Class ChannelConfig


  • public class ChannelConfig
    extends Object
    Options which apply on a per-channel basis and may change at runtime or based on negotiation with our counterparty.
    • Method Detail

      • get_forwarding_fee_proportional_millionths

        public int get_forwarding_fee_proportional_millionths()
        Amount (in millionths of a satoshi) charged per satoshi for payments forwarded outbound over the channel. This may be allowed to change at runtime in a later update, however doing so must result in update messages sent to notify all nodes of our updated relay fee. Default value: 0.
      • set_forwarding_fee_proportional_millionths

        public void set_forwarding_fee_proportional_millionths​(int val)
        Amount (in millionths of a satoshi) charged per satoshi for payments forwarded outbound over the channel. This may be allowed to change at runtime in a later update, however doing so must result in update messages sent to notify all nodes of our updated relay fee. Default value: 0.
      • get_forwarding_fee_base_msat

        public int get_forwarding_fee_base_msat()
        Amount (in milli-satoshi) charged for payments forwarded outbound over the channel, in excess of [`forwarding_fee_proportional_millionths`]. This may be allowed to change at runtime in a later update, however doing so must result in update messages sent to notify all nodes of our updated relay fee. The default value of a single satoshi roughly matches the market rate on many routing nodes as of July 2021. Adjusting it upwards or downwards may change whether nodes route through this node. Default value: 1000. [`forwarding_fee_proportional_millionths`]: ChannelConfig::forwarding_fee_proportional_millionths
      • set_forwarding_fee_base_msat

        public void set_forwarding_fee_base_msat​(int val)
        Amount (in milli-satoshi) charged for payments forwarded outbound over the channel, in excess of [`forwarding_fee_proportional_millionths`]. This may be allowed to change at runtime in a later update, however doing so must result in update messages sent to notify all nodes of our updated relay fee. The default value of a single satoshi roughly matches the market rate on many routing nodes as of July 2021. Adjusting it upwards or downwards may change whether nodes route through this node. Default value: 1000. [`forwarding_fee_proportional_millionths`]: ChannelConfig::forwarding_fee_proportional_millionths
      • get_cltv_expiry_delta

        public short get_cltv_expiry_delta()
        The difference in the CLTV value between incoming HTLCs and an outbound HTLC forwarded over the channel this config applies to. This is analogous to [`ChannelHandshakeConfig::our_to_self_delay`] but applies to in-flight HTLC balance when a channel appears on-chain whereas [`ChannelHandshakeConfig::our_to_self_delay`] applies to the remaining (non-HTLC-encumbered) balance. Thus, for HTLC-encumbered balances to be enforced on-chain when a channel is force-closed, we (or one of our watchtowers) MUST be online to check for broadcast of the current commitment transaction at least once per this many blocks (minus some margin to allow us enough time to broadcast and confirm a transaction, possibly with time in between to RBF the spending transaction). Default value: 72 (12 hours at an average of 6 blocks/hour). Minimum value: [`MIN_CLTV_EXPIRY_DELTA`], any values less than this will be treated as [`MIN_CLTV_EXPIRY_DELTA`] instead. [`MIN_CLTV_EXPIRY_DELTA`]: crate::ln::channelmanager::MIN_CLTV_EXPIRY_DELTA
      • set_cltv_expiry_delta

        public void set_cltv_expiry_delta​(short val)
        The difference in the CLTV value between incoming HTLCs and an outbound HTLC forwarded over the channel this config applies to. This is analogous to [`ChannelHandshakeConfig::our_to_self_delay`] but applies to in-flight HTLC balance when a channel appears on-chain whereas [`ChannelHandshakeConfig::our_to_self_delay`] applies to the remaining (non-HTLC-encumbered) balance. Thus, for HTLC-encumbered balances to be enforced on-chain when a channel is force-closed, we (or one of our watchtowers) MUST be online to check for broadcast of the current commitment transaction at least once per this many blocks (minus some margin to allow us enough time to broadcast and confirm a transaction, possibly with time in between to RBF the spending transaction). Default value: 72 (12 hours at an average of 6 blocks/hour). Minimum value: [`MIN_CLTV_EXPIRY_DELTA`], any values less than this will be treated as [`MIN_CLTV_EXPIRY_DELTA`] instead. [`MIN_CLTV_EXPIRY_DELTA`]: crate::ln::channelmanager::MIN_CLTV_EXPIRY_DELTA
      • get_max_dust_htlc_exposure_msat

        public long get_max_dust_htlc_exposure_msat()
        Limit our total exposure to in-flight HTLCs which are burned to fees as they are too small to claim on-chain. When an HTLC present in one of our channels is below a \"dust\" threshold, the HTLC will not be claimable on-chain, instead being turned into additional miner fees if either party force-closes the channel. Because the threshold is per-HTLC, our total exposure to such payments may be sustantial if there are many dust HTLCs present when the channel is force-closed. The dust threshold for each HTLC is based on the `dust_limit_satoshis` for each party in a channel negotiated throughout the channel open process, along with the fees required to have a broadcastable HTLC spending transaction. When a channel supports anchor outputs (specifically the zero fee HTLC transaction variant), this threshold no longer takes into account the HTLC transaction fee as it is zero. This limit is applied for sent, forwarded, and received HTLCs and limits the total exposure across all three types per-channel. Setting this too low may prevent the sending or receipt of low-value HTLCs on high-traffic nodes, and this limit is very important to prevent stealing of dust HTLCs by miners. Default value: 5_000_000 msat.
      • set_max_dust_htlc_exposure_msat

        public void set_max_dust_htlc_exposure_msat​(long val)
        Limit our total exposure to in-flight HTLCs which are burned to fees as they are too small to claim on-chain. When an HTLC present in one of our channels is below a \"dust\" threshold, the HTLC will not be claimable on-chain, instead being turned into additional miner fees if either party force-closes the channel. Because the threshold is per-HTLC, our total exposure to such payments may be sustantial if there are many dust HTLCs present when the channel is force-closed. The dust threshold for each HTLC is based on the `dust_limit_satoshis` for each party in a channel negotiated throughout the channel open process, along with the fees required to have a broadcastable HTLC spending transaction. When a channel supports anchor outputs (specifically the zero fee HTLC transaction variant), this threshold no longer takes into account the HTLC transaction fee as it is zero. This limit is applied for sent, forwarded, and received HTLCs and limits the total exposure across all three types per-channel. Setting this too low may prevent the sending or receipt of low-value HTLCs on high-traffic nodes, and this limit is very important to prevent stealing of dust HTLCs by miners. Default value: 5_000_000 msat.
      • get_force_close_avoidance_max_fee_satoshis

        public long get_force_close_avoidance_max_fee_satoshis()
        The additional fee we're willing to pay to avoid waiting for the counterparty's `to_self_delay` to reclaim funds. When we close a channel cooperatively with our counterparty, we negotiate a fee for the closing transaction which both sides find acceptable, ultimately paid by the channel funder/initiator. When we are the funder, because we have to pay the channel closing fee, we bound the acceptable fee by our [`Background`] and [`Normal`] fees, with the upper bound increased by this value. Because the on-chain fee we'd pay to force-close the channel is kept near our [`Normal`] feerate during normal operation, this value represents the additional fee we're willing to pay in order to avoid waiting for our counterparty's to_self_delay to reclaim our funds. When we are not the funder, we require the closing transaction fee pay at least our [`Background`] fee estimate, but allow our counterparty to pay as much fee as they like. Thus, this value is ignored when we are not the funder. Default value: 1000 satoshis. [`Normal`]: crate::chain::chaininterface::ConfirmationTarget::Normal [`Background`]: crate::chain::chaininterface::ConfirmationTarget::Background
      • set_force_close_avoidance_max_fee_satoshis

        public void set_force_close_avoidance_max_fee_satoshis​(long val)
        The additional fee we're willing to pay to avoid waiting for the counterparty's `to_self_delay` to reclaim funds. When we close a channel cooperatively with our counterparty, we negotiate a fee for the closing transaction which both sides find acceptable, ultimately paid by the channel funder/initiator. When we are the funder, because we have to pay the channel closing fee, we bound the acceptable fee by our [`Background`] and [`Normal`] fees, with the upper bound increased by this value. Because the on-chain fee we'd pay to force-close the channel is kept near our [`Normal`] feerate during normal operation, this value represents the additional fee we're willing to pay in order to avoid waiting for our counterparty's to_self_delay to reclaim our funds. When we are not the funder, we require the closing transaction fee pay at least our [`Background`] fee estimate, but allow our counterparty to pay as much fee as they like. Thus, this value is ignored when we are not the funder. Default value: 1000 satoshis. [`Normal`]: crate::chain::chaininterface::ConfirmationTarget::Normal [`Background`]: crate::chain::chaininterface::ConfirmationTarget::Background
      • of

        public static ChannelConfig of​(int forwarding_fee_proportional_millionths_arg,
                                       int forwarding_fee_base_msat_arg,
                                       short cltv_expiry_delta_arg,
                                       long max_dust_htlc_exposure_msat_arg,
                                       long force_close_avoidance_max_fee_satoshis_arg)
        Constructs a new ChannelConfig given each field
      • eq

        public boolean eq​(ChannelConfig b)
        Checks if two ChannelConfigs contain equal inner contents. This ignores pointers and is_owned flags and looks at the values in fields. Two objects with NULL inner values will be considered "equal" here.
      • with_default

        public static ChannelConfig with_default()
        Creates a "default" ChannelConfig. See struct and individual field documentaiton for details on which values are used.
      • write

        public byte[] write()
        Serialize the ChannelConfig object into a byte array which can be read by ChannelConfig_read