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Refactor channel funding transaction fields
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@optout21
optout21 committed Nov 17, 2023
1 parent 870a0f1 commit 97c3969
Showing 1 changed file with 97 additions and 52 deletions.
149 changes: 97 additions & 52 deletions lightning/src/ln/channel.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -686,6 +686,43 @@ impl UnfundedChannelContext {
}
}

/// Info about a transaction and its confirmation status, used mainly for funding transactions.
pub(super) struct TransactionConfirmation {
/// The transaction, or None.
transaction: Option<Transaction>,
/// The hash of the block in which the transaction was included, or None.
confirmed_in: Option<BlockHash>,
/// The height of the block in which the transaction was included, or 0.
confirmation_height: u32,
}

impl TransactionConfirmation {
/// Construct with empty values
fn default() -> Self {
Self {
transaction: None,
confirmed_in: None,
confirmation_height: 0,
}
}

/// Get the confirmation depth: height relative to the given current height.
/// Also returns a flag indicating the special case when the confirmation is in the 'future'.
/// If there is no confirmation height (it was not confirmed, or confirmed and reorged): (0, false)
/// If the confirmation height is in the 'future' (e.g. due to a reorg): (0, true)
/// Otherwise the result is height - confirmation_height + 1, a number always larger than 0.
fn confirmation_depth(&self, current_height: u32) -> (u32, bool) {
if self.confirmation_height == 0 {
(0, false)
} else {
match current_height.checked_sub(self.confirmation_height) {
None => (0, true),
Some(d) => (d + 1, false),
}
}
}
}

/// Contains everything about the channel including state, and various flags.
pub(super) struct ChannelContext<SP: Deref> where SP::Target: SignerProvider {
config: LegacyChannelConfig,
Expand Down Expand Up @@ -829,9 +866,6 @@ pub(super) struct ChannelContext<SP: Deref> where SP::Target: SignerProvider {
/// milliseconds, so any accidental force-closes here should be exceedingly rare.
expecting_peer_commitment_signed: bool,

/// The hash of the block in which the funding transaction was included.
funding_tx_confirmed_in: Option<BlockHash>,
funding_tx_confirmation_height: u32,
short_channel_id: Option<u64>,
/// Either the height at which this channel was created or the height at which it was last
/// serialized if it was serialized by versions prior to 0.0.103.
Expand Down Expand Up @@ -875,7 +909,8 @@ pub(super) struct ChannelContext<SP: Deref> where SP::Target: SignerProvider {
counterparty_forwarding_info: Option<CounterpartyForwardingInfo>,

pub(crate) channel_transaction_parameters: ChannelTransactionParameters,
funding_transaction: Option<Transaction>,
/// Info about the funding transaction and its confirmation status
funding_tx_confirmation: TransactionConfirmation,
is_batch_funding: Option<()>,

counterparty_cur_commitment_point: Option<PublicKey>,
Expand Down Expand Up @@ -1113,17 +1148,12 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider {

/// Returns the block hash in which our funding transaction was confirmed.
pub fn get_funding_tx_confirmed_in(&self) -> Option<BlockHash> {
self.funding_tx_confirmed_in
self.funding_tx_confirmation.confirmed_in
}

/// Returns the current number of confirmations on the funding transaction.
pub fn get_funding_tx_confirmations(&self, height: u32) -> u32 {
if self.funding_tx_confirmation_height == 0 {
// We either haven't seen any confirmation yet, or observed a reorg.
return 0;
}

height.checked_sub(self.funding_tx_confirmation_height).map_or(0, |c| c + 1)
self.funding_tx_confirmation.confirmation_depth(height).0
}

fn get_holder_selected_contest_delay(&self) -> u16 {
Expand Down Expand Up @@ -2048,7 +2078,7 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider {
/// Returns the transaction if there is a pending funding transaction that is yet to be
/// broadcast.
pub fn unbroadcasted_funding(&self) -> Option<Transaction> {
self.if_unbroadcasted_funding(|| self.funding_transaction.clone())
self.if_unbroadcasted_funding(|| self.funding_tx_confirmation.transaction.clone())
}

/// Returns the transaction ID if there is a pending funding transaction that is yet to be
Expand Down Expand Up @@ -3896,7 +3926,7 @@ impl<SP: Deref> Channel<SP> where
// first received the funding_signed.
let mut funding_broadcastable =
if self.context.is_outbound() && self.context.channel_state & !STATE_FLAGS >= ChannelState::FundingSent as u32 && self.context.channel_state & ChannelState::WaitingForBatch as u32 == 0 {
self.context.funding_transaction.take()
self.context.funding_tx_confirmation.transaction.take()
} else { None };
// That said, if the funding transaction is already confirmed (ie we're active with a
// minimum_depth over 0) don't bother re-broadcasting the confirmed funding tx.
Expand Down Expand Up @@ -4885,7 +4915,7 @@ impl<SP: Deref> Channel<SP> where
// Because deciding we're awaiting initial broadcast spuriously could result in
// funds-loss (as we don't have a monitor, but have the funding transaction confirmed),
// we hard-assert here, even in production builds.
if self.context.is_outbound() { assert!(self.context.funding_transaction.is_some()); }
if self.context.is_outbound() { assert!(self.context.funding_tx_confirmation.transaction.is_some()); }
assert!(self.context.monitor_pending_channel_ready);
assert_eq!(self.context.latest_monitor_update_id, 0);
return true;
Expand Down Expand Up @@ -4931,16 +4961,16 @@ impl<SP: Deref> Channel<SP> where
// Called:
// * always when a new block/transactions are confirmed with the new height
// * when funding is signed with a height of 0
if self.context.funding_tx_confirmation_height == 0 && self.context.minimum_depth != Some(0) {
if self.context.funding_tx_confirmation.confirmation_height == 0 && self.context.minimum_depth != Some(0) {
return None;
}

let funding_tx_confirmations = height as i64 - self.context.funding_tx_confirmation_height as i64 + 1;
if funding_tx_confirmations <= 0 {
self.context.funding_tx_confirmation_height = 0;
let (funding_tx_confirmations, in_future) = self.context.funding_tx_confirmation.confirmation_depth(height);
if in_future {
self.context.funding_tx_confirmation.confirmation_height = 0;
}

if funding_tx_confirmations < self.context.minimum_depth.unwrap_or(0) as i64 {
if funding_tx_confirmations < self.context.minimum_depth.unwrap_or(0) {
return None;
}

Expand All @@ -4964,7 +4994,7 @@ impl<SP: Deref> Channel<SP> where
// We got a reorg but not enough to trigger a force close, just ignore.
false
} else {
if self.context.funding_tx_confirmation_height != 0 && self.context.channel_state & !STATE_FLAGS < ChannelState::ChannelReady as u32 {
if self.context.funding_tx_confirmation.confirmation_height != 0 && self.context.channel_state & !STATE_FLAGS < ChannelState::ChannelReady as u32 {
// We should never see a funding transaction on-chain until we've received
// funding_signed (if we're an outbound channel), or seen funding_generated (if we're
// an inbound channel - before that we have no known funding TXID). The fuzzer,
Expand Down Expand Up @@ -5012,7 +5042,7 @@ impl<SP: Deref> Channel<SP> where
for &(index_in_block, tx) in txdata.iter() {
// Check if the transaction is the expected funding transaction, and if it is,
// check that it pays the right amount to the right script.
if self.context.funding_tx_confirmation_height == 0 {
if self.context.funding_tx_confirmation.confirmation_height == 0 {
if tx.txid() == funding_txo.txid {
let txo_idx = funding_txo.index as usize;
if txo_idx >= tx.output.len() || tx.output[txo_idx].script_pubkey != self.context.get_funding_redeemscript().to_v0_p2wsh() ||
Expand Down Expand Up @@ -5042,8 +5072,8 @@ impl<SP: Deref> Channel<SP> where
}
}
}
self.context.funding_tx_confirmation_height = height;
self.context.funding_tx_confirmed_in = Some(*block_hash);
self.context.funding_tx_confirmation.confirmation_height = height;
self.context.funding_tx_confirmation.confirmed_in = Some(*block_hash);
self.context.short_channel_id = match scid_from_parts(height as u64, index_in_block as u64, txo_idx as u64) {
Ok(scid) => Some(scid),
Err(_) => panic!("Block was bogus - either height was > 16 million, had > 16 million transactions, or had > 65k outputs"),
Expand Down Expand Up @@ -5137,13 +5167,10 @@ impl<SP: Deref> Channel<SP> where
let non_shutdown_state = self.context.channel_state & (!MULTI_STATE_FLAGS);
if non_shutdown_state & !STATE_FLAGS >= ChannelState::ChannelReady as u32 ||
(non_shutdown_state & ChannelState::OurChannelReady as u32) == ChannelState::OurChannelReady as u32 {
let mut funding_tx_confirmations = height as i64 - self.context.funding_tx_confirmation_height as i64 + 1;
if self.context.funding_tx_confirmation_height == 0 {
// Note that check_get_channel_ready may reset funding_tx_confirmation_height to
// zero if it has been reorged out, however in either case, our state flags
// indicate we've already sent a channel_ready
funding_tx_confirmations = 0;
}
let (funding_tx_confirmations, _) = self.context.funding_tx_confirmation.confirmation_depth(height);
// Note that check_get_channel_ready may reset funding_tx_confirmation.confirmation_height to
// zero if it has been reorged out, however in either case, our state flags
// indicate we've already sent a channel_ready

// If we've sent channel_ready (or have both sent and received channel_ready), and
// the funding transaction has become unconfirmed,
Expand All @@ -5154,15 +5181,15 @@ impl<SP: Deref> Channel<SP> where
// 0-conf channel, but not doing so may lead to the
// `ChannelManager::short_to_chan_info` map being inconsistent, so we currently have
// to.
if funding_tx_confirmations == 0 && self.context.funding_tx_confirmed_in.is_some() {
if funding_tx_confirmations == 0 && self.context.funding_tx_confirmation.confirmed_in.is_some() {
let err_reason = format!("Funding transaction was un-confirmed. Locked at {} confs, now have {} confs.",
self.context.minimum_depth.unwrap(), funding_tx_confirmations);
return Err(ClosureReason::ProcessingError { err: err_reason });
}
} else if !self.context.is_outbound() && self.context.funding_tx_confirmed_in.is_none() &&
} else if !self.context.is_outbound() && self.context.funding_tx_confirmation.confirmed_in.is_none() &&
height >= self.context.channel_creation_height + FUNDING_CONF_DEADLINE_BLOCKS {
log_info!(logger, "Closing channel {} due to funding timeout", &self.context.channel_id);
// If funding_tx_confirmed_in is unset, the channel must not be active
// If funding_tx_confirmation.confirmed_in is unset, the channel must not be active
assert!(non_shutdown_state & !STATE_FLAGS <= ChannelState::ChannelReady as u32);
assert_eq!(non_shutdown_state & ChannelState::OurChannelReady as u32, 0);
return Err(ClosureReason::FundingTimedOut);
Expand All @@ -5178,10 +5205,10 @@ impl<SP: Deref> Channel<SP> where
/// force-close the channel, but may also indicate a harmless reorganization of a block or two
/// before the channel has reached channel_ready and we can just wait for more blocks.
pub fn funding_transaction_unconfirmed<L: Deref>(&mut self, logger: &L) -> Result<(), ClosureReason> where L::Target: Logger {
if self.context.funding_tx_confirmation_height != 0 {
if self.context.funding_tx_confirmation.confirmation_height > 0 {
// We handle the funding disconnection by calling best_block_updated with a height one
// below where our funding was connected, implying a reorg back to conf_height - 1.
let reorg_height = self.context.funding_tx_confirmation_height - 1;
let reorg_height = self.context.funding_tx_confirmation.confirmation_height - 1;
// We use the time field to bump the current time we set on channel updates if its
// larger. If we don't know that time has moved forward, we can just set it to the last
// time we saw and it will be ignored.
Expand Down Expand Up @@ -5254,7 +5281,7 @@ impl<SP: Deref> Channel<SP> where
NS::Target: NodeSigner,
L::Target: Logger
{
if self.context.funding_tx_confirmation_height == 0 || self.context.funding_tx_confirmation_height + 5 > best_block_height {
if self.context.funding_tx_confirmation.confirmation_height == 0 || self.context.funding_tx_confirmation.confirmation_height + 5 > best_block_height {
return None;
}

Expand Down Expand Up @@ -5365,7 +5392,7 @@ impl<SP: Deref> Channel<SP> where
}

self.context.announcement_sigs = Some((msg.node_signature, msg.bitcoin_signature));
if self.context.funding_tx_confirmation_height == 0 || self.context.funding_tx_confirmation_height + 5 > best_block_height {
if self.context.funding_tx_confirmation.confirmation_height == 0 || self.context.funding_tx_confirmation.confirmation_height + 5 > best_block_height {
return Err(ChannelError::Ignore(
"Got announcement_signatures prior to the required six confirmations - we may not have received a block yet that our peer has".to_owned()));
}
Expand All @@ -5378,7 +5405,7 @@ impl<SP: Deref> Channel<SP> where
pub fn get_signed_channel_announcement<NS: Deref>(
&self, node_signer: &NS, chain_hash: ChainHash, best_block_height: u32, user_config: &UserConfig
) -> Option<msgs::ChannelAnnouncement> where NS::Target: NodeSigner {
if self.context.funding_tx_confirmation_height == 0 || self.context.funding_tx_confirmation_height + 5 > best_block_height {
if self.context.funding_tx_confirmation.confirmation_height == 0 || self.context.funding_tx_confirmation.confirmation_height + 5 > best_block_height {
return None;
}
let announcement = match self.get_channel_announcement(node_signer, chain_hash, user_config) {
Expand Down Expand Up @@ -6020,8 +6047,6 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
closing_fee_limits: None,
target_closing_feerate_sats_per_kw: None,

funding_tx_confirmed_in: None,
funding_tx_confirmation_height: 0,
short_channel_id: None,
channel_creation_height: current_chain_height,

Expand All @@ -6048,7 +6073,7 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
funding_outpoint: None,
channel_type_features: channel_type.clone()
},
funding_transaction: None,
funding_tx_confirmation: TransactionConfirmation::default(),
is_batch_funding: None,

counterparty_cur_commitment_point: None,
Expand Down Expand Up @@ -6127,7 +6152,7 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
self.context.minimum_depth = Some(COINBASE_MATURITY);
}

self.context.funding_transaction = Some(funding_transaction);
self.context.funding_tx_confirmation.transaction = Some(funding_transaction);
self.context.is_batch_funding = Some(()).filter(|_| is_batch_funding);

let funding_created = self.context.get_funding_created_msg(logger);
Expand Down Expand Up @@ -6653,8 +6678,6 @@ impl<SP: Deref> InboundV1Channel<SP> where SP::Target: SignerProvider {
closing_fee_limits: None,
target_closing_feerate_sats_per_kw: None,

funding_tx_confirmed_in: None,
funding_tx_confirmation_height: 0,
short_channel_id: None,
channel_creation_height: current_chain_height,

Expand Down Expand Up @@ -6685,7 +6708,7 @@ impl<SP: Deref> InboundV1Channel<SP> where SP::Target: SignerProvider {
funding_outpoint: None,
channel_type_features: channel_type.clone()
},
funding_transaction: None,
funding_tx_confirmation: TransactionConfirmation::default(),
is_batch_funding: None,

counterparty_cur_commitment_point: Some(msg.first_per_commitment_point),
Expand Down Expand Up @@ -7162,8 +7185,8 @@ impl<SP: Deref> Writeable for Channel<SP> where SP::Target: SignerProvider {
// consider the stale state on reload.
0u8.write(writer)?;

self.context.funding_tx_confirmed_in.write(writer)?;
self.context.funding_tx_confirmation_height.write(writer)?;
self.context.funding_tx_confirmation.confirmed_in.write(writer)?;
self.context.funding_tx_confirmation.confirmation_height.write(writer)?;
self.context.short_channel_id.write(writer)?;

self.context.counterparty_dust_limit_satoshis.write(writer)?;
Expand Down Expand Up @@ -7191,7 +7214,7 @@ impl<SP: Deref> Writeable for Channel<SP> where SP::Target: SignerProvider {
}

self.context.channel_transaction_parameters.write(writer)?;
self.context.funding_transaction.write(writer)?;
self.context.funding_tx_confirmation.transaction.write(writer)?;

self.context.counterparty_cur_commitment_point.write(writer)?;
self.context.counterparty_prev_commitment_point.write(writer)?;
Expand Down Expand Up @@ -7725,8 +7748,6 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, u32, &'c Ch
closing_fee_limits: None,
target_closing_feerate_sats_per_kw,

funding_tx_confirmed_in,
funding_tx_confirmation_height,
short_channel_id,
channel_creation_height: channel_creation_height.unwrap(),

Expand All @@ -7744,7 +7765,11 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, u32, &'c Ch
counterparty_forwarding_info,

channel_transaction_parameters: channel_parameters,
funding_transaction,
funding_tx_confirmation: TransactionConfirmation {
transaction: funding_transaction,
confirmed_in: funding_tx_confirmed_in,
confirmation_height: funding_tx_confirmation_height,
},
is_batch_funding,

counterparty_cur_commitment_point,
Expand Down Expand Up @@ -7799,7 +7824,7 @@ mod tests {
use crate::ln::PaymentHash;
use crate::ln::channelmanager::{self, HTLCSource, PaymentId};
use crate::ln::channel::InitFeatures;
use crate::ln::channel::{ChannelState, InboundHTLCOutput, OutboundV1Channel, InboundV1Channel, OutboundHTLCOutput, InboundHTLCState, OutboundHTLCState, HTLCCandidate, HTLCInitiator, commit_tx_fee_msat};
use crate::ln::channel::{ChannelState, InboundHTLCOutput, OutboundV1Channel, InboundV1Channel, OutboundHTLCOutput, InboundHTLCState, OutboundHTLCState, HTLCCandidate, HTLCInitiator, TransactionConfirmation, commit_tx_fee_msat};
use crate::ln::channel::{MAX_FUNDING_SATOSHIS_NO_WUMBO, TOTAL_BITCOIN_SUPPLY_SATOSHIS, MIN_THEIR_CHAN_RESERVE_SATOSHIS};
use crate::ln::features::ChannelTypeFeatures;
use crate::ln::msgs::{ChannelUpdate, DecodeError, UnsignedChannelUpdate, MAX_VALUE_MSAT};
Expand Down Expand Up @@ -7841,6 +7866,26 @@ mod tests {
"MAX_FUNDING_SATOSHIS_NO_WUMBO is greater than all satoshis in existence");
}

#[test]
fn test_transaction_confirmation_depth() {
{
let tx_conf = TransactionConfirmation { transaction: None, confirmed_in: None, confirmation_height: 0 };
assert_eq!(tx_conf.confirmation_depth(42), (0, false));
}
{
let tx_conf = TransactionConfirmation { transaction: None, confirmed_in: None, confirmation_height: 100005 };
assert_eq!(tx_conf.confirmation_depth(100008), (4, false));
}
{
let tx_conf = TransactionConfirmation { transaction: None, confirmed_in: None, confirmation_height: 100005 };
assert_eq!(tx_conf.confirmation_depth(100005), (1, false));
}
{
// confirmation_height is larger than current, 'in the future'
let tx_conf = TransactionConfirmation { transaction: None, confirmed_in: None, confirmation_height: 100005 };
assert_eq!(tx_conf.confirmation_depth(100000), (0, true));
}
}
struct Keys {
signer: InMemorySigner,
}
Expand Down

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