// This file is Copyright its original authors, visible in version control
// history.
//
// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
// You may not use this file except in accordance with one or both of these
// licenses.
//! The logic to monitor for on-chain transactions and create the relevant claim responses lives
//! here.
//!
//! ChannelMonitor objects are generated by ChannelManager in response to relevant
//! messages/actions, and MUST be persisted to disk (and, preferably, remotely) before progress can
//! be made in responding to certain messages, see [`chain::Watch`] for more.
//!
//! Note that ChannelMonitors are an important part of the lightning trust model and a copy of the
//! latest ChannelMonitor must always be actively monitoring for chain updates (and no out-of-date
//! ChannelMonitors should do so). Thus, if you're building rust-lightning into an HSM or other
//! security-domain-separated system design, you should consider having multiple paths for
//! ChannelMonitors to get out of the HSM and onto monitoring devices.
use bitcoin::blockdata::block::{Block, BlockHeader};
use bitcoin::blockdata::transaction::{TxOut,Transaction};
use bitcoin::blockdata::script::{Script, Builder};
use bitcoin::blockdata::opcodes;
use bitcoin::hashes::Hash;
use bitcoin::hashes::sha256::Hash as Sha256;
use bitcoin::hash_types::{Txid, BlockHash, WPubkeyHash};
use bitcoin::secp256k1::{Secp256k1,Signature};
use bitcoin::secp256k1::key::{SecretKey,PublicKey};
use bitcoin::secp256k1;
use ln::{PaymentHash, PaymentPreimage};
use ln::msgs::DecodeError;
use ln::chan_utils;
use ln::chan_utils::{CounterpartyCommitmentSecrets, HTLCOutputInCommitment, HTLCType, ChannelTransactionParameters, HolderCommitmentTransaction};
use ln::channelmanager::HTLCSource;
use chain;
use chain::{BestBlock, WatchedOutput};
use chain::chaininterface::{BroadcasterInterface, FeeEstimator};
use chain::transaction::{OutPoint, TransactionData};
use chain::keysinterface::{SpendableOutputDescriptor, StaticPaymentOutputDescriptor, DelayedPaymentOutputDescriptor, Sign, KeysInterface};
use chain::onchaintx::OnchainTxHandler;
use chain::package::{CounterpartyOfferedHTLCOutput, CounterpartyReceivedHTLCOutput, HolderFundingOutput, HolderHTLCOutput, PackageSolvingData, PackageTemplate, RevokedOutput, RevokedHTLCOutput};
use chain::Filter;
use util::logger::Logger;
use util::ser::{Readable, ReadableArgs, MaybeReadable, Writer, Writeable, U48, OptionDeserWrapper};
use util::byte_utils;
use util::events::Event;
use prelude::*;
use core::{cmp, mem};
use io::{self, Error};
use core::ops::Deref;
use sync::Mutex;
/// An update generated by the underlying Channel itself which contains some new information the
/// ChannelMonitor should be made aware of.
#[cfg_attr(any(test, fuzzing, feature = "_test_utils"), derive(PartialEq))]
#[derive(Clone)]
#[must_use]
pub struct ChannelMonitorUpdate {
pub(crate) updates: Vec<ChannelMonitorUpdateStep>,
/// The sequence number of this update. Updates *must* be replayed in-order according to this
/// sequence number (and updates may panic if they are not). The update_id values are strictly
/// increasing and increase by one for each new update, with one exception specified below.
///
/// This sequence number is also used to track up to which points updates which returned
/// ChannelMonitorUpdateErr::TemporaryFailure have been applied to all copies of a given
/// ChannelMonitor when ChannelManager::channel_monitor_updated is called.
///
/// The only instance where update_id values are not strictly increasing is the case where we
/// allow post-force-close updates with a special update ID of [`CLOSED_CHANNEL_UPDATE_ID`]. See
/// its docs for more details.
pub update_id: u64,
}
/// If:
/// (1) a channel has been force closed and
/// (2) we receive a preimage from a forward link that allows us to spend an HTLC output on
/// this channel's (the backward link's) broadcasted commitment transaction
/// then we allow the `ChannelManager` to send a `ChannelMonitorUpdate` with this update ID,
/// with the update providing said payment preimage. No other update types are allowed after
/// force-close.
pub const CLOSED_CHANNEL_UPDATE_ID: u64 = core::u64::MAX;
impl Writeable for ChannelMonitorUpdate {
fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
write_ver_prefix!(w, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
self.update_id.write(w)?;
(self.updates.len() as u64).write(w)?;
for update_step in self.updates.iter() {
update_step.write(w)?;
}
write_tlv_fields!(w, {});
Ok(())
}
}
impl Readable for ChannelMonitorUpdate {
fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
let _ver = read_ver_prefix!(r, SERIALIZATION_VERSION);
let update_id: u64 = Readable::read(r)?;
let len: u64 = Readable::read(r)?;
let mut updates = Vec::with_capacity(cmp::min(len as usize, MAX_ALLOC_SIZE / ::core::mem::size_of::<ChannelMonitorUpdateStep>()));
for _ in 0..len {
if let Some(upd) = MaybeReadable::read(r)? {
updates.push(upd);
}
}
read_tlv_fields!(r, {});
Ok(Self { update_id, updates })
}
}
/// An event to be processed by the ChannelManager.
#[derive(Clone, PartialEq)]
pub enum MonitorEvent {
/// A monitor event containing an HTLCUpdate.
HTLCEvent(HTLCUpdate),
/// A monitor event that the Channel's commitment transaction was confirmed.
CommitmentTxConfirmed(OutPoint),
/// Indicates a [`ChannelMonitor`] update has completed. See
/// [`ChannelMonitorUpdateErr::TemporaryFailure`] for more information on how this is used.
///
/// [`ChannelMonitorUpdateErr::TemporaryFailure`]: super::ChannelMonitorUpdateErr::TemporaryFailure
UpdateCompleted {
/// The funding outpoint of the [`ChannelMonitor`] that was updated
funding_txo: OutPoint,
/// The Update ID from [`ChannelMonitorUpdate::update_id`] which was applied or
/// [`ChannelMonitor::get_latest_update_id`].
///
/// Note that this should only be set to a given update's ID if all previous updates for the
/// same [`ChannelMonitor`] have been applied and persisted.
monitor_update_id: u64,
},
/// Indicates a [`ChannelMonitor`] update has failed. See
/// [`ChannelMonitorUpdateErr::PermanentFailure`] for more information on how this is used.
///
/// [`ChannelMonitorUpdateErr::PermanentFailure`]: super::ChannelMonitorUpdateErr::PermanentFailure
UpdateFailed(OutPoint),
}
impl_writeable_tlv_based_enum_upgradable!(MonitorEvent,
// Note that UpdateCompleted and UpdateFailed are currently never serialized to disk as they are
// generated only in ChainMonitor
(0, UpdateCompleted) => {
(0, funding_txo, required),
(2, monitor_update_id, required),
},
;
(2, HTLCEvent),
(4, CommitmentTxConfirmed),
(6, UpdateFailed),
);
/// Simple structure sent back by `chain::Watch` when an HTLC from a forward channel is detected on
/// chain. Used to update the corresponding HTLC in the backward channel. Failing to pass the
/// preimage claim backward will lead to loss of funds.
#[derive(Clone, PartialEq)]
pub struct HTLCUpdate {
pub(crate) payment_hash: PaymentHash,
pub(crate) payment_preimage: Option<PaymentPreimage>,
pub(crate) source: HTLCSource,
pub(crate) onchain_value_satoshis: Option<u64>,
}
impl_writeable_tlv_based!(HTLCUpdate, {
(0, payment_hash, required),
(1, onchain_value_satoshis, option),
(2, source, required),
(4, payment_preimage, option),
});
/// If an HTLC expires within this many blocks, don't try to claim it in a shared transaction,
/// instead claiming it in its own individual transaction.
pub(crate) const CLTV_SHARED_CLAIM_BUFFER: u32 = 12;
/// If an HTLC expires within this many blocks, force-close the channel to broadcast the
/// HTLC-Success transaction.
/// In other words, this is an upper bound on how many blocks we think it can take us to get a
/// transaction confirmed (and we use it in a few more, equivalent, places).
pub(crate) const CLTV_CLAIM_BUFFER: u32 = 18;
/// Number of blocks by which point we expect our counterparty to have seen new blocks on the
/// network and done a full update_fail_htlc/commitment_signed dance (+ we've updated all our
/// copies of ChannelMonitors, including watchtowers). We could enforce the contract by failing
/// at CLTV expiration height but giving a grace period to our peer may be profitable for us if he
/// can provide an over-late preimage. Nevertheless, grace period has to be accounted in our
/// CLTV_EXPIRY_DELTA to be secure. Following this policy we may decrease the rate of channel failures
/// due to expiration but increase the cost of funds being locked longuer in case of failure.
/// This delay also cover a low-power peer being slow to process blocks and so being behind us on
/// accurate block height.
/// In case of onchain failure to be pass backward we may see the last block of ANTI_REORG_DELAY
/// with at worst this delay, so we are not only using this value as a mercy for them but also
/// us as a safeguard to delay with enough time.
pub(crate) const LATENCY_GRACE_PERIOD_BLOCKS: u32 = 3;
/// Number of blocks we wait on seeing a HTLC output being solved before we fail corresponding
/// inbound HTLCs. This prevents us from failing backwards and then getting a reorg resulting in us
/// losing money.
///
/// Note that this is a library-wide security assumption. If a reorg deeper than this number of
/// blocks occurs, counterparties may be able to steal funds or claims made by and balances exposed
/// by a [`ChannelMonitor`] may be incorrect.
// We also use this delay to be sure we can remove our in-flight claim txn from bump candidates buffer.
// It may cause spurious generation of bumped claim txn but that's alright given the outpoint is already
// solved by a previous claim tx. What we want to avoid is reorg evicting our claim tx and us not
// keep bumping another claim tx to solve the outpoint.
pub const ANTI_REORG_DELAY: u32 = 6;
/// Number of blocks before confirmation at which we fail back an un-relayed HTLC or at which we
/// refuse to accept a new HTLC.
///
/// This is used for a few separate purposes:
/// 1) if we've received an MPP HTLC to us and it expires within this many blocks and we are
/// waiting on additional parts (or waiting on the preimage for any HTLC from the user), we will
/// fail this HTLC,
/// 2) if we receive an HTLC within this many blocks of its expiry (plus one to avoid a race
/// condition with the above), we will fail this HTLC without telling the user we received it,
///
/// (1) is all about protecting us - we need enough time to update the channel state before we hit
/// CLTV_CLAIM_BUFFER, at which point we'd go on chain to claim the HTLC with the preimage.
///
/// (2) is the same, but with an additional buffer to avoid accepting an HTLC which is immediately
/// in a race condition between the user connecting a block (which would fail it) and the user
/// providing us the preimage (which would claim it).
pub(crate) const HTLC_FAIL_BACK_BUFFER: u32 = CLTV_CLAIM_BUFFER + LATENCY_GRACE_PERIOD_BLOCKS;
// TODO(devrandom) replace this with HolderCommitmentTransaction
#[derive(Clone, PartialEq)]
struct HolderSignedTx {
/// txid of the transaction in tx, just used to make comparison faster
txid: Txid,
revocation_key: PublicKey,
a_htlc_key: PublicKey,
b_htlc_key: PublicKey,
delayed_payment_key: PublicKey,
per_commitment_point: PublicKey,
htlc_outputs: Vec<(HTLCOutputInCommitment, Option<Signature>, Option<HTLCSource>)>,
to_self_value_sat: u64,
feerate_per_kw: u32,
}
impl_writeable_tlv_based!(HolderSignedTx, {
(0, txid, required),
// Note that this is filled in with data from OnchainTxHandler if it's missing.
// For HolderSignedTx objects serialized with 0.0.100+, this should be filled in.
(1, to_self_value_sat, (default_value, u64::max_value())),
(2, revocation_key, required),
(4, a_htlc_key, required),
(6, b_htlc_key, required),
(8, delayed_payment_key, required),
(10, per_commitment_point, required),
(12, feerate_per_kw, required),
(14, htlc_outputs, vec_type)
});
/// We use this to track static counterparty commitment transaction data and to generate any
/// justice or 2nd-stage preimage/timeout transactions.
#[derive(PartialEq)]
struct CounterpartyCommitmentParameters {
counterparty_delayed_payment_base_key: PublicKey,
counterparty_htlc_base_key: PublicKey,
on_counterparty_tx_csv: u16,
}
impl Writeable for CounterpartyCommitmentParameters {
fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
w.write_all(&byte_utils::be64_to_array(0))?;
write_tlv_fields!(w, {
(0, self.counterparty_delayed_payment_base_key, required),
(2, self.counterparty_htlc_base_key, required),
(4, self.on_counterparty_tx_csv, required),
});
Ok(())
}
}
impl Readable for CounterpartyCommitmentParameters {
fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
let counterparty_commitment_transaction = {
// Versions prior to 0.0.100 had some per-HTLC state stored here, which is no longer
// used. Read it for compatibility.
let per_htlc_len: u64 = Readable::read(r)?;
for _ in 0..per_htlc_len {
let _txid: Txid = Readable::read(r)?;
let htlcs_count: u64 = Readable::read(r)?;
for _ in 0..htlcs_count {
let _htlc: HTLCOutputInCommitment = Readable::read(r)?;
}
}
let mut counterparty_delayed_payment_base_key = OptionDeserWrapper(None);
let mut counterparty_htlc_base_key = OptionDeserWrapper(None);
let mut on_counterparty_tx_csv: u16 = 0;
read_tlv_fields!(r, {
(0, counterparty_delayed_payment_base_key, required),
(2, counterparty_htlc_base_key, required),
(4, on_counterparty_tx_csv, required),
});
CounterpartyCommitmentParameters {
counterparty_delayed_payment_base_key: counterparty_delayed_payment_base_key.0.unwrap(),
counterparty_htlc_base_key: counterparty_htlc_base_key.0.unwrap(),
on_counterparty_tx_csv,
}
};
Ok(counterparty_commitment_transaction)
}
}
/// An entry for an [`OnchainEvent`], stating the block height when the event was observed and the
/// transaction causing it.
///
/// Used to determine when the on-chain event can be considered safe from a chain reorganization.
#[derive(PartialEq)]
struct OnchainEventEntry {
txid: Txid,
height: u32,
event: OnchainEvent,
}
impl OnchainEventEntry {
fn confirmation_threshold(&self) -> u32 {
let mut conf_threshold = self.height + ANTI_REORG_DELAY - 1;
match self.event {
OnchainEvent::MaturingOutput {
descriptor: SpendableOutputDescriptor::DelayedPaymentOutput(ref descriptor)
} => {
// A CSV'd transaction is confirmable in block (input height) + CSV delay, which means
// it's broadcastable when we see the previous block.
conf_threshold = cmp::max(conf_threshold, self.height + descriptor.to_self_delay as u32 - 1);
},
OnchainEvent::FundingSpendConfirmation { on_local_output_csv: Some(csv), .. } |
OnchainEvent::HTLCSpendConfirmation { on_to_local_output_csv: Some(csv), .. } => {
// A CSV'd transaction is confirmable in block (input height) + CSV delay, which means
// it's broadcastable when we see the previous block.
conf_threshold = cmp::max(conf_threshold, self.height + csv as u32 - 1);
},
_ => {},
}
conf_threshold
}
fn has_reached_confirmation_threshold(&self, best_block: &BestBlock) -> bool {
best_block.height() >= self.confirmation_threshold()
}
}
/// Upon discovering of some classes of onchain tx by ChannelMonitor, we may have to take actions on it
/// once they mature to enough confirmations (ANTI_REORG_DELAY)
#[derive(PartialEq)]
enum OnchainEvent {
/// An outbound HTLC failing after a transaction is confirmed. Used
/// * when an outbound HTLC output is spent by us after the HTLC timed out
/// * an outbound HTLC which was not present in the commitment transaction which appeared
/// on-chain (either because it was not fully committed to or it was dust).
/// Note that this is *not* used for preimage claims, as those are passed upstream immediately,
/// appearing only as an `HTLCSpendConfirmation`, below.
HTLCUpdate {
source: HTLCSource,
payment_hash: PaymentHash,
onchain_value_satoshis: Option<u64>,
/// None in the second case, above, ie when there is no relevant output in the commitment
/// transaction which appeared on chain.
input_idx: Option<u32>,
},
MaturingOutput {
descriptor: SpendableOutputDescriptor,
},
/// A spend of the funding output, either a commitment transaction or a cooperative closing
/// transaction.
FundingSpendConfirmation {
/// The CSV delay for the output of the funding spend transaction (implying it is a local
/// commitment transaction, and this is the delay on the to_self output).
on_local_output_csv: Option<u16>,
},
/// A spend of a commitment transaction HTLC output, set in the cases where *no* `HTLCUpdate`
/// is constructed. This is used when
/// * an outbound HTLC is claimed by our counterparty with a preimage, causing us to
/// immediately claim the HTLC on the inbound edge and track the resolution here,
/// * an inbound HTLC is claimed by our counterparty (with a timeout),
/// * an inbound HTLC is claimed by us (with a preimage).
/// * a revoked-state HTLC transaction was broadcasted, which was claimed by the revocation
/// signature.
HTLCSpendConfirmation {
input_idx: u32,
/// If the claim was made by either party with a preimage, this is filled in
preimage: Option<PaymentPreimage>,
/// If the claim was made by us on an inbound HTLC against a local commitment transaction,
/// we set this to the output CSV value which we will have to wait until to spend the
/// output (and generate a SpendableOutput event).
on_to_local_output_csv: Option<u16>,
},
}
impl Writeable for OnchainEventEntry {
fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
write_tlv_fields!(writer, {
(0, self.txid, required),
(2, self.height, required),
(4, self.event, required),
});
Ok(())
}
}
impl MaybeReadable for OnchainEventEntry {
fn read<R: io::Read>(reader: &mut R) -> Result<Option<Self>, DecodeError> {
let mut txid = Default::default();
let mut height = 0;
let mut event = None;
read_tlv_fields!(reader, {
(0, txid, required),
(2, height, required),
(4, event, ignorable),
});
if let Some(ev) = event {
Ok(Some(Self { txid, height, event: ev }))
} else {
Ok(None)
}
}
}
impl_writeable_tlv_based_enum_upgradable!(OnchainEvent,
(0, HTLCUpdate) => {
(0, source, required),
(1, onchain_value_satoshis, option),
(2, payment_hash, required),
(3, input_idx, option),
},
(1, MaturingOutput) => {
(0, descriptor, required),
},
(3, FundingSpendConfirmation) => {
(0, on_local_output_csv, option),
},
(5, HTLCSpendConfirmation) => {
(0, input_idx, required),
(2, preimage, option),
(4, on_to_local_output_csv, option),
},
);
#[cfg_attr(any(test, fuzzing, feature = "_test_utils"), derive(PartialEq))]
#[derive(Clone)]
pub(crate) enum ChannelMonitorUpdateStep {
LatestHolderCommitmentTXInfo {
commitment_tx: HolderCommitmentTransaction,
htlc_outputs: Vec<(HTLCOutputInCommitment, Option<Signature>, Option<HTLCSource>)>,
},
LatestCounterpartyCommitmentTXInfo {
commitment_txid: Txid,
htlc_outputs: Vec<(HTLCOutputInCommitment, Option<Box<HTLCSource>>)>,
commitment_number: u64,
their_revocation_point: PublicKey,
},
PaymentPreimage {
payment_preimage: PaymentPreimage,
},
CommitmentSecret {
idx: u64,
secret: [u8; 32],
},
/// Used to indicate that the no future updates will occur, and likely that the latest holder
/// commitment transaction(s) should be broadcast, as the channel has been force-closed.
ChannelForceClosed {
/// If set to false, we shouldn't broadcast the latest holder commitment transaction as we
/// think we've fallen behind!
should_broadcast: bool,
},
ShutdownScript {
scriptpubkey: Script,
},
}
impl ChannelMonitorUpdateStep {
fn variant_name(&self) -> &'static str {
match self {
ChannelMonitorUpdateStep::LatestHolderCommitmentTXInfo { .. } => "LatestHolderCommitmentTXInfo",
ChannelMonitorUpdateStep::LatestCounterpartyCommitmentTXInfo { .. } => "LatestCounterpartyCommitmentTXInfo",
ChannelMonitorUpdateStep::PaymentPreimage { .. } => "PaymentPreimage",
ChannelMonitorUpdateStep::CommitmentSecret { .. } => "CommitmentSecret",
ChannelMonitorUpdateStep::ChannelForceClosed { .. } => "ChannelForceClosed",
ChannelMonitorUpdateStep::ShutdownScript { .. } => "ShutdownScript",
}
}
}
impl_writeable_tlv_based_enum_upgradable!(ChannelMonitorUpdateStep,
(0, LatestHolderCommitmentTXInfo) => {
(0, commitment_tx, required),
(2, htlc_outputs, vec_type),
},
(1, LatestCounterpartyCommitmentTXInfo) => {
(0, commitment_txid, required),
(2, commitment_number, required),
(4, their_revocation_point, required),
(6, htlc_outputs, vec_type),
},
(2, PaymentPreimage) => {
(0, payment_preimage, required),
},
(3, CommitmentSecret) => {
(0, idx, required),
(2, secret, required),
},
(4, ChannelForceClosed) => {
(0, should_broadcast, required),
},
(5, ShutdownScript) => {
(0, scriptpubkey, required),
},
);
/// Details about the balance(s) available for spending once the channel appears on chain.
///
/// See [`ChannelMonitor::get_claimable_balances`] for more details on when these will or will not
/// be provided.
#[derive(Clone, Debug, PartialEq, Eq)]
#[cfg_attr(test, derive(PartialOrd, Ord))]
pub enum Balance {
/// The channel is not yet closed (or the commitment or closing transaction has not yet
/// appeared in a block). The given balance is claimable (less on-chain fees) if the channel is
/// force-closed now.
ClaimableOnChannelClose {
/// The amount available to claim, in satoshis, excluding the on-chain fees which will be
/// required to do so.
claimable_amount_satoshis: u64,
},
/// The channel has been closed, and the given balance is ours but awaiting confirmations until
/// we consider it spendable.
ClaimableAwaitingConfirmations {
/// The amount available to claim, in satoshis, possibly excluding the on-chain fees which
/// were spent in broadcasting the transaction.
claimable_amount_satoshis: u64,
/// The height at which an [`Event::SpendableOutputs`] event will be generated for this
/// amount.
confirmation_height: u32,
},
/// The channel has been closed, and the given balance should be ours but awaiting spending
/// transaction confirmation. If the spending transaction does not confirm in time, it is
/// possible our counterparty can take the funds by broadcasting an HTLC timeout on-chain.
///
/// Once the spending transaction confirms, before it has reached enough confirmations to be
/// considered safe from chain reorganizations, the balance will instead be provided via
/// [`Balance::ClaimableAwaitingConfirmations`].
ContentiousClaimable {
/// The amount available to claim, in satoshis, excluding the on-chain fees which will be
/// required to do so.
claimable_amount_satoshis: u64,
/// The height at which the counterparty may be able to claim the balance if we have not
/// done so.
timeout_height: u32,
},
/// HTLCs which we sent to our counterparty which are claimable after a timeout (less on-chain
/// fees) if the counterparty does not know the preimage for the HTLCs. These are somewhat
/// likely to be claimed by our counterparty before we do.
MaybeClaimableHTLCAwaitingTimeout {
/// The amount available to claim, in satoshis, excluding the on-chain fees which will be
/// required to do so.
claimable_amount_satoshis: u64,
/// The height at which we will be able to claim the balance if our counterparty has not
/// done so.
claimable_height: u32,
},
}
/// An HTLC which has been irrevocably resolved on-chain, and has reached ANTI_REORG_DELAY.
#[derive(PartialEq)]
struct IrrevocablyResolvedHTLC {
input_idx: u32,
/// Only set if the HTLC claim was ours using a payment preimage
payment_preimage: Option<PaymentPreimage>,
}
impl_writeable_tlv_based!(IrrevocablyResolvedHTLC, {
(0, input_idx, required),
(2, payment_preimage, option),
});
/// A ChannelMonitor handles chain events (blocks connected and disconnected) and generates
/// on-chain transactions to ensure no loss of funds occurs.
///
/// You MUST ensure that no ChannelMonitors for a given channel anywhere contain out-of-date
/// information and are actively monitoring the chain.
///
/// Pending Events or updated HTLCs which have not yet been read out by
/// get_and_clear_pending_monitor_events or get_and_clear_pending_events are serialized to disk and
/// reloaded at deserialize-time. Thus, you must ensure that, when handling events, all events
/// gotten are fully handled before re-serializing the new state.
///
/// Note that the deserializer is only implemented for (BlockHash, ChannelMonitor), which
/// tells you the last block hash which was block_connect()ed. You MUST rescan any blocks along
/// the "reorg path" (ie disconnecting blocks until you find a common ancestor from both the
/// returned block hash and the the current chain and then reconnecting blocks to get to the
/// best chain) upon deserializing the object!
pub struct ChannelMonitor<Signer: Sign> {
#[cfg(test)]
pub(crate) inner: Mutex<ChannelMonitorImpl<Signer>>,
#[cfg(not(test))]
inner: Mutex<ChannelMonitorImpl<Signer>>,
}
pub(crate) struct ChannelMonitorImpl<Signer: Sign> {
latest_update_id: u64,
commitment_transaction_number_obscure_factor: u64,
destination_script: Script,
broadcasted_holder_revokable_script: Option<(Script, PublicKey, PublicKey)>,
counterparty_payment_script: Script,
shutdown_script: Option<Script>,
channel_keys_id: [u8; 32],
holder_revocation_basepoint: PublicKey,
funding_info: (OutPoint, Script),
current_counterparty_commitment_txid: Option<Txid>,
prev_counterparty_commitment_txid: Option<Txid>,
counterparty_commitment_params: CounterpartyCommitmentParameters,
funding_redeemscript: Script,
channel_value_satoshis: u64,
// first is the idx of the first of the two revocation points
their_cur_revocation_points: Option<(u64, PublicKey, Option<PublicKey>)>,
on_holder_tx_csv: u16,
commitment_secrets: CounterpartyCommitmentSecrets,
/// The set of outpoints in each counterparty commitment transaction. We always need at least
/// the payment hash from `HTLCOutputInCommitment` to claim even a revoked commitment
/// transaction broadcast as we need to be able to construct the witness script in all cases.
counterparty_claimable_outpoints: HashMap<Txid, Vec<(HTLCOutputInCommitment, Option<Box<HTLCSource>>)>>,
/// We cannot identify HTLC-Success or HTLC-Timeout transactions by themselves on the chain.
/// Nor can we figure out their commitment numbers without the commitment transaction they are
/// spending. Thus, in order to claim them via revocation key, we track all the counterparty
/// commitment transactions which we find on-chain, mapping them to the commitment number which
/// can be used to derive the revocation key and claim the transactions.
counterparty_commitment_txn_on_chain: HashMap<Txid, u64>,
/// Cache used to make pruning of payment_preimages faster.
/// Maps payment_hash values to commitment numbers for counterparty transactions for non-revoked
/// counterparty transactions (ie should remain pretty small).
/// Serialized to disk but should generally not be sent to Watchtowers.
counterparty_hash_commitment_number: HashMap<PaymentHash, u64>,
// We store two holder commitment transactions to avoid any race conditions where we may update
// some monitors (potentially on watchtowers) but then fail to update others, resulting in the
// various monitors for one channel being out of sync, and us broadcasting a holder
// transaction for which we have deleted claim information on some watchtowers.
prev_holder_signed_commitment_tx: Option<HolderSignedTx>,
current_holder_commitment_tx: HolderSignedTx,
// Used just for ChannelManager to make sure it has the latest channel data during
// deserialization
current_counterparty_commitment_number: u64,
// Used just for ChannelManager to make sure it has the latest channel data during
// deserialization
current_holder_commitment_number: u64,
payment_preimages: HashMap<PaymentHash, PaymentPreimage>,
// Note that `MonitorEvent`s MUST NOT be generated during update processing, only generated
// during chain data processing. This prevents a race in `ChainMonitor::update_channel` (and
// presumably user implementations thereof as well) where we update the in-memory channel
// object, then before the persistence finishes (as it's all under a read-lock), we return
// pending events to the user or to the relevant `ChannelManager`. Then, on reload, we'll have
// the pre-event state here, but have processed the event in the `ChannelManager`.
// Note that because the `event_lock` in `ChainMonitor` is only taken in
// block/transaction-connected events and *not* during block/transaction-disconnected events,
// we further MUST NOT generate events during block/transaction-disconnection.
pending_monitor_events: Vec<MonitorEvent>,
pending_events: Vec<Event>,
// Used to track on-chain events (i.e., transactions part of channels confirmed on chain) on
// which to take actions once they reach enough confirmations. Each entry includes the
// transaction's id and the height when the transaction was confirmed on chain.
onchain_events_awaiting_threshold_conf: Vec<OnchainEventEntry>,
// If we get serialized out and re-read, we need to make sure that the chain monitoring
// interface knows about the TXOs that we want to be notified of spends of. We could probably
// be smart and derive them from the above storage fields, but its much simpler and more
// Obviously Correct (tm) if we just keep track of them explicitly.
outputs_to_watch: HashMap<Txid, Vec<(u32, Script)>>,
#[cfg(test)]
pub onchain_tx_handler: OnchainTxHandler<Signer>,
#[cfg(not(test))]
onchain_tx_handler: OnchainTxHandler<Signer>,
// This is set when the Channel[Manager] generated a ChannelMonitorUpdate which indicated the
// channel has been force-closed. After this is set, no further holder commitment transaction
// updates may occur, and we panic!() if one is provided.
lockdown_from_offchain: bool,
// Set once we've signed a holder commitment transaction and handed it over to our
// OnchainTxHandler. After this is set, no future updates to our holder commitment transactions
// may occur, and we fail any such monitor updates.
//
// In case of update rejection due to a locally already signed commitment transaction, we
// nevertheless store update content to track in case of concurrent broadcast by another
// remote monitor out-of-order with regards to the block view.
holder_tx_signed: bool,
// If a spend of the funding output is seen, we set this to true and reject any further
// updates. This prevents any further changes in the offchain state no matter the order
// of block connection between ChannelMonitors and the ChannelManager.
funding_spend_seen: bool,
funding_spend_confirmed: Option<Txid>,
/// The set of HTLCs which have been either claimed or failed on chain and have reached
/// the requisite confirmations on the claim/fail transaction (either ANTI_REORG_DELAY or the
/// spending CSV for revocable outputs).
htlcs_resolved_on_chain: Vec<IrrevocablyResolvedHTLC>,
// We simply modify best_block in Channel's block_connected so that serialization is
// consistent but hopefully the users' copy handles block_connected in a consistent way.
// (we do *not*, however, update them in update_monitor to ensure any local user copies keep
// their best_block from its state and not based on updated copies that didn't run through
// the full block_connected).
best_block: BestBlock,
secp_ctx: Secp256k1<secp256k1::All>, //TODO: dedup this a bit...
}
/// Transaction outputs to watch for on-chain spends.
pub type TransactionOutputs = (Txid, Vec<(u32, TxOut)>);
#[cfg(any(test, fuzzing, feature = "_test_utils"))]
/// Used only in testing and fuzzing to check serialization roundtrips don't change the underlying
/// object
impl<Signer: Sign> PartialEq for ChannelMonitor<Signer> {
fn eq(&self, other: &Self) -> bool {
let inner = self.inner.lock().unwrap();
let other = other.inner.lock().unwrap();
inner.eq(&other)
}
}
#[cfg(any(test, fuzzing, feature = "_test_utils"))]
/// Used only in testing and fuzzing to check serialization roundtrips don't change the underlying
/// object
impl<Signer: Sign> PartialEq for ChannelMonitorImpl<Signer> {
fn eq(&self, other: &Self) -> bool {
if self.latest_update_id != other.latest_update_id ||
self.commitment_transaction_number_obscure_factor != other.commitment_transaction_number_obscure_factor ||
self.destination_script != other.destination_script ||
self.broadcasted_holder_revokable_script != other.broadcasted_holder_revokable_script ||
self.counterparty_payment_script != other.counterparty_payment_script ||
self.channel_keys_id != other.channel_keys_id ||
self.holder_revocation_basepoint != other.holder_revocation_basepoint ||
self.funding_info != other.funding_info ||
self.current_counterparty_commitment_txid != other.current_counterparty_commitment_txid ||
self.prev_counterparty_commitment_txid != other.prev_counterparty_commitment_txid ||
self.counterparty_commitment_params != other.counterparty_commitment_params ||
self.funding_redeemscript != other.funding_redeemscript ||
self.channel_value_satoshis != other.channel_value_satoshis ||
self.their_cur_revocation_points != other.their_cur_revocation_points ||
self.on_holder_tx_csv != other.on_holder_tx_csv ||
self.commitment_secrets != other.commitment_secrets ||
self.counterparty_claimable_outpoints != other.counterparty_claimable_outpoints ||
self.counterparty_commitment_txn_on_chain != other.counterparty_commitment_txn_on_chain ||
self.counterparty_hash_commitment_number != other.counterparty_hash_commitment_number ||
self.prev_holder_signed_commitment_tx != other.prev_holder_signed_commitment_tx ||
self.current_counterparty_commitment_number != other.current_counterparty_commitment_number ||
self.current_holder_commitment_number != other.current_holder_commitment_number ||
self.current_holder_commitment_tx != other.current_holder_commitment_tx ||
self.payment_preimages != other.payment_preimages ||
self.pending_monitor_events != other.pending_monitor_events ||
self.pending_events.len() != other.pending_events.len() || // We trust events to round-trip properly
self.onchain_events_awaiting_threshold_conf != other.onchain_events_awaiting_threshold_conf ||
self.outputs_to_watch != other.outputs_to_watch ||
self.lockdown_from_offchain != other.lockdown_from_offchain ||
self.holder_tx_signed != other.holder_tx_signed ||
self.funding_spend_seen != other.funding_spend_seen ||
self.funding_spend_confirmed != other.funding_spend_confirmed ||
self.htlcs_resolved_on_chain != other.htlcs_resolved_on_chain
{
false
} else {
true
}
}
}
impl<Signer: Sign> Writeable for ChannelMonitor<Signer> {
fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
self.inner.lock().unwrap().write(writer)
}
}
// These are also used for ChannelMonitorUpdate, above.
const SERIALIZATION_VERSION: u8 = 1;
const MIN_SERIALIZATION_VERSION: u8 = 1;
impl<Signer: Sign> Writeable for ChannelMonitorImpl<Signer> {
fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
self.latest_update_id.write(writer)?;
// Set in initial Channel-object creation, so should always be set by now:
U48(self.commitment_transaction_number_obscure_factor).write(writer)?;
self.destination_script.write(writer)?;
if let Some(ref broadcasted_holder_revokable_script) = self.broadcasted_holder_revokable_script {
writer.write_all(&[0; 1])?;
broadcasted_holder_revokable_script.0.write(writer)?;
broadcasted_holder_revokable_script.1.write(writer)?;
broadcasted_holder_revokable_script.2.write(writer)?;
} else {
writer.write_all(&[1; 1])?;
}
self.counterparty_payment_script.write(writer)?;
match &self.shutdown_script {
Some(script) => script.write(writer)?,
None => Script::new().write(writer)?,
}
self.channel_keys_id.write(writer)?;
self.holder_revocation_basepoint.write(writer)?;
writer.write_all(&self.funding_info.0.txid[..])?;
writer.write_all(&byte_utils::be16_to_array(self.funding_info.0.index))?;
self.funding_info.1.write(writer)?;
self.current_counterparty_commitment_txid.write(writer)?;
self.prev_counterparty_commitment_txid.write(writer)?;
self.counterparty_commitment_params.write(writer)?;
self.funding_redeemscript.write(writer)?;
self.channel_value_satoshis.write(writer)?;
match self.their_cur_revocation_points {
Some((idx, pubkey, second_option)) => {
writer.write_all(&byte_utils::be48_to_array(idx))?;
writer.write_all(&pubkey.serialize())?;
match second_option {
Some(second_pubkey) => {
writer.write_all(&second_pubkey.serialize())?;
},
None => {
writer.write_all(&[0; 33])?;
},
}
},
None => {
writer.write_all(&byte_utils::be48_to_array(0))?;
},
}
writer.write_all(&byte_utils::be16_to_array(self.on_holder_tx_csv))?;
self.commitment_secrets.write(writer)?;
macro_rules! serialize_htlc_in_commitment {
($htlc_output: expr) => {
writer.write_all(&[$htlc_output.offered as u8; 1])?;
writer.write_all(&byte_utils::be64_to_array($htlc_output.amount_msat))?;
writer.write_all(&byte_utils::be32_to_array($htlc_output.cltv_expiry))?;
writer.write_all(&$htlc_output.payment_hash.0[..])?;
$htlc_output.transaction_output_index.write(writer)?;
}
}
writer.write_all(&byte_utils::be64_to_array(self.counterparty_claimable_outpoints.len() as u64))?;
for (ref txid, ref htlc_infos) in self.counterparty_claimable_outpoints.iter() {
writer.write_all(&txid[..])?;
writer.write_all(&byte_utils::be64_to_array(htlc_infos.len() as u64))?;
for &(ref htlc_output, ref htlc_source) in htlc_infos.iter() {
serialize_htlc_in_commitment!(htlc_output);
htlc_source.as_ref().map(|b| b.as_ref()).write(writer)?;
}
}
writer.write_all(&byte_utils::be64_to_array(self.counterparty_commitment_txn_on_chain.len() as u64))?;
for (ref txid, commitment_number) in self.counterparty_commitment_txn_on_chain.iter() {
writer.write_all(&txid[..])?;
writer.write_all(&byte_utils::be48_to_array(*commitment_number))?;
}
writer.write_all(&byte_utils::be64_to_array(self.counterparty_hash_commitment_number.len() as u64))?;
for (ref payment_hash, commitment_number) in self.counterparty_hash_commitment_number.iter() {
writer.write_all(&payment_hash.0[..])?;
writer.write_all(&byte_utils::be48_to_array(*commitment_number))?;
}
if let Some(ref prev_holder_tx) = self.prev_holder_signed_commitment_tx {
writer.write_all(&[1; 1])?;
prev_holder_tx.write(writer)?;
} else {
writer.write_all(&[0; 1])?;
}
self.current_holder_commitment_tx.write(writer)?;
writer.write_all(&byte_utils::be48_to_array(self.current_counterparty_commitment_number))?;
writer.write_all(&byte_utils::be48_to_array(self.current_holder_commitment_number))?;
writer.write_all(&byte_utils::be64_to_array(self.payment_preimages.len() as u64))?;
for payment_preimage in self.payment_preimages.values() {
writer.write_all(&payment_preimage.0[..])?;
}
writer.write_all(&(self.pending_monitor_events.iter().filter(|ev| match ev {
MonitorEvent::HTLCEvent(_) => true,
MonitorEvent::CommitmentTxConfirmed(_) => true,
_ => false,
}).count() as u64).to_be_bytes())?;
for event in self.pending_monitor_events.iter() {
match event {
MonitorEvent::HTLCEvent(upd) => {
0u8.write(writer)?;
upd.write(writer)?;
},
MonitorEvent::CommitmentTxConfirmed(_) => 1u8.write(writer)?,
_ => {}, // Covered in the TLV writes below
}
}
writer.write_all(&byte_utils::be64_to_array(self.pending_events.len() as u64))?;
for event in self.pending_events.iter() {
event.write(writer)?;
}
self.best_block.block_hash().write(writer)?;
writer.write_all(&byte_utils::be32_to_array(self.best_block.height()))?;
writer.write_all(&byte_utils::be64_to_array(self.onchain_events_awaiting_threshold_conf.len() as u64))?;
for ref entry in self.onchain_events_awaiting_threshold_conf.iter() {
entry.write(writer)?;
}
(self.outputs_to_watch.len() as u64).write(writer)?;
for (txid, idx_scripts) in self.outputs_to_watch.iter() {
txid.write(writer)?;
(idx_scripts.len() as u64).write(writer)?;
for (idx, script) in idx_scripts.iter() {
idx.write(writer)?;
script.write(writer)?;
}
}
self.onchain_tx_handler.write(writer)?;
self.lockdown_from_offchain.write(writer)?;
self.holder_tx_signed.write(writer)?;
write_tlv_fields!(writer, {
(1, self.funding_spend_confirmed, option),
(3, self.htlcs_resolved_on_chain, vec_type),
(5, self.pending_monitor_events, vec_type),
(7, self.funding_spend_seen, required),
});
Ok(())
}
}
impl<Signer: Sign> ChannelMonitor<Signer> {
pub(crate) fn new(secp_ctx: Secp256k1<secp256k1::All>, keys: Signer, shutdown_script: Option<Script>,
on_counterparty_tx_csv: u16, destination_script: &Script, funding_info: (OutPoint, Script),
channel_parameters: &ChannelTransactionParameters,
funding_redeemscript: Script, channel_value_satoshis: u64,
commitment_transaction_number_obscure_factor: u64,
initial_holder_commitment_tx: HolderCommitmentTransaction,
best_block: BestBlock) -> ChannelMonitor<Signer> {
assert!(commitment_transaction_number_obscure_factor <= (1 << 48));
let payment_key_hash = WPubkeyHash::hash(&keys.pubkeys().payment_point.serialize());
let counterparty_payment_script = Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0).push_slice(&payment_key_hash[..]).into_script();
let counterparty_channel_parameters = channel_parameters.counterparty_parameters.as_ref().unwrap();
let counterparty_delayed_payment_base_key = counterparty_channel_parameters.pubkeys.delayed_payment_basepoint;
let counterparty_htlc_base_key = counterparty_channel_parameters.pubkeys.htlc_basepoint;
let counterparty_commitment_params = CounterpartyCommitmentParameters { counterparty_delayed_payment_base_key, counterparty_htlc_base_key, on_counterparty_tx_csv };
let channel_keys_id = keys.channel_keys_id();
let holder_revocation_basepoint = keys.pubkeys().revocation_basepoint;
// block for Rust 1.34 compat
let (holder_commitment_tx, current_holder_commitment_number) = {
let trusted_tx = initial_holder_commitment_tx.trust();
let txid = trusted_tx.txid();
let tx_keys = trusted_tx.keys();
let holder_commitment_tx = HolderSignedTx {
txid,
revocation_key: tx_keys.revocation_key,
a_htlc_key: tx_keys.broadcaster_htlc_key,
b_htlc_key: tx_keys.countersignatory_htlc_key,
delayed_payment_key: tx_keys.broadcaster_delayed_payment_key,
per_commitment_point: tx_keys.per_commitment_point,
htlc_outputs: Vec::new(), // There are never any HTLCs in the initial commitment transactions
to_self_value_sat: initial_holder_commitment_tx.to_broadcaster_value_sat(),
feerate_per_kw: trusted_tx.feerate_per_kw(),
};
(holder_commitment_tx, trusted_tx.commitment_number())
};
let onchain_tx_handler =
OnchainTxHandler::new(destination_script.clone(), keys,
channel_parameters.clone(), initial_holder_commitment_tx, secp_ctx.clone());
let mut outputs_to_watch = HashMap::new();
outputs_to_watch.insert(funding_info.0.txid, vec![(funding_info.0.index as u32, funding_info.1.clone())]);
ChannelMonitor {
inner: Mutex::new(ChannelMonitorImpl {
latest_update_id: 0,
commitment_transaction_number_obscure_factor,
destination_script: destination_script.clone(),
broadcasted_holder_revokable_script: None,
counterparty_payment_script,
shutdown_script,
channel_keys_id,
holder_revocation_basepoint,
funding_info,
current_counterparty_commitment_txid: None,
prev_counterparty_commitment_txid: None,
counterparty_commitment_params,
funding_redeemscript,
channel_value_satoshis,
their_cur_revocation_points: None,
on_holder_tx_csv: counterparty_channel_parameters.selected_contest_delay,
commitment_secrets: CounterpartyCommitmentSecrets::new(),
counterparty_claimable_outpoints: HashMap::new(),
counterparty_commitment_txn_on_chain: HashMap::new(),
counterparty_hash_commitment_number: HashMap::new(),
prev_holder_signed_commitment_tx: None,
current_holder_commitment_tx: holder_commitment_tx,
current_counterparty_commitment_number: 1 << 48,
current_holder_commitment_number,
payment_preimages: HashMap::new(),
pending_monitor_events: Vec::new(),
pending_events: Vec::new(),
onchain_events_awaiting_threshold_conf: Vec::new(),
outputs_to_watch,
onchain_tx_handler,
lockdown_from_offchain: false,
holder_tx_signed: false,
funding_spend_seen: false,
funding_spend_confirmed: None,
htlcs_resolved_on_chain: Vec::new(),
best_block,
secp_ctx,
}),
}
}
#[cfg(test)]
fn provide_secret(&self, idx: u64, secret: [u8; 32]) -> Result<(), &'static str> {
self.inner.lock().unwrap().provide_secret(idx, secret)
}
/// Informs this monitor of the latest counterparty (ie non-broadcastable) commitment transaction.
/// The monitor watches for it to be broadcasted and then uses the HTLC information (and
/// possibly future revocation/preimage information) to claim outputs where possible.
/// We cache also the mapping hash:commitment number to lighten pruning of old preimages by watchtowers.
pub(crate) fn provide_latest_counterparty_commitment_tx<L: Deref>(
&self,
txid: Txid,
htlc_outputs: Vec<(HTLCOutputInCommitment, Option<Box<HTLCSource>>)>,
commitment_number: u64,
their_revocation_point: PublicKey,
logger: &L,
) where L::Target: Logger {
self.inner.lock().unwrap().provide_latest_counterparty_commitment_tx(
txid, htlc_outputs, commitment_number, their_revocation_point, logger)
}
#[cfg(test)]
fn provide_latest_holder_commitment_tx(
&self, holder_commitment_tx: HolderCommitmentTransaction,
htlc_outputs: Vec<(HTLCOutputInCommitment, Option<Signature>, Option<HTLCSource>)>,
) -> Result<(), ()> {
self.inner.lock().unwrap().provide_latest_holder_commitment_tx(holder_commitment_tx, htlc_outputs).map_err(|_| ())
}
#[cfg(test)]
pub(crate) fn provide_payment_preimage<B: Deref, F: Deref, L: Deref>(
&self,
payment_hash: &PaymentHash,
payment_preimage: &PaymentPreimage,
broadcaster: &B,
fee_estimator: &F,
logger: &L,
) where
B::Target: BroadcasterInterface,
F::Target: FeeEstimator,
L::Target: Logger,
{
self.inner.lock().unwrap().provide_payment_preimage(
payment_hash, payment_preimage, broadcaster, fee_estimator, logger)
}
pub(crate) fn broadcast_latest_holder_commitment_txn<B: Deref, L: Deref>(
&self,
broadcaster: &B,
logger: &L,
) where
B::Target: BroadcasterInterface,
L::Target: Logger,
{
self.inner.lock().unwrap().broadcast_latest_holder_commitment_txn(broadcaster, logger)
}
/// Updates a ChannelMonitor on the basis of some new information provided by the Channel
/// itself.
///
/// panics if the given update is not the next update by update_id.
pub fn update_monitor<B: Deref, F: Deref, L: Deref>(
&self,
updates: &ChannelMonitorUpdate,
broadcaster: &B,
fee_estimator: &F,
logger: &L,
) -> Result<(), ()>
where
B::Target: BroadcasterInterface,
F::Target: FeeEstimator,
L::Target: Logger,
{
self.inner.lock().unwrap().update_monitor(updates, broadcaster, fee_estimator, logger)
}
/// Gets the update_id from the latest ChannelMonitorUpdate which was applied to this
/// ChannelMonitor.
pub fn get_latest_update_id(&self) -> u64 {
self.inner.lock().unwrap().get_latest_update_id()
}
/// Gets the funding transaction outpoint of the channel this ChannelMonitor is monitoring for.
pub fn get_funding_txo(&self) -> (OutPoint, Script) {
self.inner.lock().unwrap().get_funding_txo().clone()
}
/// Gets a list of txids, with their output scripts (in the order they appear in the
/// transaction), which we must learn about spends of via block_connected().
pub fn get_outputs_to_watch(&self) -> Vec<(Txid, Vec<(u32, Script)>)> {
self.inner.lock().unwrap().get_outputs_to_watch()
.iter().map(|(txid, outputs)| (*txid, outputs.clone())).collect()
}
/// Loads the funding txo and outputs to watch into the given `chain::Filter` by repeatedly
/// calling `chain::Filter::register_output` and `chain::Filter::register_tx` until all outputs
/// have been registered.
pub fn load_outputs_to_watch<F: Deref>(&self, filter: &F) where F::Target: chain::Filter {
let lock = self.inner.lock().unwrap();
filter.register_tx(&lock.get_funding_txo().0.txid, &lock.get_funding_txo().1);
for (txid, outputs) in lock.get_outputs_to_watch().iter() {
for (index, script_pubkey) in outputs.iter() {
assert!(*index <= u16::max_value() as u32);
filter.register_output(WatchedOutput {
block_hash: None,
outpoint: OutPoint { txid: *txid, index: *index as u16 },
script_pubkey: script_pubkey.clone(),
});
}
}
}
/// Get the list of HTLCs who's status has been updated on chain. This should be called by
/// ChannelManager via [`chain::Watch::release_pending_monitor_events`].
pub fn get_and_clear_pending_monitor_events(&self) -> Vec<MonitorEvent> {
self.inner.lock().unwrap().get_and_clear_pending_monitor_events()
}
/// Gets the list of pending events which were generated by previous actions, clearing the list
/// in the process.
///
/// This is called by ChainMonitor::get_and_clear_pending_events() and is equivalent to
/// EventsProvider::get_and_clear_pending_events() except that it requires &mut self as we do
/// no internal locking in ChannelMonitors.
pub fn get_and_clear_pending_events(&self) -> Vec<Event> {
self.inner.lock().unwrap().get_and_clear_pending_events()
}
pub(crate) fn get_min_seen_secret(&self) -> u64 {
self.inner.lock().unwrap().get_min_seen_secret()
}
pub(crate) fn get_cur_counterparty_commitment_number(&self) -> u64 {
self.inner.lock().unwrap().get_cur_counterparty_commitment_number()
}
pub(crate) fn get_cur_holder_commitment_number(&self) -> u64 {
self.inner.lock().unwrap().get_cur_holder_commitment_number()
}
/// Used by ChannelManager deserialization to broadcast the latest holder state if its copy of
/// the Channel was out-of-date. You may use it to get a broadcastable holder toxic tx in case of
/// fallen-behind, i.e when receiving a channel_reestablish with a proof that our counterparty side knows
/// a higher revocation secret than the holder commitment number we are aware of. Broadcasting these
/// transactions are UNSAFE, as they allow counterparty side to punish you. Nevertheless you may want to
/// broadcast them if counterparty don't close channel with his higher commitment transaction after a
/// substantial amount of time (a month or even a year) to get back funds. Best may be to contact
/// out-of-band the other node operator to coordinate with him if option is available to you.
/// In any-case, choice is up to the user.
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)
}
/// Unsafe test-only version of get_latest_holder_commitment_txn used by our test framework
/// to bypass HolderCommitmentTransaction state update lockdown after signature and generate
/// revoked commitment transaction.
#[cfg(any(test, feature = "unsafe_revoked_tx_signing"))]
pub fn unsafe_get_latest_holder_commitment_txn<L: Deref>(&self, logger: &L) -> Vec<Transaction>
where L::Target: Logger {
self.inner.lock().unwrap().unsafe_get_latest_holder_commitment_txn(logger)
}
/// Processes transactions in a newly connected block, which may result in any of the following:
/// - update the monitor's state against resolved HTLCs
/// - punish the counterparty in the case of seeing a revoked commitment transaction
/// - force close the channel and claim/timeout incoming/outgoing HTLCs if near expiration
/// - detect settled outputs for later spending
/// - schedule and bump any in-flight claims
///
/// Returns any new outputs to watch from `txdata`; after called, these are also included in
/// [`get_outputs_to_watch`].
///
/// [`get_outputs_to_watch`]: #method.get_outputs_to_watch
pub fn block_connected<B: Deref, F: Deref, L: Deref>(
&self,
header: &BlockHeader,
txdata: &TransactionData,
height: u32,
broadcaster: B,
fee_estimator: F,
logger: L,
) -> Vec<TransactionOutputs>
where
B::Target: BroadcasterInterface,
F::Target: FeeEstimator,
L::Target: Logger,
{
self.inner.lock().unwrap().block_connected(
header, txdata, height, broadcaster, fee_estimator, logger)
}
/// Determines if the disconnected block contained any transactions of interest and updates
/// appropriately.
pub fn block_disconnected<B: Deref, F: Deref, L: Deref>(
&self,
header: &BlockHeader,
height: u32,
broadcaster: B,
fee_estimator: F,
logger: L,
) where
B::Target: BroadcasterInterface,
F::Target: FeeEstimator,
L::Target: Logger,
{
self.inner.lock().unwrap().block_disconnected(
header, height, broadcaster, fee_estimator, logger)
}
/// Processes transactions confirmed in a block with the given header and height, returning new
/// outputs to watch. See [`block_connected`] for details.
///
/// Used instead of [`block_connected`] by clients that are notified of transactions rather than
/// blocks. See [`chain::Confirm`] for calling expectations.
///
/// [`block_connected`]: Self::block_connected
pub fn transactions_confirmed<B: Deref, F: Deref, L: Deref>(
&self,
header: &BlockHeader,
txdata: &TransactionData,
height: u32,
broadcaster: B,
fee_estimator: F,
logger: L,
) -> Vec<TransactionOutputs>
where
B::Target: BroadcasterInterface,
F::Target: FeeEstimator,
L::Target: Logger,
{
self.inner.lock().unwrap().transactions_confirmed(
header, txdata, height, broadcaster, fee_estimator, logger)
}
/// Processes a transaction that was reorganized out of the chain.
///
/// Used instead of [`block_disconnected`] by clients that are notified of transactions rather
/// than blocks. See [`chain::Confirm`] for calling expectations.
///
/// [`block_disconnected`]: Self::block_disconnected
pub fn transaction_unconfirmed<B: Deref, F: Deref, L: Deref>(
&self,
txid: &Txid,
broadcaster: B,
fee_estimator: F,
logger: L,
) where
B::Target: BroadcasterInterface,
F::Target: FeeEstimator,
L::Target: Logger,
{
self.inner.lock().unwrap().transaction_unconfirmed(
txid, broadcaster, fee_estimator, logger);
}
/// Updates the monitor with the current best chain tip, returning new outputs to watch. See
/// [`block_connected`] for details.
///
/// Used instead of [`block_connected`] by clients that are notified of transactions rather than
/// blocks. See [`chain::Confirm`] for calling expectations.
///
/// [`block_connected`]: Self::block_connected
pub fn best_block_updated<B: Deref, F: Deref, L: Deref>(
&self,
header: &BlockHeader,
height: u32,
broadcaster: B,
fee_estimator: F,
logger: L,
) -> Vec<TransactionOutputs>
where
B::Target: BroadcasterInterface,
F::Target: FeeEstimator,
L::Target: Logger,
{
self.inner.lock().unwrap().best_block_updated(
header, height, broadcaster, fee_estimator, logger)
}
/// Returns the set of txids that should be monitored for re-organization out of the chain.
pub fn get_relevant_txids(&self) -> Vec<Txid> {
let inner = self.inner.lock().unwrap();
let mut txids: Vec<Txid> = inner.onchain_events_awaiting_threshold_conf
.iter()
.map(|entry| entry.txid)
.chain(inner.onchain_tx_handler.get_relevant_txids().into_iter())
.collect();
txids.sort_unstable();
txids.dedup();
txids
}
/// Gets the latest best block which was connected either via the [`chain::Listen`] or
/// [`chain::Confirm`] interfaces.
pub fn current_best_block(&self) -> BestBlock {
self.inner.lock().unwrap().best_block.clone()
}
/// Gets the balances in this channel which are either claimable by us if we were to
/// force-close the channel now or which are claimable on-chain (possibly awaiting
/// confirmation).
///
/// Any balances in the channel which are available on-chain (excluding on-chain fees) are
/// included here until an [`Event::SpendableOutputs`] event has been generated for the
/// balance, or until our counterparty has claimed the balance and accrued several
/// confirmations on the claim transaction.
///
/// Note that the balances available when you or your counterparty have broadcasted revoked
/// state(s) may not be fully captured here.
// TODO, fix that ^
///
/// See [`Balance`] for additional details on the types of claimable balances which
/// may be returned here and their meanings.
pub fn get_claimable_balances(&self) -> Vec<Balance> {
let mut res = Vec::new();
let us = self.inner.lock().unwrap();
let mut confirmed_txid = us.funding_spend_confirmed;
let mut pending_commitment_tx_conf_thresh = None;
let funding_spend_pending = us.onchain_events_awaiting_threshold_conf.iter().find_map(|event| {
if let OnchainEvent::FundingSpendConfirmation { .. } = event.event {
Some((event.txid, event.confirmation_threshold()))
} else { None }
});
if let Some((txid, conf_thresh)) = funding_spend_pending {
debug_assert!(us.funding_spend_confirmed.is_none(),
"We have a pending funding spend awaiting anti-reorg confirmation, we can't have confirmed it already!");
confirmed_txid = Some(txid);
pending_commitment_tx_conf_thresh = Some(conf_thresh);
}
macro_rules! walk_htlcs {
($holder_commitment: expr, $htlc_iter: expr) => {
for htlc in $htlc_iter {
if let Some(htlc_input_idx) = htlc.transaction_output_index {
if let Some(conf_thresh) = us.onchain_events_awaiting_threshold_conf.iter().find_map(|event| {
if let OnchainEvent::MaturingOutput { descriptor: SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) } = &event.event {
if descriptor.outpoint.index as u32 == htlc_input_idx { Some(event.confirmation_threshold()) } else { None }
} else { None }
}) {
debug_assert!($holder_commitment);
res.push(Balance::ClaimableAwaitingConfirmations {
claimable_amount_satoshis: htlc.amount_msat / 1000,
confirmation_height: conf_thresh,
});
} else if us.htlcs_resolved_on_chain.iter().any(|v| v.input_idx == htlc_input_idx) {
// Funding transaction spends should be fully confirmed by the time any
// HTLC transactions are resolved, unless we're talking about a holder
// commitment tx, whose resolution is delayed until the CSV timeout is
// reached, even though HTLCs may be resolved after only
// ANTI_REORG_DELAY confirmations.
debug_assert!($holder_commitment || us.funding_spend_confirmed.is_some());
} else if htlc.offered == $holder_commitment {
// If the payment was outbound, check if there's an HTLCUpdate
// indicating we have spent this HTLC with a timeout, claiming it back
// and awaiting confirmations on it.
let htlc_update_pending = us.onchain_events_awaiting_threshold_conf.iter().find_map(|event| {
if let OnchainEvent::HTLCUpdate { input_idx: Some(input_idx), .. } = event.event {
if input_idx == htlc_input_idx { Some(event.confirmation_threshold()) } else { None }
} else { None }
});
if let Some(conf_thresh) = htlc_update_pending {
res.push(Balance::ClaimableAwaitingConfirmations {
claimable_amount_satoshis: htlc.amount_msat / 1000,
confirmation_height: conf_thresh,
});
} else {
res.push(Balance::MaybeClaimableHTLCAwaitingTimeout {
claimable_amount_satoshis: htlc.amount_msat / 1000,
claimable_height: htlc.cltv_expiry,
});
}
} else if us.payment_preimages.get(&htlc.payment_hash).is_some() {
// Otherwise (the payment was inbound), only expose it as claimable if
// we know the preimage.
// Note that if there is a pending claim, but it did not use the
// preimage, we lost funds to our counterparty! We will then continue
// to show it as ContentiousClaimable until ANTI_REORG_DELAY.
let htlc_spend_pending = us.onchain_events_awaiting_threshold_conf.iter().find_map(|event| {
if let OnchainEvent::HTLCSpendConfirmation { input_idx, preimage, .. } = event.event {
if input_idx == htlc_input_idx {
Some((event.confirmation_threshold(), preimage.is_some()))
} else { None }
} else { None }
});
if let Some((conf_thresh, true)) = htlc_spend_pending {
res.push(Balance::ClaimableAwaitingConfirmations {
claimable_amount_satoshis: htlc.amount_msat / 1000,
confirmation_height: conf_thresh,
});
} else {
res.push(Balance::ContentiousClaimable {
claimable_amount_satoshis: htlc.amount_msat / 1000,
timeout_height: htlc.cltv_expiry,
});
}
}
}
}
}
}
if let Some(txid) = confirmed_txid {
let mut found_commitment_tx = false;
if Some(txid) == us.current_counterparty_commitment_txid || Some(txid) == us.prev_counterparty_commitment_txid {
walk_htlcs!(false, us.counterparty_claimable_outpoints.get(&txid).unwrap().iter().map(|(a, _)| a));
if let Some(conf_thresh) = pending_commitment_tx_conf_thresh {
if let Some(value) = us.onchain_events_awaiting_threshold_conf.iter().find_map(|event| {
if let OnchainEvent::MaturingOutput {
descriptor: SpendableOutputDescriptor::StaticPaymentOutput(descriptor)
} = &event.event {
Some(descriptor.output.value)
} else { None }
}) {
res.push(Balance::ClaimableAwaitingConfirmations {
claimable_amount_satoshis: value,
confirmation_height: conf_thresh,
});
} else {
// If a counterparty commitment transaction is awaiting confirmation, we
// should either have a StaticPaymentOutput MaturingOutput event awaiting
// confirmation with the same height or have never met our dust amount.
}
}
found_commitment_tx = true;
} else if txid == us.current_holder_commitment_tx.txid {
walk_htlcs!(true, us.current_holder_commitment_tx.htlc_outputs.iter().map(|(a, _, _)| a));
if let Some(conf_thresh) = pending_commitment_tx_conf_thresh {
res.push(Balance::ClaimableAwaitingConfirmations {
claimable_amount_satoshis: us.current_holder_commitment_tx.to_self_value_sat,
confirmation_height: conf_thresh,
});
}
found_commitment_tx = true;
} else if let Some(prev_commitment) = &us.prev_holder_signed_commitment_tx {
if txid == prev_commitment.txid {
walk_htlcs!(true, prev_commitment.htlc_outputs.iter().map(|(a, _, _)| a));
if let Some(conf_thresh) = pending_commitment_tx_conf_thresh {
res.push(Balance::ClaimableAwaitingConfirmations {
claimable_amount_satoshis: prev_commitment.to_self_value_sat,
confirmation_height: conf_thresh,
});
}
found_commitment_tx = true;
}
}
if !found_commitment_tx {
if let Some(conf_thresh) = pending_commitment_tx_conf_thresh {
// We blindly assume this is a cooperative close transaction here, and that
// neither us nor our counterparty misbehaved. At worst we've under-estimated
// the amount we can claim as we'll punish a misbehaving counterparty.
res.push(Balance::ClaimableAwaitingConfirmations {
claimable_amount_satoshis: us.current_holder_commitment_tx.to_self_value_sat,
confirmation_height: conf_thresh,
});
}
}
// TODO: Add logic to provide claimable balances for counterparty broadcasting revoked
// outputs.
} else {
let mut claimable_inbound_htlc_value_sat = 0;
for (htlc, _, _) in us.current_holder_commitment_tx.htlc_outputs.iter() {
if htlc.transaction_output_index.is_none() { continue; }
if htlc.offered {
res.push(Balance::MaybeClaimableHTLCAwaitingTimeout {
claimable_amount_satoshis: htlc.amount_msat / 1000,
claimable_height: htlc.cltv_expiry,
});
} else if us.payment_preimages.get(&htlc.payment_hash).is_some() {
claimable_inbound_htlc_value_sat += htlc.amount_msat / 1000;
}
}
res.push(Balance::ClaimableOnChannelClose {
claimable_amount_satoshis: us.current_holder_commitment_tx.to_self_value_sat + claimable_inbound_htlc_value_sat,
});
}
res
}
/// Gets the set of outbound HTLCs which are pending resolution in this channel.
/// This is used to reconstruct pending outbound payments on restart in the ChannelManager.
pub(crate) fn get_pending_outbound_htlcs(&self) -> HashMap<HTLCSource, HTLCOutputInCommitment> {
let mut res = HashMap::new();
let us = self.inner.lock().unwrap();
macro_rules! walk_htlcs {
($holder_commitment: expr, $htlc_iter: expr) => {
for (htlc, source) in $htlc_iter {
if us.htlcs_resolved_on_chain.iter().any(|v| Some(v.input_idx) == htlc.transaction_output_index) {
// We should assert that funding_spend_confirmed is_some() here, but we
// have some unit tests which violate HTLC transaction CSVs entirely and
// would fail.
// TODO: Once tests all connect transactions at consensus-valid times, we
// should assert here like we do in `get_claimable_balances`.
} else if htlc.offered == $holder_commitment {
// If the payment was outbound, check if there's an HTLCUpdate
// indicating we have spent this HTLC with a timeout, claiming it back
// and awaiting confirmations on it.
let htlc_update_confd = us.onchain_events_awaiting_threshold_conf.iter().any(|event| {
if let OnchainEvent::HTLCUpdate { input_idx: Some(input_idx), .. } = event.event {
// If the HTLC was timed out, we wait for ANTI_REORG_DELAY blocks
// before considering it "no longer pending" - this matches when we
// provide the ChannelManager an HTLC failure event.
Some(input_idx) == htlc.transaction_output_index &&
us.best_block.height() >= event.height + ANTI_REORG_DELAY - 1
} else if let OnchainEvent::HTLCSpendConfirmation { input_idx, .. } = event.event {
// If the HTLC was fulfilled with a preimage, we consider the HTLC
// immediately non-pending, matching when we provide ChannelManager
// the preimage.
Some(input_idx) == htlc.transaction_output_index
} else { false }
});
if !htlc_update_confd {
res.insert(source.clone(), htlc.clone());
}
}
}
}
}
// We're only concerned with the confirmation count of HTLC transactions, and don't
// actually care how many confirmations a commitment transaction may or may not have. Thus,
// we look for either a FundingSpendConfirmation event or a funding_spend_confirmed.
let confirmed_txid = us.funding_spend_confirmed.or_else(|| {
us.onchain_events_awaiting_threshold_conf.iter().find_map(|event| {
if let OnchainEvent::FundingSpendConfirmation { .. } = event.event {
Some(event.txid)
} else { None }
})
});
if let Some(txid) = confirmed_txid {
if Some(txid) == us.current_counterparty_commitment_txid || Some(txid) == us.prev_counterparty_commitment_txid {
walk_htlcs!(false, us.counterparty_claimable_outpoints.get(&txid).unwrap().iter().filter_map(|(a, b)| {
if let &Some(ref source) = b {
Some((a, &**source))
} else { None }
}));
} else if txid == us.current_holder_commitment_tx.txid {
walk_htlcs!(true, us.current_holder_commitment_tx.htlc_outputs.iter().filter_map(|(a, _, c)| {
if let Some(source) = c { Some((a, source)) } else { None }
}));
} else if let Some(prev_commitment) = &us.prev_holder_signed_commitment_tx {
if txid == prev_commitment.txid {
walk_htlcs!(true, prev_commitment.htlc_outputs.iter().filter_map(|(a, _, c)| {
if let Some(source) = c { Some((a, source)) } else { None }
}));
}
}
} else {
// If we have not seen a commitment transaction on-chain (ie the channel is not yet
// closed), just examine the available counterparty commitment transactions. See docs
// on `fail_unbroadcast_htlcs`, below, for justification.
macro_rules! walk_counterparty_commitment {
($txid: expr) => {
if let Some(ref latest_outpoints) = us.counterparty_claimable_outpoints.get($txid) {
for &(ref htlc, ref source_option) in latest_outpoints.iter() {
if let &Some(ref source) = source_option {
res.insert((**source).clone(), htlc.clone());
}
}
}
}
}
if let Some(ref txid) = us.current_counterparty_commitment_txid {
walk_counterparty_commitment!(txid);
}
if let Some(ref txid) = us.prev_counterparty_commitment_txid {
walk_counterparty_commitment!(txid);
}
}
res
}
}
/// Compares a broadcasted commitment transaction's HTLCs with those in the latest state,
/// failing any HTLCs which didn't make it into the broadcasted commitment transaction back
/// after ANTI_REORG_DELAY blocks.
///
/// We always compare against the set of HTLCs in counterparty commitment transactions, as those
/// are the commitment transactions which are generated by us. The off-chain state machine in
/// `Channel` will automatically resolve any HTLCs which were never included in a commitment
/// transaction when it detects channel closure, but it is up to us to ensure any HTLCs which were
/// included in a remote commitment transaction are failed back if they are not present in the
/// broadcasted commitment transaction.
///
/// Specifically, the removal process for HTLCs in `Channel` is always based on the counterparty
/// sending a `revoke_and_ack`, which causes us to clear `prev_counterparty_commitment_txid`. Thus,
/// as long as we examine both the current counterparty commitment transaction and, if it hasn't
/// been revoked yet, the previous one, we we will never "forget" to resolve an HTLC.
macro_rules! fail_unbroadcast_htlcs {
($self: expr, $commitment_tx_type: expr, $commitment_tx_conf_height: expr, $confirmed_htlcs_list: expr, $logger: expr) => { {
macro_rules! check_htlc_fails {
($txid: expr, $commitment_tx: expr) => {
if let Some(ref latest_outpoints) = $self.counterparty_claimable_outpoints.get($txid) {
for &(ref htlc, ref source_option) in latest_outpoints.iter() {
if let &Some(ref source) = source_option {
// Check if the HTLC is present in the commitment transaction that was
// broadcast, but not if it was below the dust limit, which we should
// fail backwards immediately as there is no way for us to learn the
// payment_preimage.
// Note that if the dust limit were allowed to change between
// commitment transactions we'd want to be check whether *any*
// broadcastable commitment transaction has the HTLC in it, but it
// cannot currently change after channel initialization, so we don't
// need to here.
let confirmed_htlcs_iter: &mut Iterator<Item = (&HTLCOutputInCommitment, Option<&HTLCSource>)> = &mut $confirmed_htlcs_list;
let mut matched_htlc = false;
for (ref broadcast_htlc, ref broadcast_source) in confirmed_htlcs_iter {
if broadcast_htlc.transaction_output_index.is_some() && Some(&**source) == *broadcast_source {
matched_htlc = true;
break;
}
}
if matched_htlc { continue; }
$self.onchain_events_awaiting_threshold_conf.retain(|ref entry| {
if entry.height != $commitment_tx_conf_height { return true; }
match entry.event {
OnchainEvent::HTLCUpdate { source: ref update_source, .. } => {
*update_source != **source
},
_ => true,
}
});
let entry = OnchainEventEntry {
txid: *$txid,
height: $commitment_tx_conf_height,
event: OnchainEvent::HTLCUpdate {
source: (**source).clone(),
payment_hash: htlc.payment_hash.clone(),
onchain_value_satoshis: Some(htlc.amount_msat / 1000),
input_idx: None,
},
};
log_trace!($logger, "Failing HTLC with payment_hash {} from {} counterparty commitment tx due to broadcast of {} commitment transaction, waiting for confirmation (at height {})",
log_bytes!(htlc.payment_hash.0), $commitment_tx, $commitment_tx_type, entry.confirmation_threshold());
$self.onchain_events_awaiting_threshold_conf.push(entry);
}
}
}
}
}
if let Some(ref txid) = $self.current_counterparty_commitment_txid {
check_htlc_fails!(txid, "current");
}
if let Some(ref txid) = $self.prev_counterparty_commitment_txid {
check_htlc_fails!(txid, "previous");
}
} }
}
impl<Signer: Sign> ChannelMonitorImpl<Signer> {
/// Inserts a revocation secret into this channel monitor. Prunes old preimages if neither
/// needed by holder commitment transactions HTCLs nor by counterparty ones. Unless we haven't already seen
/// counterparty commitment transaction's secret, they are de facto pruned (we can use revocation key).
fn provide_secret(&mut self, idx: u64, secret: [u8; 32]) -> Result<(), &'static str> {
if let Err(()) = self.commitment_secrets.provide_secret(idx, secret) {
return Err("Previous secret did not match new one");
}
// Prune HTLCs from the previous counterparty commitment tx so we don't generate failure/fulfill
// events for now-revoked/fulfilled HTLCs.
if let Some(txid) = self.prev_counterparty_commitment_txid.take() {
for &mut (_, ref mut source) in self.counterparty_claimable_outpoints.get_mut(&txid).unwrap() {
*source = None;
}
}
if !self.payment_preimages.is_empty() {
let cur_holder_signed_commitment_tx = &self.current_holder_commitment_tx;
let prev_holder_signed_commitment_tx = self.prev_holder_signed_commitment_tx.as_ref();
let min_idx = self.get_min_seen_secret();
let counterparty_hash_commitment_number = &mut self.counterparty_hash_commitment_number;
self.payment_preimages.retain(|&k, _| {
for &(ref htlc, _, _) in cur_holder_signed_commitment_tx.htlc_outputs.iter() {
if k == htlc.payment_hash {
return true
}
}
if let Some(prev_holder_commitment_tx) = prev_holder_signed_commitment_tx {
for &(ref htlc, _, _) in prev_holder_commitment_tx.htlc_outputs.iter() {
if k == htlc.payment_hash {
return true
}
}
}
let contains = if let Some(cn) = counterparty_hash_commitment_number.get(&k) {
if *cn < min_idx {
return true
}
true
} else { false };
if contains {
counterparty_hash_commitment_number.remove(&k);
}
false
});
}
Ok(())
}
pub(crate) fn provide_latest_counterparty_commitment_tx<L: Deref>(&mut self, txid: Txid, htlc_outputs: Vec<(HTLCOutputInCommitment, Option<Box<HTLCSource>>)>, commitment_number: u64, their_revocation_point: PublicKey, logger: &L) where L::Target: Logger {
// TODO: Encrypt the htlc_outputs data with the single-hash of the commitment transaction
// so that a remote monitor doesn't learn anything unless there is a malicious close.
// (only maybe, sadly we cant do the same for local info, as we need to be aware of
// timeouts)
for &(ref htlc, _) in &htlc_outputs {
self.counterparty_hash_commitment_number.insert(htlc.payment_hash, commitment_number);
}
log_trace!(logger, "Tracking new counterparty commitment transaction with txid {} at commitment number {} with {} HTLC outputs", txid, commitment_number, htlc_outputs.len());
self.prev_counterparty_commitment_txid = self.current_counterparty_commitment_txid.take();
self.current_counterparty_commitment_txid = Some(txid);
self.counterparty_claimable_outpoints.insert(txid, htlc_outputs.clone());
self.current_counterparty_commitment_number = commitment_number;
//TODO: Merge this into the other per-counterparty-transaction output storage stuff
match self.their_cur_revocation_points {
Some(old_points) => {
if old_points.0 == commitment_number + 1 {
self.their_cur_revocation_points = Some((old_points.0, old_points.1, Some(their_revocation_point)));
} else if old_points.0 == commitment_number + 2 {
if let Some(old_second_point) = old_points.2 {
self.their_cur_revocation_points = Some((old_points.0 - 1, old_second_point, Some(their_revocation_point)));
} else {
self.their_cur_revocation_points = Some((commitment_number, their_revocation_point, None));
}
} else {
self.their_cur_revocation_points = Some((commitment_number, their_revocation_point, None));
}
},
None => {
self.their_cur_revocation_points = Some((commitment_number, their_revocation_point, None));
}
}
let mut htlcs = Vec::with_capacity(htlc_outputs.len());
for htlc in htlc_outputs {
if htlc.0.transaction_output_index.is_some() {
htlcs.push(htlc.0);
}
}
}
/// Informs this monitor of the latest holder (ie broadcastable) commitment transaction. The
/// monitor watches for timeouts and may broadcast it if we approach such a timeout. Thus, it
/// is important that any clones of this channel monitor (including remote clones) by kept
/// up-to-date as our holder commitment transaction is updated.
/// Panics if set_on_holder_tx_csv has never been called.
fn provide_latest_holder_commitment_tx(&mut self, holder_commitment_tx: HolderCommitmentTransaction, htlc_outputs: Vec<(HTLCOutputInCommitment, Option<Signature>, Option<HTLCSource>)>) -> Result<(), &'static str> {
// block for Rust 1.34 compat
let mut new_holder_commitment_tx = {
let trusted_tx = holder_commitment_tx.trust();
let txid = trusted_tx.txid();
let tx_keys = trusted_tx.keys();
self.current_holder_commitment_number = trusted_tx.commitment_number();
HolderSignedTx {
txid,
revocation_key: tx_keys.revocation_key,
a_htlc_key: tx_keys.broadcaster_htlc_key,
b_htlc_key: tx_keys.countersignatory_htlc_key,
delayed_payment_key: tx_keys.broadcaster_delayed_payment_key,
per_commitment_point: tx_keys.per_commitment_point,
htlc_outputs,
to_self_value_sat: holder_commitment_tx.to_broadcaster_value_sat(),
feerate_per_kw: trusted_tx.feerate_per_kw(),
}
};
self.onchain_tx_handler.provide_latest_holder_tx(holder_commitment_tx);
mem::swap(&mut new_holder_commitment_tx, &mut self.current_holder_commitment_tx);
self.prev_holder_signed_commitment_tx = Some(new_holder_commitment_tx);
if self.holder_tx_signed {
return Err("Latest holder commitment signed has already been signed, update is rejected");
}
Ok(())
}
/// Provides a payment_hash->payment_preimage mapping. Will be automatically pruned when all
/// commitment_tx_infos which contain the payment hash have been revoked.
fn provide_payment_preimage<B: Deref, F: Deref, L: Deref>(&mut self, payment_hash: &PaymentHash, payment_preimage: &PaymentPreimage, broadcaster: &B, fee_estimator: &F, logger: &L)
where B::Target: BroadcasterInterface,
F::Target: FeeEstimator,
L::Target: Logger,
{
self.payment_preimages.insert(payment_hash.clone(), payment_preimage.clone());
// If the channel is force closed, try to claim the output from this preimage.
// First check if a counterparty commitment transaction has been broadcasted:
macro_rules! claim_htlcs {
($commitment_number: expr, $txid: expr) => {
let htlc_claim_reqs = self.get_counterparty_htlc_output_claim_reqs($commitment_number, $txid, None);
self.onchain_tx_handler.update_claims_view(&Vec::new(), htlc_claim_reqs, self.best_block.height(), self.best_block.height(), broadcaster, fee_estimator, logger);
}
}
if let Some(txid) = self.current_counterparty_commitment_txid {
if let Some(commitment_number) = self.counterparty_commitment_txn_on_chain.get(&txid) {
claim_htlcs!(*commitment_number, txid);
return;
}
}
if let Some(txid) = self.prev_counterparty_commitment_txid {
if let Some(commitment_number) = self.counterparty_commitment_txn_on_chain.get(&txid) {
claim_htlcs!(*commitment_number, txid);
return;
}
}
// Then if a holder commitment transaction has been seen on-chain, broadcast transactions
// claiming the HTLC output from each of the holder commitment transactions.
// Note that we can't just use `self.holder_tx_signed`, because that only covers the case where
// *we* sign a holder commitment transaction, not when e.g. a watchtower broadcasts one of our
// holder commitment transactions.
if self.broadcasted_holder_revokable_script.is_some() {
// Assume that the broadcasted commitment transaction confirmed in the current best
// block. Even if not, its a reasonable metric for the bump criteria on the HTLC
// transactions.
let (claim_reqs, _) = self.get_broadcasted_holder_claims(&self.current_holder_commitment_tx, self.best_block.height());
self.onchain_tx_handler.update_claims_view(&Vec::new(), claim_reqs, self.best_block.height(), self.best_block.height(), broadcaster, fee_estimator, logger);
if let Some(ref tx) = self.prev_holder_signed_commitment_tx {
let (claim_reqs, _) = self.get_broadcasted_holder_claims(&tx, self.best_block.height());
self.onchain_tx_handler.update_claims_view(&Vec::new(), claim_reqs, self.best_block.height(), self.best_block.height(), broadcaster, fee_estimator, logger);
}
}
}
pub(crate) fn broadcast_latest_holder_commitment_txn<B: Deref, L: Deref>(&mut self, broadcaster: &B, logger: &L)
where B::Target: BroadcasterInterface,
L::Target: Logger,
{
for tx in self.get_latest_holder_commitment_txn(logger).iter() {
log_info!(logger, "Broadcasting local {}", log_tx!(tx));
broadcaster.broadcast_transaction(tx);
}
self.pending_monitor_events.push(MonitorEvent::CommitmentTxConfirmed(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<(), ()>
where B::Target: BroadcasterInterface,
F::Target: FeeEstimator,
L::Target: Logger,
{
log_info!(logger, "Applying update to monitor {}, bringing update_id from {} to {} with {} changes.",
log_funding_info!(self), self.latest_update_id, updates.update_id, updates.updates.len());
// ChannelMonitor updates may be applied after force close if we receive a
// preimage for a broadcasted commitment transaction HTLC output that we'd
// like to claim on-chain. If this is the case, we no longer have guaranteed
// access to the monitor's update ID, so we use a sentinel value instead.
if updates.update_id == CLOSED_CHANNEL_UPDATE_ID {
assert_eq!(updates.updates.len(), 1);
match updates.updates[0] {
ChannelMonitorUpdateStep::PaymentPreimage { .. } => {},
_ => {
log_error!(logger, "Attempted to apply post-force-close ChannelMonitorUpdate of type {}", updates.updates[0].variant_name());
panic!("Attempted to apply post-force-close ChannelMonitorUpdate that wasn't providing a payment preimage");
},
}
} else if self.latest_update_id + 1 != updates.update_id {
panic!("Attempted to apply ChannelMonitorUpdates out of order, check the update_id before passing an update to update_monitor!");
}
let mut ret = Ok(());
for update in updates.updates.iter() {
match update {
ChannelMonitorUpdateStep::LatestHolderCommitmentTXInfo { commitment_tx, htlc_outputs } => {
log_trace!(logger, "Updating ChannelMonitor with latest holder commitment transaction info");
if self.lockdown_from_offchain { panic!(); }
if let Err(e) = self.provide_latest_holder_commitment_tx(commitment_tx.clone(), htlc_outputs.clone()) {
log_error!(logger, "Providing latest holder commitment transaction failed/was refused:");
log_error!(logger, " {}", e);
ret = Err(());
}
}
ChannelMonitorUpdateStep::LatestCounterpartyCommitmentTXInfo { commitment_txid, htlc_outputs, commitment_number, their_revocation_point } => {
log_trace!(logger, "Updating ChannelMonitor with latest counterparty commitment transaction info");
self.provide_latest_counterparty_commitment_tx(*commitment_txid, htlc_outputs.clone(), *commitment_number, *their_revocation_point, logger)
},
ChannelMonitorUpdateStep::PaymentPreimage { payment_preimage } => {
log_trace!(logger, "Updating ChannelMonitor with payment preimage");
self.provide_payment_preimage(&PaymentHash(Sha256::hash(&payment_preimage.0[..]).into_inner()), &payment_preimage, broadcaster, fee_estimator, logger)
},
ChannelMonitorUpdateStep::CommitmentSecret { idx, secret } => {
log_trace!(logger, "Updating ChannelMonitor with commitment secret");
if let Err(e) = self.provide_secret(*idx, *secret) {
log_error!(logger, "Providing latest counterparty commitment secret failed/was refused:");
log_error!(logger, " {}", e);
ret = Err(());
}
},
ChannelMonitorUpdateStep::ChannelForceClosed { should_broadcast } => {
log_trace!(logger, "Updating ChannelMonitor: channel force closed, should broadcast: {}", should_broadcast);
self.lockdown_from_offchain = true;
if *should_broadcast {
self.broadcast_latest_holder_commitment_txn(broadcaster, logger);
} else if !self.holder_tx_signed {
log_error!(logger, "You have a toxic holder commitment transaction avaible in channel monitor, read comment in ChannelMonitor::get_latest_holder_commitment_txn to be informed of manual action to take");
} else {
// If we generated a MonitorEvent::CommitmentTxConfirmed, 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.");
}
},
ChannelMonitorUpdateStep::ShutdownScript { scriptpubkey } => {
log_trace!(logger, "Updating ChannelMonitor with shutdown script");
if let Some(shutdown_script) = self.shutdown_script.replace(scriptpubkey.clone()) {
panic!("Attempted to replace shutdown script {} with {}", shutdown_script, scriptpubkey);
}
},
}
}
self.latest_update_id = updates.update_id;
if ret.is_ok() && self.funding_spend_seen {
log_error!(logger, "Refusing Channel Monitor Update as counterparty attempted to update commitment after funding was spent");
Err(())
} else { ret }
}
pub fn get_latest_update_id(&self) -> u64 {
self.latest_update_id
}
pub fn get_funding_txo(&self) -> &(OutPoint, Script) {
&self.funding_info
}
pub fn get_outputs_to_watch(&self) -> &HashMap<Txid, Vec<(u32, Script)>> {
// If we've detected a counterparty commitment tx on chain, we must include it in the set
// of outputs to watch for spends of, otherwise we're likely to lose user funds. Because
// its trivial to do, double-check that here.
for (txid, _) in self.counterparty_commitment_txn_on_chain.iter() {
self.outputs_to_watch.get(txid).expect("Counterparty commitment txn which have been broadcast should have outputs registered");
}
&self.outputs_to_watch
}
pub fn get_and_clear_pending_monitor_events(&mut self) -> Vec<MonitorEvent> {
let mut ret = Vec::new();
mem::swap(&mut ret, &mut self.pending_monitor_events);
ret
}
pub fn get_and_clear_pending_events(&mut self) -> Vec<Event> {
let mut ret = Vec::new();
mem::swap(&mut ret, &mut self.pending_events);
ret
}
/// Can only fail if idx is < get_min_seen_secret
fn get_secret(&self, idx: u64) -> Option<[u8; 32]> {
self.commitment_secrets.get_secret(idx)
}
pub(crate) fn get_min_seen_secret(&self) -> u64 {
self.commitment_secrets.get_min_seen_secret()
}
pub(crate) fn get_cur_counterparty_commitment_number(&self) -> u64 {
self.current_counterparty_commitment_number
}
pub(crate) fn get_cur_holder_commitment_number(&self) -> u64 {
self.current_holder_commitment_number
}
/// Attempts to claim a counterparty commitment transaction's outputs using the revocation key and
/// data in counterparty_claimable_outpoints. Will directly claim any HTLC outputs which expire at a
/// height > height + CLTV_SHARED_CLAIM_BUFFER. In any case, will install monitoring for
/// HTLC-Success/HTLC-Timeout transactions.
/// Return updates for HTLC pending in the channel and failed automatically by the broadcast of
/// revoked counterparty commitment tx
fn check_spend_counterparty_transaction<L: Deref>(&mut self, tx: &Transaction, height: u32, logger: &L) -> (Vec<PackageTemplate>, TransactionOutputs) where L::Target: Logger {
// Most secp and related errors trying to create keys means we have no hope of constructing
// a spend transaction...so we return no transactions to broadcast
let mut claimable_outpoints = Vec::new();
let mut watch_outputs = Vec::new();
let commitment_txid = tx.txid(); //TODO: This is gonna be a performance bottleneck for watchtowers!
let per_commitment_option = self.counterparty_claimable_outpoints.get(&commitment_txid);
macro_rules! ignore_error {
( $thing : expr ) => {
match $thing {
Ok(a) => a,
Err(_) => return (claimable_outpoints, (commitment_txid, watch_outputs))
}
};
}
let commitment_number = 0xffffffffffff - ((((tx.input[0].sequence as u64 & 0xffffff) << 3*8) | (tx.lock_time as u64 & 0xffffff)) ^ self.commitment_transaction_number_obscure_factor);
if commitment_number >= self.get_min_seen_secret() {
let secret = self.get_secret(commitment_number).unwrap();
let per_commitment_key = ignore_error!(SecretKey::from_slice(&secret));
let per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_key);
let revocation_pubkey = ignore_error!(chan_utils::derive_public_revocation_key(&self.secp_ctx, &per_commitment_point, &self.holder_revocation_basepoint));
let delayed_key = ignore_error!(chan_utils::derive_public_key(&self.secp_ctx, &PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_key), &self.counterparty_commitment_params.counterparty_delayed_payment_base_key));
let revokeable_redeemscript = chan_utils::get_revokeable_redeemscript(&revocation_pubkey, self.counterparty_commitment_params.on_counterparty_tx_csv, &delayed_key);
let revokeable_p2wsh = revokeable_redeemscript.to_v0_p2wsh();
// First, process non-htlc outputs (to_holder & to_counterparty)
for (idx, outp) in tx.output.iter().enumerate() {
if outp.script_pubkey == revokeable_p2wsh {
let revk_outp = RevokedOutput::build(per_commitment_point, self.counterparty_commitment_params.counterparty_delayed_payment_base_key, self.counterparty_commitment_params.counterparty_htlc_base_key, per_commitment_key, outp.value, self.counterparty_commitment_params.on_counterparty_tx_csv);
let justice_package = PackageTemplate::build_package(commitment_txid, idx as u32, PackageSolvingData::RevokedOutput(revk_outp), height + self.counterparty_commitment_params.on_counterparty_tx_csv as u32, true, height);
claimable_outpoints.push(justice_package);
}
}
// Then, try to find revoked htlc outputs
if let Some(ref per_commitment_data) = per_commitment_option {
for (_, &(ref htlc, _)) in per_commitment_data.iter().enumerate() {
if let Some(transaction_output_index) = htlc.transaction_output_index {
if transaction_output_index as usize >= tx.output.len() ||
tx.output[transaction_output_index as usize].value != htlc.amount_msat / 1000 {
return (claimable_outpoints, (commitment_txid, watch_outputs)); // Corrupted per_commitment_data, fuck this user
}
let revk_htlc_outp = RevokedHTLCOutput::build(per_commitment_point, self.counterparty_commitment_params.counterparty_delayed_payment_base_key, self.counterparty_commitment_params.counterparty_htlc_base_key, per_commitment_key, htlc.amount_msat / 1000, htlc.clone(), self.onchain_tx_handler.channel_transaction_parameters.opt_anchors.is_some());
let justice_package = PackageTemplate::build_package(commitment_txid, transaction_output_index, PackageSolvingData::RevokedHTLCOutput(revk_htlc_outp), htlc.cltv_expiry, true, height);
claimable_outpoints.push(justice_package);
}
}
}
// Last, track onchain revoked commitment transaction and fail backward outgoing HTLCs as payment path is broken
if !claimable_outpoints.is_empty() || per_commitment_option.is_some() { // ie we're confident this is actually ours
// We're definitely a counterparty commitment transaction!
log_error!(logger, "Got broadcast of revoked counterparty commitment transaction, going to generate general spend tx with {} inputs", claimable_outpoints.len());
for (idx, outp) in tx.output.iter().enumerate() {
watch_outputs.push((idx as u32, outp.clone()));
}
self.counterparty_commitment_txn_on_chain.insert(commitment_txid, commitment_number);
fail_unbroadcast_htlcs!(self, "revoked counterparty", height, [].iter().map(|a| *a), logger);
}
} else if let Some(per_commitment_data) = per_commitment_option {
// While this isn't useful yet, there is a potential race where if a counterparty
// revokes a state at the same time as the commitment transaction for that state is
// confirmed, and the watchtower receives the block before the user, the user could
// upload a new ChannelMonitor with the revocation secret but the watchtower has
// already processed the block, resulting in the counterparty_commitment_txn_on_chain entry
// not being generated by the above conditional. Thus, to be safe, we go ahead and
// insert it here.
for (idx, outp) in tx.output.iter().enumerate() {
watch_outputs.push((idx as u32, outp.clone()));
}
self.counterparty_commitment_txn_on_chain.insert(commitment_txid, commitment_number);
log_info!(logger, "Got broadcast of non-revoked counterparty commitment transaction {}", commitment_txid);
fail_unbroadcast_htlcs!(self, "counterparty", height, per_commitment_data.iter().map(|(a, b)| (a, b.as_ref().map(|b| b.as_ref()))), logger);
let htlc_claim_reqs = self.get_counterparty_htlc_output_claim_reqs(commitment_number, commitment_txid, Some(tx));
for req in htlc_claim_reqs {
claimable_outpoints.push(req);
}
}
(claimable_outpoints, (commitment_txid, watch_outputs))
}
fn get_counterparty_htlc_output_claim_reqs(&self, commitment_number: u64, commitment_txid: Txid, tx: Option<&Transaction>) -> Vec<PackageTemplate> {
let mut claimable_outpoints = Vec::new();
if let Some(htlc_outputs) = self.counterparty_claimable_outpoints.get(&commitment_txid) {
if let Some(revocation_points) = self.their_cur_revocation_points {
let revocation_point_option =
// If the counterparty commitment tx is the latest valid state, use their latest
// per-commitment point
if revocation_points.0 == commitment_number { Some(&revocation_points.1) }
else if let Some(point) = revocation_points.2.as_ref() {
// If counterparty commitment tx is the state previous to the latest valid state, use
// their previous per-commitment point (non-atomicity of revocation means it's valid for
// them to temporarily have two valid commitment txns from our viewpoint)
if revocation_points.0 == commitment_number + 1 { Some(point) } else { None }
} else { None };
if let Some(revocation_point) = revocation_point_option {
for (_, &(ref htlc, _)) in htlc_outputs.iter().enumerate() {
if let Some(transaction_output_index) = htlc.transaction_output_index {
if let Some(transaction) = tx {
if transaction_output_index as usize >= transaction.output.len() ||
transaction.output[transaction_output_index as usize].value != htlc.amount_msat / 1000 {
return claimable_outpoints; // Corrupted per_commitment_data, fuck this user
}
}
let preimage = if htlc.offered { if let Some(p) = self.payment_preimages.get(&htlc.payment_hash) { Some(*p) } else { None } } else { None };
if preimage.is_some() || !htlc.offered {
let counterparty_htlc_outp = if htlc.offered { PackageSolvingData::CounterpartyOfferedHTLCOutput(CounterpartyOfferedHTLCOutput::build(*revocation_point, self.counterparty_commitment_params.counterparty_delayed_payment_base_key, self.counterparty_commitment_params.counterparty_htlc_base_key, preimage.unwrap(), htlc.clone())) } else { PackageSolvingData::CounterpartyReceivedHTLCOutput(CounterpartyReceivedHTLCOutput::build(*revocation_point, self.counterparty_commitment_params.counterparty_delayed_payment_base_key, self.counterparty_commitment_params.counterparty_htlc_base_key, htlc.clone())) };
let aggregation = if !htlc.offered { false } else { true };
let counterparty_package = PackageTemplate::build_package(commitment_txid, transaction_output_index, counterparty_htlc_outp, htlc.cltv_expiry,aggregation, 0);
claimable_outpoints.push(counterparty_package);
}
}
}
}
}
}
claimable_outpoints
}
/// Attempts to claim a counterparty HTLC-Success/HTLC-Timeout's outputs using the revocation key
fn check_spend_counterparty_htlc<L: Deref>(&mut self, tx: &Transaction, commitment_number: u64, height: u32, logger: &L) -> (Vec<PackageTemplate>, Option<TransactionOutputs>) where L::Target: Logger {
let htlc_txid = tx.txid();
if tx.input.len() != 1 || tx.output.len() != 1 || tx.input[0].witness.len() != 5 {
return (Vec::new(), None)
}
macro_rules! ignore_error {
( $thing : expr ) => {
match $thing {
Ok(a) => a,
Err(_) => return (Vec::new(), None)
}
};
}
let secret = if let Some(secret) = self.get_secret(commitment_number) { secret } else { return (Vec::new(), None); };
let per_commitment_key = ignore_error!(SecretKey::from_slice(&secret));
let per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_key);
log_error!(logger, "Got broadcast of revoked counterparty HTLC transaction, spending {}:{}", htlc_txid, 0);
let revk_outp = RevokedOutput::build(per_commitment_point, self.counterparty_commitment_params.counterparty_delayed_payment_base_key, self.counterparty_commitment_params.counterparty_htlc_base_key, per_commitment_key, tx.output[0].value, self.counterparty_commitment_params.on_counterparty_tx_csv);
let justice_package = PackageTemplate::build_package(htlc_txid, 0, PackageSolvingData::RevokedOutput(revk_outp), height + self.counterparty_commitment_params.on_counterparty_tx_csv as u32, true, height);
let claimable_outpoints = vec!(justice_package);
let outputs = vec![(0, tx.output[0].clone())];
(claimable_outpoints, Some((htlc_txid, outputs)))
}
// Returns (1) `PackageTemplate`s that can be given to the OnChainTxHandler, so that the handler can
// broadcast transactions claiming holder HTLC commitment outputs and (2) a holder revokable
// script so we can detect whether a holder transaction has been seen on-chain.
fn get_broadcasted_holder_claims(&self, holder_tx: &HolderSignedTx, conf_height: u32) -> (Vec<PackageTemplate>, Option<(Script, PublicKey, PublicKey)>) {
let mut claim_requests = Vec::with_capacity(holder_tx.htlc_outputs.len());
let redeemscript = chan_utils::get_revokeable_redeemscript(&holder_tx.revocation_key, self.on_holder_tx_csv, &holder_tx.delayed_payment_key);
let broadcasted_holder_revokable_script = Some((redeemscript.to_v0_p2wsh(), holder_tx.per_commitment_point.clone(), holder_tx.revocation_key.clone()));
for &(ref htlc, _, _) in holder_tx.htlc_outputs.iter() {
if let Some(transaction_output_index) = htlc.transaction_output_index {
let htlc_output = if htlc.offered {
HolderHTLCOutput::build_offered(htlc.amount_msat, htlc.cltv_expiry)
} else {
let payment_preimage = if let Some(preimage) = self.payment_preimages.get(&htlc.payment_hash) {
preimage.clone()
} else {
// We can't build an HTLC-Success transaction without the preimage
continue;
};
HolderHTLCOutput::build_accepted(payment_preimage, htlc.amount_msat)
};
let htlc_package = PackageTemplate::build_package(holder_tx.txid, transaction_output_index, PackageSolvingData::HolderHTLCOutput(htlc_output), htlc.cltv_expiry, false, conf_height);
claim_requests.push(htlc_package);
}
}
(claim_requests, broadcasted_holder_revokable_script)
}
// Returns holder HTLC outputs to watch and react to in case of spending.
fn get_broadcasted_holder_watch_outputs(&self, holder_tx: &HolderSignedTx, commitment_tx: &Transaction) -> Vec<(u32, TxOut)> {
let mut watch_outputs = Vec::with_capacity(holder_tx.htlc_outputs.len());
for &(ref htlc, _, _) in holder_tx.htlc_outputs.iter() {
if let Some(transaction_output_index) = htlc.transaction_output_index {
watch_outputs.push((transaction_output_index, commitment_tx.output[transaction_output_index as usize].clone()));
}
}
watch_outputs
}
/// Attempts to claim any claimable HTLCs in a commitment transaction which was not (yet)
/// revoked using data in holder_claimable_outpoints.
/// Should not be used if check_spend_revoked_transaction succeeds.
/// Returns None unless the transaction is definitely one of our commitment transactions.
fn check_spend_holder_transaction<L: Deref>(&mut self, tx: &Transaction, height: u32, logger: &L) -> Option<(Vec<PackageTemplate>, TransactionOutputs)> where L::Target: Logger {
let commitment_txid = tx.txid();
let mut claim_requests = Vec::new();
let mut watch_outputs = Vec::new();
macro_rules! append_onchain_update {
($updates: expr, $to_watch: expr) => {
claim_requests = $updates.0;
self.broadcasted_holder_revokable_script = $updates.1;
watch_outputs.append(&mut $to_watch);
}
}
// HTLCs set may differ between last and previous holder commitment txn, in case of one them hitting chain, ensure we cancel all HTLCs backward
let mut is_holder_tx = false;
if self.current_holder_commitment_tx.txid == commitment_txid {
is_holder_tx = true;
log_info!(logger, "Got broadcast of latest holder commitment tx {}, searching for available HTLCs to claim", commitment_txid);
let res = self.get_broadcasted_holder_claims(&self.current_holder_commitment_tx, height);
let mut to_watch = self.get_broadcasted_holder_watch_outputs(&self.current_holder_commitment_tx, tx);
append_onchain_update!(res, to_watch);
fail_unbroadcast_htlcs!(self, "latest holder", height, self.current_holder_commitment_tx.htlc_outputs.iter().map(|(a, _, c)| (a, c.as_ref())), logger);
} else if let &Some(ref holder_tx) = &self.prev_holder_signed_commitment_tx {
if holder_tx.txid == commitment_txid {
is_holder_tx = true;
log_info!(logger, "Got broadcast of previous holder commitment tx {}, searching for available HTLCs to claim", commitment_txid);
let res = self.get_broadcasted_holder_claims(holder_tx, height);
let mut to_watch = self.get_broadcasted_holder_watch_outputs(holder_tx, tx);
append_onchain_update!(res, to_watch);
fail_unbroadcast_htlcs!(self, "previous holder", height, holder_tx.htlc_outputs.iter().map(|(a, _, c)| (a, c.as_ref())), logger);
}
}
if is_holder_tx {
Some((claim_requests, (commitment_txid, watch_outputs)))
} else {
None
}
}
pub fn get_latest_holder_commitment_txn<L: Deref>(&mut self, logger: &L) -> Vec<Transaction> where L::Target: Logger {
log_debug!(logger, "Getting signed latest holder commitment transaction!");
self.holder_tx_signed = true;
let commitment_tx = self.onchain_tx_handler.get_fully_signed_holder_tx(&self.funding_redeemscript);
let txid = commitment_tx.txid();
let mut holder_transactions = vec![commitment_tx];
for htlc in self.current_holder_commitment_tx.htlc_outputs.iter() {
if let Some(vout) = htlc.0.transaction_output_index {
let preimage = if !htlc.0.offered {
if let Some(preimage) = self.payment_preimages.get(&htlc.0.payment_hash) { Some(preimage.clone()) } else {
// We can't build an HTLC-Success transaction without the preimage
continue;
}
} else if htlc.0.cltv_expiry > self.best_block.height() + 1 {
// Don't broadcast HTLC-Timeout transactions immediately as they don't meet the
// current locktime requirements on-chain. We will broadcast them in
// `block_confirmed` when `should_broadcast_holder_commitment_txn` returns true.
// Note that we add + 1 as transactions are broadcastable when they can be
// confirmed in the next block.
continue;
} else { None };
if let Some(htlc_tx) = self.onchain_tx_handler.get_fully_signed_htlc_tx(
&::bitcoin::OutPoint { txid, vout }, &preimage) {
holder_transactions.push(htlc_tx);
}
}
}
// We throw away the generated waiting_first_conf data as we aren't (yet) confirmed and we don't actually know what the caller wants to do.
// The data will be re-generated and tracked in check_spend_holder_transaction if we get a confirmation.
holder_transactions
}
#[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
/// Note that this includes possibly-locktimed-in-the-future transactions!
fn unsafe_get_latest_holder_commitment_txn<L: Deref>(&mut self, logger: &L) -> Vec<Transaction> where L::Target: Logger {
log_debug!(logger, "Getting signed copy of latest holder commitment transaction!");
let commitment_tx = self.onchain_tx_handler.get_fully_signed_copy_holder_tx(&self.funding_redeemscript);
let txid = commitment_tx.txid();
let mut holder_transactions = vec![commitment_tx];
for htlc in self.current_holder_commitment_tx.htlc_outputs.iter() {
if let Some(vout) = htlc.0.transaction_output_index {
let preimage = if !htlc.0.offered {
if let Some(preimage) = self.payment_preimages.get(&htlc.0.payment_hash) { Some(preimage.clone()) } else {
// We can't build an HTLC-Success transaction without the preimage
continue;
}
} else { None };
if let Some(htlc_tx) = self.onchain_tx_handler.unsafe_get_fully_signed_htlc_tx(
&::bitcoin::OutPoint { txid, vout }, &preimage) {
holder_transactions.push(htlc_tx);
}
}
}
holder_transactions
}
pub fn block_connected<B: Deref, F: Deref, L: Deref>(&mut self, header: &BlockHeader, txdata: &TransactionData, height: u32, broadcaster: B, fee_estimator: F, logger: L) -> Vec<TransactionOutputs>
where B::Target: BroadcasterInterface,
F::Target: FeeEstimator,
L::Target: Logger,
{
let block_hash = header.block_hash();
self.best_block = BestBlock::new(block_hash, height);
self.transactions_confirmed(header, txdata, height, broadcaster, fee_estimator, logger)
}
fn best_block_updated<B: Deref, F: Deref, L: Deref>(
&mut self,
header: &BlockHeader,
height: u32,
broadcaster: B,
fee_estimator: F,
logger: L,
) -> Vec<TransactionOutputs>
where
B::Target: BroadcasterInterface,
F::Target: FeeEstimator,
L::Target: Logger,
{
let block_hash = header.block_hash();
if height > self.best_block.height() {
self.best_block = BestBlock::new(block_hash, height);
self.block_confirmed(height, vec![], vec![], vec![], &broadcaster, &fee_estimator, &logger)
} else if block_hash != self.best_block.block_hash() {
self.best_block = BestBlock::new(block_hash, height);
self.onchain_events_awaiting_threshold_conf.retain(|ref entry| entry.height <= height);
self.onchain_tx_handler.block_disconnected(height + 1, broadcaster, fee_estimator, logger);
Vec::new()
} else { Vec::new() }
}
fn transactions_confirmed<B: Deref, F: Deref, L: Deref>(
&mut self,
header: &BlockHeader,
txdata: &TransactionData,
height: u32,
broadcaster: B,
fee_estimator: F,
logger: L,
) -> Vec<TransactionOutputs>
where
B::Target: BroadcasterInterface,
F::Target: FeeEstimator,
L::Target: Logger,
{
let txn_matched = self.filter_block(txdata);
for tx in &txn_matched {
let mut output_val = 0;
for out in tx.output.iter() {
if out.value > 21_000_000_0000_0000 { panic!("Value-overflowing transaction provided to block connected"); }
output_val += out.value;
if output_val > 21_000_000_0000_0000 { panic!("Value-overflowing transaction provided to block connected"); }
}
}
let block_hash = header.block_hash();
let mut watch_outputs = Vec::new();
let mut claimable_outpoints = Vec::new();
for tx in &txn_matched {
if tx.input.len() == 1 {
// Assuming our keys were not leaked (in which case we're screwed no matter what),
// commitment transactions and HTLC transactions will all only ever have one input,
// which is an easy way to filter out any potential non-matching txn for lazy
// filters.
let prevout = &tx.input[0].previous_output;
if prevout.txid == self.funding_info.0.txid && prevout.vout == self.funding_info.0.index as u32 {
let mut balance_spendable_csv = None;
log_info!(logger, "Channel {} closed by funding output spend in txid {}.",
log_bytes!(self.funding_info.0.to_channel_id()), tx.txid());
self.funding_spend_seen = true;
if (tx.input[0].sequence >> 8*3) as u8 == 0x80 && (tx.lock_time >> 8*3) as u8 == 0x20 {
let (mut new_outpoints, new_outputs) = self.check_spend_counterparty_transaction(&tx, height, &logger);
if !new_outputs.1.is_empty() {
watch_outputs.push(new_outputs);
}
claimable_outpoints.append(&mut new_outpoints);
if new_outpoints.is_empty() {
if let Some((mut new_outpoints, new_outputs)) = self.check_spend_holder_transaction(&tx, height, &logger) {
if !new_outputs.1.is_empty() {
watch_outputs.push(new_outputs);
}
claimable_outpoints.append(&mut new_outpoints);
balance_spendable_csv = Some(self.on_holder_tx_csv);
}
}
}
let txid = tx.txid();
self.onchain_events_awaiting_threshold_conf.push(OnchainEventEntry {
txid,
height: height,
event: OnchainEvent::FundingSpendConfirmation {
on_local_output_csv: balance_spendable_csv,
},
});
} else {
if let Some(&commitment_number) = self.counterparty_commitment_txn_on_chain.get(&prevout.txid) {
let (mut new_outpoints, new_outputs_option) = self.check_spend_counterparty_htlc(&tx, commitment_number, height, &logger);
claimable_outpoints.append(&mut new_outpoints);
if let Some(new_outputs) = new_outputs_option {
watch_outputs.push(new_outputs);
}
}
}
}
// While all commitment/HTLC-Success/HTLC-Timeout transactions have one input, HTLCs
// can also be resolved in a few other ways which can have more than one output. Thus,
// we call is_resolving_htlc_output here outside of the tx.input.len() == 1 check.
self.is_resolving_htlc_output(&tx, height, &logger);
self.is_paying_spendable_output(&tx, height, &logger);
}
if height > self.best_block.height() {
self.best_block = BestBlock::new(block_hash, height);
}
self.block_confirmed(height, txn_matched, watch_outputs, claimable_outpoints, &broadcaster, &fee_estimator, &logger)
}
/// Update state for new block(s)/transaction(s) confirmed. Note that the caller must update
/// `self.best_block` before calling if a new best blockchain tip is available. More
/// concretely, `self.best_block` must never be at a lower height than `conf_height`, avoiding
/// complexity especially in `OnchainTx::update_claims_view`.
///
/// `conf_height` should be set to the height at which any new transaction(s)/block(s) were
/// confirmed at, even if it is not the current best height.
fn block_confirmed<B: Deref, F: Deref, L: Deref>(
&mut self,
conf_height: u32,
txn_matched: Vec<&Transaction>,
mut watch_outputs: Vec<TransactionOutputs>,
mut claimable_outpoints: Vec<PackageTemplate>,
broadcaster: &B,
fee_estimator: &F,
logger: &L,
) -> Vec<TransactionOutputs>
where
B::Target: BroadcasterInterface,
F::Target: FeeEstimator,
L::Target: Logger,
{
log_trace!(logger, "Processing {} matched transactions for block at height {}.", txn_matched.len(), conf_height);
debug_assert!(self.best_block.height() >= conf_height);
let should_broadcast = self.should_broadcast_holder_commitment_txn(logger);
if should_broadcast {
let funding_outp = HolderFundingOutput::build(self.funding_redeemscript.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(), false, 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.holder_tx_signed = true;
// Because we're broadcasting a commitment transaction, we should construct the package
// 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);
if !new_outputs.is_empty() {
watch_outputs.push((self.current_holder_commitment_tx.txid.clone(), new_outputs));
}
claimable_outpoints.append(&mut new_outpoints);
}
// Find which on-chain events have reached their confirmation threshold.
let onchain_events_awaiting_threshold_conf =
self.onchain_events_awaiting_threshold_conf.drain(..).collect::<Vec<_>>();
let mut onchain_events_reaching_threshold_conf = Vec::new();
for entry in onchain_events_awaiting_threshold_conf {
if entry.has_reached_confirmation_threshold(&self.best_block) {
onchain_events_reaching_threshold_conf.push(entry);
} else {
self.onchain_events_awaiting_threshold_conf.push(entry);
}
}
// Used to check for duplicate HTLC resolutions.
#[cfg(debug_assertions)]
let unmatured_htlcs: Vec<_> = self.onchain_events_awaiting_threshold_conf
.iter()
.filter_map(|entry| match &entry.event {
OnchainEvent::HTLCUpdate { source, .. } => Some(source),
_ => None,
})
.collect();
#[cfg(debug_assertions)]
let mut matured_htlcs = Vec::new();
// Produce actionable events from on-chain events having reached their threshold.
for entry in onchain_events_reaching_threshold_conf.drain(..) {
match entry.event {
OnchainEvent::HTLCUpdate { ref source, payment_hash, onchain_value_satoshis, input_idx } => {
// Check for duplicate HTLC resolutions.
#[cfg(debug_assertions)]
{
debug_assert!(
unmatured_htlcs.iter().find(|&htlc| htlc == &source).is_none(),
"An unmature HTLC transaction conflicts with a maturing one; failed to \
call either transaction_unconfirmed for the conflicting transaction \
or block_disconnected for a block containing it.");
debug_assert!(
matured_htlcs.iter().find(|&htlc| htlc == source).is_none(),
"A matured HTLC transaction conflicts with a maturing one; failed to \
call either transaction_unconfirmed for the conflicting transaction \
or block_disconnected for a block containing it.");
matured_htlcs.push(source.clone());
}
log_debug!(logger, "HTLC {} failure update has got enough confirmations to be passed upstream", log_bytes!(payment_hash.0));
self.pending_monitor_events.push(MonitorEvent::HTLCEvent(HTLCUpdate {
payment_hash,
payment_preimage: None,
source: source.clone(),
onchain_value_satoshis,
}));
if let Some(idx) = input_idx {
self.htlcs_resolved_on_chain.push(IrrevocablyResolvedHTLC { input_idx: idx, payment_preimage: None });
}
},
OnchainEvent::MaturingOutput { descriptor } => {
log_debug!(logger, "Descriptor {} has got enough confirmations to be passed upstream", log_spendable!(descriptor));
self.pending_events.push(Event::SpendableOutputs {
outputs: vec![descriptor]
});
},
OnchainEvent::HTLCSpendConfirmation { input_idx, preimage, .. } => {
self.htlcs_resolved_on_chain.push(IrrevocablyResolvedHTLC { input_idx, payment_preimage: preimage });
},
OnchainEvent::FundingSpendConfirmation { .. } => {
self.funding_spend_confirmed = Some(entry.txid);
},
}
}
self.onchain_tx_handler.update_claims_view(&txn_matched, claimable_outpoints, conf_height, self.best_block.height(), broadcaster, fee_estimator, logger);
// Determine new outputs to watch by comparing against previously known outputs to watch,
// updating the latter in the process.
watch_outputs.retain(|&(ref txid, ref txouts)| {
let idx_and_scripts = txouts.iter().map(|o| (o.0, o.1.script_pubkey.clone())).collect();
self.outputs_to_watch.insert(txid.clone(), idx_and_scripts).is_none()
});
#[cfg(test)]
{
// If we see a transaction for which we registered outputs previously,
// make sure the registered scriptpubkey at the expected index match
// the actual transaction output one. We failed this case before #653.
for tx in &txn_matched {
if let Some(outputs) = self.get_outputs_to_watch().get(&tx.txid()) {
for idx_and_script in outputs.iter() {
assert!((idx_and_script.0 as usize) < tx.output.len());
assert_eq!(tx.output[idx_and_script.0 as usize].script_pubkey, idx_and_script.1);
}
}
}
}
watch_outputs
}
pub fn block_disconnected<B: Deref, F: Deref, L: Deref>(&mut self, header: &BlockHeader, height: u32, broadcaster: B, fee_estimator: F, logger: L)
where B::Target: BroadcasterInterface,
F::Target: FeeEstimator,
L::Target: Logger,
{
log_trace!(logger, "Block {} at height {} disconnected", header.block_hash(), height);
//We may discard:
//- htlc update there as failure-trigger tx (revoked commitment tx, non-revoked commitment tx, HTLC-timeout tx) has been disconnected
//- maturing spendable output has transaction paying us has been disconnected
self.onchain_events_awaiting_threshold_conf.retain(|ref entry| entry.height < height);
self.onchain_tx_handler.block_disconnected(height, broadcaster, fee_estimator, logger);
self.best_block = BestBlock::new(header.prev_blockhash, height - 1);
}
fn transaction_unconfirmed<B: Deref, F: Deref, L: Deref>(
&mut self,
txid: &Txid,
broadcaster: B,
fee_estimator: F,
logger: L,
) where
B::Target: BroadcasterInterface,
F::Target: FeeEstimator,
L::Target: Logger,
{
self.onchain_events_awaiting_threshold_conf.retain(|ref entry| entry.txid != *txid);
self.onchain_tx_handler.transaction_unconfirmed(txid, broadcaster, fee_estimator, logger);
}
/// Filters a block's `txdata` for transactions spending watched outputs or for any child
/// transactions thereof.
fn filter_block<'a>(&self, txdata: &TransactionData<'a>) -> Vec<&'a Transaction> {
let mut matched_txn = HashSet::new();
txdata.iter().filter(|&&(_, tx)| {
let mut matches = self.spends_watched_output(tx);
for input in tx.input.iter() {
if matches { break; }
if matched_txn.contains(&input.previous_output.txid) {
matches = true;
}
}
if matches {
matched_txn.insert(tx.txid());
}
matches
}).map(|(_, tx)| *tx).collect()
}
/// Checks if a given transaction spends any watched outputs.
fn spends_watched_output(&self, tx: &Transaction) -> bool {
for input in tx.input.iter() {
if let Some(outputs) = self.get_outputs_to_watch().get(&input.previous_output.txid) {
for (idx, _script_pubkey) in outputs.iter() {
if *idx == input.previous_output.vout {
#[cfg(test)]
{
// If the expected script is a known type, check that the witness
// appears to be spending the correct type (ie that the match would
// actually succeed in BIP 158/159-style filters).
if _script_pubkey.is_v0_p2wsh() {
assert_eq!(&bitcoin::Address::p2wsh(&Script::from(input.witness.last().unwrap().clone()), bitcoin::Network::Bitcoin).script_pubkey(), _script_pubkey);
} else if _script_pubkey.is_v0_p2wpkh() {
assert_eq!(&bitcoin::Address::p2wpkh(&bitcoin::PublicKey::from_slice(&input.witness.last().unwrap()).unwrap(), bitcoin::Network::Bitcoin).unwrap().script_pubkey(), _script_pubkey);
} else { panic!(); }
}
return true;
}
}
}
}
false
}
fn should_broadcast_holder_commitment_txn<L: Deref>(&self, logger: &L) -> bool where L::Target: Logger {
// We need to consider all HTLCs which are:
// * in any unrevoked counterparty commitment transaction, as they could broadcast said
// transactions and we'd end up in a race, or
// * are in our latest holder commitment transaction, as this is the thing we will
// broadcast if we go on-chain.
// Note that we consider HTLCs which were below dust threshold here - while they don't
// strictly imply that we need to fail the channel, we need to go ahead and fail them back
// to the source, and if we don't fail the channel we will have to ensure that the next
// updates that peer sends us are update_fails, failing the channel if not. It's probably
// easier to just fail the channel as this case should be rare enough anyway.
let height = self.best_block.height();
macro_rules! scan_commitment {
($htlcs: expr, $holder_tx: expr) => {
for ref htlc in $htlcs {
// For inbound HTLCs which we know the preimage for, we have to ensure we hit the
// chain with enough room to claim the HTLC without our counterparty being able to
// time out the HTLC first.
// For outbound HTLCs which our counterparty hasn't failed/claimed, our primary
// concern is being able to claim the corresponding inbound HTLC (on another
// channel) before it expires. In fact, we don't even really care if our
// counterparty here claims such an outbound HTLC after it expired as long as we
// can still claim the corresponding HTLC. Thus, to avoid needlessly hitting the
// chain when our counterparty is waiting for expiration to off-chain fail an HTLC
// we give ourselves a few blocks of headroom after expiration before going
// on-chain for an expired HTLC.
// Note that, to avoid a potential attack whereby a node delays claiming an HTLC
// from us until we've reached the point where we go on-chain with the
// corresponding inbound HTLC, we must ensure that outbound HTLCs go on chain at
// least CLTV_CLAIM_BUFFER blocks prior to the inbound HTLC.
// aka outbound_cltv + LATENCY_GRACE_PERIOD_BLOCKS == height - CLTV_CLAIM_BUFFER
// inbound_cltv == height + CLTV_CLAIM_BUFFER
// outbound_cltv + LATENCY_GRACE_PERIOD_BLOCKS + CLTV_CLAIM_BUFFER <= inbound_cltv - CLTV_CLAIM_BUFFER
// LATENCY_GRACE_PERIOD_BLOCKS + 2*CLTV_CLAIM_BUFFER <= inbound_cltv - outbound_cltv
// CLTV_EXPIRY_DELTA <= inbound_cltv - outbound_cltv (by check in ChannelManager::decode_update_add_htlc_onion)
// LATENCY_GRACE_PERIOD_BLOCKS + 2*CLTV_CLAIM_BUFFER <= CLTV_EXPIRY_DELTA
// The final, above, condition is checked for statically in channelmanager
// with CHECK_CLTV_EXPIRY_SANITY_2.
let htlc_outbound = $holder_tx == htlc.offered;
if ( htlc_outbound && htlc.cltv_expiry + LATENCY_GRACE_PERIOD_BLOCKS <= height) ||
(!htlc_outbound && htlc.cltv_expiry <= height + CLTV_CLAIM_BUFFER && self.payment_preimages.contains_key(&htlc.payment_hash)) {
log_info!(logger, "Force-closing channel due to {} HTLC timeout, HTLC expiry is {}", if htlc_outbound { "outbound" } else { "inbound "}, htlc.cltv_expiry);
return true;
}
}
}
}
scan_commitment!(self.current_holder_commitment_tx.htlc_outputs.iter().map(|&(ref a, _, _)| a), true);
if let Some(ref txid) = self.current_counterparty_commitment_txid {
if let Some(ref htlc_outputs) = self.counterparty_claimable_outpoints.get(txid) {
scan_commitment!(htlc_outputs.iter().map(|&(ref a, _)| a), false);
}
}
if let Some(ref txid) = self.prev_counterparty_commitment_txid {
if let Some(ref htlc_outputs) = self.counterparty_claimable_outpoints.get(txid) {
scan_commitment!(htlc_outputs.iter().map(|&(ref a, _)| a), false);
}
}
false
}
/// Check if any transaction broadcasted is resolving HTLC output by a success or timeout on a holder
/// or counterparty commitment tx, if so send back the source, preimage if found and payment_hash of resolved HTLC
fn is_resolving_htlc_output<L: Deref>(&mut self, tx: &Transaction, height: u32, logger: &L) where L::Target: Logger {
'outer_loop: for input in &tx.input {
let mut payment_data = None;
let revocation_sig_claim = (input.witness.len() == 3 && HTLCType::scriptlen_to_htlctype(input.witness[2].len()) == Some(HTLCType::OfferedHTLC) && input.witness[1].len() == 33)
|| (input.witness.len() == 3 && HTLCType::scriptlen_to_htlctype(input.witness[2].len()) == Some(HTLCType::AcceptedHTLC) && input.witness[1].len() == 33);
let accepted_preimage_claim = input.witness.len() == 5 && HTLCType::scriptlen_to_htlctype(input.witness[4].len()) == Some(HTLCType::AcceptedHTLC);
#[cfg(not(fuzzing))]
let accepted_timeout_claim = input.witness.len() == 3 && HTLCType::scriptlen_to_htlctype(input.witness[2].len()) == Some(HTLCType::AcceptedHTLC) && !revocation_sig_claim;
let offered_preimage_claim = input.witness.len() == 3 && HTLCType::scriptlen_to_htlctype(input.witness[2].len()) == Some(HTLCType::OfferedHTLC) && !revocation_sig_claim;
#[cfg(not(fuzzing))]
let offered_timeout_claim = input.witness.len() == 5 && HTLCType::scriptlen_to_htlctype(input.witness[4].len()) == Some(HTLCType::OfferedHTLC);
let mut payment_preimage = PaymentPreimage([0; 32]);
if accepted_preimage_claim {
payment_preimage.0.copy_from_slice(&input.witness[3]);
} else if offered_preimage_claim {
payment_preimage.0.copy_from_slice(&input.witness[1]);
}
macro_rules! log_claim {
($tx_info: expr, $holder_tx: expr, $htlc: expr, $source_avail: expr) => {
let outbound_htlc = $holder_tx == $htlc.offered;
// HTLCs must either be claimed by a matching script type or through the
// revocation path:
#[cfg(not(fuzzing))] // Note that the fuzzer is not bound by pesky things like "signatures"
debug_assert!(!$htlc.offered || offered_preimage_claim || offered_timeout_claim || revocation_sig_claim);
#[cfg(not(fuzzing))] // Note that the fuzzer is not bound by pesky things like "signatures"
debug_assert!($htlc.offered || accepted_preimage_claim || accepted_timeout_claim || revocation_sig_claim);
// Further, only exactly one of the possible spend paths should have been
// matched by any HTLC spend:
#[cfg(not(fuzzing))] // Note that the fuzzer is not bound by pesky things like "signatures"
debug_assert_eq!(accepted_preimage_claim as u8 + accepted_timeout_claim as u8 +
offered_preimage_claim as u8 + offered_timeout_claim as u8 +
revocation_sig_claim as u8, 1);
if ($holder_tx && revocation_sig_claim) ||
(outbound_htlc && !$source_avail && (accepted_preimage_claim || offered_preimage_claim)) {
log_error!(logger, "Input spending {} ({}:{}) in {} resolves {} HTLC with payment hash {} with {}!",
$tx_info, input.previous_output.txid, input.previous_output.vout, tx.txid(),
if outbound_htlc { "outbound" } else { "inbound" }, log_bytes!($htlc.payment_hash.0),
if revocation_sig_claim { "revocation sig" } else { "preimage claim after we'd passed the HTLC resolution back" });
} else {
log_info!(logger, "Input spending {} ({}:{}) in {} resolves {} HTLC with payment hash {} with {}",
$tx_info, input.previous_output.txid, input.previous_output.vout, tx.txid(),
if outbound_htlc { "outbound" } else { "inbound" }, log_bytes!($htlc.payment_hash.0),
if revocation_sig_claim { "revocation sig" } else if accepted_preimage_claim || offered_preimage_claim { "preimage" } else { "timeout" });
}
}
}
macro_rules! check_htlc_valid_counterparty {
($counterparty_txid: expr, $htlc_output: expr) => {
if let Some(txid) = $counterparty_txid {
for &(ref pending_htlc, ref pending_source) in self.counterparty_claimable_outpoints.get(&txid).unwrap() {
if pending_htlc.payment_hash == $htlc_output.payment_hash && pending_htlc.amount_msat == $htlc_output.amount_msat {
if let &Some(ref source) = pending_source {
log_claim!("revoked counterparty commitment tx", false, pending_htlc, true);
payment_data = Some(((**source).clone(), $htlc_output.payment_hash, $htlc_output.amount_msat));
break;
}
}
}
}
}
}
macro_rules! scan_commitment {
($htlcs: expr, $tx_info: expr, $holder_tx: expr) => {
for (ref htlc_output, source_option) in $htlcs {
if Some(input.previous_output.vout) == htlc_output.transaction_output_index {
if let Some(ref source) = source_option {
log_claim!($tx_info, $holder_tx, htlc_output, true);
// We have a resolution of an HTLC either from one of our latest
// holder commitment transactions or an unrevoked counterparty commitment
// transaction. This implies we either learned a preimage, the HTLC
// has timed out, or we screwed up. In any case, we should now
// resolve the source HTLC with the original sender.
payment_data = Some(((*source).clone(), htlc_output.payment_hash, htlc_output.amount_msat));
} else if !$holder_tx {
check_htlc_valid_counterparty!(self.current_counterparty_commitment_txid, htlc_output);
if payment_data.is_none() {
check_htlc_valid_counterparty!(self.prev_counterparty_commitment_txid, htlc_output);
}
}
if payment_data.is_none() {
log_claim!($tx_info, $holder_tx, htlc_output, false);
let outbound_htlc = $holder_tx == htlc_output.offered;
if !outbound_htlc || revocation_sig_claim {
self.onchain_events_awaiting_threshold_conf.push(OnchainEventEntry {
txid: tx.txid(), height,
event: OnchainEvent::HTLCSpendConfirmation {
input_idx: input.previous_output.vout,
preimage: if accepted_preimage_claim || offered_preimage_claim {
Some(payment_preimage) } else { None },
// If this is a payment to us (!outbound_htlc, above),
// wait for the CSV delay before dropping the HTLC from
// claimable balance if the claim was an HTLC-Success
// transaction.
on_to_local_output_csv: if accepted_preimage_claim {
Some(self.on_holder_tx_csv) } else { None },
},
});
} else {
// Outbound claims should always have payment_data, unless
// we've already failed the HTLC as the commitment transaction
// which was broadcasted was revoked. In that case, we should
// spend the HTLC output here immediately, and expose that fact
// as a Balance, something which we do not yet do.
// TODO: Track the above as claimable!
}
continue 'outer_loop;
}
}
}
}
}
if input.previous_output.txid == self.current_holder_commitment_tx.txid {
scan_commitment!(self.current_holder_commitment_tx.htlc_outputs.iter().map(|&(ref a, _, ref b)| (a, b.as_ref())),
"our latest holder commitment tx", true);
}
if let Some(ref prev_holder_signed_commitment_tx) = self.prev_holder_signed_commitment_tx {
if input.previous_output.txid == prev_holder_signed_commitment_tx.txid {
scan_commitment!(prev_holder_signed_commitment_tx.htlc_outputs.iter().map(|&(ref a, _, ref b)| (a, b.as_ref())),
"our previous holder commitment tx", true);
}
}
if let Some(ref htlc_outputs) = self.counterparty_claimable_outpoints.get(&input.previous_output.txid) {
scan_commitment!(htlc_outputs.iter().map(|&(ref a, ref b)| (a, (b.as_ref().clone()).map(|boxed| &**boxed))),
"counterparty commitment tx", false);
}
// Check that scan_commitment, above, decided there is some source worth relaying an
// HTLC resolution backwards to and figure out whether we learned a preimage from it.
if let Some((source, payment_hash, amount_msat)) = payment_data {
if accepted_preimage_claim {
if !self.pending_monitor_events.iter().any(
|update| if let &MonitorEvent::HTLCEvent(ref upd) = update { upd.source == source } else { false }) {
self.onchain_events_awaiting_threshold_conf.push(OnchainEventEntry {
txid: tx.txid(),
height,
event: OnchainEvent::HTLCSpendConfirmation {
input_idx: input.previous_output.vout,
preimage: Some(payment_preimage),
on_to_local_output_csv: None,
},
});
self.pending_monitor_events.push(MonitorEvent::HTLCEvent(HTLCUpdate {
source,
payment_preimage: Some(payment_preimage),
payment_hash,
onchain_value_satoshis: Some(amount_msat / 1000),
}));
}
} else if offered_preimage_claim {
if !self.pending_monitor_events.iter().any(
|update| if let &MonitorEvent::HTLCEvent(ref upd) = update {
upd.source == source
} else { false }) {
self.onchain_events_awaiting_threshold_conf.push(OnchainEventEntry {
txid: tx.txid(),
height,
event: OnchainEvent::HTLCSpendConfirmation {
input_idx: input.previous_output.vout,
preimage: Some(payment_preimage),
on_to_local_output_csv: None,
},
});
self.pending_monitor_events.push(MonitorEvent::HTLCEvent(HTLCUpdate {
source,
payment_preimage: Some(payment_preimage),
payment_hash,
onchain_value_satoshis: Some(amount_msat / 1000),
}));
}
} else {
self.onchain_events_awaiting_threshold_conf.retain(|ref entry| {
if entry.height != height { return true; }
match entry.event {
OnchainEvent::HTLCUpdate { source: ref htlc_source, .. } => {
*htlc_source != source
},
_ => true,
}
});
let entry = OnchainEventEntry {
txid: tx.txid(),
height,
event: OnchainEvent::HTLCUpdate {
source, payment_hash,
onchain_value_satoshis: Some(amount_msat / 1000),
input_idx: Some(input.previous_output.vout),
},
};
log_info!(logger, "Failing HTLC with payment_hash {} timeout by a spend tx, waiting for confirmation (at height {})", log_bytes!(payment_hash.0), entry.confirmation_threshold());
self.onchain_events_awaiting_threshold_conf.push(entry);
}
}
}
}
/// 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, 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;
}
if outp.script_pubkey == self.destination_script {
spendable_output = Some(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 {
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,
output: outp.clone(),
revocation_pubkey: broadcasted_holder_revokable_script.2.clone(),
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 {
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 {
outpoint: OutPoint { txid: tx.txid(), index: i as u16 },
output: outp.clone(),
});
break;
}
}
if let Some(spendable_output) = spendable_output {
let entry = OnchainEventEntry {
txid: tx.txid(),
height: height,
event: OnchainEvent::MaturingOutput { descriptor: spendable_output.clone() },
};
log_info!(logger, "Received spendable output {}, spendable at height {}", log_spendable!(spendable_output), entry.confirmation_threshold());
self.onchain_events_awaiting_threshold_conf.push(entry);
}
}
}
impl<Signer: Sign, T: Deref, F: Deref, L: Deref> chain::Listen for (ChannelMonitor<Signer>, T, F, L)
where
T::Target: BroadcasterInterface,
F::Target: FeeEstimator,
L::Target: Logger,
{
fn block_connected(&self, block: &Block, height: u32) {
let txdata: Vec<_> = block.txdata.iter().enumerate().collect();
self.0.block_connected(&block.header, &txdata, height, &*self.1, &*self.2, &*self.3);
}
fn block_disconnected(&self, header: &BlockHeader, height: u32) {
self.0.block_disconnected(header, height, &*self.1, &*self.2, &*self.3);
}
}
impl<Signer: Sign, T: Deref, F: Deref, L: Deref> chain::Confirm for (ChannelMonitor<Signer>, T, F, L)
where
T::Target: BroadcasterInterface,
F::Target: FeeEstimator,
L::Target: Logger,
{
fn transactions_confirmed(&self, header: &BlockHeader, txdata: &TransactionData, height: u32) {
self.0.transactions_confirmed(header, txdata, height, &*self.1, &*self.2, &*self.3);
}
fn transaction_unconfirmed(&self, txid: &Txid) {
self.0.transaction_unconfirmed(txid, &*self.1, &*self.2, &*self.3);
}
fn best_block_updated(&self, header: &BlockHeader, height: u32) {
self.0.best_block_updated(header, height, &*self.1, &*self.2, &*self.3);
}
fn get_relevant_txids(&self) -> Vec<Txid> {
self.0.get_relevant_txids()
}
}
const MAX_ALLOC_SIZE: usize = 64*1024;
impl<'a, Signer: Sign, K: KeysInterface<Signer = Signer>> ReadableArgs<&'a K>
for (BlockHash, ChannelMonitor<Signer>) {
fn read<R: io::Read>(reader: &mut R, keys_manager: &'a K) -> Result<Self, DecodeError> {
macro_rules! unwrap_obj {
($key: expr) => {
match $key {
Ok(res) => res,
Err(_) => return Err(DecodeError::InvalidValue),
}
}
}
let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
let latest_update_id: u64 = Readable::read(reader)?;
let commitment_transaction_number_obscure_factor = <U48 as Readable>::read(reader)?.0;
let destination_script = Readable::read(reader)?;
let broadcasted_holder_revokable_script = match <u8 as Readable>::read(reader)? {
0 => {
let revokable_address = Readable::read(reader)?;
let per_commitment_point = Readable::read(reader)?;
let revokable_script = Readable::read(reader)?;
Some((revokable_address, per_commitment_point, revokable_script))
},
1 => { None },
_ => return Err(DecodeError::InvalidValue),
};
let counterparty_payment_script = Readable::read(reader)?;
let shutdown_script = {
let script = <Script as Readable>::read(reader)?;
if script.is_empty() { None } else { Some(script) }
};
let channel_keys_id = Readable::read(reader)?;
let holder_revocation_basepoint = Readable::read(reader)?;
// Technically this can fail and serialize fail a round-trip, but only for serialization of
// barely-init'd ChannelMonitors that we can't do anything with.
let outpoint = OutPoint {
txid: Readable::read(reader)?,
index: Readable::read(reader)?,
};
let funding_info = (outpoint, Readable::read(reader)?);
let current_counterparty_commitment_txid = Readable::read(reader)?;
let prev_counterparty_commitment_txid = Readable::read(reader)?;
let counterparty_commitment_params = Readable::read(reader)?;
let funding_redeemscript = Readable::read(reader)?;
let channel_value_satoshis = Readable::read(reader)?;
let their_cur_revocation_points = {
let first_idx = <U48 as Readable>::read(reader)?.0;
if first_idx == 0 {
None
} else {
let first_point = Readable::read(reader)?;
let second_point_slice: [u8; 33] = Readable::read(reader)?;
if second_point_slice[0..32] == [0; 32] && second_point_slice[32] == 0 {
Some((first_idx, first_point, None))
} else {
Some((first_idx, first_point, Some(unwrap_obj!(PublicKey::from_slice(&second_point_slice)))))
}
}
};
let on_holder_tx_csv: u16 = Readable::read(reader)?;
let commitment_secrets = Readable::read(reader)?;
macro_rules! read_htlc_in_commitment {
() => {
{
let offered: bool = Readable::read(reader)?;
let amount_msat: u64 = Readable::read(reader)?;
let cltv_expiry: u32 = Readable::read(reader)?;
let payment_hash: PaymentHash = Readable::read(reader)?;
let transaction_output_index: Option<u32> = Readable::read(reader)?;
HTLCOutputInCommitment {
offered, amount_msat, cltv_expiry, payment_hash, transaction_output_index
}
}
}
}
let counterparty_claimable_outpoints_len: u64 = Readable::read(reader)?;
let mut counterparty_claimable_outpoints = HashMap::with_capacity(cmp::min(counterparty_claimable_outpoints_len as usize, MAX_ALLOC_SIZE / 64));
for _ in 0..counterparty_claimable_outpoints_len {
let txid: Txid = Readable::read(reader)?;
let htlcs_count: u64 = Readable::read(reader)?;
let mut htlcs = Vec::with_capacity(cmp::min(htlcs_count as usize, MAX_ALLOC_SIZE / 32));
for _ in 0..htlcs_count {
htlcs.push((read_htlc_in_commitment!(), <Option<HTLCSource> as Readable>::read(reader)?.map(|o: HTLCSource| Box::new(o))));
}
if let Some(_) = counterparty_claimable_outpoints.insert(txid, htlcs) {
return Err(DecodeError::InvalidValue);
}
}
let counterparty_commitment_txn_on_chain_len: u64 = Readable::read(reader)?;
let mut counterparty_commitment_txn_on_chain = HashMap::with_capacity(cmp::min(counterparty_commitment_txn_on_chain_len as usize, MAX_ALLOC_SIZE / 32));
for _ in 0..counterparty_commitment_txn_on_chain_len {
let txid: Txid = Readable::read(reader)?;
let commitment_number = <U48 as Readable>::read(reader)?.0;
if let Some(_) = counterparty_commitment_txn_on_chain.insert(txid, commitment_number) {
return Err(DecodeError::InvalidValue);
}
}
let counterparty_hash_commitment_number_len: u64 = Readable::read(reader)?;
let mut counterparty_hash_commitment_number = HashMap::with_capacity(cmp::min(counterparty_hash_commitment_number_len as usize, MAX_ALLOC_SIZE / 32));
for _ in 0..counterparty_hash_commitment_number_len {
let payment_hash: PaymentHash = Readable::read(reader)?;
let commitment_number = <U48 as Readable>::read(reader)?.0;
if let Some(_) = counterparty_hash_commitment_number.insert(payment_hash, commitment_number) {
return Err(DecodeError::InvalidValue);
}
}
let mut prev_holder_signed_commitment_tx: Option<HolderSignedTx> =
match <u8 as Readable>::read(reader)? {
0 => None,
1 => {
Some(Readable::read(reader)?)
},
_ => return Err(DecodeError::InvalidValue),
};
let mut current_holder_commitment_tx: HolderSignedTx = Readable::read(reader)?;
let current_counterparty_commitment_number = <U48 as Readable>::read(reader)?.0;
let current_holder_commitment_number = <U48 as Readable>::read(reader)?.0;
let payment_preimages_len: u64 = Readable::read(reader)?;
let mut payment_preimages = HashMap::with_capacity(cmp::min(payment_preimages_len as usize, MAX_ALLOC_SIZE / 32));
for _ in 0..payment_preimages_len {
let preimage: PaymentPreimage = Readable::read(reader)?;
let hash = PaymentHash(Sha256::hash(&preimage.0[..]).into_inner());
if let Some(_) = payment_preimages.insert(hash, preimage) {
return Err(DecodeError::InvalidValue);
}
}
let pending_monitor_events_len: u64 = Readable::read(reader)?;
let mut pending_monitor_events = Some(
Vec::with_capacity(cmp::min(pending_monitor_events_len as usize, MAX_ALLOC_SIZE / (32 + 8*3))));
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),
_ => return Err(DecodeError::InvalidValue)
};
pending_monitor_events.as_mut().unwrap().push(ev);
}
let pending_events_len: u64 = Readable::read(reader)?;
let mut pending_events = Vec::with_capacity(cmp::min(pending_events_len as usize, MAX_ALLOC_SIZE / mem::size_of::<Event>()));
for _ in 0..pending_events_len {
if let Some(event) = MaybeReadable::read(reader)? {
pending_events.push(event);
}
}
let best_block = BestBlock::new(Readable::read(reader)?, Readable::read(reader)?);
let waiting_threshold_conf_len: u64 = Readable::read(reader)?;
let mut onchain_events_awaiting_threshold_conf = Vec::with_capacity(cmp::min(waiting_threshold_conf_len as usize, MAX_ALLOC_SIZE / 128));
for _ in 0..waiting_threshold_conf_len {
if let Some(val) = MaybeReadable::read(reader)? {
onchain_events_awaiting_threshold_conf.push(val);
}
}
let outputs_to_watch_len: u64 = Readable::read(reader)?;
let mut outputs_to_watch = HashMap::with_capacity(cmp::min(outputs_to_watch_len as usize, MAX_ALLOC_SIZE / (mem::size_of::<Txid>() + mem::size_of::<u32>() + mem::size_of::<Vec<Script>>())));
for _ in 0..outputs_to_watch_len {
let txid = Readable::read(reader)?;
let outputs_len: u64 = Readable::read(reader)?;
let mut outputs = Vec::with_capacity(cmp::min(outputs_len as usize, MAX_ALLOC_SIZE / (mem::size_of::<u32>() + mem::size_of::<Script>())));
for _ in 0..outputs_len {
outputs.push((Readable::read(reader)?, Readable::read(reader)?));
}
if let Some(_) = outputs_to_watch.insert(txid, outputs) {
return Err(DecodeError::InvalidValue);
}
}
let onchain_tx_handler: OnchainTxHandler<Signer> = ReadableArgs::read(reader, keys_manager)?;
let lockdown_from_offchain = Readable::read(reader)?;
let holder_tx_signed = Readable::read(reader)?;
if let Some(prev_commitment_tx) = prev_holder_signed_commitment_tx.as_mut() {
let prev_holder_value = onchain_tx_handler.get_prev_holder_commitment_to_self_value();
if prev_holder_value.is_none() { return Err(DecodeError::InvalidValue); }
if prev_commitment_tx.to_self_value_sat == u64::max_value() {
prev_commitment_tx.to_self_value_sat = prev_holder_value.unwrap();
} else if prev_commitment_tx.to_self_value_sat != prev_holder_value.unwrap() {
return Err(DecodeError::InvalidValue);
}
}
let cur_holder_value = onchain_tx_handler.get_cur_holder_commitment_to_self_value();
if current_holder_commitment_tx.to_self_value_sat == u64::max_value() {
current_holder_commitment_tx.to_self_value_sat = cur_holder_value;
} else if current_holder_commitment_tx.to_self_value_sat != cur_holder_value {
return Err(DecodeError::InvalidValue);
}
let mut funding_spend_confirmed = None;
let mut htlcs_resolved_on_chain = Some(Vec::new());
let mut funding_spend_seen = Some(false);
read_tlv_fields!(reader, {
(1, funding_spend_confirmed, option),
(3, htlcs_resolved_on_chain, vec_type),
(5, pending_monitor_events, vec_type),
(7, funding_spend_seen, option),
});
let mut secp_ctx = Secp256k1::new();
secp_ctx.seeded_randomize(&keys_manager.get_secure_random_bytes());
Ok((best_block.block_hash(), ChannelMonitor {
inner: Mutex::new(ChannelMonitorImpl {
latest_update_id,
commitment_transaction_number_obscure_factor,
destination_script,
broadcasted_holder_revokable_script,
counterparty_payment_script,
shutdown_script,
channel_keys_id,
holder_revocation_basepoint,
funding_info,
current_counterparty_commitment_txid,
prev_counterparty_commitment_txid,
counterparty_commitment_params,
funding_redeemscript,
channel_value_satoshis,
their_cur_revocation_points,
on_holder_tx_csv,
commitment_secrets,
counterparty_claimable_outpoints,
counterparty_commitment_txn_on_chain,
counterparty_hash_commitment_number,
prev_holder_signed_commitment_tx,
current_holder_commitment_tx,
current_counterparty_commitment_number,
current_holder_commitment_number,
payment_preimages,
pending_monitor_events: pending_monitor_events.unwrap(),
pending_events,
onchain_events_awaiting_threshold_conf,
outputs_to_watch,
onchain_tx_handler,
lockdown_from_offchain,
holder_tx_signed,
funding_spend_seen: funding_spend_seen.unwrap(),
funding_spend_confirmed,
htlcs_resolved_on_chain: htlcs_resolved_on_chain.unwrap(),
best_block,
secp_ctx,
}),
}))
}
}
#[cfg(test)]
mod tests {
use bitcoin::blockdata::block::BlockHeader;
use bitcoin::blockdata::script::{Script, Builder};
use bitcoin::blockdata::opcodes;
use bitcoin::blockdata::transaction::{Transaction, TxIn, TxOut, SigHashType};
use bitcoin::blockdata::transaction::OutPoint as BitcoinOutPoint;
use bitcoin::util::bip143;
use bitcoin::hashes::Hash;
use bitcoin::hashes::sha256::Hash as Sha256;
use bitcoin::hashes::hex::FromHex;
use bitcoin::hash_types::{BlockHash, Txid};
use bitcoin::network::constants::Network;
use bitcoin::secp256k1::key::{SecretKey,PublicKey};
use bitcoin::secp256k1::Secp256k1;
use hex;
use super::ChannelMonitorUpdateStep;
use ::{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 chain::{BestBlock, Confirm};
use chain::channelmonitor::ChannelMonitor;
use chain::package::{weight_offered_htlc, weight_received_htlc, weight_revoked_offered_htlc, weight_revoked_received_htlc, WEIGHT_REVOKED_OUTPUT};
use chain::transaction::OutPoint;
use chain::keysinterface::InMemorySigner;
use ln::{PaymentPreimage, PaymentHash};
use ln::chan_utils;
use ln::chan_utils::{HTLCOutputInCommitment, ChannelPublicKeys, ChannelTransactionParameters, HolderCommitmentTransaction, CounterpartyChannelTransactionParameters};
use ln::channelmanager::PaymentSendFailure;
use ln::features::InitFeatures;
use ln::functional_test_utils::*;
use ln::script::ShutdownScript;
use util::errors::APIError;
use util::events::{ClosureReason, MessageSendEventsProvider};
use util::test_utils::{TestLogger, TestBroadcaster, TestFeeEstimator};
use util::ser::{ReadableArgs, Writeable};
use sync::{Arc, Mutex};
use io;
use prelude::*;
fn do_test_funding_spend_refuses_updates(use_local_txn: bool) {
// Previously, monitor updates were allowed freely even after a funding-spend transaction
// confirmed. This would allow a race condition where we could receive a payment (including
// the counterparty revoking their broadcasted state!) and accept it without recourse as
// long as the ChannelMonitor receives the block first, the full commitment update dance
// occurs after the block is connected, and before the ChannelManager receives the block.
// Obviously this is an incredibly contrived race given the counterparty would be risking
// their full channel balance for it, but its worth fixing nonetheless as it makes the
// potential ChannelMonitor states simpler to reason about.
//
// This test checks said behavior, as well as ensuring a ChannelMonitorUpdate with multiple
// updates is handled correctly in such conditions.
let chanmon_cfgs = create_chanmon_cfgs(3);
let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
let nodes = create_network(3, &node_cfgs, &node_chanmgrs);
let channel = create_announced_chan_between_nodes(
&nodes, 0, 1, InitFeatures::known(), InitFeatures::known());
create_announced_chan_between_nodes(
&nodes, 1, 2, InitFeatures::known(), InitFeatures::known());
// Rebalance somewhat
send_payment(&nodes[0], &[&nodes[1]], 10_000_000);
// First route two payments for testing at the end
let payment_preimage_1 = route_payment(&nodes[0], &[&nodes[1], &nodes[2]], 1_000_000).0;
let payment_preimage_2 = route_payment(&nodes[0], &[&nodes[1], &nodes[2]], 1_000_000).0;
let local_txn = get_local_commitment_txn!(nodes[1], channel.2);
assert_eq!(local_txn.len(), 1);
let remote_txn = get_local_commitment_txn!(nodes[0], channel.2);
assert_eq!(remote_txn.len(), 3); // Commitment and two HTLC-Timeouts
check_spends!(remote_txn[1], remote_txn[0]);
check_spends!(remote_txn[2], remote_txn[0]);
let broadcast_tx = if use_local_txn { &local_txn[0] } else { &remote_txn[0] };
// Connect a commitment transaction, but only to the ChainMonitor/ChannelMonitor. The
// channel is now closed, but the ChannelManager doesn't know that yet.
let new_header = BlockHeader {
version: 2, time: 0, bits: 0, nonce: 0,
prev_blockhash: nodes[0].best_block_info().0,
merkle_root: Default::default() };
let conf_height = nodes[0].best_block_info().1 + 1;
nodes[1].chain_monitor.chain_monitor.transactions_confirmed(&new_header,
&[(0, broadcast_tx)], conf_height);
let (_, pre_update_monitor) = <(BlockHash, ChannelMonitor<InMemorySigner>)>::read(
&mut io::Cursor::new(&get_monitor!(nodes[1], channel.2).encode()),
&nodes[1].keys_manager.backing).unwrap();
// If the ChannelManager tries to update the channel, however, the ChainMonitor will pass
// the update through to the ChannelMonitor which will refuse it (as the channel is closed).
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(&route, payment_hash, &Some(payment_secret)),
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() });
// 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();
assert_eq!(replay_update.updates.len(), 1);
if let ChannelMonitorUpdateStep::LatestCounterpartyCommitmentTXInfo { .. } = replay_update.updates[0] {
} else { panic!(); }
replay_update.updates.push(ChannelMonitorUpdateStep::PaymentPreimage { payment_preimage: payment_preimage_1 });
replay_update.updates.push(ChannelMonitorUpdateStep::PaymentPreimage { payment_preimage: payment_preimage_2 });
let broadcaster = TestBroadcaster::new(Arc::clone(&nodes[1].blocks));
assert!(
pre_update_monitor.update_monitor(&replay_update, &&broadcaster, &&chanmon_cfgs[1].fee_estimator, &nodes[1].logger)
.is_err());
// Even though we error'd on the first update, we should still have generated an HTLC claim
// transaction
let txn_broadcasted = broadcaster.txn_broadcasted.lock().unwrap().split_off(0);
assert!(txn_broadcasted.len() >= 2);
let htlc_txn = txn_broadcasted.iter().filter(|tx| {
assert_eq!(tx.input.len(), 1);
tx.input[0].previous_output.txid == broadcast_tx.txid()
}).collect::<Vec<_>>();
assert_eq!(htlc_txn.len(), 2);
check_spends!(htlc_txn[0], broadcast_tx);
check_spends!(htlc_txn[1], broadcast_tx);
}
#[test]
fn test_funding_spend_refuses_updates() {
do_test_funding_spend_refuses_updates(true);
do_test_funding_spend_refuses_updates(false);
}
#[test]
fn test_prune_preimages() {
let secp_ctx = Secp256k1::new();
let logger = Arc::new(TestLogger::new());
let broadcaster = Arc::new(TestBroadcaster{txn_broadcasted: Mutex::new(Vec::new()), blocks: Arc::new(Mutex::new(Vec::new()))});
let fee_estimator = Arc::new(TestFeeEstimator { sat_per_kw: Mutex::new(253) });
let dummy_key = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
let dummy_tx = Transaction { version: 0, lock_time: 0, input: Vec::new(), output: Vec::new() };
let mut preimages = Vec::new();
{
for i in 0..20 {
let preimage = PaymentPreimage([i; 32]);
let hash = PaymentHash(Sha256::hash(&preimage.0[..]).into_inner());
preimages.push((preimage, hash));
}
}
macro_rules! preimages_slice_to_htlc_outputs {
($preimages_slice: expr) => {
{
let mut res = Vec::new();
for (idx, preimage) in $preimages_slice.iter().enumerate() {
res.push((HTLCOutputInCommitment {
offered: true,
amount_msat: 0,
cltv_expiry: 0,
payment_hash: preimage.1.clone(),
transaction_output_index: Some(idx as u32),
}, None));
}
res
}
}
}
macro_rules! preimages_to_holder_htlcs {
($preimages_slice: expr) => {
{
let mut inp = preimages_slice_to_htlc_outputs!($preimages_slice);
let res: Vec<_> = inp.drain(..).map(|e| { (e.0, None, e.1) }).collect();
res
}
}
}
macro_rules! test_preimages_exist {
($preimages_slice: expr, $monitor: expr) => {
for preimage in $preimages_slice {
assert!($monitor.inner.lock().unwrap().payment_preimages.contains_key(&preimage.1));
}
}
}
let keys = InMemorySigner::new(
&secp_ctx,
SecretKey::from_slice(&[41; 32]).unwrap(),
SecretKey::from_slice(&[41; 32]).unwrap(),
SecretKey::from_slice(&[41; 32]).unwrap(),
SecretKey::from_slice(&[41; 32]).unwrap(),
SecretKey::from_slice(&[41; 32]).unwrap(),
SecretKey::from_slice(&[41; 32]).unwrap(),
[41; 32],
0,
[0; 32]
);
let counterparty_pubkeys = ChannelPublicKeys {
funding_pubkey: PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[44; 32]).unwrap()),
revocation_basepoint: PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[45; 32]).unwrap()),
payment_point: PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[46; 32]).unwrap()),
delayed_payment_basepoint: PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[47; 32]).unwrap()),
htlc_basepoint: PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[48; 32]).unwrap())
};
let funding_outpoint = OutPoint { txid: Default::default(), index: u16::max_value() };
let channel_parameters = ChannelTransactionParameters {
holder_pubkeys: keys.holder_channel_pubkeys.clone(),
holder_selected_contest_delay: 66,
is_outbound_from_holder: true,
counterparty_parameters: Some(CounterpartyChannelTransactionParameters {
pubkeys: counterparty_pubkeys,
selected_contest_delay: 67,
}),
funding_outpoint: Some(funding_outpoint),
opt_anchors: None,
};
// Prune with one old state and a holder commitment tx holding a few overlaps with the
// old state.
let shutdown_pubkey = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
let best_block = BestBlock::from_genesis(Network::Testnet);
let monitor = ChannelMonitor::new(Secp256k1::new(), keys,
Some(ShutdownScript::new_p2wpkh_from_pubkey(shutdown_pubkey).into_inner()), 0, &Script::new(),
(OutPoint { txid: Txid::from_slice(&[43; 32]).unwrap(), index: 0 }, Script::new()),
&channel_parameters,
Script::new(), 46, 0,
HolderCommitmentTransaction::dummy(), best_block);
monitor.provide_latest_holder_commitment_tx(HolderCommitmentTransaction::dummy(), preimages_to_holder_htlcs!(preimages[0..10])).unwrap();
let dummy_txid = dummy_tx.txid();
monitor.provide_latest_counterparty_commitment_tx(dummy_txid, preimages_slice_to_htlc_outputs!(preimages[5..15]), 281474976710655, dummy_key, &logger);
monitor.provide_latest_counterparty_commitment_tx(dummy_txid, preimages_slice_to_htlc_outputs!(preimages[15..20]), 281474976710654, dummy_key, &logger);
monitor.provide_latest_counterparty_commitment_tx(dummy_txid, preimages_slice_to_htlc_outputs!(preimages[17..20]), 281474976710653, dummy_key, &logger);
monitor.provide_latest_counterparty_commitment_tx(dummy_txid, preimages_slice_to_htlc_outputs!(preimages[18..20]), 281474976710652, dummy_key, &logger);
for &(ref preimage, ref hash) in preimages.iter() {
monitor.provide_payment_preimage(hash, preimage, &broadcaster, &fee_estimator, &logger);
}
// Now provide a secret, pruning preimages 10-15
let mut secret = [0; 32];
secret[0..32].clone_from_slice(&hex::decode("7cc854b54e3e0dcdb010d7a3fee464a9687be6e8db3be6854c475621e007a5dc").unwrap());
monitor.provide_secret(281474976710655, secret.clone()).unwrap();
assert_eq!(monitor.inner.lock().unwrap().payment_preimages.len(), 15);
test_preimages_exist!(&preimages[0..10], monitor);
test_preimages_exist!(&preimages[15..20], monitor);
// Now provide a further secret, pruning preimages 15-17
secret[0..32].clone_from_slice(&hex::decode("c7518c8ae4660ed02894df8976fa1a3659c1a8b4b5bec0c4b872abeba4cb8964").unwrap());
monitor.provide_secret(281474976710654, secret.clone()).unwrap();
assert_eq!(monitor.inner.lock().unwrap().payment_preimages.len(), 13);
test_preimages_exist!(&preimages[0..10], monitor);
test_preimages_exist!(&preimages[17..20], monitor);
// Now update holder commitment tx info, pruning only element 18 as we still care about the
// previous commitment tx's preimages too
monitor.provide_latest_holder_commitment_tx(HolderCommitmentTransaction::dummy(), preimages_to_holder_htlcs!(preimages[0..5])).unwrap();
secret[0..32].clone_from_slice(&hex::decode("2273e227a5b7449b6e70f1fb4652864038b1cbf9cd7c043a7d6456b7fc275ad8").unwrap());
monitor.provide_secret(281474976710653, secret.clone()).unwrap();
assert_eq!(monitor.inner.lock().unwrap().payment_preimages.len(), 12);
test_preimages_exist!(&preimages[0..10], monitor);
test_preimages_exist!(&preimages[18..20], monitor);
// But if we do it again, we'll prune 5-10
monitor.provide_latest_holder_commitment_tx(HolderCommitmentTransaction::dummy(), preimages_to_holder_htlcs!(preimages[0..3])).unwrap();
secret[0..32].clone_from_slice(&hex::decode("27cddaa5624534cb6cb9d7da077cf2b22ab21e9b506fd4998a51d54502e99116").unwrap());
monitor.provide_secret(281474976710652, secret.clone()).unwrap();
assert_eq!(monitor.inner.lock().unwrap().payment_preimages.len(), 5);
test_preimages_exist!(&preimages[0..5], monitor);
}
#[test]
fn test_claim_txn_weight_computation() {
// We test Claim txn weight, knowing that we want expected weigth and
// not actual case to avoid sigs and time-lock delays hell variances.
let secp_ctx = Secp256k1::new();
let privkey = SecretKey::from_slice(&hex::decode("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
let pubkey = PublicKey::from_secret_key(&secp_ctx, &privkey);
macro_rules! sign_input {
($sighash_parts: expr, $idx: expr, $amount: expr, $weight: expr, $sum_actual_sigs: expr, $opt_anchors: expr) => {
let htlc = HTLCOutputInCommitment {
offered: if *$weight == weight_revoked_offered_htlc($opt_anchors) || *$weight == weight_offered_htlc($opt_anchors) { true } else { false },
amount_msat: 0,
cltv_expiry: 2 << 16,
payment_hash: PaymentHash([1; 32]),
transaction_output_index: Some($idx as u32),
};
let redeem_script = if *$weight == WEIGHT_REVOKED_OUTPUT { chan_utils::get_revokeable_redeemscript(&pubkey, 256, &pubkey) } else { chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, $opt_anchors, &pubkey, &pubkey, &pubkey) };
let sighash = hash_to_message!(&$sighash_parts.signature_hash($idx, &redeem_script, $amount, SigHashType::All)[..]);
let sig = secp_ctx.sign(&sighash, &privkey);
$sighash_parts.access_witness($idx).push(sig.serialize_der().to_vec());
$sighash_parts.access_witness($idx)[0].push(SigHashType::All as u8);
$sum_actual_sigs += $sighash_parts.access_witness($idx)[0].len();
if *$weight == WEIGHT_REVOKED_OUTPUT {
$sighash_parts.access_witness($idx).push(vec!(1));
} else if *$weight == weight_revoked_offered_htlc($opt_anchors) || *$weight == weight_revoked_received_htlc($opt_anchors) {
$sighash_parts.access_witness($idx).push(pubkey.clone().serialize().to_vec());
} else if *$weight == weight_received_htlc($opt_anchors) {
$sighash_parts.access_witness($idx).push(vec![0]);
} else {
$sighash_parts.access_witness($idx).push(PaymentPreimage([1; 32]).0.to_vec());
}
$sighash_parts.access_witness($idx).push(redeem_script.into_bytes());
println!("witness[0] {}", $sighash_parts.access_witness($idx)[0].len());
println!("witness[1] {}", $sighash_parts.access_witness($idx)[1].len());
println!("witness[2] {}", $sighash_parts.access_witness($idx)[2].len());
}
}
let script_pubkey = Builder::new().push_opcode(opcodes::all::OP_RETURN).into_script();
let txid = Txid::from_hex("56944c5d3f98413ef45cf54545538103cc9f298e0575820ad3591376e2e0f65d").unwrap();
// Justice tx with 1 to_holder, 2 revoked offered HTLCs, 1 revoked received HTLCs
for &opt_anchors in [false, true].iter() {
let mut claim_tx = Transaction { version: 0, lock_time: 0, input: Vec::new(), output: Vec::new() };
let mut sum_actual_sigs = 0;
for i in 0..4 {
claim_tx.input.push(TxIn {
previous_output: BitcoinOutPoint {
txid,
vout: i,
},
script_sig: Script::new(),
sequence: 0xfffffffd,
witness: Vec::new(),
});
}
claim_tx.output.push(TxOut {
script_pubkey: script_pubkey.clone(),
value: 0,
});
let base_weight = claim_tx.get_weight();
let inputs_weight = vec![WEIGHT_REVOKED_OUTPUT, weight_revoked_offered_htlc(opt_anchors), weight_revoked_offered_htlc(opt_anchors), weight_revoked_received_htlc(opt_anchors)];
let mut inputs_total_weight = 2; // count segwit flags
{
let mut sighash_parts = bip143::SigHashCache::new(&mut claim_tx);
for (idx, inp) in inputs_weight.iter().enumerate() {
sign_input!(sighash_parts, idx, 0, inp, sum_actual_sigs, opt_anchors);
inputs_total_weight += inp;
}
}
assert_eq!(base_weight + inputs_total_weight as usize, claim_tx.get_weight() + /* max_length_sig */ (73 * inputs_weight.len() - sum_actual_sigs));
}
// Claim tx with 1 offered HTLCs, 3 received HTLCs
for &opt_anchors in [false, true].iter() {
let mut claim_tx = Transaction { version: 0, lock_time: 0, input: Vec::new(), output: Vec::new() };
let mut sum_actual_sigs = 0;
for i in 0..4 {
claim_tx.input.push(TxIn {
previous_output: BitcoinOutPoint {
txid,
vout: i,
},
script_sig: Script::new(),
sequence: 0xfffffffd,
witness: Vec::new(),
});
}
claim_tx.output.push(TxOut {
script_pubkey: script_pubkey.clone(),
value: 0,
});
let base_weight = claim_tx.get_weight();
let inputs_weight = vec![weight_offered_htlc(opt_anchors), weight_received_htlc(opt_anchors), weight_received_htlc(opt_anchors), weight_received_htlc(opt_anchors)];
let mut inputs_total_weight = 2; // count segwit flags
{
let mut sighash_parts = bip143::SigHashCache::new(&mut claim_tx);
for (idx, inp) in inputs_weight.iter().enumerate() {
sign_input!(sighash_parts, idx, 0, inp, sum_actual_sigs, opt_anchors);
inputs_total_weight += inp;
}
}
assert_eq!(base_weight + inputs_total_weight as usize, claim_tx.get_weight() + /* max_length_sig */ (73 * inputs_weight.len() - sum_actual_sigs));
}
// Justice tx with 1 revoked HTLC-Success tx output
for &opt_anchors in [false, true].iter() {
let mut claim_tx = Transaction { version: 0, lock_time: 0, input: Vec::new(), output: Vec::new() };
let mut sum_actual_sigs = 0;
claim_tx.input.push(TxIn {
previous_output: BitcoinOutPoint {
txid,
vout: 0,
},
script_sig: Script::new(),
sequence: 0xfffffffd,
witness: Vec::new(),
});
claim_tx.output.push(TxOut {
script_pubkey: script_pubkey.clone(),
value: 0,
});
let base_weight = claim_tx.get_weight();
let inputs_weight = vec![WEIGHT_REVOKED_OUTPUT];
let mut inputs_total_weight = 2; // count segwit flags
{
let mut sighash_parts = bip143::SigHashCache::new(&mut claim_tx);
for (idx, inp) in inputs_weight.iter().enumerate() {
sign_input!(sighash_parts, idx, 0, inp, sum_actual_sigs, opt_anchors);
inputs_total_weight += inp;
}
}
assert_eq!(base_weight + inputs_total_weight as usize, claim_tx.get_weight() + /* max_length_isg */ (73 * inputs_weight.len() - sum_actual_sigs));
}
}
// Further testing is done in the ChannelManager integration tests.
}