Merge pull request #2791 from valentinewallace/2023-12-multihop-recv-followups
[rust-lightning] / lightning / src / ln / channelmanager.rs
index 01352ffa3871accfdaeeab629ec0d3dc24caa39b..d51349728fea4ebdde5be0f364703ac7ee7df2f6 100644 (file)
@@ -43,13 +43,11 @@ use crate::events::{Event, EventHandler, EventsProvider, MessageSendEvent, Messa
 // Since this struct is returned in `list_channels` methods, expose it here in case users want to
 // 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, WithChannelContext};
+use crate::ln::channel::{self, Channel, ChannelPhase, ChannelContext, ChannelError, ChannelUpdateStatus, ShutdownResult, UnfundedChannelContext, UpdateFulfillCommitFetch, OutboundV1Channel, InboundV1Channel, WithChannelContext};
 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;
-use crate::routing::router::{BlindedTail, DefaultRouter, InFlightHtlcs, Path, Payee, PaymentParameters, Route, RouteParameters, Router};
-use crate::routing::scoring::{ProbabilisticScorer, ProbabilisticScoringFeeParameters};
+use crate::routing::router::{BlindedTail, InFlightHtlcs, Path, Payee, PaymentParameters, Route, RouteParameters, Router};
 use crate::ln::onion_payment::{check_incoming_htlc_cltv, create_recv_pending_htlc_info, create_fwd_pending_htlc_info, decode_incoming_update_add_htlc_onion, InboundOnionErr, NextPacketDetails};
 use crate::ln::msgs;
 use crate::ln::onion_utils;
@@ -65,8 +63,8 @@ use crate::offers::merkle::SignError;
 use crate::offers::offer::{DerivedMetadata, Offer, OfferBuilder};
 use crate::offers::parse::Bolt12SemanticError;
 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};
+use crate::onion_message::{Destination, MessageRouter, OffersMessage, OffersMessageHandler, PendingOnionMessage, new_pending_onion_message};
+use crate::sign::{EntropySource, NodeSigner, Recipient, SignerProvider};
 use crate::sign::ecdsa::WriteableEcdsaChannelSigner;
 use crate::util::config::{UserConfig, ChannelConfig, ChannelConfigUpdate};
 use crate::util::wakers::{Future, Notifier};
@@ -75,6 +73,13 @@ use crate::util::string::UntrustedString;
 use crate::util::ser::{BigSize, FixedLengthReader, Readable, ReadableArgs, MaybeReadable, Writeable, Writer, VecWriter};
 use crate::util::logger::{Level, Logger, WithContext};
 use crate::util::errors::APIError;
+#[cfg(not(c_bindings))]
+use {
+       crate::routing::router::DefaultRouter,
+       crate::routing::gossip::NetworkGraph,
+       crate::routing::scoring::{ProbabilisticScorer, ProbabilisticScoringFeeParameters},
+       crate::sign::KeysManager,
+};
 
 use alloc::collections::{btree_map, BTreeMap};
 
@@ -545,9 +550,8 @@ impl Into<u16> for FailureCode {
 
 struct MsgHandleErrInternal {
        err: msgs::LightningError,
-       chan_id: Option<(ChannelId, u128)>, // If Some a channel of ours has been closed
+       closes_channel: bool,
        shutdown_finish: Option<(ShutdownResult, Option<msgs::ChannelUpdate>)>,
-       channel_capacity: Option<u64>,
 }
 impl MsgHandleErrInternal {
        #[inline]
@@ -562,17 +566,16 @@ impl MsgHandleErrInternal {
                                        },
                                },
                        },
-                       chan_id: None,
+                       closes_channel: false,
                        shutdown_finish: None,
-                       channel_capacity: None,
                }
        }
        #[inline]
        fn from_no_close(err: msgs::LightningError) -> Self {
-               Self { err, chan_id: None, shutdown_finish: None, channel_capacity: None }
+               Self { err, closes_channel: false, shutdown_finish: None }
        }
        #[inline]
-       fn from_finish_shutdown(err: String, channel_id: ChannelId, user_channel_id: u128, shutdown_res: ShutdownResult, channel_update: Option<msgs::ChannelUpdate>, channel_capacity: u64) -> Self {
+       fn from_finish_shutdown(err: String, channel_id: ChannelId, shutdown_res: ShutdownResult, channel_update: Option<msgs::ChannelUpdate>) -> Self {
                let err_msg = msgs::ErrorMessage { channel_id, data: err.clone() };
                let action = if shutdown_res.monitor_update.is_some() {
                        // We have a closing `ChannelMonitorUpdate`, which means the channel was funded and we
@@ -584,9 +587,8 @@ impl MsgHandleErrInternal {
                };
                Self {
                        err: LightningError { err, action },
-                       chan_id: Some((channel_id, user_channel_id)),
+                       closes_channel: true,
                        shutdown_finish: Some((shutdown_res, channel_update)),
-                       channel_capacity: Some(channel_capacity)
                }
        }
        #[inline]
@@ -617,14 +619,13 @@ impl MsgHandleErrInternal {
                                        },
                                },
                        },
-                       chan_id: None,
+                       closes_channel: false,
                        shutdown_finish: None,
-                       channel_capacity: None,
                }
        }
 
        fn closes_channel(&self) -> bool {
-               self.chan_id.is_some()
+               self.closes_channel
        }
 }
 
@@ -1150,7 +1151,7 @@ where
 //              |
 //              |__`peer_state`
 //                  |
-//                  |__`id_to_peer`
+//                  |__`outpoint_to_peer`
 //                  |
 //                  |__`short_to_chan_info`
 //                  |
@@ -1244,11 +1245,7 @@ where
        /// See `ChannelManager` struct-level documentation for lock order requirements.
        outbound_scid_aliases: Mutex<HashSet<u64>>,
 
-       /// `channel_id` -> `counterparty_node_id`.
-       ///
-       /// Only `channel_id`s are allowed as keys in this map, and not `temporary_channel_id`s. As
-       /// multiple channels with the same `temporary_channel_id` to different peers can exist,
-       /// allowing `temporary_channel_id`s in this map would cause collisions for such channels.
+       /// Channel funding outpoint -> `counterparty_node_id`.
        ///
        /// Note that this map should only be used for `MonitorEvent` handling, to be able to access
        /// the corresponding channel for the event, as we only have access to the `channel_id` during
@@ -1266,7 +1263,10 @@ where
        /// required to access the channel with the `counterparty_node_id`.
        ///
        /// See `ChannelManager` struct-level documentation for lock order requirements.
-       id_to_peer: Mutex<HashMap<ChannelId, PublicKey>>,
+       #[cfg(not(test))]
+       outpoint_to_peer: Mutex<HashMap<OutPoint, PublicKey>>,
+       #[cfg(test)]
+       pub(crate) outpoint_to_peer: Mutex<HashMap<OutPoint, PublicKey>>,
 
        /// SCIDs (and outbound SCID aliases) -> `counterparty_node_id`s and `channel_id`s.
        ///
@@ -1957,30 +1957,27 @@ macro_rules! handle_error {
 
                match $internal {
                        Ok(msg) => Ok(msg),
-                       Err(MsgHandleErrInternal { err, chan_id, shutdown_finish, channel_capacity }) => {
+                       Err(MsgHandleErrInternal { err, shutdown_finish, .. }) => {
                                let mut msg_events = Vec::with_capacity(2);
 
                                if let Some((shutdown_res, update_option)) = shutdown_finish {
+                                       let counterparty_node_id = shutdown_res.counterparty_node_id;
+                                       let channel_id = shutdown_res.channel_id;
+                                       let logger = WithContext::from(
+                                               &$self.logger, Some(counterparty_node_id), Some(channel_id),
+                                       );
+                                       log_error!(logger, "Force-closing channel: {}", err.err);
+
                                        $self.finish_close_channel(shutdown_res);
                                        if let Some(update) = update_option {
                                                msg_events.push(events::MessageSendEvent::BroadcastChannelUpdate {
                                                        msg: update
                                                });
                                        }
-                                       if let Some((channel_id, user_channel_id)) = chan_id {
-                                               $self.pending_events.lock().unwrap().push_back((events::Event::ChannelClosed {
-                                                       channel_id, user_channel_id,
-                                                       reason: ClosureReason::ProcessingError { err: err.err.clone() },
-                                                       counterparty_node_id: Some($counterparty_node_id),
-                                                       channel_capacity_sats: channel_capacity,
-                                               }, None));
-                                       }
+                               } else {
+                                       log_error!($self.logger, "Got non-closing error: {}", err.err);
                                }
 
-                               let logger = WithContext::from(
-                                       &$self.logger, Some($counterparty_node_id), chan_id.map(|(chan_id, _)| chan_id)
-                               );
-                               log_error!(logger, "{}", err.err);
                                if let msgs::ErrorAction::IgnoreError = err.action {
                                } else {
                                        msg_events.push(events::MessageSendEvent::HandleError {
@@ -2006,7 +2003,9 @@ macro_rules! handle_error {
 
 macro_rules! update_maps_on_chan_removal {
        ($self: expr, $channel_context: expr) => {{
-               $self.id_to_peer.lock().unwrap().remove(&$channel_context.channel_id());
+               if let Some(outpoint) = $channel_context.get_funding_txo() {
+                       $self.outpoint_to_peer.lock().unwrap().remove(&outpoint);
+               }
                let mut short_to_chan_info = $self.short_to_chan_info.write().unwrap();
                if let Some(short_id) = $channel_context.get_short_channel_id() {
                        short_to_chan_info.remove(&short_id);
@@ -2038,12 +2037,11 @@ macro_rules! convert_chan_phase_err {
                                let logger = WithChannelContext::from(&$self.logger, &$channel.context);
                                log_error!(logger, "Closing channel {} due to close-required error: {}", $channel_id, msg);
                                update_maps_on_chan_removal!($self, $channel.context);
-                               let shutdown_res = $channel.context.force_shutdown(true);
-                               let user_id = $channel.context.get_user_id();
-                               let channel_capacity_satoshis = $channel.context.get_value_satoshis();
-
-                               (true, MsgHandleErrInternal::from_finish_shutdown(msg, *$channel_id, user_id,
-                                       shutdown_res, $channel_update, channel_capacity_satoshis))
+                               let reason = ClosureReason::ProcessingError { err: msg.clone() };
+                               let shutdown_res = $channel.context.force_shutdown(true, reason);
+                               let err =
+                                       MsgHandleErrInternal::from_finish_shutdown(msg, *$channel_id, shutdown_res, $channel_update);
+                               (true, err)
                        },
                }
        };
@@ -2425,7 +2423,7 @@ where
                        forward_htlcs: Mutex::new(HashMap::new()),
                        claimable_payments: Mutex::new(ClaimablePayments { claimable_payments: HashMap::new(), pending_claiming_payments: HashMap::new() }),
                        pending_intercepted_htlcs: Mutex::new(HashMap::new()),
-                       id_to_peer: Mutex::new(HashMap::new()),
+                       outpoint_to_peer: Mutex::new(HashMap::new()),
                        short_to_chan_info: FairRwLock::new(HashMap::new()),
 
                        our_network_pubkey: node_signer.get_node_id(Recipient::Node).unwrap(),
@@ -2576,7 +2574,7 @@ where
        fn list_funded_channels_with_filter<Fn: FnMut(&(&ChannelId, &Channel<SP>)) -> bool + Copy>(&self, f: Fn) -> Vec<ChannelDetails> {
                // Allocate our best estimate of the number of channels we have in the `res`
                // Vec. Sadly the `short_to_chan_info` map doesn't cover channels without
-               // a scid or a scid alias, and the `id_to_peer` shouldn't be used outside
+               // a scid or a scid alias, and the `outpoint_to_peer` shouldn't be used outside
                // of the ChannelMonitor handling. Therefore reallocations may still occur, but is
                // unlikely as the `short_to_chan_info` map often contains 2 entries for
                // the same channel.
@@ -2609,7 +2607,7 @@ where
        pub fn list_channels(&self) -> Vec<ChannelDetails> {
                // Allocate our best estimate of the number of channels we have in the `res`
                // Vec. Sadly the `short_to_chan_info` map doesn't cover channels without
-               // a scid or a scid alias, and the `id_to_peer` shouldn't be used outside
+               // a scid or a scid alias, and the `outpoint_to_peer` shouldn't be used outside
                // of the ChannelMonitor handling. Therefore reallocations may still occur, but is
                // unlikely as the `short_to_chan_info` map often contains 2 entries for
                // the same channel.
@@ -2700,26 +2698,6 @@ where
                        .collect()
        }
 
-       /// Helper function that issues the channel close events
-       fn issue_channel_close_events(&self, context: &ChannelContext<SP>, closure_reason: ClosureReason) {
-               let mut pending_events_lock = self.pending_events.lock().unwrap();
-               match context.unbroadcasted_funding() {
-                       Some(transaction) => {
-                               pending_events_lock.push_back((events::Event::DiscardFunding {
-                                       channel_id: context.channel_id(), transaction
-                               }, None));
-                       },
-                       None => {},
-               }
-               pending_events_lock.push_back((events::Event::ChannelClosed {
-                       channel_id: context.channel_id(),
-                       user_channel_id: context.get_user_id(),
-                       reason: closure_reason,
-                       counterparty_node_id: Some(context.get_counterparty_node_id()),
-                       channel_capacity_sats: Some(context.get_value_satoshis()),
-               }, None));
-       }
-
        fn close_channel_internal(&self, channel_id: &ChannelId, counterparty_node_id: &PublicKey, target_feerate_sats_per_1000_weight: Option<u32>, override_shutdown_script: Option<ShutdownScript>) -> Result<(), APIError> {
                let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
 
@@ -2761,9 +2739,8 @@ where
                                                                peer_state_lock, peer_state, per_peer_state, chan);
                                                }
                                        } else {
-                                               self.issue_channel_close_events(chan_phase_entry.get().context(), ClosureReason::HolderForceClosed);
                                                let mut chan_phase = remove_channel_phase!(self, chan_phase_entry);
-                                               shutdown_result = Some(chan_phase.context_mut().force_shutdown(false));
+                                               shutdown_result = Some(chan_phase.context_mut().force_shutdown(false, ClosureReason::HolderForceClosed));
                                        }
                                },
                                hash_map::Entry::Vacant(_) => {
@@ -2860,7 +2837,9 @@ where
                let logger = WithContext::from(
                        &self.logger, Some(shutdown_res.counterparty_node_id), Some(shutdown_res.channel_id),
                );
-               log_debug!(logger, "Finishing closure of channel with {} HTLCs to fail", shutdown_res.dropped_outbound_htlcs.len());
+
+               log_debug!(logger, "Finishing closure of channel due to {} with {} HTLCs to fail",
+                       shutdown_res.closure_reason, shutdown_res.dropped_outbound_htlcs.len());
                for htlc_source in shutdown_res.dropped_outbound_htlcs.drain(..) {
                        let (source, payment_hash, counterparty_node_id, channel_id) = htlc_source;
                        let reason = HTLCFailReason::from_failure_code(0x4000 | 8);
@@ -2885,8 +2864,7 @@ where
                                        let mut peer_state = peer_state_mutex.lock().unwrap();
                                        if let Some(mut chan) = peer_state.channel_by_id.remove(&channel_id) {
                                                update_maps_on_chan_removal!(self, &chan.context());
-                                               self.issue_channel_close_events(&chan.context(), ClosureReason::FundingBatchClosure);
-                                               shutdown_results.push(chan.context_mut().force_shutdown(false));
+                                               shutdown_results.push(chan.context_mut().force_shutdown(false, ClosureReason::FundingBatchClosure));
                                        }
                                }
                                has_uncompleted_channel = Some(has_uncompleted_channel.map_or(!state, |v| v || !state));
@@ -2896,6 +2874,23 @@ where
                                "Closing a batch where all channels have completed initial monitor update",
                        );
                }
+
+               {
+                       let mut pending_events = self.pending_events.lock().unwrap();
+                       pending_events.push_back((events::Event::ChannelClosed {
+                               channel_id: shutdown_res.channel_id,
+                               user_channel_id: shutdown_res.user_channel_id,
+                               reason: shutdown_res.closure_reason,
+                               counterparty_node_id: Some(shutdown_res.counterparty_node_id),
+                               channel_capacity_sats: Some(shutdown_res.channel_capacity_satoshis),
+                       }, None));
+
+                       if let Some(transaction) = shutdown_res.unbroadcasted_funding_tx {
+                               pending_events.push_back((events::Event::DiscardFunding {
+                                       channel_id: shutdown_res.channel_id, transaction
+                               }, None));
+                       }
+               }
                for shutdown_result in shutdown_results.drain(..) {
                        self.finish_close_channel(shutdown_result);
                }
@@ -2918,17 +2913,16 @@ where
                        let logger = WithContext::from(&self.logger, Some(*peer_node_id), Some(*channel_id));
                        if let hash_map::Entry::Occupied(chan_phase_entry) = peer_state.channel_by_id.entry(channel_id.clone()) {
                                log_error!(logger, "Force-closing channel {}", channel_id);
-                               self.issue_channel_close_events(&chan_phase_entry.get().context(), closure_reason);
                                let mut chan_phase = remove_channel_phase!(self, chan_phase_entry);
                                mem::drop(peer_state);
                                mem::drop(per_peer_state);
                                match chan_phase {
                                        ChannelPhase::Funded(mut chan) => {
-                                               self.finish_close_channel(chan.context.force_shutdown(broadcast));
+                                               self.finish_close_channel(chan.context.force_shutdown(broadcast, closure_reason));
                                                (self.get_channel_update_for_broadcast(&chan).ok(), chan.context.get_counterparty_node_id())
                                        },
                                        ChannelPhase::UnfundedOutboundV1(_) | ChannelPhase::UnfundedInboundV1(_) => {
-                                               self.finish_close_channel(chan_phase.context_mut().force_shutdown(false));
+                                               self.finish_close_channel(chan_phase.context_mut().force_shutdown(false, closure_reason));
                                                // Unfunded channel has no update
                                                (None, chan_phase.context().get_counterparty_node_id())
                                        },
@@ -3748,18 +3742,18 @@ where
 
                let mut peer_state_lock = peer_state_mutex.lock().unwrap();
                let peer_state = &mut *peer_state_lock;
-               let (chan, msg_opt) = match peer_state.channel_by_id.remove(temporary_channel_id) {
+               let funding_txo;
+               let (mut chan, msg_opt) = match peer_state.channel_by_id.remove(temporary_channel_id) {
                        Some(ChannelPhase::UnfundedOutboundV1(mut chan)) => {
-                               let funding_txo = find_funding_output(&chan, &funding_transaction)?;
+                               funding_txo = find_funding_output(&chan, &funding_transaction)?;
 
                                let logger = WithChannelContext::from(&self.logger, &chan.context);
                                let funding_res = chan.get_funding_created(funding_transaction, funding_txo, is_batch_funding, &&logger)
                                        .map_err(|(mut chan, e)| if let ChannelError::Close(msg) = e {
                                                let channel_id = chan.context.channel_id();
-                                               let user_id = chan.context.get_user_id();
-                                               let shutdown_res = chan.context.force_shutdown(false);
-                                               let channel_capacity = chan.context.get_value_satoshis();
-                                               (chan, MsgHandleErrInternal::from_finish_shutdown(msg, channel_id, user_id, shutdown_res, None, channel_capacity))
+                                               let reason = ClosureReason::ProcessingError { err: msg.clone() };
+                                               let shutdown_res = chan.context.force_shutdown(false, reason);
+                                               (chan, MsgHandleErrInternal::from_finish_shutdown(msg, channel_id, shutdown_res, None))
                                        } else { unreachable!(); });
                                match funding_res {
                                        Ok(funding_msg) => (chan, funding_msg),
@@ -3798,9 +3792,21 @@ where
                                panic!("Generated duplicate funding txid?");
                        },
                        hash_map::Entry::Vacant(e) => {
-                               let mut id_to_peer = self.id_to_peer.lock().unwrap();
-                               if id_to_peer.insert(chan.context.channel_id(), chan.context.get_counterparty_node_id()).is_some() {
-                                       panic!("id_to_peer map already contained funding txid, which shouldn't be possible");
+                               let mut outpoint_to_peer = self.outpoint_to_peer.lock().unwrap();
+                               match outpoint_to_peer.entry(funding_txo) {
+                                       hash_map::Entry::Vacant(e) => { e.insert(chan.context.get_counterparty_node_id()); },
+                                       hash_map::Entry::Occupied(o) => {
+                                               let err = format!(
+                                                       "An existing channel using outpoint {} is open with peer {}",
+                                                       funding_txo, o.get()
+                                               );
+                                               mem::drop(outpoint_to_peer);
+                                               mem::drop(peer_state_lock);
+                                               mem::drop(per_peer_state);
+                                               let reason = ClosureReason::ProcessingError { err: err.clone() };
+                                               self.finish_close_channel(chan.context.force_shutdown(true, reason));
+                                               return Err(APIError::ChannelUnavailable { err });
+                                       }
                                }
                                e.insert(ChannelPhase::UnfundedOutboundV1(chan));
                        }
@@ -3964,8 +3970,8 @@ where
                                                .and_then(|mut peer_state| peer_state.channel_by_id.remove(&channel_id))
                                                .map(|mut chan| {
                                                        update_maps_on_chan_removal!(self, &chan.context());
-                                                       self.issue_channel_close_events(&chan.context(), ClosureReason::ProcessingError { err: e.clone() });
-                                                       shutdown_results.push(chan.context_mut().force_shutdown(false));
+                                                       let closure_reason = ClosureReason::ProcessingError { err: e.clone() };
+                                                       shutdown_results.push(chan.context_mut().force_shutdown(false, closure_reason));
                                                });
                                }
                        }
@@ -4882,8 +4888,7 @@ where
                                        log_error!(logger,
                                                "Force-closing pending channel with ID {} for not establishing in a timely manner", chan_id);
                                        update_maps_on_chan_removal!(self, &context);
-                                       self.issue_channel_close_events(&context, ClosureReason::HolderForceClosed);
-                                       shutdown_channels.push(context.force_shutdown(false));
+                                       shutdown_channels.push(context.force_shutdown(false, ClosureReason::HolderForceClosed));
                                        pending_msg_events.push(MessageSendEvent::HandleError {
                                                node_id: counterparty_node_id,
                                                action: msgs::ErrorAction::SendErrorMessage {
@@ -5605,6 +5610,7 @@ where
                }
                let preimage_update = ChannelMonitorUpdate {
                        update_id: CLOSED_CHANNEL_UPDATE_ID,
+                       counterparty_node_id: None,
                        updates: vec![ChannelMonitorUpdateStep::PaymentPreimage {
                                payment_preimage,
                        }],
@@ -5906,9 +5912,9 @@ where
                        Some(cp_id) => cp_id.clone(),
                        None => {
                                // TODO: Once we can rely on the counterparty_node_id from the
-                               // monitor event, this and the id_to_peer map should be removed.
-                               let id_to_peer = self.id_to_peer.lock().unwrap();
-                               match id_to_peer.get(&funding_txo.to_channel_id()) {
+                               // monitor event, this and the outpoint_to_peer map should be removed.
+                               let outpoint_to_peer = self.outpoint_to_peer.lock().unwrap();
+                               match outpoint_to_peer.get(&funding_txo) {
                                        Some(cp_id) => cp_id.clone(),
                                        None => return,
                                }
@@ -5989,13 +5995,20 @@ where
        }
 
        fn do_accept_inbound_channel(&self, temporary_channel_id: &ChannelId, counterparty_node_id: &PublicKey, accept_0conf: bool, user_channel_id: u128) -> Result<(), APIError> {
+
+               let logger = WithContext::from(&self.logger, Some(*counterparty_node_id), Some(*temporary_channel_id));
                let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
 
                let peers_without_funded_channels =
                        self.peers_without_funded_channels(|peer| { peer.total_channel_count() > 0 });
                let per_peer_state = self.per_peer_state.read().unwrap();
                let peer_state_mutex = per_peer_state.get(counterparty_node_id)
-                       .ok_or_else(|| APIError::ChannelUnavailable { err: format!("Can't find a peer matching the passed counterparty node_id {}", counterparty_node_id) })?;
+               .ok_or_else(|| {
+                       let err_str = format!("Can't find a peer matching the passed counterparty node_id {}", counterparty_node_id); 
+                       log_error!(logger, "{}", err_str);
+
+                       APIError::ChannelUnavailable { err: err_str } 
+               })?;
                let mut peer_state_lock = peer_state_mutex.lock().unwrap();
                let peer_state = &mut *peer_state_lock;
                let is_only_peer_channel = peer_state.total_channel_count() == 1;
@@ -6010,9 +6023,19 @@ where
                                InboundV1Channel::new(&self.fee_estimator, &self.entropy_source, &self.signer_provider,
                                        counterparty_node_id.clone(), &self.channel_type_features(), &peer_state.latest_features,
                                        &unaccepted_channel.open_channel_msg, user_channel_id, &self.default_configuration, best_block_height,
-                                       &self.logger, accept_0conf).map_err(|e| APIError::ChannelUnavailable { err: e.to_string() })
+                                       &self.logger, accept_0conf).map_err(|e| {
+                                               let err_str = e.to_string();
+                                               log_error!(logger, "{}", err_str);
+
+                                               APIError::ChannelUnavailable { err: err_str }
+                                       })
+                               }
+                       _ => { 
+                               let err_str = "No such channel awaiting to be accepted.".to_owned();
+                               log_error!(logger, "{}", err_str);
+
+                               Err(APIError::APIMisuseError { err: err_str })
                        }
-                       _ => Err(APIError::APIMisuseError { err: "No such channel awaiting to be accepted.".to_owned() })
                }?;
 
                if accept_0conf {
@@ -6026,7 +6049,10 @@ where
                                }
                        };
                        peer_state.pending_msg_events.push(send_msg_err_event);
-                       return Err(APIError::APIMisuseError { err: "Please use accept_inbound_channel_from_trusted_peer_0conf to accept channels with zero confirmations.".to_owned() });
+                       let err_str = "Please use accept_inbound_channel_from_trusted_peer_0conf to accept channels with zero confirmations.".to_owned();
+                       log_error!(logger, "{}", err_str);
+
+                       return Err(APIError::APIMisuseError { err: err_str });
                } else {
                        // If this peer already has some channels, a new channel won't increase our number of peers
                        // with unfunded channels, so as long as we aren't over the maximum number of unfunded
@@ -6039,7 +6065,10 @@ where
                                        }
                                };
                                peer_state.pending_msg_events.push(send_msg_err_event);
-                               return Err(APIError::APIMisuseError { err: "Too many peers with unfunded channels, refusing to accept new ones".to_owned() });
+                               let err_str = "Too many peers with unfunded channels, refusing to accept new ones".to_owned();
+                               log_error!(logger, "{}", err_str);
+
+                               return Err(APIError::APIMisuseError { err: err_str });
                        }
                }
 
@@ -6162,13 +6191,18 @@ where
 
                // If we're doing manual acceptance checks on the channel, then defer creation until we're sure we want to accept.
                if self.default_configuration.manually_accept_inbound_channels {
+                       let channel_type = channel::channel_type_from_open_channel(
+                                       &msg, &peer_state.latest_features, &self.channel_type_features()
+                               ).map_err(|e|
+                                       MsgHandleErrInternal::from_chan_no_close(e, msg.temporary_channel_id)
+                               )?;
                        let mut pending_events = self.pending_events.lock().unwrap();
                        pending_events.push_back((events::Event::OpenChannelRequest {
                                temporary_channel_id: msg.temporary_channel_id.clone(),
                                counterparty_node_id: counterparty_node_id.clone(),
                                funding_satoshis: msg.funding_satoshis,
                                push_msat: msg.push_msat,
-                               channel_type: msg.channel_type.clone().unwrap(),
+                               channel_type,
                        }, None));
                        peer_state.inbound_channel_request_by_id.insert(channel_id, InboundChannelRequest {
                                open_channel_msg: msg.clone(),
@@ -6260,50 +6294,61 @@ where
 
                let mut peer_state_lock = peer_state_mutex.lock().unwrap();
                let peer_state = &mut *peer_state_lock;
-               let (chan, funding_msg_opt, monitor) =
+               let (mut chan, funding_msg_opt, monitor) =
                        match peer_state.channel_by_id.remove(&msg.temporary_channel_id) {
                                Some(ChannelPhase::UnfundedInboundV1(inbound_chan)) => {
                                        let logger = WithChannelContext::from(&self.logger, &inbound_chan.context);
                                        match inbound_chan.funding_created(msg, best_block, &self.signer_provider, &&logger) {
                                                Ok(res) => res,
-                                               Err((mut inbound_chan, err)) => {
+                                               Err((inbound_chan, err)) => {
                                                        // We've already removed this inbound channel from the map in `PeerState`
                                                        // above so at this point we just need to clean up any lingering entries
                                                        // concerning this channel as it is safe to do so.
-                                                       update_maps_on_chan_removal!(self, &inbound_chan.context);
-                                                       let user_id = inbound_chan.context.get_user_id();
-                                                       let shutdown_res = inbound_chan.context.force_shutdown(false);
-                                                       return Err(MsgHandleErrInternal::from_finish_shutdown(format!("{}", err),
-                                                               msg.temporary_channel_id, user_id, shutdown_res, None, inbound_chan.context.get_value_satoshis()));
+                                                       debug_assert!(matches!(err, ChannelError::Close(_)));
+                                                       // Really we should be returning the channel_id the peer expects based
+                                                       // on their funding info here, but they're horribly confused anyway, so
+                                                       // there's not a lot we can do to save them.
+                                                       return Err(convert_chan_phase_err!(self, err, &mut ChannelPhase::UnfundedInboundV1(inbound_chan), &msg.temporary_channel_id).1);
                                                },
                                        }
                                },
-                               Some(ChannelPhase::Funded(_)) | Some(ChannelPhase::UnfundedOutboundV1(_)) => {
-                                       return Err(MsgHandleErrInternal::send_err_msg_no_close(format!("Got an unexpected funding_created message from peer with counterparty_node_id {}", counterparty_node_id), msg.temporary_channel_id));
+                               Some(mut phase) => {
+                                       let err_msg = format!("Got an unexpected funding_created message from peer with counterparty_node_id {}", counterparty_node_id);
+                                       let err = ChannelError::Close(err_msg);
+                                       return Err(convert_chan_phase_err!(self, err, &mut phase, &msg.temporary_channel_id).1);
                                },
                                None => 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.temporary_channel_id))
                        };
 
-               match peer_state.channel_by_id.entry(chan.context.channel_id()) {
+               let funded_channel_id = chan.context.channel_id();
+
+               macro_rules! fail_chan { ($err: expr) => { {
+                       // Note that at this point we've filled in the funding outpoint on our
+                       // channel, but its actually in conflict with another channel. Thus, if
+                       // we call `convert_chan_phase_err` immediately (thus calling
+                       // `update_maps_on_chan_removal`), we'll remove the existing channel
+                       // from `outpoint_to_peer`. Thus, we must first unset the funding outpoint
+                       // on the channel.
+                       let err = ChannelError::Close($err.to_owned());
+                       chan.unset_funding_info(msg.temporary_channel_id);
+                       return Err(convert_chan_phase_err!(self, err, chan, &funded_channel_id, UNFUNDED_CHANNEL).1);
+               } } }
+
+               match peer_state.channel_by_id.entry(funded_channel_id) {
                        hash_map::Entry::Occupied(_) => {
-                               Err(MsgHandleErrInternal::send_err_msg_no_close(
-                                       "Already had channel with the new channel_id".to_owned(),
-                                       chan.context.channel_id()
-                               ))
+                               fail_chan!("Already had channel with the new channel_id");
                        },
                        hash_map::Entry::Vacant(e) => {
-                               let mut id_to_peer_lock = self.id_to_peer.lock().unwrap();
-                               match id_to_peer_lock.entry(chan.context.channel_id()) {
+                               let mut outpoint_to_peer_lock = self.outpoint_to_peer.lock().unwrap();
+                               match outpoint_to_peer_lock.entry(monitor.get_funding_txo().0) {
                                        hash_map::Entry::Occupied(_) => {
-                                               return Err(MsgHandleErrInternal::send_err_msg_no_close(
-                                                       "The funding_created message had the same funding_txid as an existing channel - funding is not possible".to_owned(),
-                                                       chan.context.channel_id()))
+                                               fail_chan!("The funding_created message had the same funding_txid as an existing channel - funding is not possible");
                                        },
                                        hash_map::Entry::Vacant(i_e) => {
                                                let monitor_res = self.chain_monitor.watch_channel(monitor.get_funding_txo().0, monitor);
                                                if let Ok(persist_state) = monitor_res {
                                                        i_e.insert(chan.context.get_counterparty_node_id());
-                                                       mem::drop(id_to_peer_lock);
+                                                       mem::drop(outpoint_to_peer_lock);
 
                                                        // There's no problem signing a counterparty's funding transaction if our monitor
                                                        // hasn't persisted to disk yet - we can't lose money on a transaction that we haven't
@@ -6326,13 +6371,7 @@ where
                                                } else {
                                                        let logger = WithChannelContext::from(&self.logger, &chan.context);
                                                        log_error!(logger, "Persisting initial ChannelMonitor failed, implying the funding outpoint was duplicated");
-                                                       let channel_id = match funding_msg_opt {
-                                                               Some(msg) => msg.channel_id,
-                                                               None => chan.context.channel_id(),
-                                                       };
-                                                       return Err(MsgHandleErrInternal::send_err_msg_no_close(
-                                                               "The funding_created message had the same funding_txid as an existing channel - funding is not possible".to_owned(),
-                                                               channel_id));
+                                                       fail_chan!("Duplicate funding outpoint");
                                                }
                                        }
                                }
@@ -6363,7 +6402,7 @@ where
                                        let res =
                                                chan.funding_signed(&msg, best_block, &self.signer_provider, &&logger);
                                        match res {
-                                               Ok((chan, monitor)) => {
+                                               Ok((mut chan, monitor)) => {
                                                        if let Ok(persist_status) = self.chain_monitor.watch_channel(chan.context.get_funding_txo().unwrap(), monitor) {
                                                                // We really should be able to insert here without doing a second
                                                                // lookup, but sadly rust stdlib doesn't currently allow keeping
@@ -6375,6 +6414,11 @@ where
                                                                Ok(())
                                                        } else {
                                                                let e = ChannelError::Close("Channel funding outpoint was a duplicate".to_owned());
+                                                               // We weren't able to watch the channel to begin with, so no
+                                                               // updates should be made on it. Previously, full_stack_target
+                                                               // found an (unreachable) panic when the monitor update contained
+                                                               // within `shutdown_finish` was applied.
+                                                               chan.unset_funding_info(msg.channel_id);
                                                                return Err(convert_chan_phase_err!(self, e, &mut ChannelPhase::Funded(chan), &msg.channel_id).1);
                                                        }
                                                },
@@ -6497,9 +6541,8 @@ where
                                                let context = phase.context_mut();
                                                let logger = WithChannelContext::from(&self.logger, context);
                                                log_error!(logger, "Immediately closing unfunded channel {} as peer asked to cooperatively shut it down (which is unnecessary)", &msg.channel_id);
-                                               self.issue_channel_close_events(&context, ClosureReason::CounterpartyCoopClosedUnfundedChannel);
                                                let mut chan = remove_channel_phase!(self, chan_phase_entry);
-                                               finish_shutdown = Some(chan.context_mut().force_shutdown(false));
+                                               finish_shutdown = Some(chan.context_mut().force_shutdown(false, ClosureReason::CounterpartyCoopClosedUnfundedChannel));
                                        },
                                }
                        } else {
@@ -6568,7 +6611,6 @@ where
                                        msg: update
                                });
                        }
-                       self.issue_channel_close_events(&chan.context, ClosureReason::CooperativeClosure);
                }
                mem::drop(per_peer_state);
                if let Some(shutdown_result) = shutdown_result {
@@ -7207,9 +7249,9 @@ where
                                                        Some(cp_id) => Some(cp_id),
                                                        None => {
                                                                // TODO: Once we can rely on the counterparty_node_id from the
-                                                               // monitor event, this and the id_to_peer map should be removed.
-                                                               let id_to_peer = self.id_to_peer.lock().unwrap();
-                                                               id_to_peer.get(&funding_outpoint.to_channel_id()).cloned()
+                                                               // monitor event, this and the outpoint_to_peer map should be removed.
+                                                               let outpoint_to_peer = self.outpoint_to_peer.lock().unwrap();
+                                                               outpoint_to_peer.get(&funding_outpoint).cloned()
                                                        }
                                                };
                                                if let Some(counterparty_node_id) = counterparty_node_id_opt {
@@ -7220,13 +7262,12 @@ where
                                                                let pending_msg_events = &mut peer_state.pending_msg_events;
                                                                if let hash_map::Entry::Occupied(chan_phase_entry) = peer_state.channel_by_id.entry(funding_outpoint.to_channel_id()) {
                                                                        if let ChannelPhase::Funded(mut chan) = remove_channel_phase!(self, chan_phase_entry) {
-                                                                               failed_channels.push(chan.context.force_shutdown(false));
+                                                                               failed_channels.push(chan.context.force_shutdown(false, ClosureReason::HolderForceClosed));
                                                                                if let Ok(update) = self.get_channel_update_for_broadcast(&chan) {
                                                                                        pending_msg_events.push(events::MessageSendEvent::BroadcastChannelUpdate {
                                                                                                msg: update
                                                                                        });
                                                                                }
-                                                                               self.issue_channel_close_events(&chan.context, ClosureReason::HolderForceClosed);
                                                                                pending_msg_events.push(events::MessageSendEvent::HandleError {
                                                                                        node_id: chan.context.get_counterparty_node_id(),
                                                                                        action: msgs::ErrorAction::DisconnectPeer {
@@ -7317,8 +7358,7 @@ where
        /// attempted in every channel, or in the specifically provided channel.
        ///
        /// [`ChannelSigner`]: crate::sign::ChannelSigner
-       #[cfg(test)] // This is only implemented for one signer method, and should be private until we
-                    // actually finish implementing it fully.
+       #[cfg(async_signing)]
        pub fn signer_unblocked(&self, channel_opt: Option<(PublicKey, ChannelId)>) {
                let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
 
@@ -7414,8 +7454,6 @@ where
                                                                                        });
                                                                                }
 
-                                                                               self.issue_channel_close_events(&chan.context, ClosureReason::CooperativeClosure);
-
                                                                                log_info!(logger, "Broadcasting {}", log_tx!(tx));
                                                                                self.tx_broadcaster.broadcast_transactions(&[&tx]);
                                                                                update_maps_on_chan_removal!(self, &chan.context);
@@ -7479,32 +7517,43 @@ where
        ///
        /// # 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`].
+       /// Uses [`MessageRouter::create_blinded_paths`] to construct a [`BlindedPath`] for the offer.
+       /// However, if one is not found, uses a one-hop [`BlindedPath`] with
+       /// [`ChannelManager::get_our_node_id`] as the introduction node instead. In the latter case,
+       /// the node must be announced, otherwise, there is no way to find a path to the introduction in
+       /// order to send the [`InvoiceRequest`].
+       ///
+       /// Also, uses a derived signing pubkey in the offer for recipient privacy.
        ///
        /// # Limitations
        ///
        /// Requires a direct connection to the introduction node in the responding [`InvoiceRequest`]'s
        /// reply path.
        ///
+       /// # Errors
+       ///
+       /// Errors if the parameterized [`Router`] is unable to create a blinded path for the offer.
+       ///
        /// 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(
                &self, description: String
-       ) -> OfferBuilder<DerivedMetadata, secp256k1::All> {
+       ) -> Result<OfferBuilder<DerivedMetadata, secp256k1::All>, Bolt12SemanticError> {
                let node_id = self.get_our_node_id();
                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();
 
-               OfferBuilder::deriving_signing_pubkey(description, node_id, expanded_key, entropy, secp_ctx)
+               let path = self.create_blinded_path().map_err(|_| Bolt12SemanticError::MissingPaths)?;
+               let builder = OfferBuilder::deriving_signing_pubkey(
+                       description, node_id, expanded_key, entropy, secp_ctx
+               )
                        .chain_hash(self.chain_hash)
-                       .path(path)
+                       .path(path);
+
+               Ok(builder)
        }
 
        /// Creates a [`RefundBuilder`] such that the [`Refund`] it builds is recognized by the
@@ -7529,10 +7578,13 @@ where
        ///
        /// # 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`].
+       /// Uses [`MessageRouter::create_blinded_paths`] to construct a [`BlindedPath`] for the refund.
+       /// However, if one is not found, uses a one-hop [`BlindedPath`] with
+       /// [`ChannelManager::get_our_node_id`] as the introduction node instead. In the latter case,
+       /// the node must be announced, otherwise, there is no way to find a path to the introduction in
+       /// order to send the [`Bolt12Invoice`].
+       ///
+       /// Also, uses a derived payer id in the refund for payer privacy.
        ///
        /// # Limitations
        ///
@@ -7541,14 +7593,17 @@ where
        ///
        /// # Errors
        ///
-       /// Errors if a duplicate `payment_id` is provided given the caveats in the aforementioned link
-       /// or if `amount_msats` is invalid.
+       /// Errors if:
+       /// - a duplicate `payment_id` is provided given the caveats in the aforementioned link,
+       /// - `amount_msats` is invalid, or
+       /// - the parameterized [`Router`] is unable to create a blinded path for the refund.
        ///
        /// 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
+       /// [Avoiding Duplicate Payments]: #avoiding-duplicate-payments
        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>
@@ -7557,8 +7612,8 @@ 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();
 
+               let path = self.create_blinded_path().map_err(|_| Bolt12SemanticError::MissingPaths)?;
                let builder = RefundBuilder::deriving_payer_id(
                        description, node_id, expanded_key, entropy, secp_ctx, amount_msats, payment_id
                )?
@@ -7616,8 +7671,11 @@ where
        ///
        /// # 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.
+       /// Errors if:
+       /// - a duplicate `payment_id` is provided given the caveats in the aforementioned link,
+       /// - the provided parameters are invalid for the offer,
+       /// - the parameterized [`Router`] is unable to create a blinded reply path for the invoice
+       ///   request.
        ///
        /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
        /// [`InvoiceRequest::quantity`]: crate::offers::invoice_request::InvoiceRequest::quantity
@@ -7650,9 +7708,8 @@ where
                        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 reply_path = self.create_blinded_path().map_err(|_| Bolt12SemanticError::MissingPaths)?;
 
                let expiration = StaleExpiration::TimerTicks(1);
                self.pending_outbound_payments
@@ -7701,6 +7758,11 @@ where
        /// node meeting the aforementioned criteria, but there's no guarantee that they will be
        /// received and no retries will be made.
        ///
+       /// # Errors
+       ///
+       /// Errors if the parameterized [`Router`] is unable to create a blinded payment path or reply
+       /// path for the invoice.
+       ///
        /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
        pub fn request_refund_payment(&self, refund: &Refund) -> Result<(), Bolt12SemanticError> {
                let expanded_key = &self.inbound_payment_key;
@@ -7712,9 +7774,9 @@ where
 
                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),
-                               ];
+                               let payment_paths = self.create_blinded_payment_paths(amount_msats, payment_secret)
+                                       .map_err(|_| Bolt12SemanticError::MissingPaths)?;
+
                                #[cfg(not(feature = "no-std"))]
                                let builder = refund.respond_using_derived_keys(
                                        payment_paths, payment_hash, expanded_key, entropy
@@ -7728,7 +7790,8 @@ where
                                        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 reply_path = self.create_blinded_path()
+                                       .map_err(|_| Bolt12SemanticError::MissingPaths)?;
 
                                let mut pending_offers_messages = self.pending_offers_messages.lock().unwrap();
                                if refund.paths().is_empty() {
@@ -7855,24 +7918,37 @@ 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 {
+       /// Creates a blinded path by delegating to [`MessageRouter::create_blinded_paths`].
+       ///
+       /// Errors if the `MessageRouter` errors or returns an empty `Vec`.
+       fn create_blinded_path(&self) -> Result<BlindedPath, ()> {
+               let recipient = self.get_our_node_id();
                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()
+
+               let peers = self.per_peer_state.read().unwrap()
+                       .iter()
+                       .filter(|(_, peer)| peer.lock().unwrap().latest_features.supports_onion_messages())
+                       .map(|(node_id, _)| *node_id)
+                       .collect::<Vec<_>>();
+
+               self.router
+                       .create_blinded_paths(recipient, peers, entropy_source, secp_ctx)
+                       .and_then(|paths| paths.into_iter().next().ok_or(()))
        }
 
-       /// 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) {
+       /// Creates multi-hop blinded payment paths for the given `amount_msats` by delegating to
+       /// [`Router::create_blinded_payment_paths`].
+       fn create_blinded_payment_paths(
+               &self, amount_msats: u64, payment_secret: PaymentSecret
+       ) -> Result<Vec<(BlindedPayInfo, BlindedPath)>, ()> {
                let entropy_source = self.entropy_source.deref();
                let secp_ctx = &self.secp_ctx;
 
+               let first_hops = self.list_usable_channels();
                let payee_node_id = self.get_our_node_id();
-               let max_cltv_expiry = self.best_block.read().unwrap().height() + LATENCY_GRACE_PERIOD_BLOCKS;
+               let max_cltv_expiry = self.best_block.read().unwrap().height() + CLTV_FAR_FAR_AWAY
+                       + LATENCY_GRACE_PERIOD_BLOCKS;
                let payee_tlvs = ReceiveTlvs {
                        payment_secret,
                        payment_constraints: PaymentConstraints {
@@ -7880,10 +7956,9 @@ where
                                htlc_minimum_msat: 1,
                        },
                };
-               // TODO: Err for overflow?
-               BlindedPath::one_hop_for_payment(
-                       payee_node_id, payee_tlvs, entropy_source, secp_ctx
-               ).unwrap()
+               self.router.create_blinded_payment_paths(
+                       payee_node_id, first_hops, payee_tlvs, amount_msats, entropy_source, secp_ctx
+               )
        }
 
        /// Gets a fake short channel id for use in receiving [phantom node payments]. These fake scids
@@ -8391,14 +8466,13 @@ where
                                                                update_maps_on_chan_removal!(self, &channel.context);
                                                                // It looks like our counterparty went on-chain or funding transaction was
                                                                // reorged out of the main chain. Close the channel.
-                                                               failed_channels.push(channel.context.force_shutdown(true));
+                                                               let reason_message = format!("{}", reason);
+                                                               failed_channels.push(channel.context.force_shutdown(true, reason));
                                                                if let Ok(update) = self.get_channel_update_for_broadcast(&channel) {
                                                                        pending_msg_events.push(events::MessageSendEvent::BroadcastChannelUpdate {
                                                                                msg: update
                                                                        });
                                                                }
-                                                               let reason_message = format!("{}", reason);
-                                                               self.issue_channel_close_events(&channel.context, reason);
                                                                pending_msg_events.push(events::MessageSendEvent::HandleError {
                                                                        node_id: channel.context.get_counterparty_node_id(),
                                                                        action: msgs::ErrorAction::DisconnectPeer {
@@ -8796,8 +8870,7 @@ where
                                        };
                                        // Clean up for removal.
                                        update_maps_on_chan_removal!(self, &context);
-                                       self.issue_channel_close_events(&context, ClosureReason::DisconnectedPeer);
-                                       failed_channels.push(context.force_shutdown(false));
+                                       failed_channels.push(context.force_shutdown(false, ClosureReason::DisconnectedPeer));
                                        false
                                });
                                // Note that we don't bother generating any events for pre-accept channels -
@@ -8930,13 +9003,7 @@ where
                                let pending_msg_events = &mut peer_state.pending_msg_events;
 
                                peer_state.channel_by_id.iter_mut().filter_map(|(_, phase)|
-                                       if let ChannelPhase::Funded(chan) = phase { Some(chan) } else {
-                                               // Since unfunded channel maps are cleared upon disconnecting a peer, and they're not persisted
-                                               // (so won't be recovered after a crash), they shouldn't exist here and we would never need to
-                                               // worry about closing and removing them.
-                                               debug_assert!(false);
-                                               None
-                                       }
+                                       if let ChannelPhase::Funded(chan) = phase { Some(chan) } else { None }
                                ).for_each(|chan| {
                                        let logger = WithChannelContext::from(&self.logger, &chan.context);
                                        pending_msg_events.push(events::MessageSendEvent::SendChannelReestablish {
@@ -9123,7 +9190,7 @@ where
                                let amount_msats = match InvoiceBuilder::<DerivedSigningPubkey>::amount_msats(
                                        &invoice_request
                                ) {
-                                       Ok(amount_msats) => Some(amount_msats),
+                                       Ok(amount_msats) => amount_msats,
                                        Err(error) => return Some(OffersMessage::InvoiceError(error.into())),
                                };
                                let invoice_request = match invoice_request.verify(expanded_key, secp_ctx) {
@@ -9133,64 +9200,69 @@ where
                                                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),
-                                               }
+                               let relative_expiry = DEFAULT_RELATIVE_EXPIRY.as_secs() as u32;
+                               let (payment_hash, payment_secret) = match self.create_inbound_payment(
+                                       Some(amount_msats), relative_expiry, None
+                               ) {
+                                       Ok((payment_hash, payment_secret)) => (payment_hash, payment_secret),
+                                       Err(()) => {
+                                               let error = Bolt12SemanticError::InvalidAmount;
+                                               return Some(OffersMessage::InvoiceError(error.into()));
                                        },
+                               };
+
+                               let payment_paths = match self.create_blinded_payment_paths(
+                                       amount_msats, payment_secret
+                               ) {
+                                       Ok(payment_paths) => payment_paths,
                                        Err(()) => {
-                                               Some(OffersMessage::InvoiceError(Bolt12SemanticError::InvalidAmount.into()))
+                                               let error = Bolt12SemanticError::MissingPaths;
+                                               return Some(OffersMessage::InvoiceError(error.into()));
                                        },
+                               };
+
+                               #[cfg(feature = "no-std")]
+                               let created_at = Duration::from_secs(
+                                       self.highest_seen_timestamp.load(Ordering::Acquire) as u64
+                               );
+
+                               if invoice_request.keys.is_some() {
+                                       #[cfg(not(feature = "no-std"))]
+                                       let builder = invoice_request.respond_using_derived_keys(
+                                               payment_paths, payment_hash
+                                       );
+                                       #[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())),
+                                       }
+                               } else {
+                                       #[cfg(not(feature = "no-std"))]
+                                       let builder = invoice_request.respond_with(payment_paths, payment_hash);
+                                       #[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),
+                                       }
                                }
                        },
                        OffersMessage::Invoice(invoice) => {
@@ -10203,7 +10275,7 @@ where
                let channel_count: u64 = Readable::read(reader)?;
                let mut funding_txo_set = HashSet::with_capacity(cmp::min(channel_count as usize, 128));
                let mut funded_peer_channels: HashMap<PublicKey, HashMap<ChannelId, ChannelPhase<SP>>> = HashMap::with_capacity(cmp::min(channel_count as usize, 128));
-               let mut id_to_peer = HashMap::with_capacity(cmp::min(channel_count as usize, 128));
+               let mut outpoint_to_peer = HashMap::with_capacity(cmp::min(channel_count as usize, 128));
                let mut short_to_chan_info = HashMap::with_capacity(cmp::min(channel_count as usize, 128));
                let mut channel_closures = VecDeque::new();
                let mut close_background_events = Vec::new();
@@ -10238,7 +10310,7 @@ where
                                                log_error!(logger, " The ChannelMonitor for channel {} is at counterparty commitment transaction number {} but the ChannelManager is at counterparty commitment transaction number {}.",
                                                        &channel.context.channel_id(), monitor.get_cur_counterparty_commitment_number(), channel.get_cur_counterparty_commitment_transaction_number());
                                        }
-                                       let mut shutdown_result = channel.context.force_shutdown(true);
+                                       let mut shutdown_result = channel.context.force_shutdown(true, ClosureReason::OutdatedChannelManager);
                                        if shutdown_result.unbroadcasted_batch_funding_txid.is_some() {
                                                return Err(DecodeError::InvalidValue);
                                        }
@@ -10281,8 +10353,8 @@ where
                                        if let Some(short_channel_id) = channel.context.get_short_channel_id() {
                                                short_to_chan_info.insert(short_channel_id, (channel.context.get_counterparty_node_id(), channel.context.channel_id()));
                                        }
-                                       if channel.context.is_funding_broadcast() {
-                                               id_to_peer.insert(channel.context.channel_id(), channel.context.get_counterparty_node_id());
+                                       if let Some(funding_txo) = channel.context.get_funding_txo() {
+                                               outpoint_to_peer.insert(funding_txo, channel.context.get_counterparty_node_id());
                                        }
                                        match funded_peer_channels.entry(channel.context.get_counterparty_node_id()) {
                                                hash_map::Entry::Occupied(mut entry) => {
@@ -10300,7 +10372,7 @@ where
                                // If we were persisted and shut down while the initial ChannelMonitor persistence
                                // was in-progress, we never broadcasted the funding transaction and can still
                                // safely discard the channel.
-                               let _ = channel.context.force_shutdown(false);
+                               let _ = channel.context.force_shutdown(false, ClosureReason::DisconnectedPeer);
                                channel_closures.push_back((events::Event::ChannelClosed {
                                        channel_id: channel.context.channel_id(),
                                        user_channel_id: channel.context.get_user_id(),
@@ -10325,6 +10397,7 @@ where
                                        &funding_txo.to_channel_id());
                                let monitor_update = ChannelMonitorUpdate {
                                        update_id: CLOSED_CHANNEL_UPDATE_ID,
+                                       counterparty_node_id: None,
                                        updates: vec![ChannelMonitorUpdateStep::ChannelForceClosed { should_broadcast: true }],
                                };
                                close_background_events.push(BackgroundEvent::ClosedMonitorUpdateRegeneratedOnStartup((*funding_txo, monitor_update)));
@@ -10616,7 +10689,7 @@ where
                        // We only rebuild the pending payments map if we were most recently serialized by
                        // 0.0.102+
                        for (_, monitor) in args.channel_monitors.iter() {
-                               let counterparty_opt = id_to_peer.get(&monitor.get_funding_txo().0.to_channel_id());
+                               let counterparty_opt = outpoint_to_peer.get(&monitor.get_funding_txo().0);
                                if counterparty_opt.is_none() {
                                        let logger = WithChannelMonitor::from(&args.logger, monitor);
                                        for (htlc_source, (htlc, _)) in monitor.get_pending_or_resolved_outbound_htlcs() {
@@ -10909,7 +10982,7 @@ where
                                                // without the new monitor persisted - we'll end up right back here on
                                                // restart.
                                                let previous_channel_id = claimable_htlc.prev_hop.outpoint.to_channel_id();
-                                               if let Some(peer_node_id) = id_to_peer.get(&previous_channel_id){
+                                               if let Some(peer_node_id) = outpoint_to_peer.get(&claimable_htlc.prev_hop.outpoint) {
                                                        let peer_state_mutex = per_peer_state.get(peer_node_id).unwrap();
                                                        let mut peer_state_lock = peer_state_mutex.lock().unwrap();
                                                        let peer_state = &mut *peer_state_lock;
@@ -10987,7 +11060,7 @@ where
                        forward_htlcs: Mutex::new(forward_htlcs),
                        claimable_payments: Mutex::new(ClaimablePayments { claimable_payments, pending_claiming_payments: pending_claiming_payments.unwrap() }),
                        outbound_scid_aliases: Mutex::new(outbound_scid_aliases),
-                       id_to_peer: Mutex::new(id_to_peer),
+                       outpoint_to_peer: Mutex::new(outpoint_to_peer),
                        short_to_chan_info: FairRwLock::new(short_to_chan_info),
                        fake_scid_rand_bytes: fake_scid_rand_bytes.unwrap(),
 
@@ -11606,8 +11679,8 @@ mod tests {
        }
 
        #[test]
-       fn test_id_to_peer_coverage() {
-               // Test that the `ChannelManager:id_to_peer` contains channels which have been assigned
+       fn test_outpoint_to_peer_coverage() {
+               // Test that the `ChannelManager:outpoint_to_peer` contains channels which have been assigned
                // a `channel_id` (i.e. have had the funding tx created), and that they are removed once
                // the channel is successfully closed.
                let chanmon_cfgs = create_chanmon_cfgs(2);
@@ -11621,42 +11694,42 @@ mod tests {
                let accept_channel = get_event_msg!(nodes[1], MessageSendEvent::SendAcceptChannel, nodes[0].node.get_our_node_id());
                nodes[0].node.handle_accept_channel(&nodes[1].node.get_our_node_id(), &accept_channel);
 
-               let (temporary_channel_id, tx, _funding_output) = create_funding_transaction(&nodes[0], &nodes[1].node.get_our_node_id(), 1_000_000, 42);
+               let (temporary_channel_id, tx, funding_output) = create_funding_transaction(&nodes[0], &nodes[1].node.get_our_node_id(), 1_000_000, 42);
                let channel_id = ChannelId::from_bytes(tx.txid().to_byte_array());
                {
-                       // Ensure that the `id_to_peer` map is empty until either party has received the
+                       // Ensure that the `outpoint_to_peer` map is empty until either party has received the
                        // funding transaction, and have the real `channel_id`.
-                       assert_eq!(nodes[0].node.id_to_peer.lock().unwrap().len(), 0);
-                       assert_eq!(nodes[1].node.id_to_peer.lock().unwrap().len(), 0);
+                       assert_eq!(nodes[0].node.outpoint_to_peer.lock().unwrap().len(), 0);
+                       assert_eq!(nodes[1].node.outpoint_to_peer.lock().unwrap().len(), 0);
                }
 
                nodes[0].node.funding_transaction_generated(&temporary_channel_id, &nodes[1].node.get_our_node_id(), tx.clone()).unwrap();
                {
-                       // Assert that `nodes[0]`'s `id_to_peer` map is populated with the channel as soon as
+                       // Assert that `nodes[0]`'s `outpoint_to_peer` map is populated with the channel as soon as
                        // as it has the funding transaction.
-                       let nodes_0_lock = nodes[0].node.id_to_peer.lock().unwrap();
+                       let nodes_0_lock = nodes[0].node.outpoint_to_peer.lock().unwrap();
                        assert_eq!(nodes_0_lock.len(), 1);
-                       assert!(nodes_0_lock.contains_key(&channel_id));
+                       assert!(nodes_0_lock.contains_key(&funding_output));
                }
 
-               assert_eq!(nodes[1].node.id_to_peer.lock().unwrap().len(), 0);
+               assert_eq!(nodes[1].node.outpoint_to_peer.lock().unwrap().len(), 0);
 
                let funding_created_msg = get_event_msg!(nodes[0], MessageSendEvent::SendFundingCreated, nodes[1].node.get_our_node_id());
 
                nodes[1].node.handle_funding_created(&nodes[0].node.get_our_node_id(), &funding_created_msg);
                {
-                       let nodes_0_lock = nodes[0].node.id_to_peer.lock().unwrap();
+                       let nodes_0_lock = nodes[0].node.outpoint_to_peer.lock().unwrap();
                        assert_eq!(nodes_0_lock.len(), 1);
-                       assert!(nodes_0_lock.contains_key(&channel_id));
+                       assert!(nodes_0_lock.contains_key(&funding_output));
                }
                expect_channel_pending_event(&nodes[1], &nodes[0].node.get_our_node_id());
 
                {
-                       // Assert that `nodes[1]`'s `id_to_peer` map is populated with the channel as soon as
-                       // as it has the funding transaction.
-                       let nodes_1_lock = nodes[1].node.id_to_peer.lock().unwrap();
+                       // Assert that `nodes[1]`'s `outpoint_to_peer` map is populated with the channel as
+                       // soon as it has the funding transaction.
+                       let nodes_1_lock = nodes[1].node.outpoint_to_peer.lock().unwrap();
                        assert_eq!(nodes_1_lock.len(), 1);
-                       assert!(nodes_1_lock.contains_key(&channel_id));
+                       assert!(nodes_1_lock.contains_key(&funding_output));
                }
                check_added_monitors!(nodes[1], 1);
                let funding_signed = get_event_msg!(nodes[1], MessageSendEvent::SendFundingSigned, nodes[0].node.get_our_node_id());
@@ -11675,23 +11748,23 @@ mod tests {
                let closing_signed_node_0 = get_event_msg!(nodes[0], MessageSendEvent::SendClosingSigned, nodes[1].node.get_our_node_id());
                nodes[1].node.handle_closing_signed(&nodes[0].node.get_our_node_id(), &closing_signed_node_0);
                {
-                       // Assert that the channel is kept in the `id_to_peer` map for both nodes until the
+                       // Assert that the channel is kept in the `outpoint_to_peer` map for both nodes until the
                        // channel can be fully closed by both parties (i.e. no outstanding htlcs exists, the
                        // fee for the closing transaction has been negotiated and the parties has the other
                        // party's signature for the fee negotiated closing transaction.)
-                       let nodes_0_lock = nodes[0].node.id_to_peer.lock().unwrap();
+                       let nodes_0_lock = nodes[0].node.outpoint_to_peer.lock().unwrap();
                        assert_eq!(nodes_0_lock.len(), 1);
-                       assert!(nodes_0_lock.contains_key(&channel_id));
+                       assert!(nodes_0_lock.contains_key(&funding_output));
                }
 
                {
                        // At this stage, `nodes[1]` has proposed a fee for the closing transaction in the
                        // `handle_closing_signed` call above. As `nodes[1]` has not yet received the signature
                        // from `nodes[0]` for the closing transaction with the proposed fee, the channel is
-                       // kept in the `nodes[1]`'s `id_to_peer` map.
-                       let nodes_1_lock = nodes[1].node.id_to_peer.lock().unwrap();
+                       // kept in the `nodes[1]`'s `outpoint_to_peer` map.
+                       let nodes_1_lock = nodes[1].node.outpoint_to_peer.lock().unwrap();
                        assert_eq!(nodes_1_lock.len(), 1);
-                       assert!(nodes_1_lock.contains_key(&channel_id));
+                       assert!(nodes_1_lock.contains_key(&funding_output));
                }
 
                nodes[0].node.handle_closing_signed(&nodes[1].node.get_our_node_id(), &get_event_msg!(nodes[1], MessageSendEvent::SendClosingSigned, nodes[0].node.get_our_node_id()));
@@ -11699,24 +11772,24 @@ mod tests {
                        // `nodes[0]` accepts `nodes[1]`'s proposed fee for the closing transaction, and
                        // therefore has all it needs to fully close the channel (both signatures for the
                        // closing transaction).
-                       // Assert that the channel is removed from `nodes[0]`'s `id_to_peer` map as it can be
+                       // Assert that the channel is removed from `nodes[0]`'s `outpoint_to_peer` map as it can be
                        // fully closed by `nodes[0]`.
-                       assert_eq!(nodes[0].node.id_to_peer.lock().unwrap().len(), 0);
+                       assert_eq!(nodes[0].node.outpoint_to_peer.lock().unwrap().len(), 0);
 
-                       // Assert that the channel is still in `nodes[1]`'s  `id_to_peer` map, as `nodes[1]`
+                       // Assert that the channel is still in `nodes[1]`'s  `outpoint_to_peer` map, as `nodes[1]`
                        // doesn't have `nodes[0]`'s signature for the closing transaction yet.
-                       let nodes_1_lock = nodes[1].node.id_to_peer.lock().unwrap();
+                       let nodes_1_lock = nodes[1].node.outpoint_to_peer.lock().unwrap();
                        assert_eq!(nodes_1_lock.len(), 1);
-                       assert!(nodes_1_lock.contains_key(&channel_id));
+                       assert!(nodes_1_lock.contains_key(&funding_output));
                }
 
                let (_nodes_0_update, closing_signed_node_0) = get_closing_signed_broadcast!(nodes[0].node, nodes[1].node.get_our_node_id());
 
                nodes[1].node.handle_closing_signed(&nodes[0].node.get_our_node_id(), &closing_signed_node_0.unwrap());
                {
-                       // Assert that the channel has now been removed from both parties `id_to_peer` map once
+                       // Assert that the channel has now been removed from both parties `outpoint_to_peer` map once
                        // they both have everything required to fully close the channel.
-                       assert_eq!(nodes[1].node.id_to_peer.lock().unwrap().len(), 0);
+                       assert_eq!(nodes[1].node.outpoint_to_peer.lock().unwrap().len(), 0);
                }
                let (_nodes_1_update, _none) = get_closing_signed_broadcast!(nodes[1].node, nodes[0].node.get_our_node_id());