use crate::ln::msgs::DecodeError;
use crate::ln::PaymentPreimage;
#[cfg(anchors)]
-use crate::ln::chan_utils;
+use crate::ln::chan_utils::{self, HTLCOutputInCommitment};
use crate::ln::chan_utils::{ChannelTransactionParameters, HolderCommitmentTransaction};
#[cfg(anchors)]
use crate::chain::chaininterface::ConfirmationTarget;
}
}
+#[cfg(anchors)]
+/// The claim commonly referred to as the pre-signed second-stage HTLC transaction.
+pub(crate) struct ExternalHTLCClaim {
+ pub(crate) commitment_txid: Txid,
+ pub(crate) per_commitment_number: u64,
+ pub(crate) htlc: HTLCOutputInCommitment,
+ pub(crate) preimage: Option<PaymentPreimage>,
+ pub(crate) counterparty_sig: Signature,
+}
+
// Represents the different types of claims for which events are yielded externally to satisfy said
// claims.
#[cfg(anchors)]
commitment_tx: Transaction,
anchor_output_idx: u32,
},
+ /// Event yielded to signal that the commitment transaction has confirmed and its HTLCs must be
+ /// resolved by broadcasting a transaction with sufficient fee to claim them.
+ BumpHTLC {
+ target_feerate_sat_per_1000_weight: u32,
+ htlcs: Vec<ExternalHTLCClaim>,
+ },
}
/// Represents the different ways an output can be claimed (i.e., spent to an address under our
// didn't receive confirmation of it before, or not enough reorg-safe depth on top of it).
let new_timer = Some(cached_request.get_height_timer(cur_height));
if cached_request.is_malleable() {
+ #[cfg(anchors)]
+ { // Attributes are not allowed on if expressions on our current MSRV of 1.41.
+ if cached_request.requires_external_funding() {
+ let target_feerate_sat_per_1000_weight = cached_request
+ .compute_package_feerate(fee_estimator, ConfirmationTarget::HighPriority);
+ if let Some(htlcs) = cached_request.construct_malleable_package_with_external_funding(self) {
+ return Some((
+ new_timer,
+ target_feerate_sat_per_1000_weight as u64,
+ OnchainClaim::Event(ClaimEvent::BumpHTLC {
+ target_feerate_sat_per_1000_weight,
+ htlcs,
+ }),
+ ));
+ } else {
+ return None;
+ }
+ }
+ }
+
let predicted_weight = cached_request.package_weight(&self.destination_script);
- if let Some((output_value, new_feerate)) =
- cached_request.compute_package_output(predicted_weight, self.destination_script.dust_value().to_sat(), fee_estimator, logger) {
+ if let Some((output_value, new_feerate)) = cached_request.compute_package_output(
+ predicted_weight, self.destination_script.dust_value().to_sat(), fee_estimator, logger,
+ ) {
assert!(new_feerate != 0);
let transaction = cached_request.finalize_malleable_package(self, output_value, self.destination_script.clone(), logger).unwrap();
log_trace!(logger, "...with timer {} and feerate {}", new_timer.unwrap(), new_feerate);
assert!(predicted_weight >= transaction.weight());
- return Some((new_timer, new_feerate, OnchainClaim::Tx(transaction)))
+ return Some((new_timer, new_feerate, OnchainClaim::Tx(transaction)));
}
} else {
// Untractable packages cannot have their fees bumped through Replace-By-Fee. Some
debug_assert!(false, "Only HolderFundingOutput inputs should be untractable and require external funding");
None
},
- });
+ })
}
None
}
#[cfg(anchors)]
OnchainClaim::Event(claim_event) => {
log_info!(logger, "Yielding onchain event to spend inputs {:?}", req.outpoints());
- let txid = match claim_event {
- ClaimEvent::BumpCommitment { ref commitment_tx, .. } => commitment_tx.txid(),
+ let package_id = match claim_event {
+ ClaimEvent::BumpCommitment { ref commitment_tx, .. } => commitment_tx.txid().into_inner(),
+ ClaimEvent::BumpHTLC { ref htlcs, .. } => {
+ // Use the same construction as a lightning channel id to generate
+ // the package id for this request based on the first HTLC. It
+ // doesn't matter what we use as long as it's unique per request.
+ let mut package_id = [0; 32];
+ package_id[..].copy_from_slice(&htlcs[0].commitment_txid[..]);
+ let htlc_output_index = htlcs[0].htlc.transaction_output_index.unwrap();
+ package_id[30] ^= ((htlc_output_index >> 8) & 0xff) as u8;
+ package_id[31] ^= ((htlc_output_index >> 0) & 0xff) as u8;
+ package_id
+ },
};
- let package_id = txid.into_inner();
self.pending_claim_events.insert(package_id, claim_event);
package_id
},
// outpoints to know if transaction is the original claim or a bumped one issued
// by us.
let mut set_equality = true;
- if request.outpoints().len() != tx.input.len() {
- set_equality = false;
+ if !request.requires_external_funding() || !request.is_malleable() {
+ // If the claim does not require external funds to be allocated through
+ // additional inputs we can simply check the inputs in order as they
+ // cannot change under us.
+ if request.outpoints().len() != tx.input.len() {
+ set_equality = false;
+ } else {
+ for (claim_inp, tx_inp) in request.outpoints().iter().zip(tx.input.iter()) {
+ if **claim_inp != tx_inp.previous_output {
+ set_equality = false;
+ }
+ }
+ }
} else {
- for (claim_inp, tx_inp) in request.outpoints().iter().zip(tx.input.iter()) {
- if **claim_inp != tx_inp.previous_output {
- set_equality = false;
+ // Otherwise, we'll do a linear search for each input (we don't expect
+ // large input sets to exist) to ensure the request's input set is fully
+ // spent to be resilient against the external claim reordering inputs.
+ let mut spends_all_inputs = true;
+ for request_input in request.outpoints() {
+ if tx.input.iter().find(|input| input.previous_output == *request_input).is_none() {
+ spends_all_inputs = false;
+ break;
}
}
+ set_equality = spends_all_inputs;
}
macro_rules! clean_claim_request_after_safety_delay {
htlc_tx
}
+ #[cfg(anchors)]
+ pub(crate) fn generate_external_htlc_claim(
+ &mut self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>
+ ) -> Option<ExternalHTLCClaim> {
+ let find_htlc = |holder_commitment: &HolderCommitmentTransaction| -> Option<ExternalHTLCClaim> {
+ let trusted_tx = holder_commitment.trust();
+ if outp.txid != trusted_tx.txid() {
+ return None;
+ }
+ trusted_tx.htlcs().iter().enumerate()
+ .find(|(_, htlc)| if let Some(output_index) = htlc.transaction_output_index {
+ output_index == outp.vout
+ } else {
+ false
+ })
+ .map(|(htlc_idx, htlc)| {
+ let counterparty_htlc_sig = holder_commitment.counterparty_htlc_sigs[htlc_idx];
+ ExternalHTLCClaim {
+ commitment_txid: trusted_tx.txid(),
+ per_commitment_number: trusted_tx.commitment_number(),
+ htlc: htlc.clone(),
+ preimage: *preimage,
+ counterparty_sig: counterparty_htlc_sig,
+ }
+ })
+ };
+ // Check if the HTLC spends from the current holder commitment or the previous one otherwise.
+ find_htlc(&self.holder_commitment)
+ .or_else(|| self.prev_holder_commitment.as_ref().map(|c| find_htlc(c)).flatten())
+ }
+
pub(crate) fn opt_anchors(&self) -> bool {
self.channel_transaction_parameters.opt_anchors.is_some()
}
use crate::ln::msgs::DecodeError;
use crate::chain::chaininterface::{FeeEstimator, ConfirmationTarget, MIN_RELAY_FEE_SAT_PER_1000_WEIGHT};
use crate::chain::keysinterface::Sign;
+#[cfg(anchors)]
+use crate::chain::onchaintx::ExternalHTLCClaim;
use crate::chain::onchaintx::OnchainTxHandler;
use crate::util::logger::Logger;
use crate::util::ser::{Readable, Writer, Writeable};
}
fn get_finalized_tx<Signer: Sign>(&self, outpoint: &BitcoinOutPoint, onchain_handler: &mut OnchainTxHandler<Signer>) -> Option<Transaction> {
match self {
- PackageSolvingData::HolderHTLCOutput(ref outp) => { return onchain_handler.get_fully_signed_htlc_tx(outpoint, &outp.preimage); }
- PackageSolvingData::HolderFundingOutput(ref outp) => { return Some(onchain_handler.get_fully_signed_holder_tx(&outp.funding_redeemscript)); }
+ PackageSolvingData::HolderHTLCOutput(ref outp) => {
+ debug_assert!(!outp.opt_anchors());
+ return onchain_handler.get_fully_signed_htlc_tx(outpoint, &outp.preimage);
+ }
+ PackageSolvingData::HolderFundingOutput(ref outp) => {
+ return Some(onchain_handler.get_fully_signed_holder_tx(&outp.funding_redeemscript));
+ }
_ => { panic!("API Error!"); }
}
}
let output_weight = (8 + 1 + destination_script.len()) * WITNESS_SCALE_FACTOR;
inputs_weight + witnesses_weight + transaction_weight + output_weight
}
+ #[cfg(anchors)]
+ pub(crate) fn construct_malleable_package_with_external_funding<Signer: Sign>(
+ &self, onchain_handler: &mut OnchainTxHandler<Signer>,
+ ) -> Option<Vec<ExternalHTLCClaim>> {
+ debug_assert!(self.requires_external_funding());
+ let mut htlcs: Option<Vec<ExternalHTLCClaim>> = None;
+ for (previous_output, input) in &self.inputs {
+ match input {
+ PackageSolvingData::HolderHTLCOutput(ref outp) => {
+ debug_assert!(outp.opt_anchors());
+ onchain_handler.generate_external_htlc_claim(&previous_output, &outp.preimage).map(|htlc| {
+ htlcs.get_or_insert_with(|| Vec::with_capacity(self.inputs.len())).push(htlc);
+ });
+ }
+ _ => debug_assert!(false, "Expected HolderHTLCOutputs to not be aggregated with other input types"),
+ }
+ }
+ htlcs
+ }
pub(crate) fn finalize_malleable_package<L: Deref, Signer: Sign>(
&self, onchain_handler: &mut OnchainTxHandler<Signer>, value: u64, destination_script: Script, logger: &L
) -> Option<Transaction> where L::Target: Logger {
projects / rust-lightning / commitdiff