInfo, u64)>,
        pub failed_htlcs: Vec<(HTLCSource, PaymentHash, HTLCFailReason)>,
        pub finalized_claimed_htlcs: Vec<HTLCSource>,
+       pub pending_update_adds: Vec<msgs::UpdateAddHTLC>,
        pub funding_broadcastable: Option<Transaction>,
        pub channel_ready: Option<msgs::ChannelReady>,
        pub announcement_sigs: Option<msgs::AnnouncementSignatures>,
@@ -1086,6 +933,75 @@ pub(crate) struct ShutdownResult {
        pub(crate) channel_funding_txo: Option<OutPoint>,
 }
 
+/// Tracks the transaction number, along with current and next commitment points.
+/// This consolidates the logic to advance our commitment number and request new
+/// commitment points from our signer.
+#[derive(Debug, Copy, Clone)]
+enum HolderCommitmentPoint {
+       // TODO: add a variant for before our first commitment point is retrieved
+       /// We've advanced our commitment number and are waiting on the next commitment point.
+       /// Until the `get_per_commitment_point` signer method becomes async, this variant
+       /// will not be used.
+       PendingNext { transaction_number: u64, current: PublicKey },
+       /// Our current commitment point is ready, we've cached our next point,
+       /// and we are not pending a new one.
+       Available { transaction_number: u64, current: PublicKey, next: PublicKey },
+}
+
+impl HolderCommitmentPoint {
+       pub fn new<SP: Deref>(signer: &ChannelSignerType<SP>, secp_ctx: &Secp256k1<secp256k1::All>) -> Self
+               where SP::Target: SignerProvider
+       {
+               HolderCommitmentPoint::Available {
+                       transaction_number: INITIAL_COMMITMENT_NUMBER,
+                       current: signer.as_ref().get_per_commitment_point(INITIAL_COMMITMENT_NUMBER, secp_ctx),
+                       next: signer.as_ref().get_per_commitment_point(INITIAL_COMMITMENT_NUMBER - 1, secp_ctx),
+               }
+       }
+
+       pub fn is_available(&self) -> bool {
+               if let HolderCommitmentPoint::Available { .. } = self { true } else { false }
+       }
+
+       pub fn transaction_number(&self) -> u64 {
+               match self {
+                       HolderCommitmentPoint::PendingNext { transaction_number, .. } => *transaction_number,
+                       HolderCommitmentPoint::Available { transaction_number, .. } => *transaction_number,
+               }
+       }
+
+       pub fn current_point(&self) -> PublicKey {
+               match self {
+                       HolderCommitmentPoint::PendingNext { current, .. } => *current,
+                       HolderCommitmentPoint::Available { current, .. } => *current,
+               }
+       }
+
+       pub fn next_point(&self) -> Option<PublicKey> {
+               match self {
+                       HolderCommitmentPoint::PendingNext { .. } => None,
+                       HolderCommitmentPoint::Available { next, .. } => Some(*next),
+               }
+       }
+
+       pub fn advance<SP: Deref, L: Deref>(&mut self, signer: &ChannelSignerType<SP>, secp_ctx: &Secp256k1<secp256k1::All>, logger: &L)
+               where SP::Target: SignerProvider, L::Target: Logger
+       {
+               if let HolderCommitmentPoint::Available { transaction_number, next, .. } = self {
+                       *self = HolderCommitmentPoint::PendingNext {
+                               transaction_number: *transaction_number - 1,
+                               current: *next,
+                       };
+               }
+
+               if let HolderCommitmentPoint::PendingNext { transaction_number, current } = self {
+                       let next = signer.as_ref().get_per_commitment_point(*transaction_number - 1, secp_ctx);
+                       log_trace!(logger, "Retrieved next per-commitment point {}", *transaction_number - 1);
+                       *self = HolderCommitmentPoint::Available { transaction_number: *transaction_number, current: *current, next };
+               }
+       }
+}
+
 /// 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
@@ -1161,6 +1077,10 @@ impl_writeable_tlv_based!(PendingChannelMonitorUpdate, {
 pub(super) enum ChannelPhase<SP: Deref> where SP::Target: SignerProvider {
        UnfundedOutboundV1(OutboundV1Channel<SP>),
        UnfundedInboundV1(InboundV1Channel<SP>),
+       #[cfg(any(dual_funding, splicing))]
+       UnfundedOutboundV2(OutboundV2Channel<SP>),
+       #[cfg(any(dual_funding, splicing))]
+       UnfundedInboundV2(InboundV2Channel<SP>),
        Funded(Channel<SP>),
 }
 
@@ -1173,6 +1093,10 @@ impl<'a, SP: Deref> ChannelPhase<SP> where
                        ChannelPhase::Funded(chan) => &chan.context,
                        ChannelPhase::UnfundedOutboundV1(chan) => &chan.context,
                        ChannelPhase::UnfundedInboundV1(chan) => &chan.context,
+                       #[cfg(any(dual_funding, splicing))]
+                       ChannelPhase::UnfundedOutboundV2(chan) => &chan.context,
+                       #[cfg(any(dual_funding, splicing))]
+                       ChannelPhase::UnfundedInboundV2(chan) => &chan.context,
                }
        }
 
@@ -1181,6 +1105,10 @@ impl<'a, SP: Deref> ChannelPhase<SP> where
                        ChannelPhase::Funded(ref mut chan) => &mut chan.context,
                        ChannelPhase::UnfundedOutboundV1(ref mut chan) => &mut chan.context,
                        ChannelPhase::UnfundedInboundV1(ref mut chan) => &mut chan.context,
+                       #[cfg(any(dual_funding, splicing))]
+                       ChannelPhase::UnfundedOutboundV2(ref mut chan) => &mut chan.context,
+                       #[cfg(any(dual_funding, splicing))]
+                       ChannelPhase::UnfundedInboundV2(ref mut chan) => &mut chan.context,
                }
        }
 }
@@ -1252,7 +1180,7 @@ pub(super) struct ChannelContext<SP: Deref> where SP::Target: SignerProvider {
        // generation start at 0 and count up...this simplifies some parts of implementation at the
        // cost of others, but should really just be changed.
 
-       cur_holder_commitment_transaction_number: u64,
+       holder_commitment_point: HolderCommitmentPoint,
        cur_counterparty_commitment_transaction_number: u64,
        value_to_self_msat: u64, // Excluding all pending_htlcs, fees, and anchor outputs
        pending_inbound_htlcs: Vec<InboundHTLCOutput>,
@@ -1279,6 +1207,7 @@ pub(super) struct ChannelContext<SP: Deref> where SP::Target: SignerProvider {
        monitor_pending_forwards: Vec<(PendingHTLCInfo, u64)>,
        monitor_pending_failures: Vec<(HTLCSource, PaymentHash, HTLCFailReason)>,
        monitor_pending_finalized_fulfills: Vec<HTLCSource>,
+       monitor_pending_update_adds: Vec<msgs::UpdateAddHTLC>,
 
        /// If we went to send a commitment update (ie some messages then [`msgs::CommitmentSigned`])
        /// but our signer (initially) refused to give us a signature, we should retry at some point in
@@ -1357,7 +1286,7 @@ pub(super) struct ChannelContext<SP: Deref> where SP::Target: SignerProvider {
        /// Either the height at which this channel was created or the height at which it was last
        /// serialized if it was serialized by versions prior to 0.0.103.
        /// We use this to close if funding is never broadcasted.
-       channel_creation_height: u32,
+       pub(super) channel_creation_height: u32,
 
        counterparty_dust_limit_satoshis: u64,
 
@@ -1528,7 +1457,7 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                        L::Target: Logger,
                        SP::Target: SignerProvider,
        {
-               let logger = WithContext::from(logger, Some(counterparty_node_id), Some(open_channel_fields.temporary_channel_id));
+               let logger = WithContext::from(logger, Some(counterparty_node_id), Some(open_channel_fields.temporary_channel_id), None);
                let announced_channel = if (open_channel_fields.channel_flags & 1) == 1 { true } else { false };
 
                let channel_value_satoshis = our_funding_satoshis.saturating_add(open_channel_fields.funding_satoshis);
@@ -1693,6 +1622,9 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
 
                let value_to_self_msat = our_funding_satoshis * 1000 + msg_push_msat;
 
+               let holder_signer = ChannelSignerType::Ecdsa(holder_signer);
+               let holder_commitment_point = HolderCommitmentPoint::new(&holder_signer, &secp_ctx);
+
                // TODO(dual_funding): Checks for `funding_feerate_sat_per_1000_weight`?
 
                let channel_context = ChannelContext {
@@ -1718,11 +1650,11 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
 
                        latest_monitor_update_id: 0,
 
-                       holder_signer: ChannelSignerType::Ecdsa(holder_signer),
+                       holder_signer,
                        shutdown_scriptpubkey,
                        destination_script,
 
-                       cur_holder_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
+                       holder_commitment_point,
                        cur_counterparty_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
                        value_to_self_msat,
 
@@ -1743,6 +1675,7 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                        monitor_pending_forwards: Vec::new(),
                        monitor_pending_failures: Vec::new(),
                        monitor_pending_finalized_fulfills: Vec::new(),
+                       monitor_pending_update_adds: Vec::new(),
 
                        signer_pending_commitment_update: false,
                        signer_pending_funding: false,
@@ -1916,6 +1849,9 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
 
                let temporary_channel_id = temporary_channel_id.unwrap_or_else(|| ChannelId::temporary_from_entropy_source(entropy_source));
 
+               let holder_signer = ChannelSignerType::Ecdsa(holder_signer);
+               let holder_commitment_point = HolderCommitmentPoint::new(&holder_signer, &secp_ctx);
+
                Ok(Self {
                        user_id,
 
@@ -1939,11 +1875,11 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
 
                        latest_monitor_update_id: 0,
 
-                       holder_signer: ChannelSignerType::Ecdsa(holder_signer),
+                       holder_signer,
                        shutdown_scriptpubkey,
                        destination_script,
 
-                       cur_holder_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
+                       holder_commitment_point,
                        cur_counterparty_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
                        value_to_self_msat,
 
@@ -1964,6 +1900,7 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                        monitor_pending_forwards: Vec::new(),
                        monitor_pending_failures: Vec::new(),
                        monitor_pending_finalized_fulfills: Vec::new(),
+                       monitor_pending_update_adds: Vec::new(),
 
                        signer_pending_commitment_update: false,
                        signer_pending_funding: false,
@@ -2294,15 +2231,16 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                cmp::max(self.config.options.cltv_expiry_delta, MIN_CLTV_EXPIRY_DELTA)
        }
 
-       pub fn get_max_dust_htlc_exposure_msat<F: Deref>(&self,
-               fee_estimator: &LowerBoundedFeeEstimator<F>) -> u64
-       where F::Target: FeeEstimator
-       {
+       fn get_dust_exposure_limiting_feerate<F: Deref>(&self,
+               fee_estimator: &LowerBoundedFeeEstimator<F>,
+       ) -> u32 where F::Target: FeeEstimator {
+               fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::OnChainSweep)
+       }
+
+       pub fn get_max_dust_htlc_exposure_msat(&self, limiting_feerate_sat_per_kw: u32) -> u64 {
                match self.config.options.max_dust_htlc_exposure {
                        MaxDustHTLCExposure::FeeRateMultiplier(multiplier) => {
-                               let feerate_per_kw = fee_estimator.bounded_sat_per_1000_weight(
-                                       ConfirmationTarget::OnChainSweep) as u64;
-                               feerate_per_kw.saturating_mul(multiplier)
+                               (limiting_feerate_sat_per_kw as u64).saturating_mul(multiplier)
                        },
                        MaxDustHTLCExposure::FixedLimitMsat(limit) => limit,
                }
@@ -2635,8 +2573,8 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
        /// our counterparty!)
        /// The result is a transaction which we can revoke broadcastership of (ie a "local" transaction)
        /// TODO Some magic rust shit to compile-time check this?
-       fn build_holder_transaction_keys(&self, commitment_number: u64) -> TxCreationKeys {
-               let per_commitment_point = self.holder_signer.as_ref().get_per_commitment_point(commitment_number, &self.secp_ctx);
+       fn build_holder_transaction_keys(&self) -> TxCreationKeys {
+               let per_commitment_point = self.holder_commitment_point.current_point();
                let delayed_payment_base = &self.get_holder_pubkeys().delayed_payment_basepoint;
                let htlc_basepoint = &self.get_holder_pubkeys().htlc_basepoint;
                let counterparty_pubkeys = self.get_counterparty_pubkeys();
@@ -2687,7 +2625,7 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                        feerate_per_kw = cmp::max(feerate_per_kw, feerate);
                }
                let feerate_plus_quarter = feerate_per_kw.checked_mul(1250).map(|v| v / 1000);
-               cmp::max(2530, feerate_plus_quarter.unwrap_or(u32::max_value()))
+               cmp::max(feerate_per_kw + 2530, feerate_plus_quarter.unwrap_or(u32::max_value()))
        }
 
        /// Get forwarding information for the counterparty.
@@ -2695,86 +2633,111 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                self.counterparty_forwarding_info.clone()
        }
 
-       /// Returns a HTLCStats about inbound pending htlcs
-       fn get_inbound_pending_htlc_stats(&self, outbound_feerate_update: Option<u32>) -> HTLCStats {
+       /// Returns a HTLCStats about pending htlcs
+       fn get_pending_htlc_stats(&self, outbound_feerate_update: Option<u32>, dust_exposure_limiting_feerate: u32) -> HTLCStats {
                let context = self;
-               let mut stats = HTLCStats {
-                       pending_htlcs: context.pending_inbound_htlcs.len() as u32,
-                       pending_htlcs_value_msat: 0,
-                       on_counterparty_tx_dust_exposure_msat: 0,
-                       on_holder_tx_dust_exposure_msat: 0,
-                       holding_cell_msat: 0,
-                       on_holder_tx_holding_cell_htlcs_count: 0,
-               };
+               let uses_0_htlc_fee_anchors = self.get_channel_type().supports_anchors_zero_fee_htlc_tx();
 
-               let (htlc_timeout_dust_limit, htlc_success_dust_limit) = if context.get_channel_type().supports_anchors_zero_fee_htlc_tx() {
+               let dust_buffer_feerate = context.get_dust_buffer_feerate(outbound_feerate_update);
+               let (htlc_timeout_dust_limit, htlc_success_dust_limit) = if uses_0_htlc_fee_anchors {
                        (0, 0)
                } else {
-                       let dust_buffer_feerate = context.get_dust_buffer_feerate(outbound_feerate_update) as u64;
-                       (dust_buffer_feerate * htlc_timeout_tx_weight(context.get_channel_type()) / 1000,
-                               dust_buffer_feerate * htlc_success_tx_weight(context.get_channel_type()) / 1000)
+                       (dust_buffer_feerate as u64 * htlc_timeout_tx_weight(context.get_channel_type()) / 1000,
+                               dust_buffer_feerate as u64 * htlc_success_tx_weight(context.get_channel_type()) / 1000)
                };
-               let counterparty_dust_limit_timeout_sat = htlc_timeout_dust_limit + context.counterparty_dust_limit_satoshis;
-               let holder_dust_limit_success_sat = htlc_success_dust_limit + context.holder_dust_limit_satoshis;
-               for ref htlc in context.pending_inbound_htlcs.iter() {
-                       stats.pending_htlcs_value_msat += htlc.amount_msat;
-                       if htlc.amount_msat / 1000 < counterparty_dust_limit_timeout_sat {
-                               stats.on_counterparty_tx_dust_exposure_msat += htlc.amount_msat;
-                       }
-                       if htlc.amount_msat / 1000 < holder_dust_limit_success_sat {
-                               stats.on_holder_tx_dust_exposure_msat += htlc.amount_msat;
-                       }
-               }
-               stats
-       }
 
-       /// Returns a HTLCStats about pending outbound htlcs, *including* pending adds in our holding cell.
-       fn get_outbound_pending_htlc_stats(&self, outbound_feerate_update: Option<u32>) -> HTLCStats {
-               let context = self;
-               let mut stats = HTLCStats {
-                       pending_htlcs: context.pending_outbound_htlcs.len() as u32,
-                       pending_htlcs_value_msat: 0,
-                       on_counterparty_tx_dust_exposure_msat: 0,
-                       on_holder_tx_dust_exposure_msat: 0,
-                       holding_cell_msat: 0,
-                       on_holder_tx_holding_cell_htlcs_count: 0,
-               };
+               let mut on_holder_tx_dust_exposure_msat = 0;
+               let mut on_counterparty_tx_dust_exposure_msat = 0;
 
-               let (htlc_timeout_dust_limit, htlc_success_dust_limit) = if context.get_channel_type().supports_anchors_zero_fee_htlc_tx() {
-                       (0, 0)
-               } else {
-                       let dust_buffer_feerate = context.get_dust_buffer_feerate(outbound_feerate_update) as u64;
-                       (dust_buffer_feerate * htlc_timeout_tx_weight(context.get_channel_type()) / 1000,
-                               dust_buffer_feerate * htlc_success_tx_weight(context.get_channel_type()) / 1000)
-               };
-               let counterparty_dust_limit_success_sat = htlc_success_dust_limit + context.counterparty_dust_limit_satoshis;
-               let holder_dust_limit_timeout_sat = htlc_timeout_dust_limit + context.holder_dust_limit_satoshis;
-               for ref htlc in context.pending_outbound_htlcs.iter() {
-                       stats.pending_htlcs_value_msat += htlc.amount_msat;
-                       if htlc.amount_msat / 1000 < counterparty_dust_limit_success_sat {
-                               stats.on_counterparty_tx_dust_exposure_msat += htlc.amount_msat;
-                       }
-                       if htlc.amount_msat / 1000 < holder_dust_limit_timeout_sat {
-                               stats.on_holder_tx_dust_exposure_msat += htlc.amount_msat;
+               let mut on_counterparty_tx_offered_nondust_htlcs = 0;
+               let mut on_counterparty_tx_accepted_nondust_htlcs = 0;
+
+               let mut pending_inbound_htlcs_value_msat = 0;
+
+               {
+                       let counterparty_dust_limit_timeout_sat = htlc_timeout_dust_limit + context.counterparty_dust_limit_satoshis;
+                       let holder_dust_limit_success_sat = htlc_success_dust_limit + context.holder_dust_limit_satoshis;
+                       for ref htlc in context.pending_inbound_htlcs.iter() {
+                               pending_inbound_htlcs_value_msat += htlc.amount_msat;
+                               if htlc.amount_msat / 1000 < counterparty_dust_limit_timeout_sat {
+                                       on_counterparty_tx_dust_exposure_msat += htlc.amount_msat;
+                               } else {
+                                       on_counterparty_tx_offered_nondust_htlcs += 1;
+                               }
+                               if htlc.amount_msat / 1000 < holder_dust_limit_success_sat {
+                                       on_holder_tx_dust_exposure_msat += htlc.amount_msat;
+                               }
                        }
                }
 
-               for update in context.holding_cell_htlc_updates.iter() {
-                       if let &HTLCUpdateAwaitingACK::AddHTLC { ref amount_msat, .. } = update {
-                               stats.pending_htlcs += 1;
-                               stats.pending_htlcs_value_msat += amount_msat;
-                               stats.holding_cell_msat += amount_msat;
-                               if *amount_msat / 1000 < counterparty_dust_limit_success_sat {
-                                       stats.on_counterparty_tx_dust_exposure_msat += amount_msat;
-                               }
-                               if *amount_msat / 1000 < holder_dust_limit_timeout_sat {
-                                       stats.on_holder_tx_dust_exposure_msat += amount_msat;
+               let mut pending_outbound_htlcs_value_msat = 0;
+               let mut outbound_holding_cell_msat = 0;
+               let mut on_holder_tx_outbound_holding_cell_htlcs_count = 0;
+               let mut pending_outbound_htlcs = self.pending_outbound_htlcs.len();
+               {
+                       let counterparty_dust_limit_success_sat = htlc_success_dust_limit + context.counterparty_dust_limit_satoshis;
+                       let holder_dust_limit_timeout_sat = htlc_timeout_dust_limit + context.holder_dust_limit_satoshis;
+                       for ref htlc in context.pending_outbound_htlcs.iter() {
+                               pending_outbound_htlcs_value_msat += htlc.amount_msat;
+                               if htlc.amount_msat / 1000 < counterparty_dust_limit_success_sat {
+                                       on_counterparty_tx_dust_exposure_msat += htlc.amount_msat;
                                } else {
-                                       stats.on_holder_tx_holding_cell_htlcs_count += 1;
+                                       on_counterparty_tx_accepted_nondust_htlcs += 1;
+                               }
+                               if htlc.amount_msat / 1000 < holder_dust_limit_timeout_sat {
+                                       on_holder_tx_dust_exposure_msat += htlc.amount_msat;
+                               }
+                       }
+
+                       for update in context.holding_cell_htlc_updates.iter() {
+                               if let &HTLCUpdateAwaitingACK::AddHTLC { ref amount_msat, .. } = update {
+                                       pending_outbound_htlcs += 1;
+                                       pending_outbound_htlcs_value_msat += amount_msat;
+                                       outbound_holding_cell_msat += amount_msat;
+                                       if *amount_msat / 1000 < counterparty_dust_limit_success_sat {
+                                               on_counterparty_tx_dust_exposure_msat += amount_msat;
+                                       } else {
+                                               on_counterparty_tx_accepted_nondust_htlcs += 1;
+                                       }
+                                       if *amount_msat / 1000 < holder_dust_limit_timeout_sat {
+                                               on_holder_tx_dust_exposure_msat += amount_msat;
+                                       } else {
+                                               on_holder_tx_outbound_holding_cell_htlcs_count += 1;
+                                       }
                                }
                        }
                }
-               stats
+
+               // Include any mining "excess" fees in the dust calculation
+               let excess_feerate_opt = outbound_feerate_update
+                       .or(self.pending_update_fee.map(|(fee, _)| fee))
+                       .unwrap_or(self.feerate_per_kw)
+                       .checked_sub(dust_exposure_limiting_feerate);
+               if let Some(excess_feerate) = excess_feerate_opt {
+                       let on_counterparty_tx_nondust_htlcs =
+                               on_counterparty_tx_accepted_nondust_htlcs + on_counterparty_tx_offered_nondust_htlcs;
+                       on_counterparty_tx_dust_exposure_msat +=
+                               commit_tx_fee_msat(excess_feerate, on_counterparty_tx_nondust_htlcs, &self.channel_type);
+                       if !self.channel_type.supports_anchors_zero_fee_htlc_tx() {
+                               on_counterparty_tx_dust_exposure_msat +=
+                                       on_counterparty_tx_accepted_nondust_htlcs as u64 * htlc_success_tx_weight(&self.channel_type)
+                                       * excess_feerate as u64 / 1000;
+                               on_counterparty_tx_dust_exposure_msat +=
+                                       on_counterparty_tx_offered_nondust_htlcs as u64 * htlc_timeout_tx_weight(&self.channel_type)
+                                       * excess_feerate as u64 / 1000;
+                       }
+               }
+
+               HTLCStats {
+                       pending_inbound_htlcs: self.pending_inbound_htlcs.len(),
+                       pending_outbound_htlcs,
+                       pending_inbound_htlcs_value_msat,
+                       pending_outbound_htlcs_value_msat,
+                       on_counterparty_tx_dust_exposure_msat,
+                       on_holder_tx_dust_exposure_msat,
+                       outbound_holding_cell_msat,
+                       on_holder_tx_outbound_holding_cell_htlcs_count,
+               }
        }
 
        /// Returns information on all pending inbound HTLCs.
@@ -2879,9 +2842,11 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
        where F::Target: FeeEstimator
        {
                let context = &self;
-               // Note that we have to handle overflow due to the above case.
-               let inbound_stats = context.get_inbound_pending_htlc_stats(None);
-               let outbound_stats = context.get_outbound_pending_htlc_stats(None);
+               // Note that we have to handle overflow due to the case mentioned in the docs in general
+               // here.
+
+               let dust_exposure_limiting_feerate = self.get_dust_exposure_limiting_feerate(&fee_estimator);
+               let htlc_stats = context.get_pending_htlc_stats(None, dust_exposure_limiting_feerate);
 
                let mut balance_msat = context.value_to_self_msat;
                for ref htlc in context.pending_inbound_htlcs.iter() {
@@ -2889,10 +2854,10 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                                balance_msat += htlc.amount_msat;
                        }
                }
-               balance_msat -= outbound_stats.pending_htlcs_value_msat;
+               balance_msat -= htlc_stats.pending_outbound_htlcs_value_msat;
 
                let outbound_capacity_msat = context.value_to_self_msat
-                               .saturating_sub(outbound_stats.pending_htlcs_value_msat)
+                               .saturating_sub(htlc_stats.pending_outbound_htlcs_value_msat)
                                .saturating_sub(
                                        context.counterparty_selected_channel_reserve_satoshis.unwrap_or(0) * 1000);
 
@@ -2952,7 +2917,7 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
 
                        let holder_selected_chan_reserve_msat = context.holder_selected_channel_reserve_satoshis * 1000;
                        let remote_balance_msat = (context.channel_value_satoshis * 1000 - context.value_to_self_msat)
-                               .saturating_sub(inbound_stats.pending_htlcs_value_msat);
+                               .saturating_sub(htlc_stats.pending_inbound_htlcs_value_msat);
 
                        if remote_balance_msat < max_reserved_commit_tx_fee_msat + holder_selected_chan_reserve_msat + anchor_outputs_value_msat {
                                // If another HTLC's fee would reduce the remote's balance below the reserve limit
@@ -2969,7 +2934,7 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                // send above the dust limit (as the router can always overpay to meet the dust limit).
                let mut remaining_msat_below_dust_exposure_limit = None;
                let mut dust_exposure_dust_limit_msat = 0;
-               let max_dust_htlc_exposure_msat = context.get_max_dust_htlc_exposure_msat(fee_estimator);
+               let max_dust_htlc_exposure_msat = context.get_max_dust_htlc_exposure_msat(dust_exposure_limiting_feerate);
 
                let (htlc_success_dust_limit, htlc_timeout_dust_limit) = if context.get_channel_type().supports_anchors_zero_fee_htlc_tx() {
                        (context.counterparty_dust_limit_satoshis, context.holder_dust_limit_satoshis)
@@ -2978,18 +2943,32 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                        (context.counterparty_dust_limit_satoshis + dust_buffer_feerate * htlc_success_tx_weight(context.get_channel_type()) / 1000,
                         context.holder_dust_limit_satoshis       + dust_buffer_feerate * htlc_timeout_tx_weight(context.get_channel_type()) / 1000)
                };
-               let on_counterparty_dust_htlc_exposure_msat = inbound_stats.on_counterparty_tx_dust_exposure_msat + outbound_stats.on_counterparty_tx_dust_exposure_msat;
-               if on_counterparty_dust_htlc_exposure_msat as i64 + htlc_success_dust_limit as i64 * 1000 - 1 > max_dust_htlc_exposure_msat.try_into().unwrap_or(i64::max_value()) {
+
+               let excess_feerate_opt = self.feerate_per_kw.checked_sub(dust_exposure_limiting_feerate);
+               if let Some(excess_feerate) = excess_feerate_opt {
+                       let htlc_dust_exposure_msat =
+                               per_outbound_htlc_counterparty_commit_tx_fee_msat(excess_feerate, &context.channel_type);
+                       let nondust_htlc_counterparty_tx_dust_exposure =
+                               htlc_stats.on_counterparty_tx_dust_exposure_msat.saturating_add(htlc_dust_exposure_msat);
+                       if nondust_htlc_counterparty_tx_dust_exposure > max_dust_htlc_exposure_msat {
+                               // If adding an extra HTLC would put us over the dust limit in total fees, we cannot
+                               // send any non-dust HTLCs.
+                               available_capacity_msat = cmp::min(available_capacity_msat, htlc_success_dust_limit * 1000);
+                       }
+               }
+
+               if htlc_stats.on_counterparty_tx_dust_exposure_msat.saturating_add(htlc_success_dust_limit * 1000) > max_dust_htlc_exposure_msat.saturating_add(1) {
+                       // Note that we don't use the `counterparty_tx_dust_exposure` (with
+                       // `htlc_dust_exposure_msat`) here as it only applies to non-dust HTLCs.
                        remaining_msat_below_dust_exposure_limit =
-                               Some(max_dust_htlc_exposure_msat.saturating_sub(on_counterparty_dust_htlc_exposure_msat));
+                               Some(max_dust_htlc_exposure_msat.saturating_sub(htlc_stats.on_counterparty_tx_dust_exposure_msat));
                        dust_exposure_dust_limit_msat = cmp::max(dust_exposure_dust_limit_msat, htlc_success_dust_limit * 1000);
                }
 
-               let on_holder_dust_htlc_exposure_msat = inbound_stats.on_holder_tx_dust_exposure_msat + outbound_stats.on_holder_tx_dust_exposure_msat;
-               if on_holder_dust_htlc_exposure_msat as i64 + htlc_timeout_dust_limit as i64 * 1000 - 1 > max_dust_htlc_exposure_msat.try_into().unwrap_or(i64::max_value()) {
+               if htlc_stats.on_holder_tx_dust_exposure_msat as i64 + htlc_timeout_dust_limit as i64 * 1000 - 1 > max_dust_htlc_exposure_msat.try_into().unwrap_or(i64::max_value()) {
                        remaining_msat_below_dust_exposure_limit = Some(cmp::min(
                                remaining_msat_below_dust_exposure_limit.unwrap_or(u64::max_value()),
-                               max_dust_htlc_exposure_msat.saturating_sub(on_holder_dust_htlc_exposure_msat)));
+                               max_dust_htlc_exposure_msat.saturating_sub(htlc_stats.on_holder_tx_dust_exposure_msat)));
                        dust_exposure_dust_limit_msat = cmp::max(dust_exposure_dust_limit_msat, htlc_timeout_dust_limit * 1000);
                }
 
@@ -3002,16 +2981,16 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                }
 
                available_capacity_msat = cmp::min(available_capacity_msat,
-                       context.counterparty_max_htlc_value_in_flight_msat - outbound_stats.pending_htlcs_value_msat);
+                       context.counterparty_max_htlc_value_in_flight_msat - htlc_stats.pending_outbound_htlcs_value_msat);
 
-               if outbound_stats.pending_htlcs + 1 > context.counterparty_max_accepted_htlcs as u32 {
+               if htlc_stats.pending_outbound_htlcs + 1 > context.counterparty_max_accepted_htlcs as usize {
                        available_capacity_msat = 0;
                }
 
                AvailableBalances {
                        inbound_capacity_msat: cmp::max(context.channel_value_satoshis as i64 * 1000
                                        - context.value_to_self_msat as i64
-                                       - context.get_inbound_pending_htlc_stats(None).pending_htlcs_value_msat as i64
+                                       - htlc_stats.pending_inbound_htlcs_value_msat as i64
                                        - context.holder_selected_channel_reserve_satoshis as i64 * 1000,
                                0) as u64,
                        outbound_capacity_msat,
@@ -3458,7 +3437,7 @@ pub(crate) fn get_legacy_default_holder_selected_channel_reserve_satoshis(channe
 ///
 /// This is used both for outbound and inbound channels and has lower bound
 /// of `dust_limit_satoshis`.
-#[cfg(dual_funding)]
+#[cfg(any(dual_funding, splicing))]
 fn get_v2_channel_reserve_satoshis(channel_value_satoshis: u64, dust_limit_satoshis: u64) -> u64 {
        // Fixed at 1% of channel value by spec.
        let (q, _) = channel_value_satoshis.overflowing_div(100);
@@ -3480,8 +3459,19 @@ pub(crate) fn commit_tx_fee_msat(feerate_per_kw: u32, num_htlcs: usize, channel_
        (commitment_tx_base_weight(channel_type_features) + num_htlcs as u64 * COMMITMENT_TX_WEIGHT_PER_HTLC) * feerate_per_kw as u64 / 1000 * 1000
 }
 
+pub(crate) fn per_outbound_htlc_counterparty_commit_tx_fee_msat(feerate_per_kw: u32, channel_type_features: &ChannelTypeFeatures) -> u64 {
+       // Note that we need to divide before multiplying to round properly,
+       // since the lowest denomination of bitcoin on-chain is the satoshi.
+       let commitment_tx_fee = COMMITMENT_TX_WEIGHT_PER_HTLC * feerate_per_kw as u64 / 1000 * 1000;
+       if channel_type_features.supports_anchors_zero_fee_htlc_tx() {
+               commitment_tx_fee + htlc_success_tx_weight(channel_type_features) * feerate_per_kw as u64 / 1000
+       } else {
+               commitment_tx_fee
+       }
+}
+
 /// Context for dual-funded channels.
-#[cfg(dual_funding)]
+#[cfg(any(dual_funding, splicing))]
 pub(super) struct DualFundingChannelContext {
        /// The amount in satoshis we will be contributing to the channel.
        pub our_funding_satoshis: u64,
@@ -3498,7 +3488,7 @@ pub(super) struct DualFundingChannelContext {
 // Counterparty designates channel data owned by the another channel participant entity.
 pub(super) struct Channel<SP: Deref> where SP::Target: SignerProvider {
        pub context: ChannelContext<SP>,
-       #[cfg(dual_funding)]
+       #[cfg(any(dual_funding, splicing))]
        pub dual_funding_channel_context: Option<DualFundingChannelContext>,
 }
 
@@ -3569,7 +3559,7 @@ impl FailHTLCMessageName for msgs::UpdateFailMalformedHTLC {
 
 impl<SP: Deref> Channel<SP> where
        SP::Target: SignerProvider,
-       <SP::Target as SignerProvider>::EcdsaSigner: WriteableEcdsaChannelSigner
+       <SP::Target as SignerProvider>::EcdsaSigner: EcdsaChannelSigner
 {
        fn check_remote_fee<F: Deref, L: Deref>(
                channel_type: &ChannelTypeFeatures, fee_estimator: &LowerBoundedFeeEstimator<F>,
@@ -4074,23 +4064,16 @@ impl<SP: Deref> Channel<SP> where
 
                log_info!(logger, "Received channel_ready from peer for channel {}", &self.context.channel_id());
 
-               Ok(self.get_announcement_sigs(node_signer, chain_hash, user_config, best_block.height(), logger))
+               Ok(self.get_announcement_sigs(node_signer, chain_hash, user_config, best_block.height, logger))
        }
 
-       pub fn update_add_htlc<F, FE: Deref, L: Deref>(
-               &mut self, msg: &msgs::UpdateAddHTLC, mut pending_forward_status: PendingHTLCStatus,
-               create_pending_htlc_status: F, fee_estimator: &LowerBoundedFeeEstimator<FE>, logger: &L
-       ) -> Result<(), ChannelError>
-       where F: for<'a> Fn(&'a Self, PendingHTLCStatus, u16) -> PendingHTLCStatus,
-               FE::Target: FeeEstimator, L::Target: Logger,
-       {
+       pub fn update_add_htlc<F: Deref>(
+               &mut self, msg: &msgs::UpdateAddHTLC, pending_forward_status: PendingHTLCStatus,
+               fee_estimator: &LowerBoundedFeeEstimator<F>,
+       ) -> Result<(), ChannelError> where F::Target: FeeEstimator {
                if !matches!(self.context.channel_state, ChannelState::ChannelReady(_)) {
                        return Err(ChannelError::Close("Got add HTLC message when channel was not in an operational state".to_owned()));
                }
-               // We can't accept HTLCs sent after we've sent a shutdown.
-               if self.context.channel_state.is_local_shutdown_sent() {
-                       pending_forward_status = create_pending_htlc_status(self, pending_forward_status, 0x4000|8);
-               }
                // If the remote has sent a shutdown prior to adding this HTLC, then they are in violation of the spec.
                if self.context.channel_state.is_remote_shutdown_sent() {
                        return Err(ChannelError::Close("Got add HTLC message when channel was not in an operational state".to_owned()));
@@ -4108,12 +4091,12 @@ impl<SP: Deref> Channel<SP> where
                        return Err(ChannelError::Close(format!("Remote side tried to send less than our minimum HTLC value. Lower limit: ({}). Actual: ({})", self.context.holder_htlc_minimum_msat, msg.amount_msat)));
                }
 
-               let inbound_stats = self.context.get_inbound_pending_htlc_stats(None);
-               let outbound_stats = self.context.get_outbound_pending_htlc_stats(None);
-               if inbound_stats.pending_htlcs + 1 > self.context.holder_max_accepted_htlcs as u32 {
+               let dust_exposure_limiting_feerate = self.context.get_dust_exposure_limiting_feerate(&fee_estimator);
+               let htlc_stats = self.context.get_pending_htlc_stats(None, dust_exposure_limiting_feerate);
+               if htlc_stats.pending_inbound_htlcs + 1 > self.context.holder_max_accepted_htlcs as usize {
                        return Err(ChannelError::Close(format!("Remote tried to push more than our max accepted HTLCs ({})", self.context.holder_max_accepted_htlcs)));
                }
-               if inbound_stats.pending_htlcs_value_msat + msg.amount_msat > self.context.holder_max_htlc_value_in_flight_msat {
+               if htlc_stats.pending_inbound_htlcs_value_msat + msg.amount_msat > self.context.holder_max_htlc_value_in_flight_msat {
                        return Err(ChannelError::Close(format!("Remote HTLC add would put them over our max HTLC value ({})", self.context.holder_max_htlc_value_in_flight_msat)));
                }
 
@@ -4138,36 +4121,8 @@ impl<SP: Deref> Channel<SP> where
                        }
                }
 
-               let max_dust_htlc_exposure_msat = self.context.get_max_dust_htlc_exposure_msat(fee_estimator);
-               let (htlc_timeout_dust_limit, htlc_success_dust_limit) = if self.context.get_channel_type().supports_anchors_zero_fee_htlc_tx() {
-                       (0, 0)
-               } else {
-                       let dust_buffer_feerate = self.context.get_dust_buffer_feerate(None) as u64;
-                       (dust_buffer_feerate * htlc_timeout_tx_weight(self.context.get_channel_type()) / 1000,
-                               dust_buffer_feerate * htlc_success_tx_weight(self.context.get_channel_type()) / 1000)
-               };
-               let exposure_dust_limit_timeout_sats = htlc_timeout_dust_limit + self.context.counterparty_dust_limit_satoshis;
-               if msg.amount_msat / 1000 < exposure_dust_limit_timeout_sats {
-                       let on_counterparty_tx_dust_htlc_exposure_msat = inbound_stats.on_counterparty_tx_dust_exposure_msat + outbound_stats.on_counterparty_tx_dust_exposure_msat + msg.amount_msat;
-                       if on_counterparty_tx_dust_htlc_exposure_msat > max_dust_htlc_exposure_msat {
-                               log_info!(logger, "Cannot accept value that would put our exposure to dust HTLCs at {} over the limit {} on counterparty commitment tx",
-                                       on_counterparty_tx_dust_htlc_exposure_msat, max_dust_htlc_exposure_msat);
-                               pending_forward_status = create_pending_htlc_status(self, pending_forward_status, 0x1000|7);
-                       }
-               }
-
-               let exposure_dust_limit_success_sats = htlc_success_dust_limit + self.context.holder_dust_limit_satoshis;
-               if msg.amount_msat / 1000 < exposure_dust_limit_success_sats {
-                       let on_holder_tx_dust_htlc_exposure_msat = inbound_stats.on_holder_tx_dust_exposure_msat + outbound_stats.on_holder_tx_dust_exposure_msat + msg.amount_msat;
-                       if on_holder_tx_dust_htlc_exposure_msat > max_dust_htlc_exposure_msat {
-                               log_info!(logger, "Cannot accept value that would put our exposure to dust HTLCs at {} over the limit {} on holder commitment tx",
-                                       on_holder_tx_dust_htlc_exposure_msat, max_dust_htlc_exposure_msat);
-                               pending_forward_status = create_pending_htlc_status(self, pending_forward_status, 0x1000|7);
-                       }
-               }
-
                let pending_value_to_self_msat =
-                       self.context.value_to_self_msat + inbound_stats.pending_htlcs_value_msat - removed_outbound_total_msat;
+                       self.context.value_to_self_msat + htlc_stats.pending_inbound_htlcs_value_msat - removed_outbound_total_msat;
                let pending_remote_value_msat =
                        self.context.channel_value_satoshis * 1000 - pending_value_to_self_msat;
                if pending_remote_value_msat < msg.amount_msat {
@@ -4199,23 +4154,7 @@ impl<SP: Deref> Channel<SP> where
                } else {
                        0
                };
-               if !self.context.is_outbound() {
-                       // `Some(())` is for the fee spike buffer we keep for the remote. This deviates from
-                       // the spec because the fee spike buffer requirement doesn't exist on the receiver's
-                       // side, only on the sender's. Note that with anchor outputs we are no longer as
-                       // sensitive to fee spikes, so we need to account for them.
-                       let htlc_candidate = HTLCCandidate::new(msg.amount_msat, HTLCInitiator::RemoteOffered);
-                       let mut remote_fee_cost_incl_stuck_buffer_msat = self.context.next_remote_commit_tx_fee_msat(htlc_candidate, Some(()));
-                       if !self.context.get_channel_type().supports_anchors_zero_fee_htlc_tx() {
-                               remote_fee_cost_incl_stuck_buffer_msat *= FEE_SPIKE_BUFFER_FEE_INCREASE_MULTIPLE;
-                       }
-                       if pending_remote_value_msat.saturating_sub(msg.amount_msat).saturating_sub(self.context.holder_selected_channel_reserve_satoshis * 1000).saturating_sub(anchor_outputs_value_msat) < remote_fee_cost_incl_stuck_buffer_msat {
-                               // Note that if the pending_forward_status is not updated here, then it's because we're already failing
-                               // the HTLC, i.e. its status is already set to failing.
-                               log_info!(logger, "Attempting to fail HTLC due to fee spike buffer violation in channel {}. Rebalancing is required.", &self.context.channel_id());
-                               pending_forward_status = create_pending_htlc_status(self, pending_forward_status, 0x1000|7);
-                       }
-               } else {
+               if self.context.is_outbound() {
                        // Check that they won't violate our local required channel reserve by adding this HTLC.
                        let htlc_candidate = HTLCCandidate::new(msg.amount_msat, HTLCInitiator::RemoteOffered);
                        let local_commit_tx_fee_msat = self.context.next_local_commit_tx_fee_msat(htlc_candidate, None);
@@ -4243,7 +4182,9 @@ impl<SP: Deref> Channel<SP> where
                        amount_msat: msg.amount_msat,
                        payment_hash: msg.payment_hash,
                        cltv_expiry: msg.cltv_expiry,
-                       state: InboundHTLCState::RemoteAnnounced(pending_forward_status),
+                       state: InboundHTLCState::RemoteAnnounced(InboundHTLCResolution::Resolved {
+                               pending_htlc_status: pending_forward_status
+                       }),
                });
                Ok(())
        }
@@ -4329,9 +4270,9 @@ impl<SP: Deref> Channel<SP> where
 
                let funding_script = self.context.get_funding_redeemscript();
 
-               let keys = self.context.build_holder_transaction_keys(self.context.cur_holder_commitment_transaction_number);
+               let keys = self.context.build_holder_transaction_keys();
 
-               let commitment_stats = self.context.build_commitment_transaction(self.context.cur_holder_commitment_transaction_number, &keys, true, false, logger);
+               let commitment_stats = self.context.build_commitment_transaction(self.context.holder_commitment_point.transaction_number(), &keys, true, false, logger);
                let commitment_txid = {
                        let trusted_tx = commitment_stats.tx.trust();
                        let bitcoin_tx = trusted_tx.built_transaction();
@@ -4407,7 +4348,7 @@ impl<SP: Deref> Channel<SP> where
 
                                let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, &self.context.channel_type, &keys);
                                let htlc_sighashtype = if self.context.channel_type.supports_anchors_zero_fee_htlc_tx() { EcdsaSighashType::SinglePlusAnyoneCanPay } else { EcdsaSighashType::All };
-                               let htlc_sighash = hash_to_message!(&sighash::SighashCache::new(&htlc_tx).segwit_signature_hash(0, &htlc_redeemscript, htlc.amount_msat / 1000, htlc_sighashtype).unwrap()[..]);
+                               let htlc_sighash = hash_to_message!(&sighash::SighashCache::new(&htlc_tx).p2wsh_signature_hash(0, &htlc_redeemscript, htlc.to_bitcoin_amount(), htlc_sighashtype).unwrap()[..]);
                                log_trace!(logger, "Checking HTLC tx signature {} by key {} against tx {} (sighash {}) with redeemscript {} in channel {}.",
                                        log_bytes!(msg.htlc_signatures[idx].serialize_compact()[..]), log_bytes!(keys.countersignatory_htlc_key.to_public_key().serialize()),
                                        encode::serialize_hex(&htlc_tx), log_bytes!(htlc_sighash[..]), encode::serialize_hex(&htlc_redeemscript), &self.context.channel_id());
@@ -4449,13 +4390,13 @@ impl<SP: Deref> Channel<SP> where
                }
 
                for htlc in self.context.pending_inbound_htlcs.iter_mut() {
-                       let new_forward = if let &InboundHTLCState::RemoteAnnounced(ref forward_info) = &htlc.state {
-                               Some(forward_info.clone())
+                       let htlc_resolution = if let &InboundHTLCState::RemoteAnnounced(ref resolution) = &htlc.state {
+                               Some(resolution.clone())
                        } else { None };
-                       if let Some(forward_info) = new_forward {
+                       if let Some(htlc_resolution) = htlc_resolution {
                                log_trace!(logger, "Updating HTLC {} to AwaitingRemoteRevokeToAnnounce due to commitment_signed in channel {}.",
                                        &htlc.payment_hash, &self.context.channel_id);
-                               htlc.state = InboundHTLCState::AwaitingRemoteRevokeToAnnounce(forward_info);
+                               htlc.state = InboundHTLCState::AwaitingRemoteRevokeToAnnounce(htlc_resolution);
                                need_commitment = true;
                        }
                }
@@ -4494,7 +4435,7 @@ impl<SP: Deref> Channel<SP> where
                        channel_id: Some(self.context.channel_id()),
                };
 
-               self.context.cur_holder_commitment_transaction_number -= 1;
+               self.context.holder_commitment_point.advance(&self.context.holder_signer, &self.context.secp_ctx, logger);
                self.context.expecting_peer_commitment_signed = false;
                // Note that if we need_commitment & !AwaitingRemoteRevoke we'll call
                // build_commitment_no_status_check() next which will reset this to RAAFirst.
@@ -4765,6 +4706,7 @@ impl<SP: Deref> Channel<SP> where
 
                log_trace!(logger, "Updating HTLCs on receipt of RAA in channel {}...", &self.context.channel_id());
                let mut to_forward_infos = Vec::new();
+               let mut pending_update_adds = Vec::new();
                let mut revoked_htlcs = Vec::new();
                let mut finalized_claimed_htlcs = Vec::new();
                let mut update_fail_htlcs = Vec::new();
@@ -4812,29 +4754,37 @@ impl<SP: Deref> Channel<SP> where
                                        let mut state = InboundHTLCState::Committed;
                                        mem::swap(&mut state, &mut htlc.state);
 
-                                       if let InboundHTLCState::AwaitingRemoteRevokeToAnnounce(forward_info) = state {
+                                       if let InboundHTLCState::AwaitingRemoteRevokeToAnnounce(resolution) = state {
                                                log_trace!(logger, " ...promoting inbound AwaitingRemoteRevokeToAnnounce {} to AwaitingAnnouncedRemoteRevoke", &htlc.payment_hash);
-                                               htlc.state = InboundHTLCState::AwaitingAnnouncedRemoteRevoke(forward_info);
+                                               htlc.state = InboundHTLCState::AwaitingAnnouncedRemoteRevoke(resolution);
                                                require_commitment = true;
-                                       } else if let InboundHTLCState::AwaitingAnnouncedRemoteRevoke(forward_info) = state {
-                                               match forward_info {
-                                                       PendingHTLCStatus::Fail(fail_msg) => {
-                                                               log_trace!(logger, " ...promoting inbound AwaitingAnnouncedRemoteRevoke {} to LocalRemoved due to PendingHTLCStatus indicating failure", &htlc.payment_hash);
-                                                               require_commitment = true;
-                                                               match fail_msg {
-                                                                       HTLCFailureMsg::Relay(msg) => {
-                                                                               htlc.state = InboundHTLCState::LocalRemoved(InboundHTLCRemovalReason::FailRelay(msg.reason.clone()));
-                                                                               update_fail_htlcs.push(msg)
-                                                                       },
-                                                                       HTLCFailureMsg::Malformed(msg) => {
-                                                                               htlc.state = InboundHTLCState::LocalRemoved(InboundHTLCRemovalReason::FailMalformed((msg.sha256_of_onion, msg.failure_code)));
-                                                                               update_fail_malformed_htlcs.push(msg)
+                                       } else if let InboundHTLCState::AwaitingAnnouncedRemoteRevoke(resolution) = state {
+                                               match resolution {
+                                                       InboundHTLCResolution::Resolved { pending_htlc_status } =>
+                                                               match pending_htlc_status {
+                                                                       PendingHTLCStatus::Fail(fail_msg) => {
+                                                                               log_trace!(logger, " ...promoting inbound AwaitingAnnouncedRemoteRevoke {} to LocalRemoved due to PendingHTLCStatus indicating failure", &htlc.payment_hash);
+                                                                               require_commitment = true;
+                                                                               match fail_msg {
+                                                                                       HTLCFailureMsg::Relay(msg) => {
+                                                                                               htlc.state = InboundHTLCState::LocalRemoved(InboundHTLCRemovalReason::FailRelay(msg.reason.clone()));
+                                                                                               update_fail_htlcs.push(msg)
+                                                                                       },
+                                                                                       HTLCFailureMsg::Malformed(msg) => {
+                                                                                               htlc.state = InboundHTLCState::LocalRemoved(InboundHTLCRemovalReason::FailMalformed((msg.sha256_of_onion, msg.failure_code)));
+                                                                                               update_fail_malformed_htlcs.push(msg)
+                                                                                       },
+                                                                               }
                                                                        },
+                                                                       PendingHTLCStatus::Forward(forward_info) => {
+                                                                               log_trace!(logger, " ...promoting inbound AwaitingAnnouncedRemoteRevoke {} to Committed, attempting to forward", &htlc.payment_hash);
+                                                                               to_forward_infos.push((forward_info, htlc.htlc_id));
+                                                                               htlc.state = InboundHTLCState::Committed;
+                                                                       }
                                                                }
-                                                       },
-                                                       PendingHTLCStatus::Forward(forward_info) => {
+                                                       InboundHTLCResolution::Pending { update_add_htlc } => {
                                                                log_trace!(logger, " ...promoting inbound AwaitingAnnouncedRemoteRevoke {} to Committed", &htlc.payment_hash);
-                                                               to_forward_infos.push((forward_info, htlc.htlc_id));
+                                                               pending_update_adds.push(update_add_htlc);
                                                                htlc.state = InboundHTLCState::Committed;
                                                        }
                                                }
@@ -4895,6 +4845,8 @@ impl<SP: Deref> Channel<SP> where
                        }
                }
 
+               self.context.monitor_pending_update_adds.append(&mut pending_update_adds);
+
                if self.context.channel_state.is_monitor_update_in_progress() {
                        // We can't actually generate a new commitment transaction (incl by freeing holding
                        // cells) while we can't update the monitor, so we just return what we have.
@@ -4992,12 +4944,12 @@ impl<SP: Deref> Channel<SP> where
                }
 
                // Before proposing a feerate update, check that we can actually afford the new fee.
-               let inbound_stats = self.context.get_inbound_pending_htlc_stats(Some(feerate_per_kw));
-               let outbound_stats = self.context.get_outbound_pending_htlc_stats(Some(feerate_per_kw));
-               let keys = self.context.build_holder_transaction_keys(self.context.cur_holder_commitment_transaction_number);
-               let commitment_stats = self.context.build_commitment_transaction(self.context.cur_holder_commitment_transaction_number, &keys, true, true, logger);
-               let buffer_fee_msat = commit_tx_fee_sat(feerate_per_kw, commitment_stats.num_nondust_htlcs + outbound_stats.on_holder_tx_holding_cell_htlcs_count as usize + CONCURRENT_INBOUND_HTLC_FEE_BUFFER as usize, self.context.get_channel_type()) * 1000;
-               let holder_balance_msat = commitment_stats.local_balance_msat - outbound_stats.holding_cell_msat;
+               let dust_exposure_limiting_feerate = self.context.get_dust_exposure_limiting_feerate(&fee_estimator);
+               let htlc_stats = self.context.get_pending_htlc_stats(Some(feerate_per_kw), dust_exposure_limiting_feerate);
+               let keys = self.context.build_holder_transaction_keys();
+               let commitment_stats = self.context.build_commitment_transaction(self.context.holder_commitment_point.transaction_number(), &keys, true, true, logger);
+               let buffer_fee_msat = commit_tx_fee_sat(feerate_per_kw, commitment_stats.num_nondust_htlcs + htlc_stats.on_holder_tx_outbound_holding_cell_htlcs_count as usize + CONCURRENT_INBOUND_HTLC_FEE_BUFFER as usize, self.context.get_channel_type()) * 1000;
+               let holder_balance_msat = commitment_stats.local_balance_msat - htlc_stats.outbound_holding_cell_msat;
                if holder_balance_msat < buffer_fee_msat  + self.context.counterparty_selected_channel_reserve_satoshis.unwrap() * 1000 {
                        //TODO: auto-close after a number of failures?
                        log_debug!(logger, "Cannot afford to send new feerate at {}", feerate_per_kw);
@@ -5005,14 +4957,12 @@ impl<SP: Deref> Channel<SP> where
                }
 
                // Note, we evaluate pending htlc "preemptive" trimmed-to-dust threshold at the proposed `feerate_per_kw`.
-               let holder_tx_dust_exposure = inbound_stats.on_holder_tx_dust_exposure_msat + outbound_stats.on_holder_tx_dust_exposure_msat;
-               let counterparty_tx_dust_exposure = inbound_stats.on_counterparty_tx_dust_exposure_msat + outbound_stats.on_counterparty_tx_dust_exposure_msat;
-               let max_dust_htlc_exposure_msat = self.context.get_max_dust_htlc_exposure_msat(fee_estimator);
-               if holder_tx_dust_exposure > max_dust_htlc_exposure_msat {
+               let max_dust_htlc_exposure_msat = self.context.get_max_dust_htlc_exposure_msat(dust_exposure_limiting_feerate);
+               if htlc_stats.on_holder_tx_dust_exposure_msat > max_dust_htlc_exposure_msat {
                        log_debug!(logger, "Cannot afford to send new feerate at {} without infringing max dust htlc exposure", feerate_per_kw);
                        return None;
                }
-               if counterparty_tx_dust_exposure > max_dust_htlc_exposure_msat {
+               if htlc_stats.on_counterparty_tx_dust_exposure_msat > max_dust_htlc_exposure_msat {
                        log_debug!(logger, "Cannot afford to send new feerate at {} without infringing max dust htlc exposure", feerate_per_kw);
                        return None;
                }
@@ -5179,12 +5129,7 @@ impl<SP: Deref> Channel<SP> where
                        assert!(!self.context.is_outbound() || self.context.minimum_depth == Some(0),
                                "Funding transaction broadcast by the local client before it should have - LDK didn't do it!");
                        self.context.monitor_pending_channel_ready = false;
-                       let next_per_commitment_point = self.context.holder_signer.as_ref().get_per_commitment_point(self.context.cur_holder_commitment_transaction_number, &self.context.secp_ctx);
-                       Some(msgs::ChannelReady {
-                               channel_id: self.context.channel_id(),
-                               next_per_commitment_point,
-                               short_channel_id_alias: Some(self.context.outbound_scid_alias),
-                       })
+                       Some(self.get_channel_ready())
                } else { None };
 
                let announcement_sigs = self.get_announcement_sigs(node_signer, chain_hash, user_config, best_block_height, logger);
@@ -5195,13 +5140,16 @@ impl<SP: Deref> Channel<SP> where
                mem::swap(&mut failed_htlcs, &mut self.context.monitor_pending_failures);
                let mut finalized_claimed_htlcs = Vec::new();
                mem::swap(&mut finalized_claimed_htlcs, &mut self.context.monitor_pending_finalized_fulfills);
+               let mut pending_update_adds = Vec::new();
+               mem::swap(&mut pending_update_adds, &mut self.context.monitor_pending_update_adds);
 
                if self.context.channel_state.is_peer_disconnected() {
                        self.context.monitor_pending_revoke_and_ack = false;
                        self.context.monitor_pending_commitment_signed = false;
                        return MonitorRestoreUpdates {
                                raa: None, commitment_update: None, order: RAACommitmentOrder::RevokeAndACKFirst,
-                               accepted_htlcs, failed_htlcs, finalized_claimed_htlcs, funding_broadcastable, channel_ready, announcement_sigs
+                               accepted_htlcs, failed_htlcs, finalized_claimed_htlcs, pending_update_adds,
+                               funding_broadcastable, channel_ready, announcement_sigs
                        };
                }
 
@@ -5223,7 +5171,8 @@ impl<SP: Deref> Channel<SP> where
                        if commitment_update.is_some() { "a" } else { "no" }, if raa.is_some() { "an" } else { "no" },
                        match order { RAACommitmentOrder::CommitmentFirst => "commitment", RAACommitmentOrder::RevokeAndACKFirst => "RAA"});
                MonitorRestoreUpdates {
-                       raa, commitment_update, order, accepted_htlcs, failed_htlcs, finalized_claimed_htlcs, funding_broadcastable, channel_ready, announcement_sigs
+                       raa, commitment_update, order, accepted_htlcs, failed_htlcs, finalized_claimed_htlcs,
+                       pending_update_adds, funding_broadcastable, channel_ready, announcement_sigs
                }
        }
 
@@ -5241,20 +5190,16 @@ impl<SP: Deref> Channel<SP> where
                self.context.pending_update_fee = Some((msg.feerate_per_kw, FeeUpdateState::RemoteAnnounced));
                self.context.update_time_counter += 1;
                // Check that we won't be pushed over our dust exposure limit by the feerate increase.
-               if !self.context.channel_type.supports_anchors_zero_fee_htlc_tx() {
-                       let inbound_stats = self.context.get_inbound_pending_htlc_stats(None);
-                       let outbound_stats = self.context.get_outbound_pending_htlc_stats(None);
-                       let holder_tx_dust_exposure = inbound_stats.on_holder_tx_dust_exposure_msat + outbound_stats.on_holder_tx_dust_exposure_msat;
-                       let counterparty_tx_dust_exposure = inbound_stats.on_counterparty_tx_dust_exposure_msat + outbound_stats.on_counterparty_tx_dust_exposure_msat;
-                       let max_dust_htlc_exposure_msat = self.context.get_max_dust_htlc_exposure_msat(fee_estimator);
-                       if holder_tx_dust_exposure > max_dust_htlc_exposure_msat {
-                               return Err(ChannelError::Close(format!("Peer sent update_fee with a feerate ({}) which may over-expose us to dust-in-flight on our own transactions (totaling {} msat)",
-                                       msg.feerate_per_kw, holder_tx_dust_exposure)));
-                       }
-                       if counterparty_tx_dust_exposure > max_dust_htlc_exposure_msat {
-                               return Err(ChannelError::Close(format!("Peer sent update_fee with a feerate ({}) which may over-expose us to dust-in-flight on our counterparty's transactions (totaling {} msat)",
-                                       msg.feerate_per_kw, counterparty_tx_dust_exposure)));
-                       }
+               let dust_exposure_limiting_feerate = self.context.get_dust_exposure_limiting_feerate(&fee_estimator);
+               let htlc_stats = self.context.get_pending_htlc_stats(None, dust_exposure_limiting_feerate);
+               let max_dust_htlc_exposure_msat = self.context.get_max_dust_htlc_exposure_msat(dust_exposure_limiting_feerate);
+               if htlc_stats.on_holder_tx_dust_exposure_msat > max_dust_htlc_exposure_msat {
+                       return Err(ChannelError::Close(format!("Peer sent update_fee with a feerate ({}) which may over-expose us to dust-in-flight on our own transactions (totaling {} msat)",
+                               msg.feerate_per_kw, htlc_stats.on_holder_tx_dust_exposure_msat)));
+               }
+               if htlc_stats.on_counterparty_tx_dust_exposure_msat > max_dust_htlc_exposure_msat {
+                       return Err(ChannelError::Close(format!("Peer sent update_fee with a feerate ({}) which may over-expose us to dust-in-flight on our counterparty's transactions (totaling {} msat)",
+                               msg.feerate_per_kw, htlc_stats.on_counterparty_tx_dust_exposure_msat)));
                }
                Ok(())
        }
@@ -5270,7 +5215,7 @@ impl<SP: Deref> Channel<SP> where
                        self.context.get_funding_signed_msg(logger).1
                } else { None };
                let channel_ready = if funding_signed.is_some() {
-                       self.check_get_channel_ready(0)
+                       self.check_get_channel_ready(0, logger)
                } else { None };
 
                log_trace!(logger, "Signer unblocked with {} commitment_update, {} funding_signed and {} channel_ready",
@@ -5286,8 +5231,11 @@ impl<SP: Deref> Channel<SP> where
        }
 
        fn get_last_revoke_and_ack(&self) -> msgs::RevokeAndACK {
-               let next_per_commitment_point = self.context.holder_signer.as_ref().get_per_commitment_point(self.context.cur_holder_commitment_transaction_number, &self.context.secp_ctx);
-               let per_commitment_secret = self.context.holder_signer.as_ref().release_commitment_secret(self.context.cur_holder_commitment_transaction_number + 2);
+               debug_assert!(self.context.holder_commitment_point.transaction_number() <= INITIAL_COMMITMENT_NUMBER + 2);
+               // TODO: handle non-available case when get_per_commitment_point becomes async
+               debug_assert!(self.context.holder_commitment_point.is_available());
+               let next_per_commitment_point = self.context.holder_commitment_point.current_point();
+               let per_commitment_secret = self.context.holder_signer.as_ref().release_commitment_secret(self.context.holder_commitment_point.transaction_number() + 2);
                msgs::RevokeAndACK {
                        channel_id: self.context.channel_id,
                        per_commitment_secret,
@@ -5420,7 +5368,7 @@ impl<SP: Deref> Channel<SP> where
                        return Err(ChannelError::Close("Peer sent an invalid channel_reestablish to force close in a non-standard way".to_owned()));
                }
 
-               let our_commitment_transaction = INITIAL_COMMITMENT_NUMBER - self.context.cur_holder_commitment_transaction_number - 1;
+               let our_commitment_transaction = INITIAL_COMMITMENT_NUMBER - self.context.holder_commitment_point.transaction_number() - 1;
                if msg.next_remote_commitment_number > 0 {
                        let expected_point = self.context.holder_signer.as_ref().get_per_commitment_point(INITIAL_COMMITMENT_NUMBER - msg.next_remote_commitment_number + 1, &self.context.secp_ctx);
                        let given_secret = SecretKey::from_slice(&msg.your_last_per_commitment_secret)
@@ -5463,7 +5411,7 @@ impl<SP: Deref> Channel<SP> where
 
                let shutdown_msg = self.get_outbound_shutdown();
 
-               let announcement_sigs = self.get_announcement_sigs(node_signer, chain_hash, user_config, best_block.height(), logger);
+               let announcement_sigs = self.get_announcement_sigs(node_signer, chain_hash, user_config, best_block.height, logger);
 
                if matches!(self.context.channel_state, ChannelState::AwaitingChannelReady(_)) {
                        // If we're waiting on a monitor update, we shouldn't re-send any channel_ready's.
@@ -5482,13 +5430,8 @@ impl<SP: Deref> Channel<SP> where
                        }
 
                        // We have OurChannelReady set!
-                       let next_per_commitment_point = self.context.holder_signer.as_ref().get_per_commitment_point(self.context.cur_holder_commitment_transaction_number, &self.context.secp_ctx);
                        return Ok(ReestablishResponses {
-                               channel_ready: Some(msgs::ChannelReady {
-                                       channel_id: self.context.channel_id(),
-                                       next_per_commitment_point,
-                                       short_channel_id_alias: Some(self.context.outbound_scid_alias),
-                               }),
+                               channel_ready: Some(self.get_channel_ready()),
                                raa: None, commitment_update: None,
                                order: RAACommitmentOrder::CommitmentFirst,
                                shutdown_msg, announcement_sigs,
@@ -5525,14 +5468,9 @@ impl<SP: Deref> Channel<SP> where
                }
                let next_counterparty_commitment_number = INITIAL_COMMITMENT_NUMBER - self.context.cur_counterparty_commitment_transaction_number + if is_awaiting_remote_revoke { 1 } else { 0 };
 
-               let channel_ready = if msg.next_local_commitment_number == 1 && INITIAL_COMMITMENT_NUMBER - self.context.cur_holder_commitment_transaction_number == 1 {
+               let channel_ready = if msg.next_local_commitment_number == 1 && INITIAL_COMMITMENT_NUMBER - self.context.holder_commitment_point.transaction_number() == 1 {
                        // We should never have to worry about MonitorUpdateInProgress resending ChannelReady
-                       let next_per_commitment_point = self.context.holder_signer.as_ref().get_per_commitment_point(self.context.cur_holder_commitment_transaction_number, &self.context.secp_ctx);
-                       Some(msgs::ChannelReady {
-                               channel_id: self.context.channel_id(),
-                               next_per_commitment_point,
-                               short_channel_id_alias: Some(self.context.outbound_scid_alias),
-                       })
+                       Some(self.get_channel_ready())
                } else { None };
 
                if msg.next_local_commitment_number == next_counterparty_commitment_number {
@@ -5906,7 +5844,7 @@ impl<SP: Deref> Channel<SP> where
                };
 
                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 {
+                       if !outp.script_pubkey.is_witness_program() && outp.value < Amount::from_sat(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()));
                        }
                }
@@ -6087,8 +6025,98 @@ impl<SP: Deref> Channel<SP> where
                        })
        }
 
+       pub fn can_accept_incoming_htlc<F: Deref, L: Deref>(
+               &self, msg: &msgs::UpdateAddHTLC, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: L
+       ) -> Result<(), (&'static str, u16)>
+       where
+               F::Target: FeeEstimator,
+               L::Target: Logger
+       {
+               if self.context.channel_state.is_local_shutdown_sent() {
+                       return Err(("Shutdown was already sent", 0x4000|8))
+               }
+
+               let dust_exposure_limiting_feerate = self.context.get_dust_exposure_limiting_feerate(&fee_estimator);
+               let htlc_stats = self.context.get_pending_htlc_stats(None, dust_exposure_limiting_feerate);
+               let max_dust_htlc_exposure_msat = self.context.get_max_dust_htlc_exposure_msat(dust_exposure_limiting_feerate);
+               let (htlc_timeout_dust_limit, htlc_success_dust_limit) = if self.context.get_channel_type().supports_anchors_zero_fee_htlc_tx() {
+                       (0, 0)
+               } else {
+                       let dust_buffer_feerate = self.context.get_dust_buffer_feerate(None) as u64;
+                       (dust_buffer_feerate * htlc_timeout_tx_weight(self.context.get_channel_type()) / 1000,
+                               dust_buffer_feerate * htlc_success_tx_weight(self.context.get_channel_type()) / 1000)
+               };
+               let exposure_dust_limit_timeout_sats = htlc_timeout_dust_limit + self.context.counterparty_dust_limit_satoshis;
+               if msg.amount_msat / 1000 < exposure_dust_limit_timeout_sats {
+                       let on_counterparty_tx_dust_htlc_exposure_msat = htlc_stats.on_counterparty_tx_dust_exposure_msat + msg.amount_msat;
+                       if on_counterparty_tx_dust_htlc_exposure_msat > max_dust_htlc_exposure_msat {
+                               log_info!(logger, "Cannot accept value that would put our exposure to dust HTLCs at {} over the limit {} on counterparty commitment tx",
+                                       on_counterparty_tx_dust_htlc_exposure_msat, max_dust_htlc_exposure_msat);
+                               return Err(("Exceeded our dust exposure limit on counterparty commitment tx", 0x1000|7))
+                       }
+               } else {
+                       let htlc_dust_exposure_msat =
+                               per_outbound_htlc_counterparty_commit_tx_fee_msat(self.context.feerate_per_kw, &self.context.channel_type);
+                       let counterparty_tx_dust_exposure =
+                               htlc_stats.on_counterparty_tx_dust_exposure_msat.saturating_add(htlc_dust_exposure_msat);
+                       if counterparty_tx_dust_exposure > max_dust_htlc_exposure_msat {
+                               log_info!(logger, "Cannot accept value that would put our exposure to tx fee dust at {} over the limit {} on counterparty commitment tx",
+                                       counterparty_tx_dust_exposure, max_dust_htlc_exposure_msat);
+                               return Err(("Exceeded our tx fee dust exposure limit on counterparty commitment tx", 0x1000|7))
+                       }
+               }
+
+               let exposure_dust_limit_success_sats = htlc_success_dust_limit + self.context.holder_dust_limit_satoshis;
+               if msg.amount_msat / 1000 < exposure_dust_limit_success_sats {
+                       let on_holder_tx_dust_htlc_exposure_msat = htlc_stats.on_holder_tx_dust_exposure_msat + msg.amount_msat;
+                       if on_holder_tx_dust_htlc_exposure_msat > max_dust_htlc_exposure_msat {
+                               log_info!(logger, "Cannot accept value that would put our exposure to dust HTLCs at {} over the limit {} on holder commitment tx",
+                                       on_holder_tx_dust_htlc_exposure_msat, max_dust_htlc_exposure_msat);
+                               return Err(("Exceeded our dust exposure limit on holder commitment tx", 0x1000|7))
+                       }
+               }
+
+               let anchor_outputs_value_msat = if self.context.get_channel_type().supports_anchors_zero_fee_htlc_tx() {
+                       ANCHOR_OUTPUT_VALUE_SATOSHI * 2 * 1000
+               } else {
+                       0
+               };
+
+               let mut removed_outbound_total_msat = 0;
+               for ref htlc in self.context.pending_outbound_htlcs.iter() {
+                       if let OutboundHTLCState::AwaitingRemoteRevokeToRemove(OutboundHTLCOutcome::Success(_)) = htlc.state {
+                               removed_outbound_total_msat += htlc.amount_msat;
+                       } else if let OutboundHTLCState::AwaitingRemovedRemoteRevoke(OutboundHTLCOutcome::Success(_)) = htlc.state {
+                               removed_outbound_total_msat += htlc.amount_msat;
+                       }
+               }
+
+               let pending_value_to_self_msat =
+                       self.context.value_to_self_msat + htlc_stats.pending_inbound_htlcs_value_msat - removed_outbound_total_msat;
+               let pending_remote_value_msat =
+                       self.context.channel_value_satoshis * 1000 - pending_value_to_self_msat;
+
+               if !self.context.is_outbound() {
+                       // `Some(())` is for the fee spike buffer we keep for the remote. This deviates from
+                       // the spec because the fee spike buffer requirement doesn't exist on the receiver's
+                       // side, only on the sender's. Note that with anchor outputs we are no longer as
+                       // sensitive to fee spikes, so we need to account for them.
+                       let htlc_candidate = HTLCCandidate::new(msg.amount_msat, HTLCInitiator::RemoteOffered);
+                       let mut remote_fee_cost_incl_stuck_buffer_msat = self.context.next_remote_commit_tx_fee_msat(htlc_candidate, Some(()));
+                       if !self.context.get_channel_type().supports_anchors_zero_fee_htlc_tx() {
+                               remote_fee_cost_incl_stuck_buffer_msat *= FEE_SPIKE_BUFFER_FEE_INCREASE_MULTIPLE;
+                       }
+                       if pending_remote_value_msat.saturating_sub(msg.amount_msat).saturating_sub(self.context.holder_selected_channel_reserve_satoshis * 1000).saturating_sub(anchor_outputs_value_msat) < remote_fee_cost_incl_stuck_buffer_msat {
+                               log_info!(logger, "Attempting to fail HTLC due to fee spike buffer violation in channel {}. Rebalancing is required.", &self.context.channel_id());
+                               return Err(("Fee spike buffer violation", 0x1000|7));
+                       }
+               }
+
+               Ok(())
+       }
+
        pub fn get_cur_holder_commitment_transaction_number(&self) -> u64 {
-               self.context.cur_holder_commitment_transaction_number + 1
+               self.context.holder_commitment_point.transaction_number() + 1
        }
 
        pub fn get_cur_counterparty_commitment_transaction_number(&self) -> u64 {
@@ -6164,6 +6192,26 @@ impl<SP: Deref> Channel<SP> where
                }
        }
 
+       /// On startup, its possible we detect some monitor updates have actually completed (and the
+       /// ChannelManager was simply stale). In that case, we should simply drop them, which we do
+       /// here after logging them.
+       pub fn on_startup_drop_completed_blocked_mon_updates_through<L: Logger>(&mut self, logger: &L, loaded_mon_update_id: u64) {
+               let channel_id = self.context.channel_id();
+               self.context.blocked_monitor_updates.retain(|update| {
+                       if update.update.update_id <= loaded_mon_update_id {
+                               log_info!(
+                                       logger,
+                                       "Dropping completed ChannelMonitorUpdate id {} on channel {} due to a stale ChannelManager",
+                                       update.update.update_id,
+                                       channel_id,
+                               );
+                               false
+                       } else {
+                               true
+                       }
+               });
+       }
+
        pub fn blocked_monitor_updates_pending(&self) -> usize {
                self.context.blocked_monitor_updates.len()
        }
@@ -6183,7 +6231,7 @@ impl<SP: Deref> Channel<SP> where
                        debug_assert!(self.context.minimum_depth.unwrap_or(1) > 0);
                        return true;
                }
-               if self.context.cur_holder_commitment_transaction_number == INITIAL_COMMITMENT_NUMBER - 1 &&
+               if self.context.holder_commitment_point.transaction_number() == INITIAL_COMMITMENT_NUMBER - 1 &&
                        self.context.cur_counterparty_commitment_transaction_number == INITIAL_COMMITMENT_NUMBER - 1 {
                        // If we're a 0-conf channel, we'll move beyond AwaitingChannelReady immediately even while
                        // waiting for the initial monitor persistence. Thus, we check if our commitment
@@ -6242,7 +6290,9 @@ impl<SP: Deref> Channel<SP> where
                self.context.channel_update_status = status;
        }
 
-       fn check_get_channel_ready(&mut self, height: u32) -> Option<msgs::ChannelReady> {
+       fn check_get_channel_ready<L: Deref>(&mut self, height: u32, logger: &L) -> Option<msgs::ChannelReady>
+               where L::Target: Logger
+       {
                // Called:
                //  * always when a new block/transactions are confirmed with the new height
                //  * when funding is signed with a height of 0
@@ -6262,6 +6312,8 @@ impl<SP: Deref> Channel<SP> where
                // If we're still pending the signature on a funding transaction, then we're not ready to send a
                // channel_ready yet.
                if self.context.signer_pending_funding {
+                       // TODO: set signer_pending_channel_ready
+                       log_debug!(logger, "Can't produce channel_ready: the signer is pending funding.");
                        return None;
                }
 
@@ -6294,22 +6346,35 @@ impl<SP: Deref> Channel<SP> where
                        false
                };
 
-               if need_commitment_update {
-                       if !self.context.channel_state.is_monitor_update_in_progress() {
-                               if !self.context.channel_state.is_peer_disconnected() {
-                                       let next_per_commitment_point =
-                                               self.context.holder_signer.as_ref().get_per_commitment_point(INITIAL_COMMITMENT_NUMBER - 1, &self.context.secp_ctx);
-                                       return Some(msgs::ChannelReady {
-                                               channel_id: self.context.channel_id,
-                                               next_per_commitment_point,
-                                               short_channel_id_alias: Some(self.context.outbound_scid_alias),
-                                       });
-                               }
-                       } else {
-                               self.context.monitor_pending_channel_ready = true;
-                       }
+               if !need_commitment_update {
+                       log_debug!(logger, "Not producing channel_ready: we do not need a commitment update");
+                       return None;
+               }
+
+               if self.context.channel_state.is_monitor_update_in_progress() {
+                       log_debug!(logger, "Not producing channel_ready: a monitor update is in progress. Setting monitor_pending_channel_ready.");
+                       self.context.monitor_pending_channel_ready = true;
+                       return None;
+               }
+
+               if self.context.channel_state.is_peer_disconnected() {
+                       log_debug!(logger, "Not producing channel_ready: the peer is disconnected.");
+                       return None;
+               }
+
+               // TODO: when get_per_commiment_point becomes async, check if the point is
+               // available, if not, set signer_pending_channel_ready and return None
+
+               Some(self.get_channel_ready())
+       }
+
+       fn get_channel_ready(&self) -> msgs::ChannelReady {
+               debug_assert!(self.context.holder_commitment_point.is_available());
+               msgs::ChannelReady {
+                       channel_id: self.context.channel_id(),
+                       next_per_commitment_point: self.context.holder_commitment_point.current_point(),
+                       short_channel_id_alias: Some(self.context.outbound_scid_alias),
                }
-               None
        }
 
        /// When a transaction is confirmed, we check whether it is or spends the funding transaction
@@ -6331,8 +6396,8 @@ impl<SP: Deref> Channel<SP> where
                                if self.context.funding_tx_confirmation_height == 0 {
                                        if tx.txid() == funding_txo.txid {
                                                let txo_idx = funding_txo.index as usize;
-                                               if txo_idx >= tx.output.len() || tx.output[txo_idx].script_pubkey != self.context.get_funding_redeemscript().to_v0_p2wsh() ||
-                                                               tx.output[txo_idx].value != self.context.channel_value_satoshis {
+                                               if txo_idx >= tx.output.len() || tx.output[txo_idx].script_pubkey != self.context.get_funding_redeemscript().to_p2wsh() ||
+                                                               tx.output[txo_idx].value.to_sat() != self.context.channel_value_satoshis {
                                                        if self.context.is_outbound() {
                                                                // If we generated the funding transaction and it doesn't match what it
                                                                // should, the client is really broken and we should just panic and
@@ -6347,7 +6412,7 @@ impl<SP: Deref> Channel<SP> where
                                                        return Err(ClosureReason::ProcessingError { err: err_reason.to_owned() });
                                                } else {
                                                        if self.context.is_outbound() {
-                                                               if !tx.is_coin_base() {
+                                                               if !tx.is_coinbase() {
                                                                        for input in tx.input.iter() {
                                                                                if input.witness.is_empty() {
                                                                                        // We generated a malleable funding transaction, implying we've
@@ -6367,7 +6432,7 @@ impl<SP: Deref> Channel<SP> where
                                                }
                                                // If this is a coinbase transaction and not a 0-conf channel
                                                // we should update our min_depth to 100 to handle coinbase maturity
-                                               if tx.is_coin_base() &&
+                                               if tx.is_coinbase() &&
                                                        self.context.minimum_depth.unwrap_or(0) > 0 &&
                                                        self.context.minimum_depth.unwrap_or(0) < COINBASE_MATURITY {
                                                        self.context.minimum_depth = Some(COINBASE_MATURITY);
@@ -6376,7 +6441,7 @@ impl<SP: Deref> Channel<SP> where
                                        // If we allow 1-conf funding, we may need to check for channel_ready here and
                                        // send it immediately instead of waiting for a best_block_updated call (which
                                        // may have already happened for this block).
-                                       if let Some(channel_ready) = self.check_get_channel_ready(height) {
+                                       if let Some(channel_ready) = self.check_get_channel_ready(height, logger) {
                                                log_info!(logger, "Sending a channel_ready to our peer for channel {}", &self.context.channel_id);
                                                let announcement_sigs = self.get_announcement_sigs(node_signer, chain_hash, user_config, height, logger);
                                                msgs = (Some(channel_ready), announcement_sigs);
@@ -6442,7 +6507,7 @@ impl<SP: Deref> Channel<SP> where
 
                self.context.update_time_counter = cmp::max(self.context.update_time_counter, highest_header_time);
 
-               if let Some(channel_ready) = self.check_get_channel_ready(height) {
+               if let Some(channel_ready) = self.check_get_channel_ready(height, logger) {
                        let announcement_sigs = if let Some((chain_hash, node_signer, user_config)) = chain_node_signer {
                                self.get_announcement_sigs(node_signer, chain_hash, user_config, height, logger)
                        } else { None };
@@ -6745,7 +6810,7 @@ impl<SP: Deref> Channel<SP> where
 
                        // next_local_commitment_number is the next commitment_signed number we expect to
                        // receive (indicating if they need to resend one that we missed).
-                       next_local_commitment_number: INITIAL_COMMITMENT_NUMBER - self.context.cur_holder_commitment_transaction_number,
+                       next_local_commitment_number: INITIAL_COMMITMENT_NUMBER - self.context.holder_commitment_point.transaction_number(),
                        // We have to set next_remote_commitment_number to the next revoke_and_ack we expect to
                        // receive, however we track it by the next commitment number for a remote transaction
                        // (which is one further, as they always revoke previous commitment transaction, not
@@ -7297,7 +7362,7 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
                }
                if self.context.commitment_secrets.get_min_seen_secret() != (1 << 48) ||
                                self.context.cur_counterparty_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER ||
-                               self.context.cur_holder_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER {
+                               self.context.holder_commitment_point.transaction_number() != INITIAL_COMMITMENT_NUMBER {
                        panic!("Should not have advanced channel commitment tx numbers prior to funding_created");
                }
 
@@ -7311,7 +7376,7 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
 
                // If the funding transaction is a coinbase transaction, we need to set the minimum depth to 100.
                // We can skip this if it is a zero-conf channel.
-               if funding_transaction.is_coin_base() &&
+               if funding_transaction.is_coinbase() &&
                        self.context.minimum_depth.unwrap_or(0) > 0 &&
                        self.context.minimum_depth.unwrap_or(0) < COINBASE_MATURITY {
                        self.context.minimum_depth = Some(COINBASE_MATURITY);
@@ -7349,6 +7414,12 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
                Ok(self.get_open_channel(chain_hash))
        }
 
+       /// Returns true if we can resume the channel by sending the [`msgs::OpenChannel`] again.
+       pub fn is_resumable(&self) -> bool {
+               !self.context.have_received_message() &&
+                       self.context.holder_commitment_point.transaction_number() == INITIAL_COMMITMENT_NUMBER
+       }
+
        pub fn get_open_channel(&self, chain_hash: ChainHash) -> msgs::OpenChannel {
                if !self.context.is_outbound() {
                        panic!("Tried to open a channel for an inbound channel?");
@@ -7357,11 +7428,12 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
                        panic!("Cannot generate an open_channel after we've moved forward");
                }
 
-               if self.context.cur_holder_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER {
+               if self.context.holder_commitment_point.transaction_number() != INITIAL_COMMITMENT_NUMBER {
                        panic!("Tried to send an open_channel for a channel that has already advanced");
                }
 
-               let first_per_commitment_point = self.context.holder_signer.as_ref().get_per_commitment_point(self.context.cur_holder_commitment_transaction_number, &self.context.secp_ctx);
+               debug_assert!(self.context.holder_commitment_point.is_available());
+               let first_per_commitment_point = self.context.holder_commitment_point.current_point();
                let keys = self.context.get_holder_pubkeys();
 
                msgs::OpenChannel {
@@ -7542,7 +7614,7 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
                }
                if self.context.commitment_secrets.get_min_seen_secret() != (1 << 48) ||
                                self.context.cur_counterparty_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER ||
-                               self.context.cur_holder_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER {
+                               self.context.holder_commitment_point.transaction_number() != INITIAL_COMMITMENT_NUMBER {
                        panic!("Should not have advanced channel commitment tx numbers prior to funding_created");
                }
 
@@ -7556,8 +7628,8 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
                log_trace!(logger, "Initial counterparty tx for channel {} is: txid {} tx {}",
                        &self.context.channel_id(), counterparty_initial_bitcoin_tx.txid, encode::serialize_hex(&counterparty_initial_bitcoin_tx.transaction));
 
-               let holder_signer = self.context.build_holder_transaction_keys(self.context.cur_holder_commitment_transaction_number);
-               let initial_commitment_tx = self.context.build_commitment_transaction(self.context.cur_holder_commitment_transaction_number, &holder_signer, true, false, logger).tx;
+               let holder_signer = self.context.build_holder_transaction_keys();
+               let initial_commitment_tx = self.context.build_commitment_transaction(self.context.holder_commitment_point.transaction_number(), &holder_signer, true, false, logger).tx;
                {
                        let trusted_tx = initial_commitment_tx.trust();
                        let initial_commitment_bitcoin_tx = trusted_tx.built_transaction();
@@ -7584,7 +7656,7 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
 
                let funding_redeemscript = self.context.get_funding_redeemscript();
                let funding_txo = self.context.get_funding_txo().unwrap();
-               let funding_txo_script = funding_redeemscript.to_v0_p2wsh();
+               let funding_txo_script = funding_redeemscript.to_p2wsh();
                let obscure_factor = get_commitment_transaction_number_obscure_factor(&self.context.get_holder_pubkeys().payment_point, &self.context.get_counterparty_pubkeys().payment_point, self.context.is_outbound());
                let shutdown_script = self.context.shutdown_scriptpubkey.clone().map(|script| script.into_inner());
                let mut monitor_signer = signer_provider.derive_channel_signer(self.context.channel_value_satoshis, self.context.channel_keys_id);
@@ -7610,18 +7682,18 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
                } else {
                        self.context.channel_state = ChannelState::AwaitingChannelReady(AwaitingChannelReadyFlags::new());
                }
-               self.context.cur_holder_commitment_transaction_number -= 1;
+               self.context.holder_commitment_point.advance(&self.context.holder_signer, &self.context.secp_ctx, logger);
                self.context.cur_counterparty_commitment_transaction_number -= 1;
 
                log_info!(logger, "Received funding_signed from peer for channel {}", &self.context.channel_id());
 
                let mut channel = Channel {
                        context: self.context,
-                       #[cfg(dual_funding)]
+                       #[cfg(any(dual_funding, splicing))]
                        dual_funding_channel_context: None,
                };
 
-               let need_channel_ready = channel.check_get_channel_ready(0).is_some();
+               let need_channel_ready = channel.check_get_channel_ready(0, logger).is_some();
                channel.monitor_updating_paused(false, false, need_channel_ready, Vec::new(), Vec::new(), Vec::new());
                Ok((channel, channel_monitor))
        }
@@ -7691,7 +7763,7 @@ impl<SP: Deref> InboundV1Channel<SP> where SP::Target: SignerProvider {
                          F::Target: FeeEstimator,
                          L::Target: Logger,
        {
-               let logger = WithContext::from(logger, Some(counterparty_node_id), Some(msg.common_fields.temporary_channel_id));
+               let logger = WithContext::from(logger, Some(counterparty_node_id), Some(msg.common_fields.temporary_channel_id), None);
 
                // First check the channel type is known, failing before we do anything else if we don't
                // support this channel type.
@@ -7746,7 +7818,7 @@ impl<SP: Deref> InboundV1Channel<SP> where SP::Target: SignerProvider {
                ) {
                        panic!("Tried to send accept_channel after channel had moved forward");
                }
-               if self.context.cur_holder_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER {
+               if self.context.holder_commitment_point.transaction_number() != INITIAL_COMMITMENT_NUMBER {
                        panic!("Tried to send an accept_channel for a channel that has already advanced");
                }
 
@@ -7759,7 +7831,8 @@ impl<SP: Deref> InboundV1Channel<SP> where SP::Target: SignerProvider {
        ///
        /// [`msgs::AcceptChannel`]: crate::ln::msgs::AcceptChannel
        fn generate_accept_channel_message(&self) -> msgs::AcceptChannel {
-               let first_per_commitment_point = self.context.holder_signer.as_ref().get_per_commitment_point(self.context.cur_holder_commitment_transaction_number, &self.context.secp_ctx);
+               debug_assert!(self.context.holder_commitment_point.is_available());
+               let first_per_commitment_point = self.context.holder_commitment_point.current_point();
                let keys = self.context.get_holder_pubkeys();
 
                msgs::AcceptChannel {
@@ -7801,8 +7874,8 @@ impl<SP: Deref> InboundV1Channel<SP> where SP::Target: SignerProvider {
        fn check_funding_created_signature<L: Deref>(&mut self, sig: &Signature, logger: &L) -> Result<CommitmentTransaction, ChannelError> where L::Target: Logger {
                let funding_script = self.context.get_funding_redeemscript();
 
-               let keys = self.context.build_holder_transaction_keys(self.context.cur_holder_commitment_transaction_number);
-               let initial_commitment_tx = self.context.build_commitment_transaction(self.context.cur_holder_commitment_transaction_number, &keys, true, false, logger).tx;
+               let keys = self.context.build_holder_transaction_keys();
+               let initial_commitment_tx = self.context.build_commitment_transaction(self.context.holder_commitment_point.transaction_number(), &keys, true, false, logger).tx;
                let trusted_tx = initial_commitment_tx.trust();
                let initial_commitment_bitcoin_tx = trusted_tx.built_transaction();
                let sighash = initial_commitment_bitcoin_tx.get_sighash_all(&funding_script, self.context.channel_value_satoshis);
@@ -7836,7 +7909,7 @@ impl<SP: Deref> InboundV1Channel<SP> where SP::Target: SignerProvider {
                }
                if self.context.commitment_secrets.get_min_seen_secret() != (1 << 48) ||
                                self.context.cur_counterparty_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER ||
-                               self.context.cur_holder_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER {
+                               self.context.holder_commitment_point.transaction_number() != INITIAL_COMMITMENT_NUMBER {
                        panic!("Should not have advanced channel commitment tx numbers prior to funding_created");
                }
 
@@ -7876,12 +7949,12 @@ impl<SP: Deref> InboundV1Channel<SP> where SP::Target: SignerProvider {
                self.context.channel_state = ChannelState::AwaitingChannelReady(AwaitingChannelReadyFlags::new());
                self.context.channel_id = ChannelId::v1_from_funding_outpoint(funding_txo);
                self.context.cur_counterparty_commitment_transaction_number -= 1;
-               self.context.cur_holder_commitment_transaction_number -= 1;
+               self.context.holder_commitment_point.advance(&self.context.holder_signer, &self.context.secp_ctx, logger);
 
                let (counterparty_initial_commitment_tx, funding_signed) = self.context.get_funding_signed_msg(logger);
 
                let funding_redeemscript = self.context.get_funding_redeemscript();
-               let funding_txo_script = funding_redeemscript.to_v0_p2wsh();
+               let funding_txo_script = funding_redeemscript.to_p2wsh();
                let obscure_factor = get_commitment_transaction_number_obscure_factor(&self.context.get_holder_pubkeys().payment_point, &self.context.get_counterparty_pubkeys().payment_point, self.context.is_outbound());
                let shutdown_script = self.context.shutdown_scriptpubkey.clone().map(|script| script.into_inner());
                let mut monitor_signer = signer_provider.derive_channel_signer(self.context.channel_value_satoshis, self.context.channel_keys_id);
@@ -7907,10 +7980,10 @@ impl<SP: Deref> InboundV1Channel<SP> where SP::Target: SignerProvider {
                // `ChannelMonitor`.
                let mut channel = Channel {
                        context: self.context,
-                       #[cfg(dual_funding)]
+                       #[cfg(any(dual_funding, splicing))]
                        dual_funding_channel_context: None,
                };
-               let need_channel_ready = channel.check_get_channel_ready(0).is_some();
+               let need_channel_ready = channel.check_get_channel_ready(0, logger).is_some();
                channel.monitor_updating_paused(false, false, need_channel_ready, Vec::new(), Vec::new(), Vec::new());
 
                Ok((channel, funding_signed, channel_monitor))
@@ -7918,15 +7991,15 @@ impl<SP: Deref> InboundV1Channel<SP> where SP::Target: SignerProvider {
 }
 
 // A not-yet-funded outbound (from holder) channel using V2 channel establishment.
-#[cfg(dual_funding)]
+#[cfg(any(dual_funding, splicing))]
 pub(super) struct OutboundV2Channel<SP: Deref> where SP::Target: SignerProvider {
        pub context: ChannelContext<SP>,
        pub unfunded_context: UnfundedChannelContext,
-       #[cfg(dual_funding)]
+       #[cfg(any(dual_funding, splicing))]
        pub dual_funding_context: DualFundingChannelContext,
 }
 
-#[cfg(dual_funding)]
+#[cfg(any(dual_funding, splicing))]
 impl<SP: Deref> OutboundV2Channel<SP> where SP::Target: SignerProvider {
        pub fn new<ES: Deref, F: Deref>(
                fee_estimator: &LowerBoundedFeeEstimator<F>, entropy_source: &ES, signer_provider: &SP,
@@ -7997,15 +8070,15 @@ impl<SP: Deref> OutboundV2Channel<SP> where SP::Target: SignerProvider {
                        debug_assert!(false, "Cannot generate an open_channel2 after we've moved forward");
                }
 
-               if self.context.cur_holder_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER {
+               if self.context.holder_commitment_point.transaction_number() != INITIAL_COMMITMENT_NUMBER {
                        debug_assert!(false, "Tried to send an open_channel2 for a channel that has already advanced");
                }
 
                let first_per_commitment_point = self.context.holder_signer.as_ref()
-                       .get_per_commitment_point(self.context.cur_holder_commitment_transaction_number,
+                       .get_per_commitment_point(self.context.holder_commitment_point.transaction_number(),
                                &self.context.secp_ctx);
                let second_per_commitment_point = self.context.holder_signer.as_ref()
-                       .get_per_commitment_point(self.context.cur_holder_commitment_transaction_number - 1,
+                       .get_per_commitment_point(self.context.holder_commitment_point.transaction_number() - 1,
                                &self.context.secp_ctx);
                let keys = self.context.get_holder_pubkeys();
 
@@ -8042,14 +8115,14 @@ impl<SP: Deref> OutboundV2Channel<SP> where SP::Target: SignerProvider {
 }
 
 // A not-yet-funded inbound (from counterparty) channel using V2 channel establishment.
-#[cfg(dual_funding)]
+#[cfg(any(dual_funding, splicing))]
 pub(super) struct InboundV2Channel<SP: Deref> where SP::Target: SignerProvider {
        pub context: ChannelContext<SP>,
        pub unfunded_context: UnfundedChannelContext,
        pub dual_funding_context: DualFundingChannelContext,
 }
 
-#[cfg(dual_funding)]
+#[cfg(any(dual_funding, splicing))]
 impl<SP: Deref> InboundV2Channel<SP> where SP::Target: SignerProvider {
        /// Creates a new dual-funded channel from a remote side's request for one.
        /// Assumes chain_hash has already been checked and corresponds with what we expect!
@@ -8139,7 +8212,7 @@ impl<SP: Deref> InboundV2Channel<SP> where SP::Target: SignerProvider {
                ) {
                        debug_assert!(false, "Tried to send accept_channel2 after channel had moved forward");
                }
-               if self.context.cur_holder_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER {
+               if self.context.holder_commitment_point.transaction_number() != INITIAL_COMMITMENT_NUMBER {
                        debug_assert!(false, "Tried to send an accept_channel2 for a channel that has already advanced");
                }
 
@@ -8153,9 +8226,9 @@ impl<SP: Deref> InboundV2Channel<SP> where SP::Target: SignerProvider {
        /// [`msgs::AcceptChannelV2`]: crate::ln::msgs::AcceptChannelV2
        fn generate_accept_channel_v2_message(&self) -> msgs::AcceptChannelV2 {
                let first_per_commitment_point = self.context.holder_signer.as_ref().get_per_commitment_point(
-                       self.context.cur_holder_commitment_transaction_number, &self.context.secp_ctx);
+                       self.context.holder_commitment_point.transaction_number(), &self.context.secp_ctx);
                let second_per_commitment_point = self.context.holder_signer.as_ref().get_per_commitment_point(
-                       self.context.cur_holder_commitment_transaction_number - 1, &self.context.secp_ctx);
+                       self.context.holder_commitment_point.transaction_number() - 1, &self.context.secp_ctx);
                let keys = self.context.get_holder_pubkeys();
 
                msgs::AcceptChannelV2 {
@@ -8220,7 +8293,7 @@ fn get_initial_channel_type(config: &UserConfig, their_features: &InitFeatures)
        ret
 }
 
-const SERIALIZATION_VERSION: u8 = 3;
+const SERIALIZATION_VERSION: u8 = 4;
 const MIN_SERIALIZATION_VERSION: u8 = 3;
 
 impl_writeable_tlv_based_enum!(InboundHTLCRemovalReason,;
@@ -8282,7 +8355,18 @@ impl<SP: Deref> Writeable for Channel<SP> where SP::Target: SignerProvider {
                // Note that we write out as if remove_uncommitted_htlcs_and_mark_paused had just been
                // called.
 
-               write_ver_prefix!(writer, MIN_SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
+               let version_to_write = if self.context.pending_inbound_htlcs.iter().any(|htlc| match htlc.state {
+                       InboundHTLCState::AwaitingRemoteRevokeToAnnounce(ref htlc_resolution)|
+                               InboundHTLCState::AwaitingAnnouncedRemoteRevoke(ref htlc_resolution) => {
+                               matches!(htlc_resolution, InboundHTLCResolution::Pending { .. })
+                       },
+                       _ => false,
+               }) {
+                       SERIALIZATION_VERSION
+               } else {
+                       MIN_SERIALIZATION_VERSION
+               };
+               write_ver_prefix!(writer, version_to_write, MIN_SERIALIZATION_VERSION);
 
                // `user_id` used to be a single u64 value. In order to remain backwards compatible with
                // versions prior to 0.0.113, the u128 is serialized as two separate u64 values. We write
@@ -8317,7 +8401,7 @@ impl<SP: Deref> Writeable for Channel<SP> where SP::Target: SignerProvider {
                }
                self.context.destination_script.write(writer)?;
 
-               self.context.cur_holder_commitment_transaction_number.write(writer)?;
+               self.context.holder_commitment_point.transaction_number().write(writer)?;
                self.context.cur_counterparty_commitment_transaction_number.write(writer)?;
                self.context.value_to_self_msat.write(writer)?;
 
@@ -8338,13 +8422,29 @@ impl<SP: Deref> Writeable for Channel<SP> where SP::Target: SignerProvider {
                        htlc.payment_hash.write(writer)?;
                        match &htlc.state {
                                &InboundHTLCState::RemoteAnnounced(_) => unreachable!(),
-                               &InboundHTLCState::AwaitingRemoteRevokeToAnnounce(ref htlc_state) => {
+                               &InboundHTLCState::AwaitingRemoteRevokeToAnnounce(ref htlc_resolution) => {
                                        1u8.write(writer)?;
-                                       htlc_state.write(writer)?;
+                                       if version_to_write <= 3 {
+                                               if let InboundHTLCResolution::Resolved { pending_htlc_status } = htlc_resolution {
+                                                       pending_htlc_status.write(writer)?;
+                                               } else {
+                                                       panic!();
+                                               }
+                                       } else {
+                                               htlc_resolution.write(writer)?;
+                                       }
                                },
-                               &InboundHTLCState::AwaitingAnnouncedRemoteRevoke(ref htlc_state) => {
+                               &InboundHTLCState::AwaitingAnnouncedRemoteRevoke(ref htlc_resolution) => {
                                        2u8.write(writer)?;
-                                       htlc_state.write(writer)?;
+                                       if version_to_write <= 3 {
+                                               if let InboundHTLCResolution::Resolved { pending_htlc_status } = htlc_resolution {
+                                                       pending_htlc_status.write(writer)?;
+                                               } else {
+                                                       panic!();
+                                               }
+                                       } else {
+                                               htlc_resolution.write(writer)?;
+                                       }
                                },
                                &InboundHTLCState::Committed => {
                                        3u8.write(writer)?;
@@ -8570,6 +8670,15 @@ impl<SP: Deref> Writeable for Channel<SP> where SP::Target: SignerProvider {
 
                let holder_max_accepted_htlcs = if self.context.holder_max_accepted_htlcs == DEFAULT_MAX_HTLCS { None } else { Some(self.context.holder_max_accepted_htlcs) };
 
+               let mut monitor_pending_update_adds = None;
+               if !self.context.monitor_pending_update_adds.is_empty() {
+                       monitor_pending_update_adds = Some(&self.context.monitor_pending_update_adds);
+               }
+
+               // `current_point` will become optional when async signing is implemented.
+               let cur_holder_commitment_point = Some(self.context.holder_commitment_point.current_point());
+               let next_holder_commitment_point = self.context.holder_commitment_point.next_point();
+
                write_tlv_fields!(writer, {
                        (0, self.context.announcement_sigs, option),
                        // minimum_depth and counterparty_selected_channel_reserve_satoshis used to have a
@@ -8587,6 +8696,7 @@ impl<SP: Deref> Writeable for Channel<SP> where SP::Target: SignerProvider {
                        (7, self.context.shutdown_scriptpubkey, option),
                        (8, self.context.blocked_monitor_updates, optional_vec),
                        (9, self.context.target_closing_feerate_sats_per_kw, option),
+                       (10, monitor_pending_update_adds, option), // Added in 0.0.122
                        (11, self.context.monitor_pending_finalized_fulfills, required_vec),
                        (13, self.context.channel_creation_height, required),
                        (15, preimages, required_vec),
@@ -8605,7 +8715,9 @@ impl<SP: Deref> Writeable for Channel<SP> where SP::Target: SignerProvider {
                        (39, pending_outbound_blinding_points, optional_vec),
                        (41, holding_cell_blinding_points, optional_vec),
                        (43, malformed_htlcs, optional_vec), // Added in 0.0.119
-                       (45, self.context.local_initiated_shutdown, option), // Added in 0.0.122
+                       (45, cur_holder_commitment_point, option),
+                       (47, next_holder_commitment_point, option),
+                       (49, self.context.local_initiated_shutdown, option), // Added in 0.0.122
                });
 
                Ok(())
@@ -8681,8 +8793,22 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, u32, &'c Ch
                                cltv_expiry: Readable::read(reader)?,
                                payment_hash: Readable::read(reader)?,
                                state: match <u8 as Readable>::read(reader)? {
-                                       1 => InboundHTLCState::AwaitingRemoteRevokeToAnnounce(Readable::read(reader)?),
-                                       2 => InboundHTLCState::AwaitingAnnouncedRemoteRevoke(Readable::read(reader)?),
+                                       1 => {
+                                               let resolution = if ver <= 3 {
+                                                       InboundHTLCResolution::Resolved { pending_htlc_status: Readable::read(reader)? }
+                                               } else {
+                                                       Readable::read(reader)?
+                                               };
+                                               InboundHTLCState::AwaitingRemoteRevokeToAnnounce(resolution)
+                                       },
+                                       2 => {
+                                               let resolution = if ver <= 3 {
+                                                       InboundHTLCResolution::Resolved { pending_htlc_status: Readable::read(reader)? }
+                                               } else {
+                                                       Readable::read(reader)?
+                                               };
+                                               InboundHTLCState::AwaitingAnnouncedRemoteRevoke(resolution)
+                                       },
                                        3 => InboundHTLCState::Committed,
                                        4 => InboundHTLCState::LocalRemoved(Readable::read(reader)?),
                                        _ => return Err(DecodeError::InvalidValue),
@@ -8899,6 +9025,10 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, u32, &'c Ch
                let mut holding_cell_blinding_points_opt: Option<Vec<Option<PublicKey>>> = None;
 
                let mut malformed_htlcs: Option<Vec<(u64, u16, [u8; 32])>> = None;
+               let mut monitor_pending_update_adds: Option<Vec<msgs::UpdateAddHTLC>> = None;
+
+               let mut cur_holder_commitment_point_opt: Option<PublicKey> = None;
+               let mut next_holder_commitment_point_opt: Option<PublicKey> = None;
 
                read_tlv_fields!(reader, {
                        (0, announcement_sigs, option),
@@ -8911,6 +9041,7 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, u32, &'c Ch
                        (7, shutdown_scriptpubkey, option),
                        (8, blocked_monitor_updates, optional_vec),
                        (9, target_closing_feerate_sats_per_kw, option),
+                       (10, monitor_pending_update_adds, option), // Added in 0.0.122
                        (11, monitor_pending_finalized_fulfills, optional_vec),
                        (13, channel_creation_height, option),
                        (15, preimages_opt, optional_vec),
@@ -8929,7 +9060,9 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, u32, &'c Ch
                        (39, pending_outbound_blinding_points_opt, optional_vec),
                        (41, holding_cell_blinding_points_opt, optional_vec),
                        (43, malformed_htlcs, optional_vec), // Added in 0.0.119
-                       (45, local_initiated_shutdown, option),
+                       (45, cur_holder_commitment_point_opt, option),
+                       (47, next_holder_commitment_point_opt, option),
+                       (49, local_initiated_shutdown, option),
                });
 
                let (channel_keys_id, holder_signer) = if let Some(channel_keys_id) = channel_keys_id {
@@ -9040,6 +9173,24 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, u32, &'c Ch
                        }
                }
 
+               // If we're restoring this channel for the first time after an upgrade, then we require that the
+               // signer be available so that we can immediately populate the current commitment point. Channel
+               // restoration will fail if this is not possible.
+               let holder_commitment_point = match (cur_holder_commitment_point_opt, next_holder_commitment_point_opt) {
+                       (Some(current), Some(next)) => HolderCommitmentPoint::Available {
+                               transaction_number: cur_holder_commitment_transaction_number, current, next
+                       },
+                       (Some(current), _) => HolderCommitmentPoint::Available {
+                               transaction_number: cur_holder_commitment_transaction_number, current,
+                               next: holder_signer.get_per_commitment_point(cur_holder_commitment_transaction_number - 1, &secp_ctx),
+                       },
+                       (_, _) => HolderCommitmentPoint::Available {
+                               transaction_number: cur_holder_commitment_transaction_number,
+                               current: holder_signer.get_per_commitment_point(cur_holder_commitment_transaction_number, &secp_ctx),
+                               next: holder_signer.get_per_commitment_point(cur_holder_commitment_transaction_number - 1, &secp_ctx),
+                       },
+               };
+
                Ok(Channel {
                        context: ChannelContext {
                                user_id,
@@ -9065,7 +9216,7 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, u32, &'c Ch
                                shutdown_scriptpubkey,
                                destination_script,
 
-                               cur_holder_commitment_transaction_number,
+                               holder_commitment_point,
                                cur_counterparty_commitment_transaction_number,
                                value_to_self_msat,
 
@@ -9082,6 +9233,7 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, u32, &'c Ch
                                monitor_pending_forwards,
                                monitor_pending_failures,
                                monitor_pending_finalized_fulfills: monitor_pending_finalized_fulfills.unwrap(),
+                               monitor_pending_update_adds: monitor_pending_update_adds.unwrap_or(Vec::new()),
 
                                signer_pending_commitment_update: false,
                                signer_pending_funding: false,
@@ -9164,7 +9316,7 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, u32, &'c Ch
 
                                blocked_monitor_updates: blocked_monitor_updates.unwrap(),
                        },
-                       #[cfg(dual_funding)]
+                       #[cfg(any(dual_funding, splicing))]
                        dual_funding_channel_context: None,
                })
        }
@@ -9173,13 +9325,14 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, u32, &'c Ch
 #[cfg(test)]
 mod tests {
        use std::cmp;
+       use bitcoin::amount::Amount;
        use bitcoin::blockdata::constants::ChainHash;
        use bitcoin::blockdata::script::{ScriptBuf, Builder};
-       use bitcoin::blockdata::transaction::{Transaction, TxOut};
+       use bitcoin::blockdata::transaction::{Transaction, TxOut, Version};
        use bitcoin::blockdata::opcodes;
-       use bitcoin::network::constants::Network;
+       use bitcoin::network::Network;
        use crate::ln::onion_utils::INVALID_ONION_BLINDING;
-       use crate::ln::{PaymentHash, PaymentPreimage};
+       use crate::ln::types::{PaymentHash, PaymentPreimage};
        use crate::ln::channel_keys::{RevocationKey, RevocationBasepoint};
        use crate::ln::channelmanager::{self, HTLCSource, PaymentId};
        use crate::ln::channel::InitFeatures;
@@ -9206,9 +9359,8 @@ mod tests {
        use bitcoin::hashes::sha256::Hash as Sha256;
        use bitcoin::hashes::Hash;
        use bitcoin::hashes::hex::FromHex;
-       use bitcoin::hash_types::WPubkeyHash;
        use bitcoin::blockdata::locktime::absolute::LockTime;
-       use bitcoin::address::{WitnessProgram, WitnessVersion};
+       use bitcoin::{WitnessProgram, WitnessVersion, WPubkeyHash};
        use crate::prelude::*;
 
        #[test]
@@ -9364,8 +9516,8 @@ mod tests {
 
                // Node A --> Node B: funding created
                let output_script = node_a_chan.context.get_funding_redeemscript();
-               let tx = Transaction { version: 1, lock_time: LockTime::ZERO, input: Vec::new(), output: vec![TxOut {
-                       value: 10000000, script_pubkey: output_script.clone(),
+               let tx = Transaction { version: Version::ONE, lock_time: LockTime::ZERO, input: Vec::new(), output: vec![TxOut {
+                       value: Amount::from_sat(10000000), script_pubkey: output_script.clone(),
                }]};
                let funding_outpoint = OutPoint{ txid: tx.txid(), index: 0 };
                let funding_created_msg = node_a_chan.get_funding_created(tx.clone(), funding_outpoint, false, &&logger).map_err(|_| ()).unwrap();
@@ -9493,8 +9645,8 @@ mod tests {
 
                // Node A --> Node B: funding created
                let output_script = node_a_chan.context.get_funding_redeemscript();
-               let tx = Transaction { version: 1, lock_time: LockTime::ZERO, input: Vec::new(), output: vec![TxOut {
-                       value: 10000000, script_pubkey: output_script.clone(),
+               let tx = Transaction { version: Version::ONE, lock_time: LockTime::ZERO, input: Vec::new(), output: vec![TxOut {
+                       value: Amount::from_sat(10000000), script_pubkey: output_script.clone(),
                }]};
                let funding_outpoint = OutPoint{ txid: tx.txid(), index: 0 };
                let funding_created_msg = node_a_chan.get_funding_created(tx.clone(), funding_outpoint, false, &&logger).map_err(|_| ()).unwrap();
@@ -9682,8 +9834,8 @@ mod tests {
 
                // Node A --> Node B: funding created
                let output_script = node_a_chan.context.get_funding_redeemscript();
-               let tx = Transaction { version: 1, lock_time: LockTime::ZERO, input: Vec::new(), output: vec![TxOut {
-                       value: 10000000, script_pubkey: output_script.clone(),
+               let tx = Transaction { version: Version::ONE, lock_time: LockTime::ZERO, input: Vec::new(), output: vec![TxOut {
+                       value: Amount::from_sat(10000000), script_pubkey: output_script.clone(),
                }]};
                let funding_outpoint = OutPoint{ txid: tx.txid(), index: 0 };
                let funding_created_msg = node_a_chan.get_funding_created(tx.clone(), funding_outpoint, false, &&logger).map_err(|_| ()).unwrap();
@@ -9749,8 +9901,8 @@ mod tests {
                        &features, &outbound_chan.get_open_channel(ChainHash::using_genesis_block(network)), 7, &config, 0, &&logger, false
                ).unwrap();
                outbound_chan.accept_channel(&inbound_chan.get_accept_channel_message(), &config.channel_handshake_limits, &features).unwrap();
-               let tx = Transaction { version: 1, lock_time: LockTime::ZERO, input: Vec::new(), output: vec![TxOut {
-                       value: 10000000, script_pubkey: outbound_chan.context.get_funding_redeemscript(),
+               let tx = Transaction { version: Version::ONE, lock_time: LockTime::ZERO, input: Vec::new(), output: vec![TxOut {
+                       value: Amount::from_sat(10000000), script_pubkey: outbound_chan.context.get_funding_redeemscript(),
                }]};
                let funding_outpoint = OutPoint{ txid: tx.txid(), index: 0 };
                let funding_created = outbound_chan.get_funding_created(tx.clone(), funding_outpoint, false, &&logger).map_err(|_| ()).unwrap().unwrap();
@@ -10007,7 +10159,7 @@ mod tests {
                                                &htlc, $opt_anchors, &keys.broadcaster_delayed_payment_key, &keys.revocation_key);
                                        let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, $opt_anchors, &keys);
                                        let htlc_sighashtype = if $opt_anchors.supports_anchors_zero_fee_htlc_tx() { EcdsaSighashType::SinglePlusAnyoneCanPay } else { EcdsaSighashType::All };
-                                       let htlc_sighash = Message::from_slice(&sighash::SighashCache::new(&htlc_tx).segwit_signature_hash(0, &htlc_redeemscript, htlc.amount_msat / 1000, htlc_sighashtype).unwrap()[..]).unwrap();
+                                       let htlc_sighash = Message::from_digest(sighash::SighashCache::new(&htlc_tx).p2wsh_signature_hash(0, &htlc_redeemscript, htlc.to_bitcoin_amount(), htlc_sighashtype).unwrap().as_raw_hash().to_byte_array());
                                        assert!(secp_ctx.verify_ecdsa(&htlc_sighash, &remote_signature, &keys.countersignatory_htlc_key.to_public_key()).is_ok(), "verify counterparty htlc sig");
 
                                        let mut preimage: Option<PaymentPreimage> = None;
@@ -10873,15 +11025,15 @@ mod tests {
                // Fund the channel with a batch funding transaction.
                let output_script = node_a_chan.context.get_funding_redeemscript();
                let tx = Transaction {
-                       version: 1,
+                       version: Version::ONE,
                        lock_time: LockTime::ZERO,
                        input: Vec::new(),
                        output: vec![
                                TxOut {
-                                       value: 10000000, script_pubkey: output_script.clone(),
+                                       value: Amount::from_sat(10000000), script_pubkey: output_script.clone(),
                                },
                                TxOut {
-                                       value: 10000000, script_pubkey: Builder::new().into_script(),
+                                       value: Amount::from_sat(10000000), script_pubkey: Builder::new().into_script(),
                                },
                        ]};
                let funding_outpoint = OutPoint{ txid: tx.txid(), index: 0 };
@@ -10938,6 +11090,6 @@ mod tests {
                // Clear the ChannelState::WaitingForBatch only when called by ChannelManager.
                node_a_chan.set_batch_ready();
                assert_eq!(node_a_chan.context.channel_state, ChannelState::AwaitingChannelReady(AwaitingChannelReadyFlags::THEIR_CHANNEL_READY));
-               assert!(node_a_chan.check_get_channel_ready(0).is_some());
+               assert!(node_a_chan.check_get_channel_ready(0, &&logger).is_some());
        }
 }