*/
public enum ConfirmationTarget {
/**
- * We'd like a transaction to confirm in the future, but don't want to commit most of the fees
- * required to do so yet. The remaining fees will come via a Child-Pays-For-Parent (CPFP) fee
- * bump of the transaction.
+ * We have some funds available on chain which we need to spend prior to some expiry time at
+ * which point our counterparty may be able to steal them. Generally we have in the high tens
+ * to low hundreds of blocks to get our transaction on-chain, but we shouldn't risk too low a
+ * fee - this should be a relatively high priority feerate.
+ */
+ LDKConfirmationTarget_OnChainSweep,
+ /**
+ * The highest feerate we will allow our channel counterparty to have in a non-anchor channel.
+ *
+ * This is the feerate on the transaction which we (or our counterparty) will broadcast in
+ * order to close the channel unilaterally. Because our counterparty must ensure they can
+ * always broadcast the latest state, this value being too low will cause immediate
+ * force-closures.
*
- * The feerate returned should be the absolute minimum feerate required to enter most node
- * mempools across the network. Note that if you are not able to obtain this feerate estimate,
- * you should likely use the furthest-out estimate allowed by your fee estimator.
+ * Allowing this value to be too high can allow our counterparty to burn our HTLC outputs to
+ * dust, which can result in HTLCs failing or force-closures (when the dust HTLCs exceed
+ * [`ChannelConfig::max_dust_htlc_exposure`]).
+ *
+ * Because most nodes use a feerate estimate which is based on a relatively high priority
+ * transaction entering the current mempool, setting this to a small multiple of your current
+ * high priority feerate estimate should suffice.
+ *
+ * [`ChannelConfig::max_dust_htlc_exposure`]: crate::util::config::ChannelConfig::max_dust_htlc_exposure
*/
- LDKConfirmationTarget_MempoolMinimum,
+ LDKConfirmationTarget_MaxAllowedNonAnchorChannelRemoteFee,
/**
- * We are happy with a transaction confirming slowly, at least within a day or so worth of
- * blocks.
+ * This is the lowest feerate we will allow our channel counterparty to have in an anchor
+ * channel in order to close the channel if a channel party goes away.
+ *
+ * This needs to be sufficient to get into the mempool when the channel needs to
+ * be force-closed. Setting too high may result in force-closures if our counterparty attempts
+ * to use a lower feerate. Because this is for anchor channels, we can always bump the feerate
+ * later; the feerate here only needs to be sufficient to enter the mempool.
+ *
+ * A good estimate is the expected mempool minimum at the time of force-closure. Obviously this
+ * is not an estimate which is very easy to calculate because we do not know the future. Using
+ * a simple long-term fee estimate or tracking of the mempool minimum is a good approach to
+ * ensure you can always close the channel. A future change to Bitcoin's P2P network
+ * (package relay) may obviate the need for this entirely.
*/
- LDKConfirmationTarget_Background,
+ LDKConfirmationTarget_MinAllowedAnchorChannelRemoteFee,
/**
- * We'd like a transaction to confirm without major delayed, i.e., within the next 12-24 blocks.
+ * The lowest feerate we will allow our channel counterparty to have in a non-anchor channel.
+ *
+ * This is the feerate on the transaction which we (or our counterparty) will broadcast in
+ * order to close the channel if a channel party goes away. Setting this value too high will
+ * cause immediate force-closures in order to avoid having an unbroadcastable state.
+ *
+ * This feerate represents the fee we pick now, which must be sufficient to enter a block at an
+ * arbitrary time in the future. Obviously this is not an estimate which is very easy to
+ * calculate. This can leave channels subject to being unable to close if feerates rise, and in
+ * general you should prefer anchor channels to ensure you can increase the feerate when the
+ * transactions need broadcasting.
+ *
+ * Do note some fee estimators round up to the next full sat/vbyte (ie 250 sats per kw),
+ * causing occasional issues with feerate disagreements between an initiator that wants a
+ * feerate of 1.1 sat/vbyte and a receiver that wants 1.1 rounded up to 2. If your fee
+ * estimator rounds subtracting 250 to your desired feerate here can help avoid this issue.
+ *
+ * [`ChannelConfig::max_dust_htlc_exposure`]: crate::util::config::ChannelConfig::max_dust_htlc_exposure
*/
- LDKConfirmationTarget_Normal,
+ LDKConfirmationTarget_MinAllowedNonAnchorChannelRemoteFee,
/**
- * We'd like a transaction to confirm in the next few blocks.
+ * This is the feerate on the transaction which we (or our counterparty) will broadcast in
+ * order to close the channel if a channel party goes away.
+ *
+ * This needs to be sufficient to get into the mempool when the channel needs to
+ * be force-closed. Setting too low may result in force-closures. Because this is for anchor
+ * channels, it can be a low value as we can always bump the feerate later.
+ *
+ * A good estimate is the expected mempool minimum at the time of force-closure. Obviously this
+ * is not an estimate which is very easy to calculate because we do not know the future. Using
+ * a simple long-term fee estimate or tracking of the mempool minimum is a good approach to
+ * ensure you can always close the channel. A future change to Bitcoin's P2P network
+ * (package relay) may obviate the need for this entirely.
+ */
+ LDKConfirmationTarget_AnchorChannelFee,
+ /**
+ * Lightning is built around the ability to broadcast a transaction in the future to close our
+ * channel and claim all pending funds. In order to do so, non-anchor channels are built with
+ * transactions which we need to be able to broadcast at some point in the future.
+ *
+ * This feerate represents the fee we pick now, which must be sufficient to enter a block at an
+ * arbitrary time in the future. Obviously this is not an estimate which is very easy to
+ * calculate, so most lightning nodes use some relatively high-priority feerate using the
+ * current mempool. This leaves channels subject to being unable to close if feerates rise, and
+ * in general you should prefer anchor channels to ensure you can increase the feerate when the
+ * transactions need broadcasting.
+ *
+ * Since this should represent the feerate of a channel close that does not need fee
+ * bumping, this is also used as an upper bound for our attempted feerate when doing cooperative
+ * closure of any channel.
+ */
+ LDKConfirmationTarget_NonAnchorChannelFee,
+ /**
+ * When cooperatively closing a channel, this is the minimum feerate we will accept.
+ * Recommended at least within a day or so worth of blocks.
+ *
+ * This will also be used when initiating a cooperative close of a channel. When closing a
+ * channel you can override this fee by using
+ * [`ChannelManager::close_channel_with_feerate_and_script`].
+ *
+ * [`ChannelManager::close_channel_with_feerate_and_script`]: crate::ln::channelmanager::ChannelManager::close_channel_with_feerate_and_script
*/
- LDKConfirmationTarget_HighPriority,
+ LDKConfirmationTarget_ChannelCloseMinimum,
}} } }
projects / ldk-java / blobdiff