Merge pull request #2761 from yellowred/self_sufficient_psbt
[rust-lightning] / lightning / src / chain / channelmonitor.rs
index 5c81a513713f2d79d1b18a42dcc84789f9016f40..66d083377b0e6c23b5f863adb1c2f2aa0b7f98a4 100644 (file)
@@ -50,13 +50,14 @@ use crate::chain::Filter;
 use crate::util::logger::{Logger, Record};
 use crate::util::ser::{Readable, ReadableArgs, RequiredWrapper, MaybeReadable, UpgradableRequired, Writer, Writeable, U48};
 use crate::util::byte_utils;
-use crate::events::{Event, EventHandler};
+use crate::events::{ClosureReason, Event, EventHandler};
 use crate::events::bump_transaction::{AnchorDescriptor, BumpTransactionEvent};
 
+#[allow(unused_imports)]
 use crate::prelude::*;
+
 use core::{cmp, mem};
 use crate::io::{self, Error};
-use core::convert::TryInto;
 use core::ops::Deref;
 use crate::sync::{Mutex, LockTestExt};
 
@@ -155,6 +156,17 @@ pub enum MonitorEvent {
        /// A monitor event containing an HTLCUpdate.
        HTLCEvent(HTLCUpdate),
 
+       /// Indicates we broadcasted the channel's latest commitment transaction and thus closed the
+       /// channel. Holds information about the channel and why it was closed.
+       HolderForceClosedWithInfo {
+               /// The reason the channel was closed.
+               reason: ClosureReason,
+               /// The funding outpoint of the channel.
+               outpoint: OutPoint,
+               /// The channel ID of the channel.
+               channel_id: ChannelId,
+       },
+
        /// Indicates we broadcasted the channel's latest commitment transaction and thus closed the
        /// channel.
        HolderForceClosed(OutPoint),
@@ -184,6 +196,11 @@ impl_writeable_tlv_based_enum_upgradable!(MonitorEvent,
                (2, monitor_update_id, required),
                (4, channel_id, required),
        },
+       (5, HolderForceClosedWithInfo) => {
+               (0, reason, upgradable_required),
+               (2, outpoint, required),
+               (4, channel_id, required),
+       },
 ;
        (2, HTLCEvent),
        (4, HolderForceClosed),
@@ -918,6 +935,9 @@ pub(crate) struct ChannelMonitorImpl<Signer: WriteableEcdsaChannelSigner> {
        /// Ordering of tuple data: (their_per_commitment_point, feerate_per_kw, to_broadcaster_sats,
        /// to_countersignatory_sats)
        initial_counterparty_commitment_info: Option<(PublicKey, u32, u64, u64)>,
+
+       /// The first block height at which we had no remaining claimable balances.
+       balances_empty_height: Option<u32>,
 }
 
 /// Transaction outputs to watch for on-chain spends.
@@ -1059,6 +1079,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Writeable for ChannelMonitorImpl<Signe
                writer.write_all(&(self.pending_monitor_events.iter().filter(|ev| match ev {
                        MonitorEvent::HTLCEvent(_) => true,
                        MonitorEvent::HolderForceClosed(_) => true,
+                       MonitorEvent::HolderForceClosedWithInfo { .. } => true,
                        _ => false,
                }).count() as u64).to_be_bytes())?;
                for event in self.pending_monitor_events.iter() {
@@ -1068,6 +1089,10 @@ impl<Signer: WriteableEcdsaChannelSigner> Writeable for ChannelMonitorImpl<Signe
                                        upd.write(writer)?;
                                },
                                MonitorEvent::HolderForceClosed(_) => 1u8.write(writer)?,
+                               // `HolderForceClosedWithInfo` replaced `HolderForceClosed` in v0.0.122. To keep
+                               // backwards compatibility, we write a `HolderForceClosed` event along with the
+                               // `HolderForceClosedWithInfo` event. This is deduplicated in the reader.
+                               MonitorEvent::HolderForceClosedWithInfo { .. } => 1u8.write(writer)?,
                                _ => {}, // Covered in the TLV writes below
                        }
                }
@@ -1099,10 +1124,23 @@ impl<Signer: WriteableEcdsaChannelSigner> Writeable for ChannelMonitorImpl<Signe
                self.lockdown_from_offchain.write(writer)?;
                self.holder_tx_signed.write(writer)?;
 
+               // If we have a `HolderForceClosedWithInfo` event, we need to write the `HolderForceClosed` for backwards compatibility.
+               let pending_monitor_events = match self.pending_monitor_events.iter().find(|ev| match ev {
+                       MonitorEvent::HolderForceClosedWithInfo { .. } => true,
+                       _ => false,
+               }) {
+                       Some(MonitorEvent::HolderForceClosedWithInfo { outpoint, .. }) => {
+                               let mut pending_monitor_events = self.pending_monitor_events.clone();
+                               pending_monitor_events.push(MonitorEvent::HolderForceClosed(*outpoint));
+                               pending_monitor_events
+                       }
+                       _ => self.pending_monitor_events.clone(),
+               };
+
                write_tlv_fields!(writer, {
                        (1, self.funding_spend_confirmed, option),
                        (3, self.htlcs_resolved_on_chain, required_vec),
-                       (5, self.pending_monitor_events, required_vec),
+                       (5, pending_monitor_events, required_vec),
                        (7, self.funding_spend_seen, required),
                        (9, self.counterparty_node_id, option),
                        (11, self.confirmed_commitment_tx_counterparty_output, option),
@@ -1110,6 +1148,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Writeable for ChannelMonitorImpl<Signe
                        (15, self.counterparty_fulfilled_htlcs, required),
                        (17, self.initial_counterparty_commitment_info, option),
                        (19, self.channel_id, required),
+                       (21, self.balances_empty_height, option),
                });
 
                Ok(())
@@ -1293,6 +1332,7 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitor<Signer> {
                        best_block,
                        counterparty_node_id: Some(counterparty_node_id),
                        initial_counterparty_commitment_info: None,
+                       balances_empty_height: None,
                })
        }
 
@@ -1821,6 +1861,52 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitor<Signer> {
                spendable_outputs
        }
 
+       /// Checks if the monitor is fully resolved. Resolved monitor is one that has claimed all of
+       /// its outputs and balances (i.e. [`Self::get_claimable_balances`] returns an empty set).
+       ///
+       /// This function returns true only if [`Self::get_claimable_balances`] has been empty for at least
+       /// 2016 blocks as an additional protection against any bugs resulting in spuriously empty balance sets.
+       pub fn is_fully_resolved<L: Logger>(&self, logger: &L) -> bool {
+               let mut is_all_funds_claimed = self.get_claimable_balances().is_empty();
+               let current_height = self.current_best_block().height;
+               let mut inner = self.inner.lock().unwrap();
+
+               if is_all_funds_claimed {
+                       if !inner.funding_spend_seen {
+                               debug_assert!(false, "We should see funding spend by the time a monitor clears out");
+                               is_all_funds_claimed = false;
+                       }
+               }
+
+               match (inner.balances_empty_height, is_all_funds_claimed) {
+                       (Some(balances_empty_height), true) => {
+                               // Claimed all funds, check if reached the blocks threshold.
+                               const BLOCKS_THRESHOLD: u32 = 4032; // ~four weeks
+                               return current_height >= balances_empty_height + BLOCKS_THRESHOLD;
+                       },
+                       (Some(_), false) => {
+                               // previously assumed we claimed all funds, but we have new funds to claim.
+                               // Should not happen in practice.
+                               debug_assert!(false, "Thought we were done claiming funds, but claimable_balances now has entries");
+                               log_error!(logger,
+                                       "WARNING: LDK thought it was done claiming all the available funds in the ChannelMonitor for channel {}, but later decided it had more to claim. This is potentially an important bug in LDK, please report it at https://github.com/lightningdevkit/rust-lightning/issues/new",
+                                       inner.get_funding_txo().0);
+                               inner.balances_empty_height = None;
+                               false
+                       },
+                       (None, true) => {
+                               // Claimed all funds but `balances_empty_height` is None. It is set to the
+                               // current block height.
+                               inner.balances_empty_height = Some(current_height);
+                               false
+                       },
+                       (None, false) => {
+                               // Have funds to claim.
+                               false
+                       },
+               }
+       }
+
        #[cfg(test)]
        pub fn get_counterparty_payment_script(&self) -> ScriptBuf {
                self.inner.lock().unwrap().counterparty_payment_script.clone()
@@ -2727,7 +2813,7 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
                }
        }
 
-       fn generate_claimable_outpoints_and_watch_outputs(&mut self) -> (Vec<PackageTemplate>, Vec<TransactionOutputs>) {
+       fn generate_claimable_outpoints_and_watch_outputs(&mut self, reason: ClosureReason) -> (Vec<PackageTemplate>, Vec<TransactionOutputs>) {
                let funding_outp = HolderFundingOutput::build(
                        self.funding_redeemscript.clone(),
                        self.channel_value_satoshis,
@@ -2739,7 +2825,13 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
                        self.best_block.height, self.best_block.height
                );
                let mut claimable_outpoints = vec![commitment_package];
-               self.pending_monitor_events.push(MonitorEvent::HolderForceClosed(self.funding_info.0));
+               let event = MonitorEvent::HolderForceClosedWithInfo {
+                       reason,
+                       outpoint: self.funding_info.0,
+                       channel_id: self.channel_id,
+               };
+               self.pending_monitor_events.push(event);
+
                // 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.
@@ -2775,7 +2867,7 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
                F::Target: FeeEstimator,
                L::Target: Logger,
        {
-               let (claimable_outpoints, _) = self.generate_claimable_outpoints_and_watch_outputs();
+               let (claimable_outpoints, _) = self.generate_claimable_outpoints_and_watch_outputs(ClosureReason::HolderForceClosed);
                self.onchain_tx_handler.update_claims_view_from_requests(
                        claimable_outpoints, self.best_block.height, self.best_block.height, broadcaster,
                        fee_estimator, logger
@@ -3778,7 +3870,7 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
 
                let should_broadcast = self.should_broadcast_holder_commitment_txn(logger);
                if should_broadcast {
-                       let (mut new_outpoints, mut new_outputs) = self.generate_claimable_outpoints_and_watch_outputs();
+                       let (mut new_outpoints, mut new_outputs) = self.generate_claimable_outpoints_and_watch_outputs(ClosureReason::HTLCsTimedOut);
                        claimable_outpoints.append(&mut new_outpoints);
                        watch_outputs.append(&mut new_outputs);
                }
@@ -4289,6 +4381,7 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
                                                revocation_pubkey: broadcasted_holder_revokable_script.2,
                                                channel_keys_id: self.channel_keys_id,
                                                channel_value_satoshis: self.channel_value_satoshis,
+                                               channel_transaction_parameters: Some(self.onchain_tx_handler.channel_transaction_parameters.clone()),
                                        }));
                                }
                        }
@@ -4591,6 +4684,7 @@ impl<'a, 'b, ES: EntropySource, SP: SignerProvider> ReadableArgs<(&'a ES, &'b SP
                let mut spendable_txids_confirmed = Some(Vec::new());
                let mut counterparty_fulfilled_htlcs = Some(new_hash_map());
                let mut initial_counterparty_commitment_info = None;
+               let mut balances_empty_height = None;
                let mut channel_id = None;
                read_tlv_fields!(reader, {
                        (1, funding_spend_confirmed, option),
@@ -4603,8 +4697,19 @@ impl<'a, 'b, ES: EntropySource, SP: SignerProvider> ReadableArgs<(&'a ES, &'b SP
                        (15, counterparty_fulfilled_htlcs, option),
                        (17, initial_counterparty_commitment_info, option),
                        (19, channel_id, option),
+                       (21, balances_empty_height, option),
                });
 
+               // `HolderForceClosedWithInfo` replaced `HolderForceClosed` in v0.0.122. If we have both
+               // events, we can remove the `HolderForceClosed` event and just keep the `HolderForceClosedWithInfo`.
+               if let Some(ref mut pending_monitor_events) = pending_monitor_events {
+                       if pending_monitor_events.iter().any(|e| matches!(e, MonitorEvent::HolderForceClosed(_))) &&
+                               pending_monitor_events.iter().any(|e| matches!(e, MonitorEvent::HolderForceClosedWithInfo { .. }))
+                       {
+                               pending_monitor_events.retain(|e| !matches!(e, MonitorEvent::HolderForceClosed(_)));
+                       }
+               }
+
                // Monitors for anchor outputs channels opened in v0.0.116 suffered from a bug in which the
                // wrong `counterparty_payment_script` was being tracked. Fix it now on deserialization to
                // give them a chance to recognize the spendable output.
@@ -4671,6 +4776,7 @@ impl<'a, 'b, ES: EntropySource, SP: SignerProvider> ReadableArgs<(&'a ES, &'b SP
                        best_block,
                        counterparty_node_id,
                        initial_counterparty_commitment_info,
+                       balances_empty_height,
                })))
        }
 }
@@ -4715,6 +4821,8 @@ mod tests {
        use crate::sync::{Arc, Mutex};
        use crate::io;
        use crate::ln::features::ChannelTypeFeatures;
+
+       #[allow(unused_imports)]
        use crate::prelude::*;
 
        use std::str::FromStr;