//! few other things.
use chain::keysinterface::SpendableOutputDescriptor;
+use ln::chan_utils::HTLCOutputInCommitment;
use ln::channelmanager::PaymentId;
use ln::channel::FUNDING_CONF_DEADLINE_BLOCKS;
use ln::features::ChannelTypeFeatures;
use util::ser::{BigSize, FixedLengthReader, Writeable, Writer, MaybeReadable, Readable, VecReadWrapper, VecWriteWrapper};
use routing::router::{RouteHop, RouteParameters};
-use bitcoin::{PackedLockTime, Transaction};
+use bitcoin::{PackedLockTime, Transaction, OutPoint};
use bitcoin::blockdata::script::Script;
use bitcoin::hashes::Hash;
use bitcoin::hashes::sha256::Hash as Sha256;
}
);
+/// A descriptor used to sign for a commitment transaction's anchor output.
+#[derive(Clone, Debug)]
+pub struct AnchorDescriptor {
+ /// 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 transaction input's outpoint corresponding to the commitment transaction's anchor
+ /// output.
+ pub outpoint: OutPoint,
+}
+
+/// Represents the different types of transactions, originating from LDK, to be bumped.
+#[derive(Clone, Debug)]
+pub enum BumpTransactionEvent {
+ /// Indicates that a channel featuring anchor outputs is to be closed by broadcasting the local
+ /// commitment transaction. Since commitment transactions have a static feerate pre-agreed upon,
+ /// they may need additional fees to be attached through a child transaction using the popular
+ /// [Child-Pays-For-Parent](https://bitcoinops.org/en/topics/cpfp) fee bumping technique. This
+ /// child transaction must include the anchor input described within `anchor_descriptor` along
+ /// with additional inputs to meet the target feerate. Failure to meet the target feerate
+ /// decreases the confirmation odds of the transaction package (which includes the commitment
+ /// and child anchor transactions), possibly resulting in a loss of funds. Once the transaction
+ /// is constructed, it must be fully signed for and broadcasted by the consumer of the event
+ /// along with the `commitment_tx` enclosed. Note that the `commitment_tx` must always be
+ /// broadcast first, as the child anchor transaction depends on it.
+ ///
+ /// 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`].
+ ///
+ /// 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
+ /// be taken by the consumer of the event to ensure any future iterations of the child anchor
+ /// 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 they are no longer
+ /// able to commit external confirmed funds to the child anchor transaction.
+ ///
+ /// The set of `pending_htlcs` on the commitment transaction to be broadcast can be inspected to
+ /// determine whether a significant portion of the channel's funds are allocated to HTLCs,
+ /// enabling users to make their own decisions regarding the importance of the commitment
+ /// transaction's confirmation. Note that this is not required, but simply exists as an option
+ /// for users to override LDK's behavior. On commitments with no HTLCs (indicated by those with
+ /// an empty `pending_htlcs`), confirmation of the commitment transaction can be considered to
+ /// be not urgent.
+ ///
+ /// [`InMemorySigner`]: crate::chain::keysinterface::InMemorySigner
+ /// [`KeysManager::derive_channel_keys`]: crate::chain::keysinterface::KeysManager::derive_channel_keys
+ ChannelClose {
+ /// The target feerate that the transaction package, which consists of the commitment
+ /// transaction and the to-be-crafted child anchor transaction, must meet.
+ package_target_feerate_sat_per_1000_weight: u32,
+ /// The channel's commitment transaction to bump the fee of. This transaction should be
+ /// broadcast along with the anchor transaction constructed as a result of consuming this
+ /// event.
+ commitment_tx: Transaction,
+ /// The absolute fee in satoshis of the commitment transaction. This can be used along the
+ /// with weight of the commitment transaction to determine its feerate.
+ commitment_tx_fee_satoshis: u64,
+ /// The descriptor to sign the anchor input of the anchor transaction constructed as a
+ /// result of consuming this event.
+ anchor_descriptor: AnchorDescriptor,
+ /// The set of pending HTLCs on the commitment transaction that need to be resolved once the
+ /// commitment transaction confirms.
+ pending_htlcs: Vec<HTLCOutputInCommitment>,
+ },
+}
+
/// An Event which you should probably take some action in response to.
///
/// Note that while Writeable and Readable are implemented for Event, you probably shouldn't use
/// Destination of the HTLC that failed to be processed.
failed_next_destination: HTLCDestination,
},
+ #[cfg(anchors)]
+ /// Indicates that a transaction originating from LDK needs to have its fee bumped. This event
+ /// requires confirmed external funds to be readily available to spend.
+ ///
+ /// LDK does not currently generate this event. It is limited to the scope of channels with
+ /// anchor outputs, which will be introduced in a future release.
+ BumpTransaction(BumpTransactionEvent),
}
impl Writeable for Event {
(2, failed_next_destination, required),
})
},
+ #[cfg(anchors)]
+ &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.
+ BumpTransactionEvent::ChannelClose { .. } => {}
+ }
+ }
// Note that, going forward, all new events must only write data inside of
// `write_tlv_fields`. Versions 0.0.101+ will ignore odd-numbered events that write
// data via `write_tlv_fields`.
projects / rust-lightning / blobdiff