Introduce FeerateStrategy enum for onchain claims
[rust-lightning] / lightning / src / chain / onchaintx.rs
index 21b4717e1d9786dfd2b0eb68092e41f7b3d19afd..a629ecdefc273295563f5e77c57a16ea03a7c0e5 100644 (file)
 //! OnchainTxHandler objects are fully-part of ChannelMonitor and encapsulates all
 //! building, tracking, bumping and notifications functions.
 
-#[cfg(anchors)]
-use bitcoin::PackedLockTime;
+use bitcoin::blockdata::locktime::absolute::LockTime;
 use bitcoin::blockdata::transaction::Transaction;
 use bitcoin::blockdata::transaction::OutPoint as BitcoinOutPoint;
-use bitcoin::blockdata::script::Script;
-
+use bitcoin::blockdata::script::{Script, ScriptBuf};
+use bitcoin::hashes::{Hash, HashEngine};
+use bitcoin::hashes::sha256::Hash as Sha256;
 use bitcoin::hash_types::{Txid, BlockHash};
-
 use bitcoin::secp256k1::{Secp256k1, ecdsa::Signature};
 use bitcoin::secp256k1;
 
-use crate::sign::{ChannelSigner, EntropySource, SignerProvider};
+use crate::chain::chaininterface::compute_feerate_sat_per_1000_weight;
+use crate::sign::{ChannelDerivationParameters, HTLCDescriptor, ChannelSigner, EntropySource, SignerProvider, ecdsa::WriteableEcdsaChannelSigner};
 use crate::ln::msgs::DecodeError;
 use crate::ln::PaymentPreimage;
-#[cfg(anchors)]
-use crate::ln::chan_utils::{self, HTLCOutputInCommitment};
-use crate::ln::chan_utils::{ChannelTransactionParameters, HolderCommitmentTransaction};
-#[cfg(anchors)]
-use crate::chain::chaininterface::ConfirmationTarget;
-use crate::chain::chaininterface::{FeeEstimator, BroadcasterInterface, LowerBoundedFeeEstimator};
+use crate::ln::chan_utils::{self, ChannelTransactionParameters, HTLCOutputInCommitment, HolderCommitmentTransaction};
+use crate::chain::ClaimId;
+use crate::chain::chaininterface::{ConfirmationTarget, FeeEstimator, BroadcasterInterface, LowerBoundedFeeEstimator};
 use crate::chain::channelmonitor::{ANTI_REORG_DELAY, CLTV_SHARED_CLAIM_BUFFER};
-use crate::sign::WriteableEcdsaChannelSigner;
-#[cfg(anchors)]
-use crate::chain::package::PackageSolvingData;
-use crate::chain::package::PackageTemplate;
+use crate::chain::package::{PackageSolvingData, PackageTemplate};
 use crate::util::logger::Logger;
 use crate::util::ser::{Readable, ReadableArgs, MaybeReadable, UpgradableRequired, Writer, Writeable, VecWriter};
 
@@ -46,9 +40,8 @@ use alloc::collections::BTreeMap;
 use core::cmp;
 use core::ops::Deref;
 use core::mem::replace;
-#[cfg(anchors)]
 use core::mem::swap;
-use bitcoin::hashes::Hash;
+use crate::ln::features::ChannelTypeFeatures;
 
 const MAX_ALLOC_SIZE: usize = 64*1024;
 
@@ -56,7 +49,7 @@ const MAX_ALLOC_SIZE: usize = 64*1024;
 /// transaction causing it.
 ///
 /// Used to determine when the on-chain event can be considered safe from a chain reorganization.
-#[derive(PartialEq, Eq)]
+#[derive(Clone, PartialEq, Eq)]
 struct OnchainEventEntry {
        txid: Txid,
        height: u32,
@@ -76,14 +69,14 @@ impl OnchainEventEntry {
 
 /// Events for claims the [`OnchainTxHandler`] has generated. Once the events are considered safe
 /// from a chain reorg, the [`OnchainTxHandler`] will act accordingly.
-#[derive(PartialEq, Eq)]
+#[derive(Clone, PartialEq, Eq)]
 enum OnchainEvent {
        /// A pending request has been claimed by a transaction spending the exact same set of outpoints
        /// as the request. This claim can either be ours or from the counterparty. Once the claiming
        /// transaction has met [`ANTI_REORG_DELAY`] confirmations, we consider it final and remove the
        /// pending request.
        Claim {
-               package_id: PackageID,
+               claim_id: ClaimId,
        },
        /// The counterparty has claimed an outpoint from one of our pending requests through a
        /// different transaction than ours. If our transaction was attempting to claim multiple
@@ -126,7 +119,7 @@ impl MaybeReadable for OnchainEventEntry {
 
 impl_writeable_tlv_based_enum_upgradable!(OnchainEvent,
        (0, Claim) => {
-               (0, package_id, required),
+               (0, claim_id, required),
        },
        (1, ContentiousOutpoint) => {
                (0, package, required),
@@ -177,8 +170,8 @@ impl Writeable for Option<Vec<Option<(usize, Signature)>>> {
        }
 }
 
-#[cfg(anchors)]
 /// The claim commonly referred to as the pre-signed second-stage HTLC transaction.
+#[derive(Clone, PartialEq, Eq)]
 pub(crate) struct ExternalHTLCClaim {
        pub(crate) commitment_txid: Txid,
        pub(crate) per_commitment_number: u64,
@@ -189,7 +182,7 @@ pub(crate) struct ExternalHTLCClaim {
 
 // Represents the different types of claims for which events are yielded externally to satisfy said
 // claims.
-#[cfg(anchors)]
+#[derive(Clone, PartialEq, Eq)]
 pub(crate) enum ClaimEvent {
        /// Event yielded to signal that the commitment transaction fee must be bumped to claim any
        /// encumbered funds and proceed to HTLC resolution, if any HTLCs exist.
@@ -203,7 +196,7 @@ pub(crate) enum ClaimEvent {
        BumpHTLC {
                target_feerate_sat_per_1000_weight: u32,
                htlcs: Vec<ExternalHTLCClaim>,
-               tx_lock_time: PackedLockTime,
+               tx_lock_time: LockTime,
        },
 }
 
@@ -212,26 +205,29 @@ pub(crate) enum ClaimEvent {
 pub(crate) enum OnchainClaim {
        /// A finalized transaction pending confirmation spending the output to claim.
        Tx(Transaction),
-       #[cfg(anchors)]
        /// An event yielded externally to signal additional inputs must be added to a transaction
        /// pending confirmation spending the output to claim.
        Event(ClaimEvent),
 }
 
-/// An internal identifier to track pending package claims within the `OnchainTxHandler`.
-type PackageID = [u8; 32];
+/// Represents the different feerates a pending request can use when generating a claim.
+pub(crate) enum FeerateStrategy {
+       /// We must pick the highest between the most recently used and the current feerate estimate.
+       HighestOfPreviousOrNew,
+       /// We must force a bump of the most recently used feerate, either by using the current feerate
+       /// estimate if it's higher, or manually bumping.
+       ForceBump,
+}
 
 /// OnchainTxHandler receives claiming requests, aggregates them if it's sound, broadcast and
 /// do RBF bumping if possible.
+#[derive(Clone)]
 pub struct OnchainTxHandler<ChannelSigner: WriteableEcdsaChannelSigner> {
-       destination_script: Script,
+       channel_value_satoshis: u64,
+       channel_keys_id: [u8; 32],
+       destination_script: ScriptBuf,
        holder_commitment: HolderCommitmentTransaction,
-       // holder_htlc_sigs and prev_holder_htlc_sigs are in the order as they appear in the commitment
-       // transaction outputs (hence the Option<>s inside the Vec). The first usize is the index in
-       // the set of HTLCs in the HolderCommitmentTransaction.
-       holder_htlc_sigs: Option<Vec<Option<(usize, Signature)>>>,
        prev_holder_commitment: Option<HolderCommitmentTransaction>,
-       prev_holder_htlc_sigs: Option<Vec<Option<(usize, Signature)>>>,
 
        pub(super) signer: ChannelSigner,
        pub(crate) channel_transaction_parameters: ChannelTransactionParameters,
@@ -248,13 +244,13 @@ pub struct OnchainTxHandler<ChannelSigner: WriteableEcdsaChannelSigner> {
        // us and is immutable until all outpoint of the claimable set are post-anti-reorg-delay solved.
        // Entry is cache of elements need to generate a bumped claiming transaction (see ClaimTxBumpMaterial)
        #[cfg(test)] // Used in functional_test to verify sanitization
-       pub(crate) pending_claim_requests: HashMap<PackageID, PackageTemplate>,
+       pub(crate) pending_claim_requests: HashMap<ClaimId, PackageTemplate>,
        #[cfg(not(test))]
-       pending_claim_requests: HashMap<PackageID, PackageTemplate>,
+       pending_claim_requests: HashMap<ClaimId, PackageTemplate>,
 
        // Used to track external events that need to be forwarded to the `ChainMonitor`. This `Vec`
        // essentially acts as an insertion-ordered `HashMap` – there should only ever be one occurrence
-       // of a `PackageID`, which tracks its latest `ClaimEvent`, i.e., if a pending claim exists, and
+       // of a `ClaimId`, which tracks its latest `ClaimEvent`, i.e., if a pending claim exists, and
        // a new block has been connected, resulting in a new claim, the previous will be replaced with
        // the new.
        //
@@ -262,8 +258,7 @@ pub struct OnchainTxHandler<ChannelSigner: WriteableEcdsaChannelSigner> {
        //      - A channel has been force closed by broadcasting the holder's latest commitment transaction
        //      - A block being connected/disconnected
        //      - Learning the preimage for an HTLC we can claim onchain
-       #[cfg(anchors)]
-       pending_claim_events: Vec<(PackageID, ClaimEvent)>,
+       pending_claim_events: Vec<(ClaimId, ClaimEvent)>,
 
        // Used to link outpoints claimed in a connected block to a pending claim request. The keys
        // represent the outpoints that our `ChannelMonitor` has detected we have keys/scripts to
@@ -272,9 +267,9 @@ pub struct OnchainTxHandler<ChannelSigner: WriteableEcdsaChannelSigner> {
        // [`ANTI_REORG_DELAY`]. The initial confirmation block height is used to remove the entry if
        // the block gets disconnected.
        #[cfg(test)] // Used in functional_test to verify sanitization
-       pub claimable_outpoints: HashMap<BitcoinOutPoint, (PackageID, u32)>,
+       pub claimable_outpoints: HashMap<BitcoinOutPoint, (ClaimId, u32)>,
        #[cfg(not(test))]
-       claimable_outpoints: HashMap<BitcoinOutPoint, (PackageID, u32)>,
+       claimable_outpoints: HashMap<BitcoinOutPoint, (ClaimId, u32)>,
 
        locktimed_packages: BTreeMap<u32, Vec<PackageTemplate>>,
 
@@ -286,11 +281,11 @@ pub struct OnchainTxHandler<ChannelSigner: WriteableEcdsaChannelSigner> {
 impl<ChannelSigner: WriteableEcdsaChannelSigner> PartialEq for OnchainTxHandler<ChannelSigner> {
        fn eq(&self, other: &Self) -> bool {
                // `signer`, `secp_ctx`, and `pending_claim_events` are excluded on purpose.
-               self.destination_script == other.destination_script &&
+               self.channel_value_satoshis == other.channel_value_satoshis &&
+                       self.channel_keys_id == other.channel_keys_id &&
+                       self.destination_script == other.destination_script &&
                        self.holder_commitment == other.holder_commitment &&
-                       self.holder_htlc_sigs == other.holder_htlc_sigs &&
                        self.prev_holder_commitment == other.prev_holder_commitment &&
-                       self.prev_holder_htlc_sigs == other.prev_holder_htlc_sigs &&
                        self.channel_transaction_parameters == other.channel_transaction_parameters &&
                        self.pending_claim_requests == other.pending_claim_requests &&
                        self.claimable_outpoints == other.claimable_outpoints &&
@@ -308,9 +303,9 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
 
                self.destination_script.write(writer)?;
                self.holder_commitment.write(writer)?;
-               self.holder_htlc_sigs.write(writer)?;
+               None::<Option<Vec<Option<(usize, Signature)>>>>.write(writer)?; // holder_htlc_sigs
                self.prev_holder_commitment.write(writer)?;
-               self.prev_holder_htlc_sigs.write(writer)?;
+               None::<Option<Vec<Option<(usize, Signature)>>>>.write(writer)?; // prev_holder_htlc_sigs
 
                self.channel_transaction_parameters.write(writer)?;
 
@@ -353,7 +348,7 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
        }
 }
 
-impl<'a, 'b, ES: EntropySource, SP: SignerProvider> ReadableArgs<(&'a ES, &'b SP, u64, [u8; 32])> for OnchainTxHandler<SP::Signer> {
+impl<'a, 'b, ES: EntropySource, SP: SignerProvider> ReadableArgs<(&'a ES, &'b SP, u64, [u8; 32])> for OnchainTxHandler<SP::EcdsaSigner> {
        fn read<R: io::Read>(reader: &mut R, args: (&'a ES, &'b SP, u64, [u8; 32])) -> Result<Self, DecodeError> {
                let entropy_source = args.0;
                let signer_provider = args.1;
@@ -365,9 +360,9 @@ impl<'a, 'b, ES: EntropySource, SP: SignerProvider> ReadableArgs<(&'a ES, &'b SP
                let destination_script = Readable::read(reader)?;
 
                let holder_commitment = Readable::read(reader)?;
-               let holder_htlc_sigs = Readable::read(reader)?;
+               let _holder_htlc_sigs: Option<Vec<Option<(usize, Signature)>>> = Readable::read(reader)?;
                let prev_holder_commitment = Readable::read(reader)?;
-               let prev_holder_htlc_sigs = Readable::read(reader)?;
+               let _prev_holder_htlc_sigs: Option<Vec<Option<(usize, Signature)>>> = Readable::read(reader)?;
 
                let channel_parameters = Readable::read(reader)?;
 
@@ -388,13 +383,13 @@ impl<'a, 'b, ES: EntropySource, SP: SignerProvider> ReadableArgs<(&'a ES, &'b SP
                signer.provide_channel_parameters(&channel_parameters);
 
                let pending_claim_requests_len: u64 = Readable::read(reader)?;
-               let mut pending_claim_requests = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
+               let mut pending_claim_requests = hash_map_with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
                for _ in 0..pending_claim_requests_len {
                        pending_claim_requests.insert(Readable::read(reader)?, Readable::read(reader)?);
                }
 
                let claimable_outpoints_len: u64 = Readable::read(reader)?;
-               let mut claimable_outpoints = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
+               let mut claimable_outpoints = hash_map_with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
                for _ in 0..claimable_outpoints_len {
                        let outpoint = Readable::read(reader)?;
                        let ancestor_claim_txid = Readable::read(reader)?;
@@ -428,18 +423,17 @@ impl<'a, 'b, ES: EntropySource, SP: SignerProvider> ReadableArgs<(&'a ES, &'b SP
                secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
 
                Ok(OnchainTxHandler {
+                       channel_value_satoshis,
+                       channel_keys_id,
                        destination_script,
                        holder_commitment,
-                       holder_htlc_sigs,
                        prev_holder_commitment,
-                       prev_holder_htlc_sigs,
                        signer,
                        channel_transaction_parameters: channel_parameters,
                        claimable_outpoints,
                        locktimed_packages,
                        pending_claim_requests,
                        onchain_events_awaiting_threshold_conf,
-                       #[cfg(anchors)]
                        pending_claim_events: Vec::new(),
                        secp_ctx,
                })
@@ -447,20 +441,23 @@ impl<'a, 'b, ES: EntropySource, SP: SignerProvider> ReadableArgs<(&'a ES, &'b SP
 }
 
 impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner> {
-       pub(crate) fn new(destination_script: Script, signer: ChannelSigner, channel_parameters: ChannelTransactionParameters, holder_commitment: HolderCommitmentTransaction, secp_ctx: Secp256k1<secp256k1::All>) -> Self {
+       pub(crate) fn new(
+               channel_value_satoshis: u64, channel_keys_id: [u8; 32], destination_script: ScriptBuf,
+               signer: ChannelSigner, channel_parameters: ChannelTransactionParameters,
+               holder_commitment: HolderCommitmentTransaction, secp_ctx: Secp256k1<secp256k1::All>
+       ) -> Self {
                OnchainTxHandler {
+                       channel_value_satoshis,
+                       channel_keys_id,
                        destination_script,
                        holder_commitment,
-                       holder_htlc_sigs: None,
                        prev_holder_commitment: None,
-                       prev_holder_htlc_sigs: None,
                        signer,
                        channel_transaction_parameters: channel_parameters,
-                       pending_claim_requests: HashMap::new(),
-                       claimable_outpoints: HashMap::new(),
+                       pending_claim_requests: new_hash_map(),
+                       claimable_outpoints: new_hash_map(),
                        locktimed_packages: BTreeMap::new(),
                        onchain_events_awaiting_threshold_conf: Vec::new(),
-                       #[cfg(anchors)]
                        pending_claim_events: Vec::new(),
                        secp_ctx,
                }
@@ -474,11 +471,10 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
                self.holder_commitment.to_broadcaster_value_sat()
        }
 
-       #[cfg(anchors)]
-       pub(crate) fn get_and_clear_pending_claim_events(&mut self) -> Vec<ClaimEvent> {
+       pub(crate) fn get_and_clear_pending_claim_events(&mut self) -> Vec<(ClaimId, ClaimEvent)> {
                let mut events = Vec::new();
                swap(&mut events, &mut self.pending_claim_events);
-               events.into_iter().map(|(_, event)| event).collect()
+               events
        }
 
        /// Triggers rebroadcasts/fee-bumps of pending claims from a force-closed channel. This is
@@ -486,26 +482,25 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
        /// feerate changes between blocks, and ensuring reliability if broadcasting fails. We recommend
        /// invoking this every 30 seconds, or lower if running in an environment with spotty
        /// connections, like on mobile.
-       pub(crate) fn rebroadcast_pending_claims<B: Deref, F: Deref, L: Deref>(
-               &mut self, current_height: u32, broadcaster: &B, fee_estimator: &LowerBoundedFeeEstimator<F>,
-               logger: &L,
+       pub(super) fn rebroadcast_pending_claims<B: Deref, F: Deref, L: Logger>(
+               &mut self, current_height: u32, feerate_strategy: FeerateStrategy, broadcaster: &B,
+               fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L,
        )
        where
                B::Target: BroadcasterInterface,
                F::Target: FeeEstimator,
-               L::Target: Logger,
        {
                let mut bump_requests = Vec::with_capacity(self.pending_claim_requests.len());
-               for (package_id, request) in self.pending_claim_requests.iter() {
+               for (claim_id, request) in self.pending_claim_requests.iter() {
                        let inputs = request.outpoints();
                        log_info!(logger, "Triggering rebroadcast/fee-bump for request with inputs {:?}", inputs);
-                       bump_requests.push((*package_id, request.clone()));
+                       bump_requests.push((*claim_id, request.clone()));
                }
-               for (package_id, request) in bump_requests {
-                       self.generate_claim(current_height, &request, false /* force_feerate_bump */, fee_estimator, logger)
+               for (claim_id, request) in bump_requests {
+                       self.generate_claim(current_height, &request, &feerate_strategy, fee_estimator, logger)
                                .map(|(_, new_feerate, claim)| {
                                        let mut bumped_feerate = false;
-                                       if let Some(mut_request) = self.pending_claim_requests.get_mut(&package_id) {
+                                       if let Some(mut_request) = self.pending_claim_requests.get_mut(&claim_id) {
                                                bumped_feerate = request.previous_feerate() > new_feerate;
                                                mut_request.set_feerate(new_feerate);
                                        }
@@ -513,9 +508,8 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
                                                OnchainClaim::Tx(tx) => {
                                                        let log_start = if bumped_feerate { "Broadcasting RBF-bumped" } else { "Rebroadcasting" };
                                                        log_info!(logger, "{} onchain {}", log_start, log_tx!(tx));
-                                                       broadcaster.broadcast_transaction(&tx);
+                                                       broadcaster.broadcast_transactions(&[&tx]);
                                                },
-                                               #[cfg(anchors)]
                                                OnchainClaim::Event(event) => {
                                                        let log_start = if bumped_feerate { "Yielding fee-bumped" } else { "Replaying" };
                                                        log_info!(logger, "{} onchain event to spend inputs {:?}", log_start,
@@ -523,11 +517,11 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
                                                        #[cfg(debug_assertions)] {
                                                                debug_assert!(request.requires_external_funding());
                                                                let num_existing = self.pending_claim_events.iter()
-                                                                       .filter(|entry| entry.0 == package_id).count();
+                                                                       .filter(|entry| entry.0 == claim_id).count();
                                                                assert!(num_existing == 0 || num_existing == 1);
                                                        }
-                                                       self.pending_claim_events.retain(|event| event.0 != package_id);
-                                                       self.pending_claim_events.push((package_id, event));
+                                                       self.pending_claim_events.retain(|event| event.0 != claim_id);
+                                                       self.pending_claim_events.push((claim_id, event));
                                                }
                                        }
                                });
@@ -542,13 +536,11 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
        ///
        /// Panics if there are signing errors, because signing operations in reaction to on-chain
        /// events are not expected to fail, and if they do, we may lose funds.
-       fn generate_claim<F: Deref, L: Deref>(
-               &mut self, cur_height: u32, cached_request: &PackageTemplate, force_feerate_bump: bool,
+       fn generate_claim<F: Deref, L: Logger>(
+               &mut self, cur_height: u32, cached_request: &PackageTemplate, feerate_strategy: &FeerateStrategy,
                fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L,
        ) -> Option<(u32, u64, OnchainClaim)>
-       where
-               F::Target: FeeEstimator,
-               L::Target: Logger,
+       where F::Target: FeeEstimator,
        {
                let request_outpoints = cached_request.outpoints();
                if request_outpoints.is_empty() {
@@ -564,12 +556,12 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
                // transaction is reorged out.
                let mut all_inputs_have_confirmed_spend = true;
                for outpoint in request_outpoints.iter() {
-                       if let Some((request_package_id, _)) = self.claimable_outpoints.get(*outpoint) {
+                       if let Some((request_claim_id, _)) = self.claimable_outpoints.get(*outpoint) {
                                // We check for outpoint spends within claims individually rather than as a set
                                // since requests can have outpoints split off.
                                if !self.onchain_events_awaiting_threshold_conf.iter()
-                                       .any(|event_entry| if let OnchainEvent::Claim { package_id } = event_entry.event {
-                                               *request_package_id == package_id
+                                       .any(|event_entry| if let OnchainEvent::Claim { claim_id } = event_entry.event {
+                                               *request_claim_id == claim_id
                                        } else {
                                                // The onchain event is not a claim, keep seeking until we find one.
                                                false
@@ -592,32 +584,29 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
                // didn't receive confirmation of it before, or not enough reorg-safe depth on top of it).
                let new_timer = cached_request.get_height_timer(cur_height);
                if cached_request.is_malleable() {
-                       #[cfg(anchors)]
-                       { // Attributes are not allowed on if expressions on our current MSRV of 1.41.
-                               if cached_request.requires_external_funding() {
-                                       let target_feerate_sat_per_1000_weight = cached_request.compute_package_feerate(
-                                               fee_estimator, ConfirmationTarget::HighPriority, force_feerate_bump
-                                       );
-                                       if let Some(htlcs) = cached_request.construct_malleable_package_with_external_funding(self) {
-                                               return Some((
-                                                       new_timer,
-                                                       target_feerate_sat_per_1000_weight as u64,
-                                                       OnchainClaim::Event(ClaimEvent::BumpHTLC {
-                                                               target_feerate_sat_per_1000_weight,
-                                                               htlcs,
-                                                               tx_lock_time: PackedLockTime(cached_request.package_locktime(cur_height)),
-                                                       }),
-                                               ));
-                                       } else {
-                                               return None;
-                                       }
+                       if cached_request.requires_external_funding() {
+                               let target_feerate_sat_per_1000_weight = cached_request.compute_package_feerate(
+                                       fee_estimator, ConfirmationTarget::OnChainSweep, feerate_strategy,
+                               );
+                               if let Some(htlcs) = cached_request.construct_malleable_package_with_external_funding(self) {
+                                       return Some((
+                                               new_timer,
+                                               target_feerate_sat_per_1000_weight as u64,
+                                               OnchainClaim::Event(ClaimEvent::BumpHTLC {
+                                                       target_feerate_sat_per_1000_weight,
+                                                       htlcs,
+                                                       tx_lock_time: LockTime::from_consensus(cached_request.package_locktime(cur_height)),
+                                               }),
+                                       ));
+                               } else {
+                                       return None;
                                }
                        }
 
                        let predicted_weight = cached_request.package_weight(&self.destination_script);
                        if let Some((output_value, new_feerate)) = cached_request.compute_package_output(
                                predicted_weight, self.destination_script.dust_value().to_sat(),
-                               force_feerate_bump, fee_estimator, logger,
+                               feerate_strategy, fee_estimator, logger,
                        ) {
                                assert!(new_feerate != 0);
 
@@ -625,16 +614,13 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
                                        cur_height, self, output_value, self.destination_script.clone(), logger
                                ).unwrap();
                                log_trace!(logger, "...with timer {} and feerate {}", new_timer, new_feerate);
-                               assert!(predicted_weight >= transaction.weight());
+                               assert!(predicted_weight >= transaction.weight().to_wu());
                                return Some((new_timer, new_feerate, OnchainClaim::Tx(transaction)));
                        }
                } else {
                        // Untractable packages cannot have their fees bumped through Replace-By-Fee. Some
                        // packages may support fee bumping through Child-Pays-For-Parent, indicated by those
                        // which require external funding.
-                       #[cfg(not(anchors))]
-                       let inputs = cached_request.inputs();
-                       #[cfg(anchors)]
                        let mut inputs = cached_request.inputs();
                        debug_assert_eq!(inputs.len(), 1);
                        let tx = match cached_request.finalize_untractable_package(self, logger) {
@@ -644,13 +630,28 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
                        if !cached_request.requires_external_funding() {
                                return Some((new_timer, 0, OnchainClaim::Tx(tx)));
                        }
-                       #[cfg(anchors)]
                        return inputs.find_map(|input| match input {
                                // Commitment inputs with anchors support are the only untractable inputs supported
                                // thus far that require external funding.
-                               PackageSolvingData::HolderFundingOutput(..) => {
+                               PackageSolvingData::HolderFundingOutput(output) => {
                                        debug_assert_eq!(tx.txid(), self.holder_commitment.trust().txid(),
                                                "Holder commitment transaction mismatch");
+
+                                       let conf_target = ConfirmationTarget::OnChainSweep;
+                                       let package_target_feerate_sat_per_1000_weight = cached_request
+                                               .compute_package_feerate(fee_estimator, conf_target, feerate_strategy);
+                                       if let Some(input_amount_sat) = output.funding_amount {
+                                               let fee_sat = input_amount_sat - tx.output.iter().map(|output| output.value).sum::<u64>();
+                                               let commitment_tx_feerate_sat_per_1000_weight =
+                                                       compute_feerate_sat_per_1000_weight(fee_sat, tx.weight().to_wu());
+                                               if commitment_tx_feerate_sat_per_1000_weight >= package_target_feerate_sat_per_1000_weight {
+                                                       log_debug!(logger, "Pre-signed {} already has feerate {} sat/kW above required {} sat/kW",
+                                                               log_tx!(tx), commitment_tx_feerate_sat_per_1000_weight,
+                                                               package_target_feerate_sat_per_1000_weight);
+                                                       return Some((new_timer, 0, OnchainClaim::Tx(tx.clone())));
+                                               }
+                                       }
+
                                        // We'll locate an anchor output we can spend within the commitment transaction.
                                        let funding_pubkey = &self.channel_transaction_parameters.holder_pubkeys.funding_pubkey;
                                        match chan_utils::get_anchor_output(&tx, funding_pubkey) {
@@ -658,9 +659,6 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
                                                Some((idx, _)) => {
                                                        // TODO: Use a lower confirmation target when both our and the
                                                        // counterparty's latest commitment don't have any HTLCs present.
-                                                       let conf_target = ConfirmationTarget::HighPriority;
-                                                       let package_target_feerate_sat_per_1000_weight = cached_request
-                                                               .compute_package_feerate(fee_estimator, conf_target, force_feerate_bump);
                                                        Some((
                                                                new_timer,
                                                                package_target_feerate_sat_per_1000_weight as u64,
@@ -687,6 +685,25 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
                None
        }
 
+       pub fn abandon_claim(&mut self, outpoint: &BitcoinOutPoint) {
+               let claim_id = self.claimable_outpoints.get(outpoint).map(|(claim_id, _)| *claim_id)
+                       .or_else(|| {
+                               self.pending_claim_requests.iter()
+                                       .find(|(_, claim)| claim.outpoints().iter().any(|claim_outpoint| *claim_outpoint == outpoint))
+                                       .map(|(claim_id, _)| *claim_id)
+                       });
+               if let Some(claim_id) = claim_id {
+                       if let Some(claim) = self.pending_claim_requests.remove(&claim_id) {
+                               for outpoint in claim.outpoints() {
+                                       self.claimable_outpoints.remove(outpoint);
+                               }
+                       }
+               } else {
+                       self.locktimed_packages.values_mut().for_each(|claims|
+                               claims.retain(|claim| !claim.outpoints().iter().any(|claim_outpoint| *claim_outpoint == outpoint)));
+               }
+       }
+
        /// Upon channelmonitor.block_connected(..) or upon provision of a preimage on the forward link
        /// for this channel, provide new relevant on-chain transactions and/or new claim requests.
        /// Together with `update_claims_view_from_matched_txn` this used to be named
@@ -696,13 +713,12 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
        /// `conf_height` represents the height at which the request was generated. This
        /// does not need to equal the current blockchain tip height, which should be provided via
        /// `cur_height`, however it must never be higher than `cur_height`.
-       pub(crate) fn update_claims_view_from_requests<B: Deref, F: Deref, L: Deref>(
+       pub(super) fn update_claims_view_from_requests<B: Deref, F: Deref, L: Logger>(
                &mut self, requests: Vec<PackageTemplate>, conf_height: u32, cur_height: u32,
                broadcaster: &B, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L
        ) where
                B::Target: BroadcasterInterface,
                F::Target: FeeEstimator,
-               L::Target: Logger,
        {
                log_debug!(logger, "Updating claims view at height {} with {} claim requests", cur_height, requests.len());
                let mut preprocessed_requests = Vec::with_capacity(requests.len());
@@ -760,43 +776,53 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
                // height timer expiration (i.e in how many blocks we're going to take action).
                for mut req in preprocessed_requests {
                        if let Some((new_timer, new_feerate, claim)) = self.generate_claim(
-                               cur_height, &req, true /* force_feerate_bump */, &*fee_estimator, &*logger,
+                               cur_height, &req, &FeerateStrategy::ForceBump, &*fee_estimator, &*logger,
                        ) {
                                req.set_timer(new_timer);
                                req.set_feerate(new_feerate);
-                               let package_id = match claim {
+                               // Once a pending claim has an id assigned, it remains fixed until the claim is
+                               // satisfied, regardless of whether the claim switches between different variants of
+                               // `OnchainClaim`.
+                               let claim_id = match claim {
                                        OnchainClaim::Tx(tx) => {
                                                log_info!(logger, "Broadcasting onchain {}", log_tx!(tx));
-                                               broadcaster.broadcast_transaction(&tx);
-                                               tx.txid().into_inner()
+                                               broadcaster.broadcast_transactions(&[&tx]);
+                                               ClaimId(tx.txid().to_byte_array())
                                        },
-                                       #[cfg(anchors)]
                                        OnchainClaim::Event(claim_event) => {
                                                log_info!(logger, "Yielding onchain event to spend inputs {:?}", req.outpoints());
-                                               let package_id = match claim_event {
-                                                       ClaimEvent::BumpCommitment { ref commitment_tx, .. } => commitment_tx.txid().into_inner(),
+                                               let claim_id = match claim_event {
+                                                       ClaimEvent::BumpCommitment { ref commitment_tx, .. } =>
+                                                               // For commitment claims, we can just use their txid as it should
+                                                               // already be unique.
+                                                               ClaimId(commitment_tx.txid().to_byte_array()),
                                                        ClaimEvent::BumpHTLC { ref htlcs, .. } => {
-                                                               // Use the same construction as a lightning channel id to generate
-                                                               // the package id for this request based on the first HTLC. It
-                                                               // doesn't matter what we use as long as it's unique per request.
-                                                               let mut package_id = [0; 32];
-                                                               package_id[..].copy_from_slice(&htlcs[0].commitment_txid[..]);
-                                                               let htlc_output_index = htlcs[0].htlc.transaction_output_index.unwrap();
-                                                               package_id[30] ^= ((htlc_output_index >> 8) & 0xff) as u8;
-                                                               package_id[31] ^= ((htlc_output_index >> 0) & 0xff) as u8;
-                                                               package_id
+                                                               // For HTLC claims, commit to the entire set of HTLC outputs to
+                                                               // claim, which will always be unique per request. Once a claim ID
+                                                               // is generated, it is assigned and remains unchanged, even if the
+                                                               // underlying set of HTLCs changes.
+                                                               let mut engine = Sha256::engine();
+                                                               for htlc in htlcs {
+                                                                       engine.input(&htlc.commitment_txid.to_byte_array());
+                                                                       engine.input(&htlc.htlc.transaction_output_index.unwrap().to_be_bytes());
+                                                               }
+                                                               ClaimId(Sha256::from_engine(engine).to_byte_array())
                                                        },
                                                };
-                                               debug_assert_eq!(self.pending_claim_events.iter().filter(|entry| entry.0 == package_id).count(), 0);
-                                               self.pending_claim_events.push((package_id, claim_event));
-                                               package_id
+                                               debug_assert!(self.pending_claim_requests.get(&claim_id).is_none());
+                                               debug_assert_eq!(self.pending_claim_events.iter().filter(|entry| entry.0 == claim_id).count(), 0);
+                                               self.pending_claim_events.push((claim_id, claim_event));
+                                               claim_id
                                        },
                                };
+                               // Because fuzzing can cause hash collisions, we can end up with conflicting claim
+                               // ids here, so we only assert when not fuzzing.
+                               debug_assert!(cfg!(fuzzing) || self.pending_claim_requests.get(&claim_id).is_none());
                                for k in req.outpoints() {
                                        log_info!(logger, "Registering claiming request for {}:{}", k.txid, k.vout);
-                                       self.claimable_outpoints.insert(k.clone(), (package_id, conf_height));
+                                       self.claimable_outpoints.insert(k.clone(), (claim_id, conf_height));
                                }
-                               self.pending_claim_requests.insert(package_id, req);
+                               self.pending_claim_requests.insert(claim_id, req);
                        }
                }
        }
@@ -809,23 +835,22 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
        /// `conf_height` represents the height at which the transactions in `txn_matched` were
        /// confirmed. This does not need to equal the current blockchain tip height, which should be
        /// provided via `cur_height`, however it must never be higher than `cur_height`.
-       pub(crate) fn update_claims_view_from_matched_txn<B: Deref, F: Deref, L: Deref>(
+       pub(super) fn update_claims_view_from_matched_txn<B: Deref, F: Deref, L: Logger>(
                &mut self, txn_matched: &[&Transaction], conf_height: u32, conf_hash: BlockHash,
                cur_height: u32, broadcaster: &B, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L
        ) where
                B::Target: BroadcasterInterface,
                F::Target: FeeEstimator,
-               L::Target: Logger,
        {
                log_debug!(logger, "Updating claims view at height {} with {} matched transactions in block {}", cur_height, txn_matched.len(), conf_height);
-               let mut bump_candidates = HashMap::new();
+               let mut bump_candidates = new_hash_map();
                for tx in txn_matched {
                        // Scan all input to verify is one of the outpoint spent is of interest for us
                        let mut claimed_outputs_material = Vec::new();
                        for inp in &tx.input {
-                               if let Some((package_id, _)) = self.claimable_outpoints.get(&inp.previous_output) {
+                               if let Some((claim_id, _)) = self.claimable_outpoints.get(&inp.previous_output) {
                                        // If outpoint has claim request pending on it...
-                                       if let Some(request) = self.pending_claim_requests.get_mut(package_id) {
+                                       if let Some(request) = self.pending_claim_requests.get_mut(claim_id) {
                                                //... we need to verify equality between transaction outpoints and claim request
                                                // outpoints to know if transaction is the original claim or a bumped one issued
                                                // by us.
@@ -845,7 +870,7 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
                                                                        txid: tx.txid(),
                                                                        height: conf_height,
                                                                        block_hash: Some(conf_hash),
-                                                                       event: OnchainEvent::Claim { package_id: *package_id }
+                                                                       event: OnchainEvent::Claim { claim_id: *claim_id }
                                                                };
                                                                if !self.onchain_events_awaiting_threshold_conf.contains(&entry) {
                                                                        self.onchain_events_awaiting_threshold_conf.push(entry);
@@ -872,21 +897,19 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
                                                        }
                                                        //TODO: recompute soonest_timelock to avoid wasting a bit on fees
                                                        if at_least_one_drop {
-                                                               bump_candidates.insert(*package_id, request.clone());
+                                                               bump_candidates.insert(*claim_id, request.clone());
                                                                // If we have any pending claim events for the request being updated
                                                                // that have yet to be consumed, we'll remove them since they will
                                                                // end up producing an invalid transaction by double spending
                                                                // input(s) that already have a confirmed spend. If such spend is
                                                                // reorged out of the chain, then we'll attempt to re-spend the
                                                                // inputs once we see it.
-                                                               #[cfg(anchors)] {
-                                                                       #[cfg(debug_assertions)] {
-                                                                               let existing = self.pending_claim_events.iter()
-                                                                                       .filter(|entry| entry.0 == *package_id).count();
-                                                                               assert!(existing == 0 || existing == 1);
-                                                                       }
-                                                                       self.pending_claim_events.retain(|entry| entry.0 != *package_id);
+                                                               #[cfg(debug_assertions)] {
+                                                                       let existing = self.pending_claim_events.iter()
+                                                                               .filter(|entry| entry.0 == *claim_id).count();
+                                                                       assert!(existing == 0 || existing == 1);
                                                                }
+                                                               self.pending_claim_events.retain(|entry| entry.0 != *claim_id);
                                                        }
                                                }
                                                break; //No need to iterate further, either tx is our or their
@@ -914,23 +937,21 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
                for entry in onchain_events_awaiting_threshold_conf {
                        if entry.has_reached_confirmation_threshold(cur_height) {
                                match entry.event {
-                                       OnchainEvent::Claim { package_id } => {
+                                       OnchainEvent::Claim { claim_id } => {
                                                // We may remove a whole set of claim outpoints here, as these one may have
                                                // been aggregated in a single tx and claimed so atomically
-                                               if let Some(request) = self.pending_claim_requests.remove(&package_id) {
+                                               if let Some(request) = self.pending_claim_requests.remove(&claim_id) {
                                                        for outpoint in request.outpoints() {
                                                                log_debug!(logger, "Removing claim tracking for {} due to maturation of claim package {}.",
-                                                                       outpoint, log_bytes!(package_id));
+                                                                       outpoint, log_bytes!(claim_id.0));
                                                                self.claimable_outpoints.remove(outpoint);
                                                        }
-                                                       #[cfg(anchors)] {
-                                                               #[cfg(debug_assertions)] {
-                                                                       let num_existing = self.pending_claim_events.iter()
-                                                                               .filter(|entry| entry.0 == package_id).count();
-                                                                       assert!(num_existing == 0 || num_existing == 1);
-                                                               }
-                                                               self.pending_claim_events.retain(|(id, _)| *id != package_id);
+                                                       #[cfg(debug_assertions)] {
+                                                               let num_existing = self.pending_claim_events.iter()
+                                                                       .filter(|entry| entry.0 == claim_id).count();
+                                                               assert!(num_existing == 0 || num_existing == 1);
                                                        }
+                                                       self.pending_claim_events.retain(|(id, _)| *id != claim_id);
                                                }
                                        },
                                        OnchainEvent::ContentiousOutpoint { package } => {
@@ -945,36 +966,35 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
                }
 
                // Check if any pending claim request must be rescheduled
-               for (package_id, request) in self.pending_claim_requests.iter() {
+               for (claim_id, request) in self.pending_claim_requests.iter() {
                        if cur_height >= request.timer() {
-                               bump_candidates.insert(*package_id, request.clone());
+                               bump_candidates.insert(*claim_id, request.clone());
                        }
                }
 
                // Build, bump and rebroadcast tx accordingly
                log_trace!(logger, "Bumping {} candidates", bump_candidates.len());
-               for (package_id, request) in bump_candidates.iter() {
+               for (claim_id, request) in bump_candidates.iter() {
                        if let Some((new_timer, new_feerate, bump_claim)) = self.generate_claim(
-                               cur_height, &request, true /* force_feerate_bump */, &*fee_estimator, &*logger,
+                               cur_height, &request, &FeerateStrategy::ForceBump, &*fee_estimator, &*logger,
                        ) {
                                match bump_claim {
                                        OnchainClaim::Tx(bump_tx) => {
                                                log_info!(logger, "Broadcasting RBF-bumped onchain {}", log_tx!(bump_tx));
-                                               broadcaster.broadcast_transaction(&bump_tx);
+                                               broadcaster.broadcast_transactions(&[&bump_tx]);
                                        },
-                                       #[cfg(anchors)]
                                        OnchainClaim::Event(claim_event) => {
                                                log_info!(logger, "Yielding RBF-bumped onchain event to spend inputs {:?}", request.outpoints());
                                                #[cfg(debug_assertions)] {
                                                        let num_existing = self.pending_claim_events.iter().
-                                                               filter(|entry| entry.0 == *package_id).count();
+                                                               filter(|entry| entry.0 == *claim_id).count();
                                                        assert!(num_existing == 0 || num_existing == 1);
                                                }
-                                               self.pending_claim_events.retain(|event| event.0 != *package_id);
-                                               self.pending_claim_events.push((*package_id, claim_event));
+                                               self.pending_claim_events.retain(|event| event.0 != *claim_id);
+                                               self.pending_claim_events.push((*claim_id, claim_event));
                                        },
                                }
-                               if let Some(request) = self.pending_claim_requests.get_mut(package_id) {
+                               if let Some(request) = self.pending_claim_requests.get_mut(claim_id) {
                                        request.set_timer(new_timer);
                                        request.set_feerate(new_feerate);
                                }
@@ -982,16 +1002,15 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
                }
        }
 
-       pub(crate) fn transaction_unconfirmed<B: Deref, F: Deref, L: Deref>(
+       pub(super) fn transaction_unconfirmed<B: Deref, F: Deref, L: Logger>(
                &mut self,
                txid: &Txid,
                broadcaster: B,
                fee_estimator: &LowerBoundedFeeEstimator<F>,
-               logger: L,
+               logger: &L,
        ) where
                B::Target: BroadcasterInterface,
                F::Target: FeeEstimator,
-               L::Target: Logger,
        {
                let mut height = None;
                for entry in self.onchain_events_awaiting_threshold_conf.iter() {
@@ -1006,12 +1025,11 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
                }
        }
 
-       pub(crate) fn block_disconnected<B: Deref, F: Deref, L: Deref>(&mut self, height: u32, broadcaster: B, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: L)
+       pub(super) fn block_disconnected<B: Deref, F: Deref, L: Logger>(&mut self, height: u32, broadcaster: B, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L)
                where B::Target: BroadcasterInterface,
-                     F::Target: FeeEstimator,
-                                       L::Target: Logger,
+                       F::Target: FeeEstimator,
        {
-               let mut bump_candidates = HashMap::new();
+               let mut bump_candidates = new_hash_map();
                let onchain_events_awaiting_threshold_conf =
                        self.onchain_events_awaiting_threshold_conf.drain(..).collect::<Vec<_>>();
                for entry in onchain_events_awaiting_threshold_conf {
@@ -1035,29 +1053,28 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
                                self.onchain_events_awaiting_threshold_conf.push(entry);
                        }
                }
-               for ((_package_id, _), ref mut request) in bump_candidates.iter_mut() {
+               for ((_claim_id, _), ref mut request) in bump_candidates.iter_mut() {
                        // `height` is the height being disconnected, so our `current_height` is 1 lower.
                        let current_height = height - 1;
                        if let Some((new_timer, new_feerate, bump_claim)) = self.generate_claim(
-                               current_height, &request, true /* force_feerate_bump */, fee_estimator, &&*logger
+                               current_height, &request, &FeerateStrategy::ForceBump, fee_estimator, logger
                        ) {
                                request.set_timer(new_timer);
                                request.set_feerate(new_feerate);
                                match bump_claim {
                                        OnchainClaim::Tx(bump_tx) => {
                                                log_info!(logger, "Broadcasting onchain {}", log_tx!(bump_tx));
-                                               broadcaster.broadcast_transaction(&bump_tx);
+                                               broadcaster.broadcast_transactions(&[&bump_tx]);
                                        },
-                                       #[cfg(anchors)]
                                        OnchainClaim::Event(claim_event) => {
                                                log_info!(logger, "Yielding onchain event after reorg to spend inputs {:?}", request.outpoints());
                                                #[cfg(debug_assertions)] {
                                                        let num_existing = self.pending_claim_events.iter()
-                                                               .filter(|entry| entry.0 == *_package_id).count();
+                                                               .filter(|entry| entry.0 == *_claim_id).count();
                                                        assert!(num_existing == 0 || num_existing == 1);
                                                }
-                                               self.pending_claim_events.retain(|event| event.0 != *_package_id);
-                                               self.pending_claim_events.push((*_package_id, claim_event));
+                                               self.pending_claim_events.retain(|event| event.0 != *_claim_id);
+                                               self.pending_claim_events.push((*_claim_id, claim_event));
                                        },
                                }
                        }
@@ -1082,103 +1099,79 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
                self.claimable_outpoints.get(outpoint).is_some()
        }
 
-       pub(crate) fn get_relevant_txids(&self) -> Vec<(Txid, Option<BlockHash>)> {
-               let mut txids: Vec<(Txid, Option<BlockHash>)> = self.onchain_events_awaiting_threshold_conf
+       pub(crate) fn get_relevant_txids(&self) -> Vec<(Txid, u32, Option<BlockHash>)> {
+               let mut txids: Vec<(Txid, u32, Option<BlockHash>)> = self.onchain_events_awaiting_threshold_conf
                        .iter()
-                       .map(|entry| (entry.txid, entry.block_hash))
+                       .map(|entry| (entry.txid, entry.height, entry.block_hash))
                        .collect();
-               txids.sort_unstable_by_key(|(txid, _)| *txid);
-               txids.dedup();
+               txids.sort_unstable_by(|a, b| a.0.cmp(&b.0).then(b.1.cmp(&a.1)));
+               txids.dedup_by_key(|(txid, _, _)| *txid);
                txids
        }
 
        pub(crate) fn provide_latest_holder_tx(&mut self, tx: HolderCommitmentTransaction) {
                self.prev_holder_commitment = Some(replace(&mut self.holder_commitment, tx));
-               self.holder_htlc_sigs = None;
        }
 
-       // Normally holder HTLCs are signed at the same time as the holder commitment tx.  However,
-       // in some configurations, the holder commitment tx has been signed and broadcast by a
-       // ChannelMonitor replica, so we handle that case here.
-       fn sign_latest_holder_htlcs(&mut self) {
-               if self.holder_htlc_sigs.is_none() {
-                       let (_sig, sigs) = self.signer.sign_holder_commitment_and_htlcs(&self.holder_commitment, &self.secp_ctx).expect("sign holder commitment");
-                       self.holder_htlc_sigs = Some(Self::extract_holder_sigs(&self.holder_commitment, sigs));
-               }
-       }
-
-       // Normally only the latest commitment tx and HTLCs need to be signed.  However, in some
-       // configurations we may have updated our holder commitment but a replica of the ChannelMonitor
-       // broadcast the previous one before we sync with it.  We handle that case here.
-       fn sign_prev_holder_htlcs(&mut self) {
-               if self.prev_holder_htlc_sigs.is_none() {
-                       if let Some(ref holder_commitment) = self.prev_holder_commitment {
-                               let (_sig, sigs) = self.signer.sign_holder_commitment_and_htlcs(holder_commitment, &self.secp_ctx).expect("sign previous holder commitment");
-                               self.prev_holder_htlc_sigs = Some(Self::extract_holder_sigs(holder_commitment, sigs));
-                       }
-               }
-       }
-
-       fn extract_holder_sigs(holder_commitment: &HolderCommitmentTransaction, sigs: Vec<Signature>) -> Vec<Option<(usize, Signature)>> {
-               let mut ret = Vec::new();
-               for (htlc_idx, (holder_sig, htlc)) in sigs.iter().zip(holder_commitment.htlcs().iter()).enumerate() {
-                       let tx_idx = htlc.transaction_output_index.unwrap();
-                       if ret.len() <= tx_idx as usize { ret.resize(tx_idx as usize + 1, None); }
-                       ret[tx_idx as usize] = Some((htlc_idx, holder_sig.clone()));
-               }
-               ret
+       pub(crate) fn get_unsigned_holder_commitment_tx(&self) -> &Transaction {
+               &self.holder_commitment.trust().built_transaction().transaction
        }
 
        //TODO: getting lastest holder transactions should be infallible and result in us "force-closing the channel", but we may
-       // have empty holder commitment transaction if a ChannelMonitor is asked to force-close just after Channel::get_outbound_funding_created,
+       // have empty holder commitment transaction if a ChannelMonitor is asked to force-close just after OutboundV1Channel::get_funding_created,
        // before providing a initial commitment transaction. For outbound channel, init ChannelMonitor at Channel::funding_signed, there is nothing
        // to monitor before.
        pub(crate) fn get_fully_signed_holder_tx(&mut self, funding_redeemscript: &Script) -> Transaction {
-               let (sig, htlc_sigs) = self.signer.sign_holder_commitment_and_htlcs(&self.holder_commitment, &self.secp_ctx).expect("signing holder commitment");
-               self.holder_htlc_sigs = Some(Self::extract_holder_sigs(&self.holder_commitment, htlc_sigs));
+               let sig = self.signer.sign_holder_commitment(&self.holder_commitment, &self.secp_ctx).expect("signing holder commitment");
                self.holder_commitment.add_holder_sig(funding_redeemscript, sig)
        }
 
        #[cfg(any(test, feature="unsafe_revoked_tx_signing"))]
        pub(crate) fn get_fully_signed_copy_holder_tx(&mut self, funding_redeemscript: &Script) -> Transaction {
-               let (sig, htlc_sigs) = self.signer.unsafe_sign_holder_commitment_and_htlcs(&self.holder_commitment, &self.secp_ctx).expect("sign holder commitment");
-               self.holder_htlc_sigs = Some(Self::extract_holder_sigs(&self.holder_commitment, htlc_sigs));
+               let sig = self.signer.unsafe_sign_holder_commitment(&self.holder_commitment, &self.secp_ctx).expect("sign holder commitment");
                self.holder_commitment.add_holder_sig(funding_redeemscript, sig)
        }
 
        pub(crate) fn get_fully_signed_htlc_tx(&mut self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>) -> Option<Transaction> {
-               let mut htlc_tx = None;
-               let commitment_txid = self.holder_commitment.trust().txid();
-               // Check if the HTLC spends from the current holder commitment
-               if commitment_txid == outp.txid {
-                       self.sign_latest_holder_htlcs();
-                       if let &Some(ref htlc_sigs) = &self.holder_htlc_sigs {
-                               let &(ref htlc_idx, ref htlc_sig) = htlc_sigs[outp.vout as usize].as_ref().unwrap();
-                               let trusted_tx = self.holder_commitment.trust();
-                               let counterparty_htlc_sig = self.holder_commitment.counterparty_htlc_sigs[*htlc_idx];
-                               htlc_tx = Some(trusted_tx
-                                       .get_signed_htlc_tx(&self.channel_transaction_parameters.as_holder_broadcastable(), *htlc_idx, &counterparty_htlc_sig, htlc_sig, preimage));
-                       }
-               }
-               // If the HTLC doesn't spend the current holder commitment, check if it spends the previous one
-               if htlc_tx.is_none() && self.prev_holder_commitment.is_some() {
-                       let commitment_txid = self.prev_holder_commitment.as_ref().unwrap().trust().txid();
-                       if commitment_txid == outp.txid {
-                               self.sign_prev_holder_htlcs();
-                               if let &Some(ref htlc_sigs) = &self.prev_holder_htlc_sigs {
-                                       let &(ref htlc_idx, ref htlc_sig) = htlc_sigs[outp.vout as usize].as_ref().unwrap();
-                                       let holder_commitment = self.prev_holder_commitment.as_ref().unwrap();
-                                       let trusted_tx = holder_commitment.trust();
-                                       let counterparty_htlc_sig = holder_commitment.counterparty_htlc_sigs[*htlc_idx];
-                                       htlc_tx = Some(trusted_tx
-                                               .get_signed_htlc_tx(&self.channel_transaction_parameters.as_holder_broadcastable(), *htlc_idx, &counterparty_htlc_sig, htlc_sig, preimage));
-                               }
+               let get_signed_htlc_tx = |holder_commitment: &HolderCommitmentTransaction| {
+                       let trusted_tx = holder_commitment.trust();
+                       if trusted_tx.txid() != outp.txid {
+                               return None;
                        }
-               }
-               htlc_tx
+                       let (htlc_idx, htlc) = trusted_tx.htlcs().iter().enumerate()
+                               .find(|(_, htlc)| htlc.transaction_output_index.unwrap() == outp.vout)
+                               .unwrap();
+                       let counterparty_htlc_sig = holder_commitment.counterparty_htlc_sigs[htlc_idx];
+                       let mut htlc_tx = trusted_tx.build_unsigned_htlc_tx(
+                               &self.channel_transaction_parameters.as_holder_broadcastable(), htlc_idx, preimage,
+                       );
+
+                       let htlc_descriptor = HTLCDescriptor {
+                               channel_derivation_parameters: ChannelDerivationParameters {
+                                       value_satoshis: self.channel_value_satoshis,
+                                       keys_id: self.channel_keys_id,
+                                       transaction_parameters: self.channel_transaction_parameters.clone(),
+                               },
+                               commitment_txid: trusted_tx.txid(),
+                               per_commitment_number: trusted_tx.commitment_number(),
+                               per_commitment_point: trusted_tx.per_commitment_point(),
+                               feerate_per_kw: trusted_tx.feerate_per_kw(),
+                               htlc: htlc.clone(),
+                               preimage: preimage.clone(),
+                               counterparty_sig: counterparty_htlc_sig.clone(),
+                       };
+                       let htlc_sig = self.signer.sign_holder_htlc_transaction(&htlc_tx, 0, &htlc_descriptor, &self.secp_ctx).unwrap();
+                       htlc_tx.input[0].witness = trusted_tx.build_htlc_input_witness(
+                               htlc_idx, &counterparty_htlc_sig, &htlc_sig, preimage,
+                       );
+                       Some(htlc_tx)
+               };
+
+               // Check if the HTLC spends from the current holder commitment first, or the previous.
+               get_signed_htlc_tx(&self.holder_commitment)
+                       .or_else(|| self.prev_holder_commitment.as_ref().and_then(|prev_holder_commitment| get_signed_htlc_tx(prev_holder_commitment)))
        }
 
-       #[cfg(anchors)]
        pub(crate) fn generate_external_htlc_claim(
                &self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>
        ) -> Option<ExternalHTLCClaim> {
@@ -1209,21 +1202,7 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
                        .or_else(|| self.prev_holder_commitment.as_ref().map(|c| find_htlc(c)).flatten())
        }
 
-       pub(crate) fn opt_anchors(&self) -> bool {
-               self.channel_transaction_parameters.opt_anchors.is_some()
-       }
-
-       #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
-       pub(crate) fn unsafe_get_fully_signed_htlc_tx(&mut self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>) -> Option<Transaction> {
-               let latest_had_sigs = self.holder_htlc_sigs.is_some();
-               let prev_had_sigs = self.prev_holder_htlc_sigs.is_some();
-               let ret = self.get_fully_signed_htlc_tx(outp, preimage);
-               if !latest_had_sigs {
-                       self.holder_htlc_sigs = None;
-               }
-               if !prev_had_sigs {
-                       self.prev_holder_htlc_sigs = None;
-               }
-               ret
+       pub(crate) fn channel_type_features(&self) -> &ChannelTypeFeatures {
+               &self.channel_transaction_parameters.channel_type_features
        }
 }