Merge pull request #2591 from TheBlueMatt/2023-09-2562-followups
[rust-lightning] / lightning / src / chain / channelmonitor.rs
index 257d794eaf5cc63354e890389ad211e3753edc15..7088d32d1607e1f4fa0137d6ceda9182d32ca3b2 100644 (file)
@@ -134,7 +134,7 @@ pub enum MonitorEvent {
        HTLCEvent(HTLCUpdate),
 
        /// A monitor event that the Channel's commitment transaction was confirmed.
-       CommitmentTxConfirmed(OutPoint),
+       HolderForceClosed(OutPoint),
 
        /// Indicates a [`ChannelMonitor`] update has completed. See
        /// [`ChannelMonitorUpdateStatus::InProgress`] for more information on how this is used.
@@ -150,24 +150,18 @@ pub enum MonitorEvent {
                /// same [`ChannelMonitor`] have been applied and persisted.
                monitor_update_id: u64,
        },
-
-       /// Indicates a [`ChannelMonitor`] update has failed. See
-       /// [`ChannelMonitorUpdateStatus::PermanentFailure`] for more information on how this is used.
-       ///
-       /// [`ChannelMonitorUpdateStatus::PermanentFailure`]: super::ChannelMonitorUpdateStatus::PermanentFailure
-       UpdateFailed(OutPoint),
 }
 impl_writeable_tlv_based_enum_upgradable!(MonitorEvent,
-       // Note that Completed and UpdateFailed are currently never serialized to disk as they are
-       // generated only in ChainMonitor
+       // Note that Completed is currently never serialized to disk as it is generated only in
+       // ChainMonitor.
        (0, Completed) => {
                (0, funding_txo, required),
                (2, monitor_update_id, required),
        },
 ;
        (2, HTLCEvent),
-       (4, CommitmentTxConfirmed),
-       (6, UpdateFailed),
+       (4, HolderForceClosed),
+       // 6 was `UpdateFailed` until LDK 0.0.117
 );
 
 /// Simple structure sent back by `chain::Watch` when an HTLC from a forward channel is detected on
@@ -1037,7 +1031,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Writeable for ChannelMonitorImpl<Signe
 
                writer.write_all(&(self.pending_monitor_events.iter().filter(|ev| match ev {
                        MonitorEvent::HTLCEvent(_) => true,
-                       MonitorEvent::CommitmentTxConfirmed(_) => true,
+                       MonitorEvent::HolderForceClosed(_) => true,
                        _ => false,
                }).count() as u64).to_be_bytes())?;
                for event in self.pending_monitor_events.iter() {
@@ -1046,7 +1040,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Writeable for ChannelMonitorImpl<Signe
                                        0u8.write(writer)?;
                                        upd.write(writer)?;
                                },
-                               MonitorEvent::CommitmentTxConfirmed(_) => 1u8.write(writer)?,
+                               MonitorEvent::HolderForceClosed(_) => 1u8.write(writer)?,
                                _ => {}, // Covered in the TLV writes below
                        }
                }
@@ -1488,21 +1482,20 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitor<Signer> {
                self.inner.lock().unwrap().counterparty_node_id
        }
 
-       /// Used by ChannelManager deserialization to broadcast the latest holder state if its copy of
-       /// the Channel was out-of-date.
+       /// Used by [`ChannelManager`] deserialization to broadcast the latest holder state if its copy
+       /// of the channel state was out-of-date.
        ///
        /// You may also use this to broadcast the latest local commitment transaction, either because
-       /// a monitor update failed with [`ChannelMonitorUpdateStatus::PermanentFailure`] or because we've
-       /// fallen behind (i.e. we've received proof that our counterparty side knows a revocation
-       /// secret we gave them that they shouldn't know).
+       /// a monitor update failed or because we've fallen behind (i.e. we've received proof that our
+       /// counterparty side knows a revocation secret we gave them that they shouldn't know).
        ///
        /// Broadcasting these transactions in the second case is UNSAFE, as they allow counterparty
        /// side to punish you. Nevertheless you may want to broadcast them if counterparty doesn't
        /// close channel with their commitment transaction after a substantial amount of time. Best
        /// may be to contact the other node operator out-of-band to coordinate other options available
-       /// to you. In any-case, the choice is up to you.
+       /// to you.
        ///
-       /// [`ChannelMonitorUpdateStatus::PermanentFailure`]: super::ChannelMonitorUpdateStatus::PermanentFailure
+       /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
        pub fn get_latest_holder_commitment_txn<L: Deref>(&self, logger: &L) -> Vec<Transaction>
        where L::Target: Logger {
                self.inner.lock().unwrap().get_latest_holder_commitment_txn(logger)
@@ -1676,6 +1669,33 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitor<Signer> {
                        current_height, &broadcaster, &fee_estimator, &logger,
                );
        }
+
+       /// Returns the descriptors for relevant outputs (i.e., those that we can spend) within the
+       /// transaction if they exist and the transaction has at least [`ANTI_REORG_DELAY`]
+       /// confirmations.
+       ///
+       /// Descriptors returned by this method are primarily exposed via [`Event::SpendableOutputs`]
+       /// once they are no longer under reorg risk. This method serves as a way to retrieve these
+       /// descriptors at a later time, either for historical purposes, or to replay any
+       /// missed/unhandled descriptors. For the purpose of gathering historical records, if the
+       /// channel close has fully resolved (i.e., [`ChannelMonitor::get_claimable_balances`] returns
+       /// an empty set), you can retrieve all spendable outputs by providing all descendant spending
+       /// transactions starting from the channel's funding or closing transaction that have at least
+       /// [`ANTI_REORG_DELAY`] confirmations.
+       ///
+       /// `tx` is a transaction we'll scan the outputs of. Any transaction can be provided. If any
+       /// outputs which can be spent by us are found, at least one descriptor is returned.
+       ///
+       /// `confirmation_height` must be the height of the block in which `tx` was included in.
+       pub fn get_spendable_outputs(&self, tx: &Transaction, confirmation_height: u32) -> Vec<SpendableOutputDescriptor> {
+               let inner = self.inner.lock().unwrap();
+               let current_height = inner.best_block.height;
+               if current_height.saturating_sub(ANTI_REORG_DELAY) + 1 >= confirmation_height {
+                       inner.get_spendable_outputs(tx)
+               } else {
+                       Vec::new()
+               }
+       }
 }
 
 impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
@@ -2533,7 +2553,7 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
                        txs.push(tx);
                }
                broadcaster.broadcast_transactions(&txs);
-               self.pending_monitor_events.push(MonitorEvent::CommitmentTxConfirmed(self.funding_info.0));
+               self.pending_monitor_events.push(MonitorEvent::HolderForceClosed(self.funding_info.0));
        }
 
        pub fn update_monitor<B: Deref, F: Deref, L: Deref>(&mut self, updates: &ChannelMonitorUpdate, broadcaster: &B, fee_estimator: F, logger: &L) -> Result<(), ()>
@@ -2599,6 +2619,7 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
                                ChannelMonitorUpdateStep::CommitmentSecret { idx, secret } => {
                                        log_trace!(logger, "Updating ChannelMonitor with commitment secret");
                                        if let Err(e) = self.provide_secret(*idx, *secret) {
+                                               debug_assert!(false, "Latest counterparty commitment secret was invalid");
                                                log_error!(logger, "Providing latest counterparty commitment secret failed/was refused:");
                                                log_error!(logger, "    {}", e);
                                                ret = Err(());
@@ -2645,7 +2666,7 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
                                                log_error!(logger, "    in channel monitor for channel {}!", &self.funding_info.0.to_channel_id());
                                                log_error!(logger, "    Read the docs for ChannelMonitor::get_latest_holder_commitment_txn and take manual action!");
                                        } else {
-                                               // If we generated a MonitorEvent::CommitmentTxConfirmed, the ChannelManager
+                                               // If we generated a MonitorEvent::HolderForceClosed, the ChannelManager
                                                // will still give us a ChannelForceClosed event with !should_broadcast, but we
                                                // shouldn't print the scary warning above.
                                                log_info!(logger, "Channel off-chain state closed after we broadcasted our latest commitment transaction.");
@@ -3447,7 +3468,7 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
                                }
                                self.is_resolving_htlc_output(&tx, height, &block_hash, &logger);
 
-                               self.is_paying_spendable_output(&tx, height, &block_hash, &logger);
+                               self.check_tx_and_push_spendable_outputs(&tx, height, &block_hash, &logger);
                        }
                }
 
@@ -3490,8 +3511,10 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
                        let funding_outp = HolderFundingOutput::build(self.funding_redeemscript.clone(), self.channel_value_satoshis, self.onchain_tx_handler.channel_type_features().clone());
                        let commitment_package = PackageTemplate::build_package(self.funding_info.0.txid.clone(), self.funding_info.0.index as u32, PackageSolvingData::HolderFundingOutput(funding_outp), self.best_block.height(), self.best_block.height());
                        claimable_outpoints.push(commitment_package);
-                       self.pending_monitor_events.push(MonitorEvent::CommitmentTxConfirmed(self.funding_info.0));
-                       let commitment_tx = self.onchain_tx_handler.get_fully_signed_holder_tx(&self.funding_redeemscript);
+                       self.pending_monitor_events.push(MonitorEvent::HolderForceClosed(self.funding_info.0));
+                       // Although we aren't signing the transaction directly here, the transaction will be signed
+                       // in the claim that is queued to OnchainTxHandler. We set holder_tx_signed here to reject
+                       // new channel updates.
                        self.holder_tx_signed = true;
                        // We can't broadcast our HTLC transactions while the commitment transaction is
                        // unconfirmed. We'll delay doing so until we detect the confirmed commitment in
@@ -3501,7 +3524,8 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
                                // assuming it gets confirmed in the next block. Sadly, we have code which considers
                                // "not yet confirmed" things as discardable, so we cannot do that here.
                                let (mut new_outpoints, _) = self.get_broadcasted_holder_claims(&self.current_holder_commitment_tx, self.best_block.height());
-                               let new_outputs = self.get_broadcasted_holder_watch_outputs(&self.current_holder_commitment_tx, &commitment_tx);
+                               let unsigned_commitment_tx = self.onchain_tx_handler.get_unsigned_holder_commitment_tx();
+                               let new_outputs = self.get_broadcasted_holder_watch_outputs(&self.current_holder_commitment_tx, &unsigned_commitment_tx);
                                if !new_outputs.is_empty() {
                                        watch_outputs.push((self.current_holder_commitment_tx.txid.clone(), new_outputs));
                                }
@@ -3990,34 +4014,18 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
                }
        }
 
-       /// Check if any transaction broadcasted is paying fund back to some address we can assume to own
-       fn is_paying_spendable_output<L: Deref>(&mut self, tx: &Transaction, height: u32, block_hash: &BlockHash, logger: &L) where L::Target: Logger {
-               let mut spendable_output = None;
-               for (i, outp) in tx.output.iter().enumerate() { // There is max one spendable output for any channel tx, including ones generated by us
-                       if i > ::core::u16::MAX as usize {
-                               // While it is possible that an output exists on chain which is greater than the
-                               // 2^16th output in a given transaction, this is only possible if the output is not
-                               // in a lightning transaction and was instead placed there by some third party who
-                               // wishes to give us money for no reason.
-                               // Namely, any lightning transactions which we pre-sign will never have anywhere
-                               // near 2^16 outputs both because such transactions must have ~2^16 outputs who's
-                               // scripts are not longer than one byte in length and because they are inherently
-                               // non-standard due to their size.
-                               // Thus, it is completely safe to ignore such outputs, and while it may result in
-                               // us ignoring non-lightning fund to us, that is only possible if someone fills
-                               // nearly a full block with garbage just to hit this case.
-                               continue;
-                       }
+       fn get_spendable_outputs(&self, tx: &Transaction) -> Vec<SpendableOutputDescriptor> {
+               let mut spendable_outputs = Vec::new();
+               for (i, outp) in tx.output.iter().enumerate() {
                        if outp.script_pubkey == self.destination_script {
-                               spendable_output =  Some(SpendableOutputDescriptor::StaticOutput {
+                               spendable_outputs.push(SpendableOutputDescriptor::StaticOutput {
                                        outpoint: OutPoint { txid: tx.txid(), index: i as u16 },
                                        output: outp.clone(),
                                });
-                               break;
                        }
                        if let Some(ref broadcasted_holder_revokable_script) = self.broadcasted_holder_revokable_script {
                                if broadcasted_holder_revokable_script.0 == outp.script_pubkey {
-                                       spendable_output =  Some(SpendableOutputDescriptor::DelayedPaymentOutput(DelayedPaymentOutputDescriptor {
+                                       spendable_outputs.push(SpendableOutputDescriptor::DelayedPaymentOutput(DelayedPaymentOutputDescriptor {
                                                outpoint: OutPoint { txid: tx.txid(), index: i as u16 },
                                                per_commitment_point: broadcasted_holder_revokable_script.1,
                                                to_self_delay: self.on_holder_tx_csv,
@@ -4026,27 +4034,32 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
                                                channel_keys_id: self.channel_keys_id,
                                                channel_value_satoshis: self.channel_value_satoshis,
                                        }));
-                                       break;
                                }
                        }
                        if self.counterparty_payment_script == outp.script_pubkey {
-                               spendable_output = Some(SpendableOutputDescriptor::StaticPaymentOutput(StaticPaymentOutputDescriptor {
+                               spendable_outputs.push(SpendableOutputDescriptor::StaticPaymentOutput(StaticPaymentOutputDescriptor {
                                        outpoint: OutPoint { txid: tx.txid(), index: i as u16 },
                                        output: outp.clone(),
                                        channel_keys_id: self.channel_keys_id,
                                        channel_value_satoshis: self.channel_value_satoshis,
                                }));
-                               break;
                        }
                        if self.shutdown_script.as_ref() == Some(&outp.script_pubkey) {
-                               spendable_output = Some(SpendableOutputDescriptor::StaticOutput {
+                               spendable_outputs.push(SpendableOutputDescriptor::StaticOutput {
                                        outpoint: OutPoint { txid: tx.txid(), index: i as u16 },
                                        output: outp.clone(),
                                });
-                               break;
                        }
                }
-               if let Some(spendable_output) = spendable_output {
+               spendable_outputs
+       }
+
+       /// Checks if the confirmed transaction is paying funds back to some address we can assume to
+       /// own.
+       fn check_tx_and_push_spendable_outputs<L: Deref>(
+               &mut self, tx: &Transaction, height: u32, block_hash: &BlockHash, logger: &L,
+       ) where L::Target: Logger {
+               for spendable_output in self.get_spendable_outputs(tx) {
                        let entry = OnchainEventEntry {
                                txid: tx.txid(),
                                transaction: Some(tx.clone()),
@@ -4251,7 +4264,7 @@ impl<'a, 'b, ES: EntropySource, SP: SignerProvider> ReadableArgs<(&'a ES, &'b SP
                for _ in 0..pending_monitor_events_len {
                        let ev = match <u8 as Readable>::read(reader)? {
                                0 => MonitorEvent::HTLCEvent(Readable::read(reader)?),
-                               1 => MonitorEvent::CommitmentTxConfirmed(funding_info.0),
+                               1 => MonitorEvent::HolderForceClosed(funding_info.0),
                                _ => return Err(DecodeError::InvalidValue)
                        };
                        pending_monitor_events.as_mut().unwrap().push(ev);
@@ -4410,13 +4423,12 @@ mod tests {
        use crate::chain::chaininterface::LowerBoundedFeeEstimator;
 
        use super::ChannelMonitorUpdateStep;
-       use crate::{check_added_monitors, check_closed_broadcast, check_closed_event, check_spends, get_local_commitment_txn, get_monitor, get_route_and_payment_hash, unwrap_send_err};
+       use crate::{check_added_monitors, check_spends, get_local_commitment_txn, get_monitor, get_route_and_payment_hash, unwrap_send_err};
        use crate::chain::{BestBlock, Confirm};
        use crate::chain::channelmonitor::ChannelMonitor;
        use crate::chain::package::{weight_offered_htlc, weight_received_htlc, weight_revoked_offered_htlc, weight_revoked_received_htlc, WEIGHT_REVOKED_OUTPUT};
        use crate::chain::transaction::OutPoint;
        use crate::sign::InMemorySigner;
-       use crate::events::ClosureReason;
        use crate::ln::{PaymentPreimage, PaymentHash};
        use crate::ln::chan_utils;
        use crate::ln::chan_utils::{HTLCOutputInCommitment, ChannelPublicKeys, ChannelTransactionParameters, HolderCommitmentTransaction, CounterpartyChannelTransactionParameters};
@@ -4482,18 +4494,14 @@ mod tests {
                let (route, payment_hash, _, payment_secret) = get_route_and_payment_hash!(nodes[1], nodes[0], 100_000);
                unwrap_send_err!(nodes[1].node.send_payment_with_route(&route, payment_hash,
                                RecipientOnionFields::secret_only(payment_secret), PaymentId(payment_hash.0)
-                       ), true, APIError::ChannelUnavailable { ref err },
-                       assert!(err.contains("ChannelMonitor storage failure")));
-               check_added_monitors!(nodes[1], 2); // After the failure we generate a close-channel monitor update
-               check_closed_broadcast!(nodes[1], true);
-               check_closed_event!(nodes[1], 1, ClosureReason::ProcessingError { err: "ChannelMonitor storage failure".to_string() }, 
-                       [nodes[0].node.get_our_node_id()], 100000);
+                       ), false, APIError::MonitorUpdateInProgress, {});
+               check_added_monitors!(nodes[1], 1);
 
                // Build a new ChannelMonitorUpdate which contains both the failing commitment tx update
                // and provides the claim preimages for the two pending HTLCs. The first update generates
                // an error, but the point of this test is to ensure the later updates are still applied.
                let monitor_updates = nodes[1].chain_monitor.monitor_updates.lock().unwrap();
-               let mut replay_update = monitor_updates.get(&channel.2).unwrap().iter().rev().skip(1).next().unwrap().clone();
+               let mut replay_update = monitor_updates.get(&channel.2).unwrap().iter().rev().next().unwrap().clone();
                assert_eq!(replay_update.updates.len(), 1);
                if let ChannelMonitorUpdateStep::LatestCounterpartyCommitmentTXInfo { .. } = replay_update.updates[0] {
                } else { panic!(); }