Get per commitment point for channel ready using HolderCommitmentPoint
[rust-lightning] / lightning / src / ln / channel.rs
index 33df5303814da439f5f83fd33a2acf53963b115f..68e70faf171e94504872ced0dc6b558b4d55bf6b 100644 (file)
@@ -24,7 +24,7 @@ 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;
@@ -37,7 +37,7 @@ 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 +50,6 @@ 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 +103,38 @@ 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 +164,13 @@ 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
@@ -896,25 +923,28 @@ 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 +1001,16 @@ 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 +1076,7 @@ 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 +1119,75 @@ 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
@@ -1161,9 +1263,9 @@ impl_writeable_tlv_based!(PendingChannelMonitorUpdate, {
 pub(super) enum ChannelPhase<SP: Deref> where SP::Target: SignerProvider {
        UnfundedOutboundV1(OutboundV1Channel<SP>),
        UnfundedInboundV1(InboundV1Channel<SP>),
-       #[cfg(dual_funding)]
+       #[cfg(any(dual_funding, splicing))]
        UnfundedOutboundV2(OutboundV2Channel<SP>),
-       #[cfg(dual_funding)]
+       #[cfg(any(dual_funding, splicing))]
        UnfundedInboundV2(InboundV2Channel<SP>),
        Funded(Channel<SP>),
 }
@@ -1177,9 +1279,9 @@ impl<'a, SP: Deref> ChannelPhase<SP> where
                        ChannelPhase::Funded(chan) => &chan.context,
                        ChannelPhase::UnfundedOutboundV1(chan) => &chan.context,
                        ChannelPhase::UnfundedInboundV1(chan) => &chan.context,
-                       #[cfg(dual_funding)]
+                       #[cfg(any(dual_funding, splicing))]
                        ChannelPhase::UnfundedOutboundV2(chan) => &chan.context,
-                       #[cfg(dual_funding)]
+                       #[cfg(any(dual_funding, splicing))]
                        ChannelPhase::UnfundedInboundV2(chan) => &chan.context,
                }
        }
@@ -1189,9 +1291,9 @@ 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(dual_funding)]
+                       #[cfg(any(dual_funding, splicing))]
                        ChannelPhase::UnfundedOutboundV2(ref mut chan) => &mut chan.context,
-                       #[cfg(dual_funding)]
+                       #[cfg(any(dual_funding, splicing))]
                        ChannelPhase::UnfundedInboundV2(ref mut chan) => &mut chan.context,
                }
        }
@@ -1264,7 +1366,7 @@ 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>,
@@ -1291,6 +1393,7 @@ 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
@@ -1369,7 +1472,7 @@ 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,
 
@@ -1540,7 +1643,7 @@ 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);
@@ -1705,6 +1808,9 @@ 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 {
@@ -1730,11 +1836,11 @@ 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,
 
@@ -1755,6 +1861,7 @@ 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,
@@ -1928,6 +2035,9 @@ 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,
 
@@ -1951,11 +2061,11 @@ 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,
 
@@ -1976,6 +2086,7 @@ 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,
@@ -2306,15 +2417,16 @@ 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,
                }
@@ -2699,7 +2811,7 @@ 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.
@@ -2707,86 +2819,111 @@ 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;
+                                       }
+                               }
+                       }
+               }
+
+               // 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,
                }
-               stats
        }
 
        /// Returns information on all pending inbound HTLCs.
@@ -2891,9 +3028,11 @@ 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() {
@@ -2901,10 +3040,10 @@ 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);
 
@@ -2964,7 +3103,7 @@ 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
@@ -2981,7 +3120,7 @@ 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)
@@ -2990,18 +3129,32 @@ 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);
                }
 
@@ -3014,16 +3167,16 @@ 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,
@@ -3470,7 +3623,7 @@ 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);
@@ -3492,8 +3645,19 @@ 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,
@@ -3510,7 +3674,7 @@ 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>,
 }
 
@@ -3581,7 +3745,7 @@ 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>,
@@ -4089,20 +4253,13 @@ impl<SP: Deref> Channel<SP> where
                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()));
@@ -4120,12 +4277,12 @@ 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)));
                }
 
@@ -4150,36 +4307,8 @@ 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 {
@@ -4211,23 +4340,7 @@ 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);
@@ -4255,7 +4368,9 @@ 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(())
        }
@@ -4341,9 +4456,9 @@ 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(self.context.holder_commitment_point.transaction_number());
 
-               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();
@@ -4461,13 +4576,13 @@ 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;
                        }
                }
@@ -4506,7 +4621,7 @@ 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.
@@ -4777,6 +4892,7 @@ 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();
@@ -4824,29 +4940,37 @@ 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;
                                                        }
                                                }
@@ -4907,6 +5031,8 @@ 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.
@@ -5004,12 +5130,12 @@ 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(self.context.holder_commitment_point.transaction_number());
+               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);
@@ -5017,14 +5143,12 @@ 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;
                }
@@ -5191,12 +5315,7 @@ 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);
@@ -5207,13 +5326,16 @@ 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
                        };
                }
 
@@ -5235,7 +5357,8 @@ 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
                }
        }
 
@@ -5253,20 +5376,16 @@ 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(())
        }
@@ -5282,7 +5401,7 @@ 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",
@@ -5298,8 +5417,8 @@ 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);
+               let next_per_commitment_point = self.context.holder_signer.as_ref().get_per_commitment_point(self.context.holder_commitment_point.transaction_number(), &self.context.secp_ctx);
+               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,
@@ -5432,7 +5551,7 @@ 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)
@@ -5494,13 +5613,8 @@ 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,
@@ -5537,14 +5651,9 @@ 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 {
@@ -6099,8 +6208,98 @@ 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 {
@@ -6176,6 +6375,26 @@ 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()
        }
@@ -6195,7 +6414,7 @@ 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
@@ -6254,7 +6473,9 @@ 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
@@ -6274,6 +6495,8 @@ 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;
                }
 
@@ -6306,22 +6529,35 @@ 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
@@ -6388,7 +6624,7 @@ 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);
@@ -6454,7 +6690,7 @@ 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 };
@@ -6757,7 +6993,7 @@ 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
@@ -7309,7 +7545,7 @@ 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");
                }
 
@@ -7361,6 +7597,12 @@ 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?");
@@ -7369,11 +7611,11 @@ 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);
+               let first_per_commitment_point = self.context.holder_signer.as_ref().get_per_commitment_point(self.context.holder_commitment_point.transaction_number(), &self.context.secp_ctx);
                let keys = self.context.get_holder_pubkeys();
 
                msgs::OpenChannel {
@@ -7554,7 +7796,7 @@ 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");
                }
 
@@ -7568,8 +7810,8 @@ 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(self.context.holder_commitment_point.transaction_number());
+               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();
@@ -7622,18 +7864,18 @@ 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))
        }
@@ -7703,7 +7945,7 @@ 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.
@@ -7758,7 +8000,7 @@ 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");
                }
 
@@ -7771,7 +8013,7 @@ 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);
+               let first_per_commitment_point = self.context.holder_signer.as_ref().get_per_commitment_point(self.context.holder_commitment_point.transaction_number(), &self.context.secp_ctx);
                let keys = self.context.get_holder_pubkeys();
 
                msgs::AcceptChannel {
@@ -7813,8 +8055,8 @@ 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(self.context.holder_commitment_point.transaction_number());
+               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);
@@ -7848,7 +8090,7 @@ 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");
                }
 
@@ -7888,7 +8130,7 @@ 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);
 
@@ -7919,10 +8161,10 @@ 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))
@@ -7930,15 +8172,15 @@ 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,
@@ -8009,15 +8251,15 @@ 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();
 
@@ -8054,14 +8296,14 @@ 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!
@@ -8151,7 +8393,7 @@ 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");
                }
 
@@ -8165,9 +8407,9 @@ 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 {
@@ -8232,7 +8474,7 @@ 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,;
@@ -8294,7 +8536,18 @@ 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
@@ -8329,7 +8582,7 @@ 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)?;
 
@@ -8350,13 +8603,29 @@ 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)?;
@@ -8582,6 +8851,15 @@ 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
@@ -8599,6 +8877,7 @@ 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),
@@ -8617,7 +8896,9 @@ 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(())
@@ -8693,8 +8974,22 @@ 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),
@@ -8911,6 +9206,10 @@ 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),
@@ -8923,6 +9222,7 @@ 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),
@@ -8941,7 +9241,9 @@ 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 {
@@ -9052,6 +9354,24 @@ 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,
@@ -9077,7 +9397,7 @@ 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,
 
@@ -9094,6 +9414,7 @@ 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,
@@ -9176,7 +9497,7 @@ 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,
                })
        }
@@ -9191,7 +9512,7 @@ mod tests {
        use bitcoin::blockdata::opcodes;
        use bitcoin::network::constants::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;
@@ -10950,6 +11271,6 @@ 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());
        }
 }