use crate::chain::keysinterface::SpendableOutputDescriptor;
#[cfg(anchors)]
-use crate::ln::chan_utils::HTLCOutputInCommitment;
+use crate::ln::chan_utils::{self, ChannelTransactionParameters, HTLCOutputInCommitment};
use crate::ln::channelmanager::{InterceptId, PaymentId};
use crate::ln::channel::FUNDING_CONF_DEADLINE_BLOCKS;
use crate::ln::features::ChannelTypeFeatures;
use bitcoin::{PackedLockTime, Transaction};
#[cfg(anchors)]
-use bitcoin::OutPoint;
+use bitcoin::{OutPoint, Txid, TxIn, TxOut, Witness};
use bitcoin::blockdata::script::Script;
use bitcoin::hashes::Hash;
use bitcoin::hashes::sha256::Hash as Sha256;
use bitcoin::secp256k1::PublicKey;
+#[cfg(anchors)]
+use bitcoin::secp256k1::{self, Secp256k1};
+#[cfg(anchors)]
+use bitcoin::secp256k1::ecdsa::Signature;
use crate::io;
use crate::prelude::*;
use core::time::Duration;
pub outpoint: OutPoint,
}
+#[cfg(anchors)]
+/// A descriptor used to sign for a commitment transaction's HTLC output.
+#[derive(Clone, Debug)]
+pub struct HTLCDescriptor {
+ /// A unique identifier used along with `channel_value_satoshis` to re-derive the
+ /// [`InMemorySigner`] required to sign `input`.
+ ///
+ /// [`InMemorySigner`]: crate::chain::keysinterface::InMemorySigner
+ pub channel_keys_id: [u8; 32],
+ /// The value in satoshis of the channel we're attempting to spend the anchor output of. This is
+ /// used along with `channel_keys_id` to re-derive the [`InMemorySigner`] required to sign
+ /// `input`.
+ ///
+ /// [`InMemorySigner`]: crate::chain::keysinterface::InMemorySigner
+ pub channel_value_satoshis: u64,
+ /// The necessary channel parameters that need to be provided to the re-derived
+ /// [`InMemorySigner`] through [`BaseSign::ready_channel`].
+ ///
+ /// [`InMemorySigner`]: crate::chain::keysinterface::InMemorySigner
+ /// [`BaseSign::ready_channel`]: crate::chain::keysinterface::BaseSign::ready_channel
+ pub channel_parameters: ChannelTransactionParameters,
+ /// The txid of the commitment transaction in which the HTLC output lives.
+ pub commitment_txid: Txid,
+ /// The number of the commitment transaction in which the HTLC output lives.
+ pub per_commitment_number: u64,
+ /// The details of the HTLC as it appears in the commitment transaction.
+ pub htlc: HTLCOutputInCommitment,
+ /// The preimage, if `Some`, to claim the HTLC output with. If `None`, the timeout path must be
+ /// taken.
+ pub preimage: Option<PaymentPreimage>,
+ /// The counterparty's signature required to spend the HTLC output.
+ pub counterparty_sig: Signature
+}
+
+#[cfg(anchors)]
+impl HTLCDescriptor {
+ /// Returns the unsigned transaction input spending the HTLC output in the commitment
+ /// transaction.
+ pub fn unsigned_tx_input(&self) -> TxIn {
+ chan_utils::build_htlc_input(&self.commitment_txid, &self.htlc, true /* opt_anchors */)
+ }
+
+ /// Returns the delayed output created as a result of spending the HTLC output in the commitment
+ /// transaction.
+ pub fn tx_output<C: secp256k1::Signing + secp256k1::Verification>(
+ &self, per_commitment_point: &PublicKey, secp: &Secp256k1<C>
+ ) -> TxOut {
+ let channel_params = self.channel_parameters.as_holder_broadcastable();
+ let broadcaster_keys = channel_params.broadcaster_pubkeys();
+ let counterparty_keys = channel_params.countersignatory_pubkeys();
+ let broadcaster_delayed_key = chan_utils::derive_public_key(
+ secp, per_commitment_point, &broadcaster_keys.delayed_payment_basepoint
+ );
+ let counterparty_revocation_key = chan_utils::derive_public_revocation_key(
+ secp, per_commitment_point, &counterparty_keys.revocation_basepoint
+ );
+ chan_utils::build_htlc_output(
+ 0 /* feerate_per_kw */, channel_params.contest_delay(), &self.htlc, true /* opt_anchors */,
+ false /* use_non_zero_fee_anchors */, &broadcaster_delayed_key, &counterparty_revocation_key
+ )
+ }
+
+ /// Returns the witness script of the HTLC output in the commitment transaction.
+ pub fn witness_script<C: secp256k1::Signing + secp256k1::Verification>(
+ &self, per_commitment_point: &PublicKey, secp: &Secp256k1<C>
+ ) -> Script {
+ let channel_params = self.channel_parameters.as_holder_broadcastable();
+ let broadcaster_keys = channel_params.broadcaster_pubkeys();
+ let counterparty_keys = channel_params.countersignatory_pubkeys();
+ let broadcaster_htlc_key = chan_utils::derive_public_key(
+ secp, per_commitment_point, &broadcaster_keys.htlc_basepoint
+ );
+ let counterparty_htlc_key = chan_utils::derive_public_key(
+ secp, per_commitment_point, &counterparty_keys.htlc_basepoint
+ );
+ let counterparty_revocation_key = chan_utils::derive_public_revocation_key(
+ secp, per_commitment_point, &counterparty_keys.revocation_basepoint
+ );
+ chan_utils::get_htlc_redeemscript_with_explicit_keys(
+ &self.htlc, true /* opt_anchors */, &broadcaster_htlc_key, &counterparty_htlc_key,
+ &counterparty_revocation_key,
+ )
+ }
+
+ /// Returns the fully signed witness required to spend the HTLC output in the commitment
+ /// transaction.
+ pub fn tx_input_witness(&self, signature: &Signature, witness_script: &Script) -> Witness {
+ chan_utils::build_htlc_input_witness(
+ signature, &self.counterparty_sig, &self.preimage, witness_script, true /* opt_anchors */
+ )
+ }
+}
+
#[cfg(anchors)]
/// Represents the different types of transactions, originating from LDK, to be bumped.
#[derive(Clone, Debug)]
/// The consumer should be able to sign for any of the additional inputs included within the
/// child anchor transaction. To sign its anchor input, an [`InMemorySigner`] should be
/// re-derived through [`KeysManager::derive_channel_keys`] with the help of
- /// [`AnchorDescriptor::channel_keys_id`] and [`AnchorDescriptor::channel_value_satoshis`].
+ /// [`AnchorDescriptor::channel_keys_id`] and [`AnchorDescriptor::channel_value_satoshis`]. The
+ /// anchor input signature can be computed with [`BaseSign::sign_holder_anchor_input`],
+ /// which can then be provided to [`build_anchor_input_witness`] along with the `funding_pubkey`
+ /// to obtain the full witness required to spend.
///
/// It is possible to receive more than one instance of this event if a valid child anchor
/// transaction is never broadcast or is but not with a sufficient fee to be mined. Care should
///
/// [`InMemorySigner`]: crate::chain::keysinterface::InMemorySigner
/// [`KeysManager::derive_channel_keys`]: crate::chain::keysinterface::KeysManager::derive_channel_keys
+ /// [`BaseSign::sign_holder_anchor_input`]: crate::chain::keysinterface::BaseSign::sign_holder_anchor_input
+ /// [`build_anchor_input_witness`]: crate::ln::chan_utils::build_anchor_input_witness
ChannelClose {
/// The target feerate that the transaction package, which consists of the commitment
/// transaction and the to-be-crafted child anchor transaction, must meet.
/// commitment transaction confirms.
pending_htlcs: Vec<HTLCOutputInCommitment>,
},
+ /// Indicates that a channel featuring anchor outputs has unilaterally closed on-chain by a
+ /// holder commitment transaction and its HTLC(s) need to be resolved on-chain. With the
+ /// zero-HTLC-transaction-fee variant of anchor outputs, the pre-signed HTLC
+ /// transactions have a zero fee, thus requiring additional inputs and/or outputs to be attached
+ /// for a timely confirmation within the chain. These additional inputs and/or outputs must be
+ /// appended to the resulting HTLC transaction to meet the target feerate. Failure to meet the
+ /// target feerate decreases the confirmation odds of the transaction, possibly resulting in a
+ /// loss of funds. Once the transaction meets the target feerate, it must be signed for and
+ /// broadcast by the consumer of the event.
+ ///
+ /// The consumer should be able to sign for any of the non-HTLC inputs added to the resulting
+ /// HTLC transaction. To sign HTLC inputs, an [`InMemorySigner`] should be re-derived through
+ /// [`KeysManager::derive_channel_keys`] with the help of `channel_keys_id` and
+ /// `channel_value_satoshis`. Each HTLC input's signature can be computed with
+ /// [`BaseSign::sign_holder_htlc_transaction`], which can then be provided to
+ /// [`HTLCDescriptor::tx_input_witness`] to obtain the fully signed witness required to spend.
+ ///
+ /// It is possible to receive more than one instance of this event if a valid HTLC transaction
+ /// is never broadcast or is but not with a sufficient fee to be mined. Care should be taken by
+ /// the consumer of the event to ensure any future iterations of the HTLC transaction adhere to
+ /// the [Replace-By-Fee
+ /// rules](https://github.com/bitcoin/bitcoin/blob/master/doc/policy/mempool-replacements.md)
+ /// for fee bumps to be accepted into the mempool, and eventually the chain. As the frequency of
+ /// these events is not user-controlled, users may ignore/drop the event if either they are no
+ /// longer able to commit external confirmed funds to the HTLC transaction or the fee committed
+ /// to the HTLC transaction is greater in value than the HTLCs being claimed.
+ ///
+ /// [`InMemorySigner`]: crate::chain::keysinterface::InMemorySigner
+ /// [`KeysManager::derive_channel_keys`]: crate::chain::keysinterface::KeysManager::derive_channel_keys
+ /// [`BaseSign::sign_holder_htlc_transaction`]: crate::chain::keysinterface::BaseSign::sign_holder_htlc_transaction
+ /// [`HTLCDescriptor::tx_input_witness`]: HTLCDescriptor::tx_input_witness
+ HTLCResolution {
+ target_feerate_sat_per_1000_weight: u32,
+ htlc_descriptors: Vec<HTLCDescriptor>,
+ },
}
/// Will be used in [`Event::HTLCIntercepted`] to identify the next hop in the HTLC's path.
&Event::BumpTransaction(ref event)=> {
27u8.write(writer)?;
match event {
- // We never write the ChannelClose events as they'll be replayed upon restarting
- // anyway if the commitment transaction remains unconfirmed.
+ // We never write the ChannelClose|HTLCResolution events as they'll be replayed
+ // upon restarting anyway if they remain unresolved.
BumpTransactionEvent::ChannelClose { .. } => {}
+ BumpTransactionEvent::HTLCResolution { .. } => {}
}
}
&Event::ChannelReady { ref channel_id, ref user_channel_id, ref counterparty_node_id, ref channel_type } => {
projects / rust-lightning / commitdiff