Hard-code scorer parameters to `ProbabilisticScoringFeeParameters`
[rust-lightning] / lightning / src / ln / channelmanager.rs
index 3810cfb8171eeca169e29eb5b36f68ca5b23fdfe..1b34ab824d2174c576ced34d35b01d5e209e0b74 100644 (file)
@@ -30,6 +30,8 @@ use bitcoin::secp256k1::{SecretKey,PublicKey};
 use bitcoin::secp256k1::Secp256k1;
 use bitcoin::{LockTime, secp256k1, Sequence};
 
+use crate::blinded_path::BlindedPath;
+use crate::blinded_path::payment::{PaymentConstraints, ReceiveTlvs};
 use crate::chain;
 use crate::chain::{Confirm, ChannelMonitorUpdateStatus, Watch, BestBlock};
 use crate::chain::chaininterface::{BroadcasterInterface, ConfirmationTarget, FeeEstimator, LowerBoundedFeeEstimator};
@@ -41,7 +43,7 @@ use crate::events::{Event, EventHandler, EventsProvider, MessageSendEvent, Messa
 // construct one themselves.
 use crate::ln::{inbound_payment, ChannelId, PaymentHash, PaymentPreimage, PaymentSecret};
 use crate::ln::channel::{Channel, ChannelPhase, ChannelContext, ChannelError, ChannelUpdateStatus, ShutdownResult, UnfundedChannelContext, UpdateFulfillCommitFetch, OutboundV1Channel, InboundV1Channel};
-use crate::ln::features::{ChannelFeatures, ChannelTypeFeatures, InitFeatures, NodeFeatures};
+use crate::ln::features::{Bolt12InvoiceFeatures, ChannelFeatures, ChannelTypeFeatures, InitFeatures, NodeFeatures};
 #[cfg(any(feature = "_test_utils", test))]
 use crate::ln::features::Bolt11InvoiceFeatures;
 use crate::routing::gossip::NetworkGraph;
@@ -53,11 +55,15 @@ use crate::ln::onion_utils::HTLCFailReason;
 use crate::ln::msgs::{ChannelMessageHandler, DecodeError, LightningError};
 #[cfg(test)]
 use crate::ln::outbound_payment;
-use crate::ln::outbound_payment::{OutboundPayments, PaymentAttempts, PendingOutboundPayment, SendAlongPathArgs};
+use crate::ln::outbound_payment::{Bolt12PaymentError, OutboundPayments, PaymentAttempts, PendingOutboundPayment, SendAlongPathArgs, StaleExpiration};
 use crate::ln::wire::Encode;
-use crate::offers::offer::{DerivedMetadata, OfferBuilder};
+use crate::offers::invoice::{BlindedPayInfo, Bolt12Invoice, DEFAULT_RELATIVE_EXPIRY, DerivedSigningPubkey, InvoiceBuilder};
+use crate::offers::invoice_error::InvoiceError;
+use crate::offers::merkle::SignError;
+use crate::offers::offer::{DerivedMetadata, Offer, OfferBuilder};
 use crate::offers::parse::Bolt12SemanticError;
-use crate::offers::refund::RefundBuilder;
+use crate::offers::refund::{Refund, RefundBuilder};
+use crate::onion_message::{Destination, OffersMessage, OffersMessageHandler, PendingOnionMessage, new_pending_onion_message};
 use crate::sign::{EntropySource, KeysManager, NodeSigner, Recipient, SignerProvider, WriteableEcdsaChannelSigner};
 use crate::util::config::{UserConfig, ChannelConfig, ChannelConfigUpdate};
 use crate::util::wakers::{Future, Notifier};
@@ -80,7 +86,7 @@ use core::time::Duration;
 use core::ops::Deref;
 
 // Re-export this for use in the public API.
-pub use crate::ln::outbound_payment::{PaymentSendFailure, ProbeSendFailure, Retry, RetryableSendFailure, RecipientOnionFields};
+pub(crate) use crate::ln::outbound_payment::{PaymentSendFailure, ProbeSendFailure, Retry, RetryableSendFailure, RecipientOnionFields};
 use crate::ln::script::ShutdownScript;
 
 // We hold various information about HTLC relay in the HTLC objects in Channel itself:
@@ -567,6 +573,7 @@ struct ClaimablePayments {
 /// usually because we're running pre-full-init. They are handled immediately once we detect we are
 /// running normally, and specifically must be processed before any other non-background
 /// [`ChannelMonitorUpdate`]s are applied.
+#[derive(Debug)]
 enum BackgroundEvent {
        /// Handle a ChannelMonitorUpdate which closes the channel or for an already-closed channel.
        /// This is only separated from [`Self::MonitorUpdateRegeneratedOnStartup`] as the
@@ -619,10 +626,34 @@ pub(crate) enum MonitorUpdateCompletionAction {
                event: events::Event,
                downstream_counterparty_and_funding_outpoint: Option<(PublicKey, OutPoint, RAAMonitorUpdateBlockingAction)>,
        },
+       /// Indicates we should immediately resume the operation of another channel, unless there is
+       /// some other reason why the channel is blocked. In practice this simply means immediately
+       /// removing the [`RAAMonitorUpdateBlockingAction`] provided from the blocking set.
+       ///
+       /// This is usually generated when we've forwarded an HTLC and want to block the outbound edge
+       /// from completing a monitor update which removes the payment preimage until the inbound edge
+       /// completes a monitor update containing the payment preimage. However, we use this variant
+       /// instead of [`Self::EmitEventAndFreeOtherChannel`] when we discover that the claim was in
+       /// fact duplicative and we simply want to resume the outbound edge channel immediately.
+       ///
+       /// This variant should thus never be written to disk, as it is processed inline rather than
+       /// stored for later processing.
+       FreeOtherChannelImmediately {
+               downstream_counterparty_node_id: PublicKey,
+               downstream_funding_outpoint: OutPoint,
+               blocking_action: RAAMonitorUpdateBlockingAction,
+       },
 }
 
 impl_writeable_tlv_based_enum_upgradable!(MonitorUpdateCompletionAction,
        (0, PaymentClaimed) => { (0, payment_hash, required) },
+       // Note that FreeOtherChannelImmediately should never be written - we were supposed to free
+       // *immediately*. However, for simplicity we implement read/write here.
+       (1, FreeOtherChannelImmediately) => {
+               (0, downstream_counterparty_node_id, required),
+               (2, downstream_funding_outpoint, required),
+               (4, blocking_action, required),
+       },
        (2, EmitEventAndFreeOtherChannel) => {
                (0, event, upgradable_required),
                // LDK prior to 0.0.116 did not have this field as the monitor update application order was
@@ -796,7 +827,8 @@ struct PendingInboundPayment {
 /// or, respectively, [`Router`] for its router, but this type alias chooses the concrete types
 /// of [`KeysManager`] and [`DefaultRouter`].
 ///
-/// This is not exported to bindings users as Arcs don't make sense in bindings
+/// This is not exported to bindings users as type aliases aren't supported in most languages.
+#[cfg(not(c_bindings))]
 pub type SimpleArcChannelManager<M, T, F, L> = ChannelManager<
        Arc<M>,
        Arc<T>,
@@ -808,8 +840,6 @@ pub type SimpleArcChannelManager<M, T, F, L> = ChannelManager<
                Arc<NetworkGraph<Arc<L>>>,
                Arc<L>,
                Arc<RwLock<ProbabilisticScorer<Arc<NetworkGraph<Arc<L>>>, Arc<L>>>>,
-               ProbabilisticScoringFeeParameters,
-               ProbabilisticScorer<Arc<NetworkGraph<Arc<L>>>, Arc<L>>,
        >>,
        Arc<L>
 >;
@@ -824,7 +854,8 @@ pub type SimpleArcChannelManager<M, T, F, L> = ChannelManager<
 /// or, respectively, [`Router`]  for its router, but this type alias chooses the concrete types
 /// of [`KeysManager`] and [`DefaultRouter`].
 ///
-/// This is not exported to bindings users as Arcs don't make sense in bindings
+/// This is not exported to bindings users as type aliases aren't supported in most languages.
+#[cfg(not(c_bindings))]
 pub type SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L> =
        ChannelManager<
                &'a M,
@@ -837,8 +868,6 @@ pub type SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L> =
                        &'f NetworkGraph<&'g L>,
                        &'g L,
                        &'h RwLock<ProbabilisticScorer<&'f NetworkGraph<&'g L>, &'g L>>,
-                       ProbabilisticScoringFeeParameters,
-                       ProbabilisticScorer<&'f NetworkGraph<&'g L>, &'g L>
                >,
                &'g L
        >;
@@ -982,6 +1011,8 @@ where
 //
 // Lock order tree:
 //
+// `pending_offers_messages`
+//
 // `total_consistency_lock`
 //  |
 //  |__`forward_htlcs`
@@ -989,26 +1020,26 @@ where
 //  |   |__`pending_intercepted_htlcs`
 //  |
 //  |__`per_peer_state`
-//  |   |
-//  |   |__`pending_inbound_payments`
-//  |       |
-//  |       |__`claimable_payments`
-//  |       |
-//  |       |__`pending_outbound_payments` // This field's struct contains a map of pending outbounds
-//  |           |
-//  |           |__`peer_state`
-//  |               |
-//  |               |__`id_to_peer`
-//  |               |
-//  |               |__`short_to_chan_info`
-//  |               |
-//  |               |__`outbound_scid_aliases`
-//  |               |
-//  |               |__`best_block`
-//  |               |
-//  |               |__`pending_events`
-//  |                   |
-//  |                   |__`pending_background_events`
+//      |
+//      |__`pending_inbound_payments`
+//          |
+//          |__`claimable_payments`
+//          |
+//          |__`pending_outbound_payments` // This field's struct contains a map of pending outbounds
+//              |
+//              |__`peer_state`
+//                  |
+//                  |__`id_to_peer`
+//                  |
+//                  |__`short_to_chan_info`
+//                  |
+//                  |__`outbound_scid_aliases`
+//                  |
+//                  |__`best_block`
+//                  |
+//                  |__`pending_events`
+//                      |
+//                      |__`pending_background_events`
 //
 pub struct ChannelManager<M: Deref, T: Deref, ES: Deref, NS: Deref, SP: Deref, F: Deref, R: Deref, L: Deref>
 where
@@ -1220,6 +1251,8 @@ where
        event_persist_notifier: Notifier,
        needs_persist_flag: AtomicBool,
 
+       pending_offers_messages: Mutex<Vec<PendingOnionMessage<OffersMessage>>>,
+
        entropy_source: ES,
        node_signer: NS,
        signer_provider: SP,
@@ -2300,6 +2333,8 @@ where
                        needs_persist_flag: AtomicBool::new(false),
                        funding_batch_states: Mutex::new(BTreeMap::new()),
 
+                       pending_offers_messages: Mutex::new(Vec::new()),
+
                        entropy_source,
                        node_signer,
                        signer_provider,
@@ -2644,11 +2679,11 @@ where
        /// will be accepted on the given channel, and after additional timeout/the closing of all
        /// pending HTLCs, the channel will be closed on chain.
        ///
-       ///  * If we are the channel initiator, we will pay between our [`Background`] and
-       ///    [`ChannelConfig::force_close_avoidance_max_fee_satoshis`] plus our [`Normal`] fee
-       ///    estimate.
+       ///  * If we are the channel initiator, we will pay between our [`ChannelCloseMinimum`] and
+       ///    [`ChannelConfig::force_close_avoidance_max_fee_satoshis`] plus our [`NonAnchorChannelFee`]
+       ///    fee estimate.
        ///  * If our counterparty is the channel initiator, we will require a channel closing
-       ///    transaction feerate of at least our [`Background`] feerate or the feerate which
+       ///    transaction feerate of at least our [`ChannelCloseMinimum`] feerate or the feerate which
        ///    would appear on a force-closure transaction, whichever is lower. We will allow our
        ///    counterparty to pay as much fee as they'd like, however.
        ///
@@ -2660,8 +2695,8 @@ where
        /// channel.
        ///
        /// [`ChannelConfig::force_close_avoidance_max_fee_satoshis`]: crate::util::config::ChannelConfig::force_close_avoidance_max_fee_satoshis
-       /// [`Background`]: crate::chain::chaininterface::ConfirmationTarget::Background
-       /// [`Normal`]: crate::chain::chaininterface::ConfirmationTarget::Normal
+       /// [`ChannelCloseMinimum`]: crate::chain::chaininterface::ConfirmationTarget::ChannelCloseMinimum
+       /// [`NonAnchorChannelFee`]: crate::chain::chaininterface::ConfirmationTarget::NonAnchorChannelFee
        /// [`SendShutdown`]: crate::events::MessageSendEvent::SendShutdown
        pub fn close_channel(&self, channel_id: &ChannelId, counterparty_node_id: &PublicKey) -> Result<(), APIError> {
                self.close_channel_internal(channel_id, counterparty_node_id, None, None)
@@ -2675,8 +2710,8 @@ where
        /// the channel being closed or not:
        ///  * If we are the channel initiator, we will pay at least this feerate on the closing
        ///    transaction. The upper-bound is set by
-       ///    [`ChannelConfig::force_close_avoidance_max_fee_satoshis`] plus our [`Normal`] fee
-       ///    estimate (or `target_feerate_sat_per_1000_weight`, if it is greater).
+       ///    [`ChannelConfig::force_close_avoidance_max_fee_satoshis`] plus our [`NonAnchorChannelFee`]
+       ///    fee estimate (or `target_feerate_sat_per_1000_weight`, if it is greater).
        ///  * If our counterparty is the channel initiator, we will refuse to accept a channel closure
        ///    transaction feerate below `target_feerate_sat_per_1000_weight` (or the feerate which
        ///    will appear on a force-closure transaction, whichever is lower).
@@ -2694,8 +2729,7 @@ where
        /// channel.
        ///
        /// [`ChannelConfig::force_close_avoidance_max_fee_satoshis`]: crate::util::config::ChannelConfig::force_close_avoidance_max_fee_satoshis
-       /// [`Background`]: crate::chain::chaininterface::ConfirmationTarget::Background
-       /// [`Normal`]: crate::chain::chaininterface::ConfirmationTarget::Normal
+       /// [`NonAnchorChannelFee`]: crate::chain::chaininterface::ConfirmationTarget::NonAnchorChannelFee
        /// [`SendShutdown`]: crate::events::MessageSendEvent::SendShutdown
        pub fn close_channel_with_feerate_and_script(&self, channel_id: &ChannelId, counterparty_node_id: &PublicKey, target_feerate_sats_per_1000_weight: Option<u32>, shutdown_script: Option<ShutdownScript>) -> Result<(), APIError> {
                self.close_channel_internal(channel_id, counterparty_node_id, target_feerate_sats_per_1000_weight, shutdown_script)
@@ -3351,7 +3385,7 @@ where
                // If we returned an error and the `node_signer` cannot provide a signature for whatever
                // reason`, we wouldn't be able to receive inbound payments through the corresponding
                // channel.
-               let sig = self.node_signer.sign_gossip_message(msgs::UnsignedGossipMessage::ChannelUpdate(&unsigned)).unwrap();
+               let sig = self.node_signer.sign_gossip_message(msgs::UnsignedGossipMessage::ChannelUpdate(unsigned.clone())).unwrap();
 
                Ok(msgs::ChannelUpdate {
                        signature: sig,
@@ -3544,6 +3578,17 @@ where
                self.pending_outbound_payments.test_set_payment_metadata(payment_id, new_payment_metadata);
        }
 
+       pub(super) fn send_payment_for_bolt12_invoice(&self, invoice: &Bolt12Invoice, payment_id: PaymentId) -> Result<(), Bolt12PaymentError> {
+               let best_block_height = self.best_block.read().unwrap().height();
+               let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
+               self.pending_outbound_payments
+                       .send_payment_for_bolt12_invoice(
+                               invoice, payment_id, &self.router, self.list_usable_channels(),
+                               || self.compute_inflight_htlcs(), &self.entropy_source, &self.node_signer,
+                               best_block_height, &self.logger, &self.pending_events,
+                               |args| self.send_payment_along_path(args)
+                       )
+       }
 
        /// Signals that no further attempts for the given payment should occur. Useful if you have a
        /// pending outbound payment with retries remaining, but wish to stop retrying the payment before
@@ -3558,10 +3603,20 @@ where
        /// wait until you receive either a [`Event::PaymentFailed`] or [`Event::PaymentSent`] event to
        /// determine the ultimate status of a payment.
        ///
+       /// # Requested Invoices
+       ///
+       /// In the case of paying a [`Bolt12Invoice`] via [`ChannelManager::pay_for_offer`], abandoning
+       /// the payment prior to receiving the invoice will result in an [`Event::InvoiceRequestFailed`]
+       /// and prevent any attempts at paying it once received. The other events may only be generated
+       /// once the invoice has been received.
+       ///
        /// # Restart Behavior
        ///
        /// If an [`Event::PaymentFailed`] is generated and we restart without first persisting the
-       /// [`ChannelManager`], another [`Event::PaymentFailed`] may be generated.
+       /// [`ChannelManager`], another [`Event::PaymentFailed`] may be generated; likewise for
+       /// [`Event::InvoiceRequestFailed`].
+       ///
+       /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
        pub fn abandon_payment(&self, payment_id: PaymentId) {
                let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
                self.pending_outbound_payments.abandon_payment(payment_id, PaymentFailureReason::UserAbandoned, &self.pending_events);
@@ -4759,8 +4814,8 @@ where
                PersistenceNotifierGuard::optionally_notify(self, || {
                        let mut should_persist = NotifyOption::SkipPersistNoEvents;
 
-                       let normal_feerate = self.fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::Normal);
-                       let min_mempool_feerate = self.fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::MempoolMinimum);
+                       let non_anchor_feerate = self.fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::NonAnchorChannelFee);
+                       let anchor_feerate = self.fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::AnchorChannelFee);
 
                        let per_peer_state = self.per_peer_state.read().unwrap();
                        for (_cp_id, peer_state_mutex) in per_peer_state.iter() {
@@ -4770,9 +4825,9 @@ where
                                        |(chan_id, phase)| if let ChannelPhase::Funded(chan) = phase { Some((chan_id, chan)) } else { None }
                                ) {
                                        let new_feerate = if chan.context.get_channel_type().supports_anchors_zero_fee_htlc_tx() {
-                                               min_mempool_feerate
+                                               anchor_feerate
                                        } else {
-                                               normal_feerate
+                                               non_anchor_feerate
                                        };
                                        let chan_needs_persist = self.update_channel_fee(chan_id, chan, new_feerate);
                                        if chan_needs_persist == NotifyOption::DoPersist { should_persist = NotifyOption::DoPersist; }
@@ -4796,8 +4851,8 @@ where
        ///  * Force-closing and removing channels which have not completed establishment in a timely manner.
        ///  * Forgetting about stale outbound payments, either those that have already been fulfilled
        ///    or those awaiting an invoice that hasn't been delivered in the necessary amount of time.
-       ///    The latter is determined using the system clock in `std` and the block time minus two
-       ///    hours in `no-std`.
+       ///    The latter is determined using the system clock in `std` and the highest seen block time
+       ///    minus two hours in `no-std`.
        ///
        /// Note that this may cause reentrancy through [`chain::Watch::update_channel`] calls or feerate
        /// estimate fetches.
@@ -4808,8 +4863,8 @@ where
                PersistenceNotifierGuard::optionally_notify(self, || {
                        let mut should_persist = NotifyOption::SkipPersistNoEvents;
 
-                       let normal_feerate = self.fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::Normal);
-                       let min_mempool_feerate = self.fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::MempoolMinimum);
+                       let non_anchor_feerate = self.fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::NonAnchorChannelFee);
+                       let anchor_feerate = self.fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::AnchorChannelFee);
 
                        let mut handle_errors: Vec<(Result<(), _>, _)> = Vec::new();
                        let mut timed_out_mpp_htlcs = Vec::new();
@@ -4856,9 +4911,9 @@ where
                                                match phase {
                                                        ChannelPhase::Funded(chan) => {
                                                                let new_feerate = if chan.context.get_channel_type().supports_anchors_zero_fee_htlc_tx() {
-                                                                       min_mempool_feerate
+                                                                       anchor_feerate
                                                                } else {
-                                                                       normal_feerate
+                                                                       non_anchor_feerate
                                                                };
                                                                let chan_needs_persist = self.update_channel_fee(chan_id, chan, new_feerate);
                                                                if chan_needs_persist == NotifyOption::DoPersist { should_persist = NotifyOption::DoPersist; }
@@ -5377,8 +5432,11 @@ where
                        for htlc in sources.drain(..) {
                                if let Err((pk, err)) = self.claim_funds_from_hop(
                                        htlc.prev_hop, payment_preimage,
-                                       |_| Some(MonitorUpdateCompletionAction::PaymentClaimed { payment_hash }))
-                               {
+                                       |_, definitely_duplicate| {
+                                               debug_assert!(!definitely_duplicate, "We shouldn't claim duplicatively from a payment");
+                                               Some(MonitorUpdateCompletionAction::PaymentClaimed { payment_hash })
+                                       }
+                               ) {
                                        if let msgs::ErrorAction::IgnoreError = err.err.action {
                                                // We got a temporary failure updating monitor, but will claim the
                                                // HTLC when the monitor updating is restored (or on chain).
@@ -5406,7 +5464,7 @@ where
                }
        }
 
-       fn claim_funds_from_hop<ComplFunc: FnOnce(Option<u64>) -> Option<MonitorUpdateCompletionAction>>(&self,
+       fn claim_funds_from_hop<ComplFunc: FnOnce(Option<u64>, bool) -> Option<MonitorUpdateCompletionAction>>(&self,
                prev_hop: HTLCPreviousHopData, payment_preimage: PaymentPreimage, completion_action: ComplFunc)
        -> Result<(), (PublicKey, MsgHandleErrInternal)> {
                //TODO: Delay the claimed_funds relaying just like we do outbound relay!
@@ -5416,6 +5474,11 @@ where
                // `BackgroundEvent`s.
                let during_init = !self.background_events_processed_since_startup.load(Ordering::Acquire);
 
+               // As we may call handle_monitor_update_completion_actions in rather rare cases, check that
+               // the required mutexes are not held before we start.
+               debug_assert_ne!(self.pending_events.held_by_thread(), LockHeldState::HeldByThread);
+               debug_assert_ne!(self.claimable_payments.held_by_thread(), LockHeldState::HeldByThread);
+
                {
                        let per_peer_state = self.per_peer_state.read().unwrap();
                        let chan_id = prev_hop.outpoint.to_channel_id();
@@ -5437,25 +5500,70 @@ where
                                                let counterparty_node_id = chan.context.get_counterparty_node_id();
                                                let fulfill_res = chan.get_update_fulfill_htlc_and_commit(prev_hop.htlc_id, payment_preimage, &self.logger);
 
-                                               if let UpdateFulfillCommitFetch::NewClaim { htlc_value_msat, monitor_update } = fulfill_res {
-                                                       if let Some(action) = completion_action(Some(htlc_value_msat)) {
-                                                               log_trace!(self.logger, "Tracking monitor update completion action for channel {}: {:?}",
-                                                                       chan_id, action);
-                                                               peer_state.monitor_update_blocked_actions.entry(chan_id).or_insert(Vec::new()).push(action);
+                                               match fulfill_res {
+                                                       UpdateFulfillCommitFetch::NewClaim { htlc_value_msat, monitor_update } => {
+                                                               if let Some(action) = completion_action(Some(htlc_value_msat), false) {
+                                                                       log_trace!(self.logger, "Tracking monitor update completion action for channel {}: {:?}",
+                                                                               chan_id, action);
+                                                                       peer_state.monitor_update_blocked_actions.entry(chan_id).or_insert(Vec::new()).push(action);
+                                                               }
+                                                               if !during_init {
+                                                                       handle_new_monitor_update!(self, prev_hop.outpoint, monitor_update, peer_state_lock,
+                                                                               peer_state, per_peer_state, chan);
+                                                               } else {
+                                                                       // If we're running during init we cannot update a monitor directly -
+                                                                       // they probably haven't actually been loaded yet. Instead, push the
+                                                                       // monitor update as a background event.
+                                                                       self.pending_background_events.lock().unwrap().push(
+                                                                               BackgroundEvent::MonitorUpdateRegeneratedOnStartup {
+                                                                                       counterparty_node_id,
+                                                                                       funding_txo: prev_hop.outpoint,
+                                                                                       update: monitor_update.clone(),
+                                                                               });
+                                                               }
                                                        }
-                                                       if !during_init {
-                                                               handle_new_monitor_update!(self, prev_hop.outpoint, monitor_update, peer_state_lock,
-                                                                       peer_state, per_peer_state, chan);
-                                                       } else {
-                                                               // If we're running during init we cannot update a monitor directly -
-                                                               // they probably haven't actually been loaded yet. Instead, push the
-                                                               // monitor update as a background event.
-                                                               self.pending_background_events.lock().unwrap().push(
-                                                                       BackgroundEvent::MonitorUpdateRegeneratedOnStartup {
-                                                                               counterparty_node_id,
-                                                                               funding_txo: prev_hop.outpoint,
-                                                                               update: monitor_update.clone(),
-                                                                       });
+                                                       UpdateFulfillCommitFetch::DuplicateClaim {} => {
+                                                               let action = if let Some(action) = completion_action(None, true) {
+                                                                       action
+                                                               } else {
+                                                                       return Ok(());
+                                                               };
+                                                               mem::drop(peer_state_lock);
+
+                                                               log_trace!(self.logger, "Completing monitor update completion action for channel {} as claim was redundant: {:?}",
+                                                                       chan_id, action);
+                                                               let (node_id, funding_outpoint, blocker) =
+                                                               if let MonitorUpdateCompletionAction::FreeOtherChannelImmediately {
+                                                                       downstream_counterparty_node_id: node_id,
+                                                                       downstream_funding_outpoint: funding_outpoint,
+                                                                       blocking_action: blocker,
+                                                               } = action {
+                                                                       (node_id, funding_outpoint, blocker)
+                                                               } else {
+                                                                       debug_assert!(false,
+                                                                               "Duplicate claims should always free another channel immediately");
+                                                                       return Ok(());
+                                                               };
+                                                               if let Some(peer_state_mtx) = per_peer_state.get(&node_id) {
+                                                                       let mut peer_state = peer_state_mtx.lock().unwrap();
+                                                                       if let Some(blockers) = peer_state
+                                                                               .actions_blocking_raa_monitor_updates
+                                                                               .get_mut(&funding_outpoint.to_channel_id())
+                                                                       {
+                                                                               let mut found_blocker = false;
+                                                                               blockers.retain(|iter| {
+                                                                                       // Note that we could actually be blocked, in
+                                                                                       // which case we need to only remove the one
+                                                                                       // blocker which was added duplicatively.
+                                                                                       let first_blocker = !found_blocker;
+                                                                                       if *iter == blocker { found_blocker = true; }
+                                                                                       *iter != blocker || !first_blocker
+                                                                               });
+                                                                               debug_assert!(found_blocker);
+                                                                       }
+                                                               } else {
+                                                                       debug_assert!(false);
+                                                               }
                                                        }
                                                }
                                        }
@@ -5503,7 +5611,7 @@ where
                // `ChannelMonitor` we've provided the above update to. Instead, note that `Event`s are
                // generally always allowed to be duplicative (and it's specifically noted in
                // `PaymentForwarded`).
-               self.handle_monitor_update_completion_actions(completion_action(None));
+               self.handle_monitor_update_completion_actions(completion_action(None, false));
                Ok(())
        }
 
@@ -5512,7 +5620,7 @@ where
        }
 
        fn claim_funds_internal(&self, source: HTLCSource, payment_preimage: PaymentPreimage,
-               forwarded_htlc_value_msat: Option<u64>, from_onchain: bool,
+               forwarded_htlc_value_msat: Option<u64>, from_onchain: bool, startup_replay: bool,
                next_channel_counterparty_node_id: Option<PublicKey>, next_channel_outpoint: OutPoint
        ) {
                match source {
@@ -5533,13 +5641,84 @@ where
                        HTLCSource::PreviousHopData(hop_data) => {
                                let prev_outpoint = hop_data.outpoint;
                                let completed_blocker = RAAMonitorUpdateBlockingAction::from_prev_hop_data(&hop_data);
+                               #[cfg(debug_assertions)]
+                               let claiming_chan_funding_outpoint = hop_data.outpoint;
                                let res = self.claim_funds_from_hop(hop_data, payment_preimage,
-                                       |htlc_claim_value_msat| {
-                                               if let Some(forwarded_htlc_value) = forwarded_htlc_value_msat {
-                                                       let fee_earned_msat = if let Some(claimed_htlc_value) = htlc_claim_value_msat {
-                                                               Some(claimed_htlc_value - forwarded_htlc_value)
-                                                       } else { None };
+                                       |htlc_claim_value_msat, definitely_duplicate| {
+                                               let chan_to_release =
+                                                       if let Some(node_id) = next_channel_counterparty_node_id {
+                                                               Some((node_id, next_channel_outpoint, completed_blocker))
+                                                       } else {
+                                                               // We can only get `None` here if we are processing a
+                                                               // `ChannelMonitor`-originated event, in which case we
+                                                               // don't care about ensuring we wake the downstream
+                                                               // channel's monitor updating - the channel is already
+                                                               // closed.
+                                                               None
+                                                       };
 
+                                               if definitely_duplicate && startup_replay {
+                                                       // On startup we may get redundant claims which are related to
+                                                       // monitor updates still in flight. In that case, we shouldn't
+                                                       // immediately free, but instead let that monitor update complete
+                                                       // in the background.
+                                                       #[cfg(debug_assertions)] {
+                                                               let background_events = self.pending_background_events.lock().unwrap();
+                                                               // There should be a `BackgroundEvent` pending...
+                                                               assert!(background_events.iter().any(|ev| {
+                                                                       match ev {
+                                                                               // to apply a monitor update that blocked the claiming channel,
+                                                                               BackgroundEvent::MonitorUpdateRegeneratedOnStartup {
+                                                                                       funding_txo, update, ..
+                                                                               } => {
+                                                                                       if *funding_txo == claiming_chan_funding_outpoint {
+                                                                                               assert!(update.updates.iter().any(|upd|
+                                                                                                       if let ChannelMonitorUpdateStep::PaymentPreimage {
+                                                                                                               payment_preimage: update_preimage
+                                                                                                       } = upd {
+                                                                                                               payment_preimage == *update_preimage
+                                                                                                       } else { false }
+                                                                                               ), "{:?}", update);
+                                                                                               true
+                                                                                       } else { false }
+                                                                               },
+                                                                               // or the channel we'd unblock is already closed,
+                                                                               BackgroundEvent::ClosedMonitorUpdateRegeneratedOnStartup(
+                                                                                       (funding_txo, monitor_update)
+                                                                               ) => {
+                                                                                       if *funding_txo == next_channel_outpoint {
+                                                                                               assert_eq!(monitor_update.updates.len(), 1);
+                                                                                               assert!(matches!(
+                                                                                                       monitor_update.updates[0],
+                                                                                                       ChannelMonitorUpdateStep::ChannelForceClosed { .. }
+                                                                                               ));
+                                                                                               true
+                                                                                       } else { false }
+                                                                               },
+                                                                               // or the monitor update has completed and will unblock
+                                                                               // immediately once we get going.
+                                                                               BackgroundEvent::MonitorUpdatesComplete {
+                                                                                       channel_id, ..
+                                                                               } =>
+                                                                                       *channel_id == claiming_chan_funding_outpoint.to_channel_id(),
+                                                                       }
+                                                               }), "{:?}", *background_events);
+                                                       }
+                                                       None
+                                               } else if definitely_duplicate {
+                                                       if let Some(other_chan) = chan_to_release {
+                                                               Some(MonitorUpdateCompletionAction::FreeOtherChannelImmediately {
+                                                                       downstream_counterparty_node_id: other_chan.0,
+                                                                       downstream_funding_outpoint: other_chan.1,
+                                                                       blocking_action: other_chan.2,
+                                                               })
+                                                       } else { None }
+                                               } else {
+                                                       let fee_earned_msat = if let Some(forwarded_htlc_value) = forwarded_htlc_value_msat {
+                                                               if let Some(claimed_htlc_value) = htlc_claim_value_msat {
+                                                                       Some(claimed_htlc_value - forwarded_htlc_value)
+                                                               } else { None }
+                                                       } else { None };
                                                        Some(MonitorUpdateCompletionAction::EmitEventAndFreeOtherChannel {
                                                                event: events::Event::PaymentForwarded {
                                                                        fee_earned_msat,
@@ -5548,19 +5727,9 @@ where
                                                                        next_channel_id: Some(next_channel_outpoint.to_channel_id()),
                                                                        outbound_amount_forwarded_msat: forwarded_htlc_value_msat,
                                                                },
-                                                               downstream_counterparty_and_funding_outpoint:
-                                                                       if let Some(node_id) = next_channel_counterparty_node_id {
-                                                                               Some((node_id, next_channel_outpoint, completed_blocker))
-                                                                       } else {
-                                                                               // We can only get `None` here if we are processing a
-                                                                               // `ChannelMonitor`-originated event, in which case we
-                                                                               // don't care about ensuring we wake the downstream
-                                                                               // channel's monitor updating - the channel is already
-                                                                               // closed.
-                                                                               None
-                                                                       },
+                                                               downstream_counterparty_and_funding_outpoint: chan_to_release,
                                                        })
-                                               } else { None }
+                                               }
                                        });
                                if let Err((pk, err)) = res {
                                        let result: Result<(), _> = Err(err);
@@ -5576,6 +5745,10 @@ where
        }
 
        fn handle_monitor_update_completion_actions<I: IntoIterator<Item=MonitorUpdateCompletionAction>>(&self, actions: I) {
+               debug_assert_ne!(self.pending_events.held_by_thread(), LockHeldState::HeldByThread);
+               debug_assert_ne!(self.claimable_payments.held_by_thread(), LockHeldState::HeldByThread);
+               debug_assert_ne!(self.per_peer_state.held_by_thread(), LockHeldState::HeldByThread);
+
                for action in actions.into_iter() {
                        match action {
                                MonitorUpdateCompletionAction::PaymentClaimed { payment_hash } => {
@@ -5605,6 +5778,15 @@ where
                                                self.handle_monitor_update_release(node_id, funding_outpoint, Some(blocker));
                                        }
                                },
+                               MonitorUpdateCompletionAction::FreeOtherChannelImmediately {
+                                       downstream_counterparty_node_id, downstream_funding_outpoint, blocking_action,
+                               } => {
+                                       self.handle_monitor_update_release(
+                                               downstream_counterparty_node_id,
+                                               downstream_funding_outpoint,
+                                               Some(blocking_action),
+                                       );
+                               },
                        }
                }
        }
@@ -6407,6 +6589,9 @@ where
                                        if let ChannelPhase::Funded(chan) = chan_phase_entry.get_mut() {
                                                let res = try_chan_phase_entry!(self, chan.update_fulfill_htlc(&msg), chan_phase_entry);
                                                if let HTLCSource::PreviousHopData(prev_hop) = &res.0 {
+                                                       log_trace!(self.logger,
+                                                               "Holding the next revoke_and_ack from {} until the preimage is durably persisted in the inbound edge's ChannelMonitor",
+                                                               msg.channel_id);
                                                        peer_state.actions_blocking_raa_monitor_updates.entry(msg.channel_id)
                                                                .or_insert_with(Vec::new)
                                                                .push(RAAMonitorUpdateBlockingAction::from_prev_hop_data(&prev_hop));
@@ -6427,7 +6612,7 @@ where
                                hash_map::Entry::Vacant(_) => return Err(MsgHandleErrInternal::send_err_msg_no_close(format!("Got a message for a channel from the wrong node! No such channel for the passed counterparty_node_id {}", counterparty_node_id), msg.channel_id))
                        }
                };
-               self.claim_funds_internal(htlc_source, msg.payment_preimage.clone(), Some(forwarded_htlc_value), false, Some(*counterparty_node_id), funding_txo);
+               self.claim_funds_internal(htlc_source, msg.payment_preimage.clone(), Some(forwarded_htlc_value), false, false, Some(*counterparty_node_id), funding_txo);
                Ok(())
        }
 
@@ -6915,7 +7100,7 @@ where
                                        MonitorEvent::HTLCEvent(htlc_update) => {
                                                if let Some(preimage) = htlc_update.payment_preimage {
                                                        log_trace!(self.logger, "Claiming HTLC with preimage {} from our monitor", preimage);
-                                                       self.claim_funds_internal(htlc_update.source, preimage, htlc_update.htlc_value_satoshis.map(|v| v * 1000), true, counterparty_node_id, funding_outpoint);
+                                                       self.claim_funds_internal(htlc_update.source, preimage, htlc_update.htlc_value_satoshis.map(|v| v * 1000), true, false, counterparty_node_id, funding_outpoint);
                                                } else {
                                                        log_trace!(self.logger, "Failing HTLC with hash {} from our monitor", &htlc_update.payment_hash);
                                                        let receiver = HTLCDestination::NextHopChannel { node_id: counterparty_node_id, channel_id: funding_outpoint.to_channel_id() };
@@ -7130,6 +7315,20 @@ where
        /// [`ChannelManager`] when handling [`InvoiceRequest`] messages for the offer. The offer will
        /// not have an expiration unless otherwise set on the builder.
        ///
+       /// # Privacy
+       ///
+       /// Uses a one-hop [`BlindedPath`] for the offer with [`ChannelManager::get_our_node_id`] as the
+       /// introduction node and a derived signing pubkey for recipient privacy. As such, currently,
+       /// the node must be announced. Otherwise, there is no way to find a path to the introduction
+       /// node in order to send the [`InvoiceRequest`].
+       ///
+       /// # Limitations
+       ///
+       /// Requires a direct connection to the introduction node in the responding [`InvoiceRequest`]'s
+       /// reply path.
+       ///
+       /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
+       ///
        /// [`Offer`]: crate::offers::offer::Offer
        /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
        pub fn create_offer_builder(
@@ -7139,21 +7338,55 @@ where
                let expanded_key = &self.inbound_payment_key;
                let entropy = &*self.entropy_source;
                let secp_ctx = &self.secp_ctx;
+               let path = self.create_one_hop_blinded_path();
 
-               // TODO: Set blinded paths
                OfferBuilder::deriving_signing_pubkey(description, node_id, expanded_key, entropy, secp_ctx)
                        .chain_hash(self.chain_hash)
+                       .path(path)
        }
 
        /// Creates a [`RefundBuilder`] such that the [`Refund`] it builds is recognized by the
-       /// [`ChannelManager`] when handling [`Bolt12Invoice`] messages for the refund. The builder will
-       /// have the provided expiration set. Any changes to the expiration on the returned builder will
-       /// not be honored by [`ChannelManager`].
+       /// [`ChannelManager`] when handling [`Bolt12Invoice`] messages for the refund.
+       ///
+       /// # Payment
        ///
        /// The provided `payment_id` is used to ensure that only one invoice is paid for the refund.
+       /// See [Avoiding Duplicate Payments] for other requirements once the payment has been sent.
+       ///
+       /// The builder will have the provided expiration set. Any changes to the expiration on the
+       /// returned builder will not be honored by [`ChannelManager`]. For `no-std`, the highest seen
+       /// block time minus two hours is used for the current time when determining if the refund has
+       /// expired.
+       ///
+       /// To revoke the refund, use [`ChannelManager::abandon_payment`] prior to receiving the
+       /// invoice. If abandoned, or an invoice isn't received before expiration, the payment will fail
+       /// with an [`Event::InvoiceRequestFailed`].
+       ///
+       /// If `max_total_routing_fee_msat` is not specified, The default from
+       /// [`RouteParameters::from_payment_params_and_value`] is applied.
+       ///
+       /// # Privacy
+       ///
+       /// Uses a one-hop [`BlindedPath`] for the refund with [`ChannelManager::get_our_node_id`] as
+       /// the introduction node and a derived payer id for payer privacy. As such, currently, the
+       /// node must be announced. Otherwise, there is no way to find a path to the introduction node
+       /// in order to send the [`Bolt12Invoice`].
+       ///
+       /// # Limitations
+       ///
+       /// Requires a direct connection to an introduction node in the responding
+       /// [`Bolt12Invoice::payment_paths`].
+       ///
+       /// # Errors
+       ///
+       /// Errors if a duplicate `payment_id` is provided given the caveats in the aforementioned link
+       /// or if `amount_msats` is invalid.
+       ///
+       /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
        ///
        /// [`Refund`]: crate::offers::refund::Refund
        /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
+       /// [`Bolt12Invoice::payment_paths`]: crate::offers::invoice::Bolt12Invoice::payment_paths
        pub fn create_refund_builder(
                &self, description: String, amount_msats: u64, absolute_expiry: Duration,
                payment_id: PaymentId, retry_strategy: Retry, max_total_routing_fee_msat: Option<u64>
@@ -7162,23 +7395,204 @@ where
                let expanded_key = &self.inbound_payment_key;
                let entropy = &*self.entropy_source;
                let secp_ctx = &self.secp_ctx;
+               let path = self.create_one_hop_blinded_path();
 
-               // TODO: Set blinded paths
                let builder = RefundBuilder::deriving_payer_id(
                        description, node_id, expanded_key, entropy, secp_ctx, amount_msats, payment_id
                )?
                        .chain_hash(self.chain_hash)
-                       .absolute_expiry(absolute_expiry);
+                       .absolute_expiry(absolute_expiry)
+                       .path(path);
 
+               let expiration = StaleExpiration::AbsoluteTimeout(absolute_expiry);
                self.pending_outbound_payments
                        .add_new_awaiting_invoice(
-                               payment_id, absolute_expiry, retry_strategy, max_total_routing_fee_msat,
+                               payment_id, expiration, retry_strategy, max_total_routing_fee_msat,
                        )
                        .map_err(|_| Bolt12SemanticError::DuplicatePaymentId)?;
 
                Ok(builder)
        }
 
+       /// Pays for an [`Offer`] using the given parameters by creating an [`InvoiceRequest`] and
+       /// enqueuing it to be sent via an onion message. [`ChannelManager`] will pay the actual
+       /// [`Bolt12Invoice`] once it is received.
+       ///
+       /// Uses [`InvoiceRequestBuilder`] such that the [`InvoiceRequest`] it builds is recognized by
+       /// the [`ChannelManager`] when handling a [`Bolt12Invoice`] message in response to the request.
+       /// The optional parameters are used in the builder, if `Some`:
+       /// - `quantity` for [`InvoiceRequest::quantity`] which must be set if
+       ///   [`Offer::expects_quantity`] is `true`.
+       /// - `amount_msats` if overpaying what is required for the given `quantity` is desired, and
+       /// - `payer_note` for [`InvoiceRequest::payer_note`].
+       ///
+       /// If `max_total_routing_fee_msat` is not specified, The default from
+       /// [`RouteParameters::from_payment_params_and_value`] is applied.
+       ///
+       /// # Payment
+       ///
+       /// The provided `payment_id` is used to ensure that only one invoice is paid for the request
+       /// when received. See [Avoiding Duplicate Payments] for other requirements once the payment has
+       /// been sent.
+       ///
+       /// To revoke the request, use [`ChannelManager::abandon_payment`] prior to receiving the
+       /// invoice. If abandoned, or an invoice isn't received in a reasonable amount of time, the
+       /// payment will fail with an [`Event::InvoiceRequestFailed`].
+       ///
+       /// # Privacy
+       ///
+       /// Uses a one-hop [`BlindedPath`] for the reply path with [`ChannelManager::get_our_node_id`]
+       /// as the introduction node and a derived payer id for payer privacy. As such, currently, the
+       /// node must be announced. Otherwise, there is no way to find a path to the introduction node
+       /// in order to send the [`Bolt12Invoice`].
+       ///
+       /// # Limitations
+       ///
+       /// Requires a direct connection to an introduction node in [`Offer::paths`] or to
+       /// [`Offer::signing_pubkey`], if empty. A similar restriction applies to the responding
+       /// [`Bolt12Invoice::payment_paths`].
+       ///
+       /// # Errors
+       ///
+       /// Errors if a duplicate `payment_id` is provided given the caveats in the aforementioned link
+       /// or if the provided parameters are invalid for the offer.
+       ///
+       /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
+       /// [`InvoiceRequest::quantity`]: crate::offers::invoice_request::InvoiceRequest::quantity
+       /// [`InvoiceRequest::payer_note`]: crate::offers::invoice_request::InvoiceRequest::payer_note
+       /// [`InvoiceRequestBuilder`]: crate::offers::invoice_request::InvoiceRequestBuilder
+       /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
+       /// [`Bolt12Invoice::payment_paths`]: crate::offers::invoice::Bolt12Invoice::payment_paths
+       /// [Avoiding Duplicate Payments]: #avoiding-duplicate-payments
+       pub fn pay_for_offer(
+               &self, offer: &Offer, quantity: Option<u64>, amount_msats: Option<u64>,
+               payer_note: Option<String>, payment_id: PaymentId, retry_strategy: Retry,
+               max_total_routing_fee_msat: Option<u64>
+       ) -> Result<(), Bolt12SemanticError> {
+               let expanded_key = &self.inbound_payment_key;
+               let entropy = &*self.entropy_source;
+               let secp_ctx = &self.secp_ctx;
+
+               let builder = offer
+                       .request_invoice_deriving_payer_id(expanded_key, entropy, secp_ctx, payment_id)?
+                       .chain_hash(self.chain_hash)?;
+               let builder = match quantity {
+                       None => builder,
+                       Some(quantity) => builder.quantity(quantity)?,
+               };
+               let builder = match amount_msats {
+                       None => builder,
+                       Some(amount_msats) => builder.amount_msats(amount_msats)?,
+               };
+               let builder = match payer_note {
+                       None => builder,
+                       Some(payer_note) => builder.payer_note(payer_note),
+               };
+
+               let invoice_request = builder.build_and_sign()?;
+               let reply_path = self.create_one_hop_blinded_path();
+
+               let expiration = StaleExpiration::TimerTicks(1);
+               self.pending_outbound_payments
+                       .add_new_awaiting_invoice(
+                               payment_id, expiration, retry_strategy, max_total_routing_fee_msat
+                       )
+                       .map_err(|_| Bolt12SemanticError::DuplicatePaymentId)?;
+
+               let mut pending_offers_messages = self.pending_offers_messages.lock().unwrap();
+               if offer.paths().is_empty() {
+                       let message = new_pending_onion_message(
+                               OffersMessage::InvoiceRequest(invoice_request),
+                               Destination::Node(offer.signing_pubkey()),
+                               Some(reply_path),
+                       );
+                       pending_offers_messages.push(message);
+               } else {
+                       // Send as many invoice requests as there are paths in the offer (with an upper bound).
+                       // Using only one path could result in a failure if the path no longer exists. But only
+                       // one invoice for a given payment id will be paid, even if more than one is received.
+                       const REQUEST_LIMIT: usize = 10;
+                       for path in offer.paths().into_iter().take(REQUEST_LIMIT) {
+                               let message = new_pending_onion_message(
+                                       OffersMessage::InvoiceRequest(invoice_request.clone()),
+                                       Destination::BlindedPath(path.clone()),
+                                       Some(reply_path.clone()),
+                               );
+                               pending_offers_messages.push(message);
+                       }
+               }
+
+               Ok(())
+       }
+
+       /// Creates a [`Bolt12Invoice`] for a [`Refund`] and enqueues it to be sent via an onion
+       /// message.
+       ///
+       /// The resulting invoice uses a [`PaymentHash`] recognized by the [`ChannelManager`] and a
+       /// [`BlindedPath`] containing the [`PaymentSecret`] needed to reconstruct the corresponding
+       /// [`PaymentPreimage`].
+       ///
+       /// # Limitations
+       ///
+       /// Requires a direct connection to an introduction node in [`Refund::paths`] or to
+       /// [`Refund::payer_id`], if empty. This request is best effort; an invoice will be sent to each
+       /// node meeting the aforementioned criteria, but there's no guarantee that they will be
+       /// received and no retries will be made.
+       ///
+       /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
+       pub fn request_refund_payment(&self, refund: &Refund) -> Result<(), Bolt12SemanticError> {
+               let expanded_key = &self.inbound_payment_key;
+               let entropy = &*self.entropy_source;
+               let secp_ctx = &self.secp_ctx;
+
+               let amount_msats = refund.amount_msats();
+               let relative_expiry = DEFAULT_RELATIVE_EXPIRY.as_secs() as u32;
+
+               match self.create_inbound_payment(Some(amount_msats), relative_expiry, None) {
+                       Ok((payment_hash, payment_secret)) => {
+                               let payment_paths = vec![
+                                       self.create_one_hop_blinded_payment_path(payment_secret),
+                               ];
+                               #[cfg(not(feature = "no-std"))]
+                               let builder = refund.respond_using_derived_keys(
+                                       payment_paths, payment_hash, expanded_key, entropy
+                               )?;
+                               #[cfg(feature = "no-std")]
+                               let created_at = Duration::from_secs(
+                                       self.highest_seen_timestamp.load(Ordering::Acquire) as u64
+                               );
+                               #[cfg(feature = "no-std")]
+                               let builder = refund.respond_using_derived_keys_no_std(
+                                       payment_paths, payment_hash, created_at, expanded_key, entropy
+                               )?;
+                               let invoice = builder.allow_mpp().build_and_sign(secp_ctx)?;
+                               let reply_path = self.create_one_hop_blinded_path();
+
+                               let mut pending_offers_messages = self.pending_offers_messages.lock().unwrap();
+                               if refund.paths().is_empty() {
+                                       let message = new_pending_onion_message(
+                                               OffersMessage::Invoice(invoice),
+                                               Destination::Node(refund.payer_id()),
+                                               Some(reply_path),
+                                       );
+                                       pending_offers_messages.push(message);
+                               } else {
+                                       for path in refund.paths() {
+                                               let message = new_pending_onion_message(
+                                                       OffersMessage::Invoice(invoice.clone()),
+                                                       Destination::BlindedPath(path.clone()),
+                                                       Some(reply_path.clone()),
+                                               );
+                                               pending_offers_messages.push(message);
+                                       }
+                               }
+
+                               Ok(())
+                       },
+                       Err(()) => Err(Bolt12SemanticError::InvalidAmount),
+               }
+       }
+
        /// Gets a payment secret and payment hash for use in an invoice given to a third party wishing
        /// to pay us.
        ///
@@ -7279,6 +7693,37 @@ where
                inbound_payment::get_payment_preimage(payment_hash, payment_secret, &self.inbound_payment_key)
        }
 
+       /// Creates a one-hop blinded path with [`ChannelManager::get_our_node_id`] as the introduction
+       /// node.
+       fn create_one_hop_blinded_path(&self) -> BlindedPath {
+               let entropy_source = self.entropy_source.deref();
+               let secp_ctx = &self.secp_ctx;
+               BlindedPath::one_hop_for_message(self.get_our_node_id(), entropy_source, secp_ctx).unwrap()
+       }
+
+       /// Creates a one-hop blinded path with [`ChannelManager::get_our_node_id`] as the introduction
+       /// node.
+       fn create_one_hop_blinded_payment_path(
+               &self, payment_secret: PaymentSecret
+       ) -> (BlindedPayInfo, BlindedPath) {
+               let entropy_source = self.entropy_source.deref();
+               let secp_ctx = &self.secp_ctx;
+
+               let payee_node_id = self.get_our_node_id();
+               let max_cltv_expiry = self.best_block.read().unwrap().height() + LATENCY_GRACE_PERIOD_BLOCKS;
+               let payee_tlvs = ReceiveTlvs {
+                       payment_secret,
+                       payment_constraints: PaymentConstraints {
+                               max_cltv_expiry,
+                               htlc_minimum_msat: 1,
+                       },
+               };
+               // TODO: Err for overflow?
+               BlindedPath::one_hop_for_payment(
+                       payee_node_id, payee_tlvs, entropy_source, secp_ctx
+               ).unwrap()
+       }
+
        /// Gets a fake short channel id for use in receiving [phantom node payments]. These fake scids
        /// are used when constructing the phantom invoice's route hints.
        ///
@@ -7884,35 +8329,41 @@ where
                self.best_block.read().unwrap().clone()
        }
 
-       /// Fetches the set of [`NodeFeatures`] flags which are provided by or required by
+       /// Fetches the set of [`NodeFeatures`] flags that are provided by or required by
        /// [`ChannelManager`].
        pub fn node_features(&self) -> NodeFeatures {
                provided_node_features(&self.default_configuration)
        }
 
-       /// Fetches the set of [`Bolt11InvoiceFeatures`] flags which are provided by or required by
+       /// Fetches the set of [`Bolt11InvoiceFeatures`] flags that are provided by or required by
        /// [`ChannelManager`].
        ///
        /// Note that the invoice feature flags can vary depending on if the invoice is a "phantom invoice"
        /// or not. Thus, this method is not public.
        #[cfg(any(feature = "_test_utils", test))]
-       pub fn invoice_features(&self) -> Bolt11InvoiceFeatures {
-               provided_invoice_features(&self.default_configuration)
+       pub fn bolt11_invoice_features(&self) -> Bolt11InvoiceFeatures {
+               provided_bolt11_invoice_features(&self.default_configuration)
+       }
+
+       /// Fetches the set of [`Bolt12InvoiceFeatures`] flags that are provided by or required by
+       /// [`ChannelManager`].
+       fn bolt12_invoice_features(&self) -> Bolt12InvoiceFeatures {
+               provided_bolt12_invoice_features(&self.default_configuration)
        }
 
-       /// Fetches the set of [`ChannelFeatures`] flags which are provided by or required by
+       /// Fetches the set of [`ChannelFeatures`] flags that are provided by or required by
        /// [`ChannelManager`].
        pub fn channel_features(&self) -> ChannelFeatures {
                provided_channel_features(&self.default_configuration)
        }
 
-       /// Fetches the set of [`ChannelTypeFeatures`] flags which are provided by or required by
+       /// Fetches the set of [`ChannelTypeFeatures`] flags that are provided by or required by
        /// [`ChannelManager`].
        pub fn channel_type_features(&self) -> ChannelTypeFeatures {
                provided_channel_type_features(&self.default_configuration)
        }
 
-       /// Fetches the set of [`InitFeatures`] flags which are provided by or required by
+       /// Fetches the set of [`InitFeatures`] flags that are provided by or required by
        /// [`ChannelManager`].
        pub fn init_features(&self) -> InitFeatures {
                provided_init_features(&self.default_configuration)
@@ -8443,7 +8894,128 @@ where
        }
 }
 
-/// Fetches the set of [`NodeFeatures`] flags which are provided by or required by
+impl<M: Deref, T: Deref, ES: Deref, NS: Deref, SP: Deref, F: Deref, R: Deref, L: Deref>
+OffersMessageHandler for ChannelManager<M, T, ES, NS, SP, F, R, L>
+where
+       M::Target: chain::Watch<<SP::Target as SignerProvider>::Signer>,
+       T::Target: BroadcasterInterface,
+       ES::Target: EntropySource,
+       NS::Target: NodeSigner,
+       SP::Target: SignerProvider,
+       F::Target: FeeEstimator,
+       R::Target: Router,
+       L::Target: Logger,
+{
+       fn handle_message(&self, message: OffersMessage) -> Option<OffersMessage> {
+               let secp_ctx = &self.secp_ctx;
+               let expanded_key = &self.inbound_payment_key;
+
+               match message {
+                       OffersMessage::InvoiceRequest(invoice_request) => {
+                               let amount_msats = match InvoiceBuilder::<DerivedSigningPubkey>::amount_msats(
+                                       &invoice_request
+                               ) {
+                                       Ok(amount_msats) => Some(amount_msats),
+                                       Err(error) => return Some(OffersMessage::InvoiceError(error.into())),
+                               };
+                               let invoice_request = match invoice_request.verify(expanded_key, secp_ctx) {
+                                       Ok(invoice_request) => invoice_request,
+                                       Err(()) => {
+                                               let error = Bolt12SemanticError::InvalidMetadata;
+                                               return Some(OffersMessage::InvoiceError(error.into()));
+                                       },
+                               };
+                               let relative_expiry = DEFAULT_RELATIVE_EXPIRY.as_secs() as u32;
+
+                               match self.create_inbound_payment(amount_msats, relative_expiry, None) {
+                                       Ok((payment_hash, payment_secret)) if invoice_request.keys.is_some() => {
+                                               let payment_paths = vec![
+                                                       self.create_one_hop_blinded_payment_path(payment_secret),
+                                               ];
+                                               #[cfg(not(feature = "no-std"))]
+                                               let builder = invoice_request.respond_using_derived_keys(
+                                                       payment_paths, payment_hash
+                                               );
+                                               #[cfg(feature = "no-std")]
+                                               let created_at = Duration::from_secs(
+                                                       self.highest_seen_timestamp.load(Ordering::Acquire) as u64
+                                               );
+                                               #[cfg(feature = "no-std")]
+                                               let builder = invoice_request.respond_using_derived_keys_no_std(
+                                                       payment_paths, payment_hash, created_at
+                                               );
+                                               match builder.and_then(|b| b.allow_mpp().build_and_sign(secp_ctx)) {
+                                                       Ok(invoice) => Some(OffersMessage::Invoice(invoice)),
+                                                       Err(error) => Some(OffersMessage::InvoiceError(error.into())),
+                                               }
+                                       },
+                                       Ok((payment_hash, payment_secret)) => {
+                                               let payment_paths = vec![
+                                                       self.create_one_hop_blinded_payment_path(payment_secret),
+                                               ];
+                                               #[cfg(not(feature = "no-std"))]
+                                               let builder = invoice_request.respond_with(payment_paths, payment_hash);
+                                               #[cfg(feature = "no-std")]
+                                               let created_at = Duration::from_secs(
+                                                       self.highest_seen_timestamp.load(Ordering::Acquire) as u64
+                                               );
+                                               #[cfg(feature = "no-std")]
+                                               let builder = invoice_request.respond_with_no_std(
+                                                       payment_paths, payment_hash, created_at
+                                               );
+                                               let response = builder.and_then(|builder| builder.allow_mpp().build())
+                                                       .map_err(|e| OffersMessage::InvoiceError(e.into()))
+                                                       .and_then(|invoice|
+                                                               match invoice.sign(|invoice| self.node_signer.sign_bolt12_invoice(invoice)) {
+                                                                       Ok(invoice) => Ok(OffersMessage::Invoice(invoice)),
+                                                                       Err(SignError::Signing(())) => Err(OffersMessage::InvoiceError(
+                                                                                       InvoiceError::from_string("Failed signing invoice".to_string())
+                                                                       )),
+                                                                       Err(SignError::Verification(_)) => Err(OffersMessage::InvoiceError(
+                                                                                       InvoiceError::from_string("Failed invoice signature verification".to_string())
+                                                                       )),
+                                                               });
+                                               match response {
+                                                       Ok(invoice) => Some(invoice),
+                                                       Err(error) => Some(error),
+                                               }
+                                       },
+                                       Err(()) => {
+                                               Some(OffersMessage::InvoiceError(Bolt12SemanticError::InvalidAmount.into()))
+                                       },
+                               }
+                       },
+                       OffersMessage::Invoice(invoice) => {
+                               match invoice.verify(expanded_key, secp_ctx) {
+                                       Err(()) => {
+                                               Some(OffersMessage::InvoiceError(InvoiceError::from_string("Unrecognized invoice".to_owned())))
+                                       },
+                                       Ok(_) if invoice.invoice_features().requires_unknown_bits_from(&self.bolt12_invoice_features()) => {
+                                               Some(OffersMessage::InvoiceError(Bolt12SemanticError::UnknownRequiredFeatures.into()))
+                                       },
+                                       Ok(payment_id) => {
+                                               if let Err(e) = self.send_payment_for_bolt12_invoice(&invoice, payment_id) {
+                                                       log_trace!(self.logger, "Failed paying invoice: {:?}", e);
+                                                       Some(OffersMessage::InvoiceError(InvoiceError::from_string(format!("{:?}", e))))
+                                               } else {
+                                                       None
+                                               }
+                                       },
+                               }
+                       },
+                       OffersMessage::InvoiceError(invoice_error) => {
+                               log_trace!(self.logger, "Received invoice_error: {}", invoice_error);
+                               None
+                       },
+               }
+       }
+
+       fn release_pending_messages(&self) -> Vec<PendingOnionMessage<OffersMessage>> {
+               core::mem::take(&mut self.pending_offers_messages.lock().unwrap())
+       }
+}
+
+/// Fetches the set of [`NodeFeatures`] flags that are provided by or required by
 /// [`ChannelManager`].
 pub(crate) fn provided_node_features(config: &UserConfig) -> NodeFeatures {
        let mut node_features = provided_init_features(config).to_context();
@@ -8451,29 +9023,35 @@ pub(crate) fn provided_node_features(config: &UserConfig) -> NodeFeatures {
        node_features
 }
 
-/// Fetches the set of [`Bolt11InvoiceFeatures`] flags which are provided by or required by
+/// Fetches the set of [`Bolt11InvoiceFeatures`] flags that are provided by or required by
 /// [`ChannelManager`].
 ///
 /// Note that the invoice feature flags can vary depending on if the invoice is a "phantom invoice"
 /// or not. Thus, this method is not public.
 #[cfg(any(feature = "_test_utils", test))]
-pub(crate) fn provided_invoice_features(config: &UserConfig) -> Bolt11InvoiceFeatures {
+pub(crate) fn provided_bolt11_invoice_features(config: &UserConfig) -> Bolt11InvoiceFeatures {
        provided_init_features(config).to_context()
 }
 
-/// Fetches the set of [`ChannelFeatures`] flags which are provided by or required by
+/// Fetches the set of [`Bolt12InvoiceFeatures`] flags that are provided by or required by
+/// [`ChannelManager`].
+pub(crate) fn provided_bolt12_invoice_features(config: &UserConfig) -> Bolt12InvoiceFeatures {
+       provided_init_features(config).to_context()
+}
+
+/// Fetches the set of [`ChannelFeatures`] flags that are provided by or required by
 /// [`ChannelManager`].
 pub(crate) fn provided_channel_features(config: &UserConfig) -> ChannelFeatures {
        provided_init_features(config).to_context()
 }
 
-/// Fetches the set of [`ChannelTypeFeatures`] flags which are provided by or required by
+/// Fetches the set of [`ChannelTypeFeatures`] flags that are provided by or required by
 /// [`ChannelManager`].
 pub(crate) fn provided_channel_type_features(config: &UserConfig) -> ChannelTypeFeatures {
        ChannelTypeFeatures::from_init(&provided_init_features(config))
 }
 
-/// Fetches the set of [`InitFeatures`] flags which are provided by or required by
+/// Fetches the set of [`InitFeatures`] flags that are provided by or required by
 /// [`ChannelManager`].
 pub fn provided_init_features(config: &UserConfig) -> InitFeatures {
        // Note that if new features are added here which other peers may (eventually) require, we
@@ -10082,6 +10660,9 @@ where
                                                                Some((blocked_node_id, blocked_channel_outpoint, blocking_action)), ..
                                                } = action {
                                                        if let Some(blocked_peer_state) = per_peer_state.get(&blocked_node_id) {
+                                                               log_trace!(args.logger,
+                                                                       "Holding the next revoke_and_ack from {} until the preimage is durably persisted in the inbound edge's ChannelMonitor",
+                                                                       blocked_channel_outpoint.to_channel_id());
                                                                blocked_peer_state.lock().unwrap().actions_blocking_raa_monitor_updates
                                                                        .entry(blocked_channel_outpoint.to_channel_id())
                                                                        .or_insert_with(Vec::new).push(blocking_action.clone());
@@ -10093,6 +10674,9 @@ where
                                                                // anymore.
                                                        }
                                                }
+                                               if let MonitorUpdateCompletionAction::FreeOtherChannelImmediately { .. } = action {
+                                                       debug_assert!(false, "Non-event-generating channel freeing should not appear in our queue");
+                                               }
                                        }
                                }
                                peer_state.lock().unwrap().monitor_update_blocked_actions = monitor_update_blocked_actions;
@@ -10143,6 +10727,8 @@ where
 
                        funding_batch_states: Mutex::new(BTreeMap::new()),
 
+                       pending_offers_messages: Mutex::new(Vec::new()),
+
                        entropy_source: args.entropy_source,
                        node_signer: args.node_signer,
                        signer_provider: args.signer_provider,
@@ -10163,7 +10749,7 @@ where
                        // don't remember in the `ChannelMonitor` where we got a preimage from, but if the
                        // channel is closed we just assume that it probably came from an on-chain claim.
                        channel_manager.claim_funds_internal(source, preimage, Some(downstream_value),
-                               downstream_closed, downstream_node_id, downstream_funding);
+                               downstream_closed, true, downstream_node_id, downstream_funding);
                }
 
                //TODO: Broadcast channel update for closed channels, but only after we've made a
@@ -11620,7 +12206,7 @@ pub mod bench {
                macro_rules! send_payment {
                        ($node_a: expr, $node_b: expr) => {
                                let payment_params = PaymentParameters::from_node_id($node_b.get_our_node_id(), TEST_FINAL_CLTV)
-                                       .with_bolt11_features($node_b.invoice_features()).unwrap();
+                                       .with_bolt11_features($node_b.bolt11_invoice_features()).unwrap();
                                let mut payment_preimage = PaymentPreimage([0; 32]);
                                payment_preimage.0[0..8].copy_from_slice(&payment_count.to_le_bytes());
                                payment_count += 1;