Add config support for 'their_channel_reserve_proportional_millionths' [#1498]

[rust-lightning] / lightning / src / util / config.rs

diff --git a/lightning/src/util/config.rs b/lightning/src/util/config.rs
index 2f65e958f8b60d0f0a0f72d3cd3b7ca1b009085a..54ea6178798d25a3e6103c39419b886632024ca9 100644 (file)
--- a/lightning/src/util/config.rs
+++ b/lightning/src/util/config.rs
@@ -126,6 +126,30 @@ pub struct ChannelHandshakeConfig {
        ///
        /// [`KeysInterface::get_shutdown_scriptpubkey`]: crate::chain::keysinterface::KeysInterface::get_shutdown_scriptpubkey
        pub commit_upfront_shutdown_pubkey: bool,
+
+       /// The Proportion of the channel value to configure as counterparty's channel reserve,
+       /// i.e., `their_channel_reserve_satoshis` for both outbound and inbound channels.
+       ///
+       /// `their_channel_reserve_satoshis` is the minimum balance that the other node has to maintain
+       /// on their side, at all times.
+       /// This ensures that if our counterparty broadcasts a revoked state, we can punish them by
+       /// claiming at least this value on chain.
+       ///
+       /// Channel reserve values greater than 30% could be considered highly unreasonable, since that
+       /// amount can never be used for payments.
+       /// Also, if our selected channel reserve for counterparty and counterparty's selected
+       /// channel reserve for us sum up to equal or greater than channel value, channel negotiations
+       /// will fail.
+       ///
+       /// Note: Versions of LDK earlier than v0.0.104 will fail to read channels with any channel reserve
+       /// other than the default value.
+       ///
+       /// Default value: 1% of channel value, i.e., configured as 10,000 millionths.
+       /// Minimum value: If the calculated proportional value is less than 1000 sats, it will be treated
+       ///                as 1000 sats instead, which is a safe implementation-specific lower bound.
+       /// Maximum value: 1,000,000, any values larger than 1 Million will be treated as 1 Million (or 100%)
+       ///                instead, although channel negotiations will fail in that case.
+       pub their_channel_reserve_proportional_millionths: u32
 }
 
 impl Default for ChannelHandshakeConfig {
@@ -138,6 +162,7 @@ impl Default for ChannelHandshakeConfig {
                        negotiate_scid_privacy: false,
                        announced_channel: false,
                        commit_upfront_shutdown_pubkey: true,
+                       their_channel_reserve_proportional_millionths: 10_000,
                }
        }
 }