Make the base fee configurable in ChannelConfig

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

diff --git a/lightning/src/util/config.rs b/lightning/src/util/config.rs
index d5ff2885cc4ae4131c95a63a9b8ab2095fd7bb15..f3fd0ce70793451fbe6e58ce3e2efc81ca84b3b5 100644 (file)
--- a/lightning/src/util/config.rs
+++ b/lightning/src/util/config.rs
@@ -140,12 +140,26 @@ impl Default for ChannelHandshakeLimits {
 /// with our counterparty.
 #[derive(Copy, Clone, Debug)]
 pub struct ChannelConfig {
-       /// Amount (in millionths of a satoshi) the channel will charge per transferred satoshi.
+       /// 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.
-       pub fee_proportional_millionths: u32,
+       pub forwarding_fee_proportional_millionths: u32,
+       /// 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
+       pub forwarding_fee_base_msat: u32,
        /// The difference in the CLTV value between incoming HTLCs and an outbound HTLC forwarded over
        /// the channel this config applies to.
        ///
@@ -196,7 +210,8 @@ impl Default for ChannelConfig {
        /// Provides sane defaults for most configurations (but with zero relay fees!).
        fn default() -> Self {
                ChannelConfig {
-                       fee_proportional_millionths: 0,
+                       forwarding_fee_proportional_millionths: 0,
+                       forwarding_fee_base_msat: 1000,
                        cltv_expiry_delta: 6 * 12, // 6 blocks/hour * 12 hours
                        announced_channel: false,
                        commit_upfront_shutdown_pubkey: true,
@@ -205,10 +220,11 @@ impl Default for ChannelConfig {
 }
 
 impl_writeable_tlv_based!(ChannelConfig, {
-       (0, fee_proportional_millionths, required),
+       (0, forwarding_fee_proportional_millionths, required),
        (2, cltv_expiry_delta, required),
        (4, announced_channel, required),
        (6, commit_upfront_shutdown_pubkey, required),
+       (8, forwarding_fee_base_msat, required),
 });
 
 /// Top-level config which holds ChannelHandshakeLimits and ChannelConfig.