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WIP, Implement funding_tx_constructed()
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@optout21
optout21 committed Mar 4, 2025
1 parent 1ef4df0 commit 7dba1df
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Showing 2 changed files with 187 additions and 41 deletions.
223 changes: 183 additions & 40 deletions lightning/src/ln/channel.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1335,6 +1335,7 @@ impl<SP: Deref> Channel<SP> where
}
}

#[cfg(splicing)]
fn as_splicing_mut(&mut self) -> Option<&mut SplicingChannel<SP>> {
if let ChannelPhase::RefundingV2(channel) = &mut self.phase {
Some(channel)
Expand Down Expand Up @@ -1481,6 +1482,7 @@ impl<SP: Deref> Channel<SP> where
if let Some(unfunded) = self.as_unfunded_v2_mut() {
return unfunded.tx_add_input(msg);
}
#[cfg(splicing)]
if let Some(splicing) = self.as_splicing_mut() {
return splicing.tx_add_input(msg);
}
Expand All @@ -1492,6 +1494,7 @@ impl<SP: Deref> Channel<SP> where
if let Some(unfunded) = self.as_unfunded_v2_mut() {
return unfunded.tx_add_output(msg);
}
#[cfg(splicing)]
if let Some(splicing) = self.as_splicing_mut() {
return splicing.tx_add_output(msg);
}
Expand All @@ -1503,6 +1506,7 @@ impl<SP: Deref> Channel<SP> where
if let Some(unfunded) = self.as_unfunded_v2_mut() {
return unfunded.tx_complete(msg);
}
#[cfg(splicing)]
if let Some(splicing) = self.as_splicing_mut() {
return splicing.tx_complete(msg);
}
Expand Down Expand Up @@ -1546,22 +1550,55 @@ impl<SP: Deref> Channel<SP> where
where
L::Target: Logger
{
if let ChannelPhase::UnfundedV2(chan) = &mut self.phase {
let logger = WithChannelContext::from(logger, &chan.context, None);
chan.funding_tx_constructed(signing_session, &&logger)
} else {
Err(ChannelError::Warn("Got a tx_complete message with no interactive transaction construction expected or in-progress".to_owned()))
}
let phase = core::mem::replace(&mut self.phase, ChannelPhase::Undefined);
let result = match phase {
ChannelPhase::UnfundedV2(mut chan) => {
let logger = WithChannelContext::from(logger, &chan.context, None);
match chan.funding_tx_constructed(signing_session, &&logger) {
Ok((commitment_signed, event)) => {
// TODO: Transition to Funded ? Which chan? // self.phase = ChannelPhase::Funded(chan);
self.phase = ChannelPhase::UnfundedV2(chan);
Ok((commitment_signed, event))
},
Err(e) => {
// revert
self.phase = ChannelPhase::UnfundedV2(chan);
Err(e)
},
}
}
#[cfg(splicing)]
ChannelPhase::RefundingV2(chan) => {
let logger = WithChannelContext::from(logger, &chan.pre_funded.context, None);
match chan.funding_tx_constructed(signing_session, &&logger) {
Ok((signing_session, holder_commitment_point, commitment_signed, event)) => {
let _res = self.phase_from_splice_to_funded(signing_session, holder_commitment_point)?;
Ok((commitment_signed, event))
},
Err((chan, e)) => {
// revert
self.phase = ChannelPhase::RefundingV2(chan);
Err(e)
},
}
}
_ => {
self.phase = phase;
Err(ChannelError::Warn("Got a tx_complete message with no interactive transaction construction expected or in-progress".to_owned()))
}
};

debug_assert!(!matches!(self.phase, ChannelPhase::Undefined));
result
}

/// Transition the channel from Funded to SplicingChannel.
/// Done in one go, as the existing ('pre') channel is put in the new channel (alongside a new one).
#[cfg(splicing)]
fn phase_to_splice(&mut self, post_funding: FundingScope, dual_funding_context: DualFundingChannelContext, pending_splice_post: PendingSplicePost) -> Result<(), ChannelError>
{
fn phase_from_funded_to_splice(&mut self, post_funding: FundingScope, dual_funding_context: DualFundingChannelContext, unfunded_context: UnfundedChannelContext, pending_splice_post: PendingSplicePost) -> Result<(), ChannelError> {
let phase = core::mem::replace(&mut self.phase, ChannelPhase::Undefined);
let result = if let ChannelPhase::Funded(prev_chan) = phase {
self.phase = ChannelPhase::RefundingV2(SplicingChannel::new(prev_chan, post_funding, dual_funding_context, pending_splice_post));
self.phase = ChannelPhase::RefundingV2(SplicingChannel::new(prev_chan, post_funding, dual_funding_context, unfunded_context, pending_splice_post));
Ok(())
} else {
// revert phase
Expand All @@ -1572,6 +1609,30 @@ impl<SP: Deref> Channel<SP> where
result
}

/// Transition the channel from SplicingChannel to Funded, after negotiating new funded.
#[cfg(splicing)]
fn phase_from_splice_to_funded(&mut self, signing_session: InteractiveTxSigningSession, holder_commitment_point: HolderCommitmentPoint) -> Result<(), ChannelError> {
let phase = core::mem::replace(&mut self.phase, ChannelPhase::Undefined);
let result = if let ChannelPhase::RefundingV2(chan) = phase {
self.phase = ChannelPhase::Funded(FundedChannel {
funding: chan.post_funding,
context: chan.pre_funded.context,
interactive_tx_signing_session: Some(signing_session),
holder_commitment_point,
is_v2_established: true,
pending_splice_pre: None,
pending_splice_post: None,
});
Ok(())
} else {
// revert phase
self.phase = phase;
Err(ChannelError::Warn("Cannot transition away from splicing, not in splicing phase".to_owned()))
};
debug_assert!(!matches!(self.phase, ChannelPhase::Undefined));
result
}

#[cfg(splicing)]
pub fn splice_init<ES: Deref, L: Deref>(
&mut self, msg: &msgs::SpliceInit, our_funding_contribution: i64,
Expand All @@ -1583,10 +1644,10 @@ impl<SP: Deref> Channel<SP> where
{
// Explicit check for Funded, not as_funded; RefundingV2 not allowed
if let ChannelPhase::Funded(prev_chan) = &mut self.phase {
let (pending_splice_post, post_funding, dual_funding_context) =
let (pending_splice_post, post_funding, dual_funding_context, unfunded_context) =
prev_chan.splice_init(msg, our_funding_contribution)?;

let _res = self.phase_to_splice(post_funding, dual_funding_context, pending_splice_post)?;
let _res = self.phase_from_funded_to_splice(post_funding, dual_funding_context, unfunded_context, pending_splice_post)?;

if let ChannelPhase::RefundingV2(chan) = &mut self.phase {
let splice_ack_msg = chan.splice_init(msg, our_funding_contribution, signer_provider, entropy_source, our_node_id, logger)?;
Expand All @@ -1610,10 +1671,10 @@ impl<SP: Deref> Channel<SP> where
{
// Explicit check for Funded, not as_funded; RefundingV2 not allowed
if let ChannelPhase::Funded(prev_chan) = &mut self.phase {
let (pending_splice_post, post_funding, dual_funding_context, our_funding_contribution) =
let (pending_splice_post, post_funding, dual_funding_context, unfunded_context, our_funding_contribution) =
prev_chan.splice_ack(msg)?;

let _res = self.phase_to_splice(post_funding, dual_funding_context, pending_splice_post)?;
let _res = self.phase_from_funded_to_splice(post_funding, dual_funding_context, unfunded_context, pending_splice_post)?;

if let ChannelPhase::RefundingV2(chan) = &mut self.phase {
let tx_msg_opt = chan.splice_ack(msg, our_funding_contribution, signer_provider, entropy_source, our_node_id, logger)?;
Expand Down Expand Up @@ -1740,9 +1801,9 @@ pub(super) struct SplicingChannel<SP: Deref> where SP::Target: SignerProvider {
/// TODO: replace it with its fields; done with trait?
pub pre_funded: FundedChannel<SP>,

// Fields for PendingV2Channel follow, except ChannelContext
// Fields from PendingV2Channel follow, except ChannelContext, which is reused from above
pub post_funding: FundingScope,
// pub unfunded_context: Option<UnfundedChannelContext>,
pub unfunded_context: UnfundedChannelContext,
/// Used when negotiating the splice transaction
pub dual_funding_context: DualFundingChannelContext,
/// The current interactive transaction construction session under negotiation.
Expand All @@ -1755,18 +1816,18 @@ pub(super) struct SplicingChannel<SP: Deref> where SP::Target: SignerProvider {

#[cfg(splicing)]
impl<SP: Deref> SplicingChannel<SP> where SP::Target: SignerProvider {
fn new(pre_funded: FundedChannel<SP>, post_funding: FundingScope, dual_funding_context: DualFundingChannelContext, pending_splice_post: PendingSplicePost) -> Self {
fn new(pre_funded: FundedChannel<SP>, post_funding: FundingScope, dual_funding_context: DualFundingChannelContext, unfunded_context: UnfundedChannelContext, pending_splice_post: PendingSplicePost) -> Self {
Self {
pre_funded,
post_funding,
dual_funding_context,
unfunded_context,
interactive_tx_constructor: None,
pending_splice_post,
}
}

/// Handle splice_init
#[cfg(splicing)]
pub fn splice_init<ES: Deref, L: Deref>(
&mut self, _msg: &msgs::SpliceInit, our_funding_contribution: i64,
signer_provider: &SP, entropy_source: &ES, holder_node_id: &PublicKey, logger: &L,
Expand All @@ -1788,7 +1849,6 @@ impl<SP: Deref> SplicingChannel<SP> where SP::Target: SignerProvider {
}

/// Handle splice_ack
#[cfg(splicing)]
pub fn splice_ack<ES: Deref, L: Deref>(
&mut self, msg: &msgs::SpliceAck, our_funding_contribution: i64,
signer_provider: &SP, entropy_source: &ES, holder_node_id: &PublicKey, logger: &L,
Expand Down Expand Up @@ -1824,7 +1884,6 @@ impl<SP: Deref> SplicingChannel<SP> where SP::Target: SignerProvider {
}

/// Splice process starting; update state, log, etc.
#[cfg(splicing)]
pub(crate) fn splice_start<L: Deref>(&mut self, is_outgoing: bool, logger: &L) where L::Target: Logger {
// Set state, by this point splice_init/splice_ack handshake is complete
// TODO(splicing)
Expand Down Expand Up @@ -1997,15 +2056,99 @@ impl<SP: Deref> SplicingChannel<SP> where SP::Target: SignerProvider {
HandleTxCompleteResult(Ok(tx_complete))
}

// TODO implement and use
// pub fn funding_tx_constructed<L: Deref>(
// self, signing_session: InteractiveTxSigningSession, logger: &L
// ) -> Result<(msgs::CommitmentSigned, Option<Event>), ChannelError> where L::Target: Logger {
// match self.post_pending.funding_tx_constructed(signing_session, logger) {
// Ok((_chan, msg, event)) => Ok((msg, event)),
// Err((_chan, err)) => Err(err),
// }
// }
/// Copied from PendingV2Channel::funding_tx_constructed
/// TODO avoid code duplication with traits
fn funding_tx_constructed<L: Deref>(
mut self, mut signing_session: InteractiveTxSigningSession, logger: &L
) -> Result<(InteractiveTxSigningSession, HolderCommitmentPoint, msgs::CommitmentSigned, Option<Event>), (SplicingChannel<SP>, ChannelError)>
where
L::Target: Logger
{
let our_funding_satoshis = self.dual_funding_context.our_funding_satoshis;
let transaction_number = self.unfunded_context.transaction_number();

let mut output_index = None;
let expected_spk = self.pre_funded.funding.get_funding_redeemscript().to_p2wsh();
for (idx, outp) in signing_session.unsigned_tx.outputs().enumerate() {
if outp.script_pubkey() == &expected_spk && outp.value() == self.post_funding.get_value_satoshis() {
if output_index.is_some() {
return Err(ChannelError::Close((
"Multiple outputs matched the expected script and value".to_owned(),
ClosureReason::HolderForceClosed { broadcasted_latest_txn: Some(false) },
))).map_err(|e| (self, e));
}
output_index = Some(idx as u16);
}
}
let outpoint = if let Some(output_index) = output_index {
OutPoint { txid: signing_session.unsigned_tx.compute_txid(), index: output_index }
} else {
return Err(ChannelError::Close((
"No output matched the funding script_pubkey".to_owned(),
ClosureReason::HolderForceClosed { broadcasted_latest_txn: Some(false) },
))).map_err(|e| (self, e));
};
self.pre_funded.funding.channel_transaction_parameters.funding_outpoint = Some(outpoint);
// self.pre_funded.context.holder_signer.as_mut_ecdsa().provide_channel_parameters(&self.pre_funded.funding.channel_transaction_parameters);

self.pre_funded.context.assert_no_commitment_advancement(transaction_number, "initial commitment_signed");
let commitment_signed = self.pre_funded.context.get_initial_commitment_signed(&self.post_funding, logger);
let commitment_signed = match commitment_signed {
Ok(commitment_signed) => {
self.pre_funded.funding.funding_transaction = Some(signing_session.unsigned_tx.build_unsigned_tx());
commitment_signed
},
Err(err) => {
self.pre_funded.funding.channel_transaction_parameters.funding_outpoint = None;
return Err(ChannelError::Close((err.to_string(), ClosureReason::HolderForceClosed { broadcasted_latest_txn: Some(false) })))
.map_err(|e| (self, e));
},
};

let funding_ready_for_sig_event = None;
if signing_session.local_inputs_count() == 0 {
debug_assert_eq!(our_funding_satoshis, 0);
if signing_session.provide_holder_witnesses(self.pre_funded.context.channel_id, Vec::new()).is_err() {
debug_assert!(
false,
"Zero inputs were provided & zero witnesses were provided, but a count mismatch was somehow found",
);
}
} else {
// TODO(dual_funding): Send event for signing if we've contributed funds.
// Inform the user that SIGHASH_ALL must be used for all signatures when contributing
// inputs/signatures.
// Also warn the user that we don't do anything to prevent the counterparty from
// providing non-standard witnesses which will prevent the funding transaction from
// confirming. This warning must appear in doc comments wherever the user is contributing
// funds, whether they are initiator or acceptor.
//
// The following warning can be used when the APIs allowing contributing inputs become available:
// <div class="warning">
// WARNING: LDK makes no attempt to prevent the counterparty from using non-standard inputs which
// will prevent the funding transaction from being relayed on the bitcoin network and hence being
// confirmed.
// </div>
}

self.pre_funded.context.channel_state = ChannelState::FundingNegotiated;

// Clear the interactive transaction constructor
self.interactive_tx_constructor.take();

match self.unfunded_context.holder_commitment_point {
Some(holder_commitment_point) => {
Ok((signing_session, holder_commitment_point, commitment_signed, funding_ready_for_sig_event))
},
None => {
let err = ChannelError::close(format!(
"Expected to have holder commitment points available upon finishing interactive tx construction for channel {}",
self.pre_funded.context.channel_id(),
));
Err((self, err))
},
}
}
}

/// Contains all state common to unfunded inbound/outbound channels.
Expand Down Expand Up @@ -9213,7 +9356,7 @@ impl<SP: Deref> FundedChannel<SP> where
#[cfg(splicing)]
fn splice_init(
&mut self, msg: &msgs::SpliceInit, our_funding_contribution: i64,
) -> Result<(PendingSplicePost, FundingScope, DualFundingChannelContext), ChannelError>
) -> Result<(PendingSplicePost, FundingScope, DualFundingChannelContext, UnfundedChannelContext), ChannelError>
{
let _res = self.splice_init_checks(msg)?;

Expand Down Expand Up @@ -9264,12 +9407,12 @@ impl<SP: Deref> FundedChannel<SP> where
funding_feerate_sat_per_1000_weight: msg.funding_feerate_per_kw,
our_funding_inputs: Vec::new(),
};
// let unfunded_context = UnfundedChannelContext {
// unfunded_channel_age_ticks: 0,
// holder_commitment_point: HolderCommitmentPoint::new(&context.holder_signer, &context.secp_ctx),
// };
let unfunded_context = UnfundedChannelContext {
unfunded_channel_age_ticks: 0,
holder_commitment_point: HolderCommitmentPoint::new(&self.context.holder_signer, &self.context.secp_ctx),
};

Ok((pending_splice_post, post_funding, dual_funding_context))
Ok((pending_splice_post, post_funding, dual_funding_context, unfunded_context))
}

/// Get the splice_ack message that can be sent in response to splice initiation.
Expand Down Expand Up @@ -9301,7 +9444,7 @@ impl<SP: Deref> FundedChannel<SP> where
#[cfg(splicing)]
fn splice_ack(
&mut self, msg: &msgs::SpliceAck,
) -> Result<(PendingSplicePost, FundingScope, DualFundingChannelContext, i64), ChannelError>
) -> Result<(PendingSplicePost, FundingScope, DualFundingChannelContext, UnfundedChannelContext, i64), ChannelError>
{
let pending_splice = self.splice_ack_checks()?;

Expand Down Expand Up @@ -9352,12 +9495,12 @@ impl<SP: Deref> FundedChannel<SP> where
funding_feerate_sat_per_1000_weight: pending_splice.funding_feerate_per_kw,
our_funding_inputs: pending_splice.our_funding_inputs.clone(),
};
// let unfunded_context = UnfundedChannelContext {
// unfunded_channel_age_ticks: 0,
// holder_commitment_point: HolderCommitmentPoint::new(&context.holder_signer, &context.secp_ctx),
// };
let unfunded_context = UnfundedChannelContext {
unfunded_channel_age_ticks: 0,
holder_commitment_point: HolderCommitmentPoint::new(&self.context.holder_signer, &self.context.secp_ctx),
};

Ok((pending_splice_post, post_funding, dual_funding_context, pending_splice.our_funding_contribution))
Ok((pending_splice_post, post_funding, dual_funding_context, unfunded_context, pending_splice.our_funding_contribution))
}

// Send stuff to our remote peers:
Expand Down
5 changes: 4 additions & 1 deletion lightning/src/ln/channelmanager.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -8548,7 +8548,9 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
if let Some(msg_send_event) = msg_send_event_opt {
peer_state.pending_msg_events.push(msg_send_event);
};
if let Some(signing_session) = signing_session_opt {
if let Some(_signing_session) = signing_session_opt {
panic!("TODO Fix commitment handling, execution should get to here");
/*
let (commitment_signed, funding_ready_for_sig_event_opt) = chan_entry
.get_mut()
.funding_tx_constructed(signing_session, &self.logger)
Expand All @@ -8568,6 +8570,7 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
update_fee: None,
},
});
*/
}
Ok(())
},
Expand Down

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