Add implementation for UpdateChannelConfig Api.

protos/src/lib.rs

@@ -229,6 +229,24 @@ pub struct OpenChannelResponse {
 	#[prost(bytes = "bytes", tag = "1")]
 	pub user_channel_id: ::prost::bytes::Bytes,
 }
+/// Update the config for a previously opened channel.
+/// See more: <https://docs.rs/ldk-node/latest/ldk_node/struct.Node.html#method.update_channel_config>
+#[allow(clippy::derive_partial_eq_without_eq)]
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct UpdateChannelConfigRequest {
+	/// The hex-encoded local `user_channel_id` of this channel.
+	#[prost(string, tag = "1")]
+	pub user_channel_id: ::prost::alloc::string::String,
+	/// The hex-encoded public key of the counterparty node to update channel config with.
+	#[prost(string, tag = "2")]
+	pub counterparty_node_id: ::prost::alloc::string::String,
+	/// The updated channel configuration settings for a channel.
+	#[prost(message, optional, tag = "3")]
+	pub channel_config: ::core::option::Option<ChannelConfig>,
+}
+#[allow(clippy::derive_partial_eq_without_eq)]
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct UpdateChannelConfigResponse {}
 /// ChannelConfig represents the configuration settings for a channel in a Lightning Network node.
 /// See more: <https://docs.rs/lightning/latest/lightning/util/config/struct.ChannelConfig.html>
 #[allow(clippy::derive_partial_eq_without_eq)]

protos/src/proto/ldk_node_server.proto

@@ -220,6 +220,23 @@ message OpenChannelResponse {
   bytes user_channel_id = 1;
 }
 
+// Update the config for a previously opened channel.
+// See more: https://docs.rs/ldk-node/latest/ldk_node/struct.Node.html#method.update_channel_config
+message UpdateChannelConfigRequest {
+
+  // The hex-encoded local `user_channel_id` of this channel.
+  string user_channel_id = 1;
+
+  // The hex-encoded public key of the counterparty node to update channel config with.
+  string counterparty_node_id = 2;
+
+  // The updated channel configuration settings for a channel.
+  ChannelConfig channel_config = 3;
+}
+
+message UpdateChannelConfigResponse {
+}
+
 // ChannelConfig represents the configuration settings for a channel in a Lightning Network node.
 // See more: https://docs.rs/lightning/latest/lightning/util/config/struct.ChannelConfig.html
 message ChannelConfig {

server/src/api/mod.rs

@@ -10,3 +10,4 @@ pub(crate) mod list_payments;
 pub(crate) mod onchain_receive;
 pub(crate) mod onchain_send;
 pub(crate) mod open_channel;
+pub(crate) mod update_channel_config;

server/src/api/update_channel_config.rs

@@ -0,0 +1,75 @@
+use ldk_node::bitcoin::secp256k1::PublicKey;
+use ldk_node::config::{ChannelConfig, MaxDustHTLCExposure};
+use ldk_node::{Node, UserChannelId};
+use protos::channel_config::MaxDustHtlcExposure;
+use protos::{UpdateChannelConfigRequest, UpdateChannelConfigResponse};
+use std::str::FromStr;
+use std::sync::Arc;
+
+pub(crate) const UPDATE_CHANNEL_CONFIG_PATH: &str = "UpdateChannelConfig";
+
+pub(crate) fn handle_update_channel_config_request(
+	node: Arc<Node>, request: UpdateChannelConfigRequest,
+) -> Result<UpdateChannelConfigResponse, ldk_node::NodeError> {
+	let user_channel_id: u128 =
+		request.user_channel_id.parse().map_err(|_| ldk_node::NodeError::InvalidChannelId)?;
+
+	//FIXME: Use ldk/ldk-node's partial config update api.
+	let current_config = node
+		.list_channels()
+		.into_iter()
+		.find(|c| c.user_channel_id.0 == user_channel_id)
+		.ok_or_else(|| ldk_node::NodeError::InvalidChannelId)?
+		.config;
+
+	let updated_channel_config =
+		build_updated_channel_config(current_config, request.channel_config.unwrap());
+
+	let counterparty_node_id = PublicKey::from_str(&request.counterparty_node_id)
+		.map_err(|_| ldk_node::NodeError::InvalidPublicKey)?;
+	node.update_channel_config(
+		&UserChannelId(user_channel_id),
+		counterparty_node_id,
+		updated_channel_config,
+	)
+	.map_err(ldk_node::NodeError::from)?;
+
+	Ok(UpdateChannelConfigResponse {})
+}
+
+fn build_updated_channel_config(
+	current_config: ChannelConfig, proto_channel_config: protos::ChannelConfig,
+) -> ChannelConfig {
+	let max_dust_htlc_exposure = proto_channel_config
+		.max_dust_htlc_exposure
+		.map(|max_dust_htlc_exposure| match max_dust_htlc_exposure {
+			MaxDustHtlcExposure::FixedLimitMsat(limit_msat) => {
+				MaxDustHTLCExposure::FixedLimit { limit_msat }
+			},
+			MaxDustHtlcExposure::FeeRateMultiplier(multiplier) => {
+				MaxDustHTLCExposure::FeeRateMultiplier { multiplier }
+			},
+		})
+		.unwrap_or(current_config.max_dust_htlc_exposure);
+
+	let cltv_expiry_delta = proto_channel_config
+		.cltv_expiry_delta.map(|c| u16::try_from(c).unwrap())
+		.unwrap_or(current_config.cltv_expiry_delta);
+
+	ChannelConfig {
+		forwarding_fee_proportional_millionths: proto_channel_config
+			.forwarding_fee_proportional_millionths
+			.unwrap_or(current_config.forwarding_fee_proportional_millionths),
+		forwarding_fee_base_msat: proto_channel_config
+			.forwarding_fee_base_msat
+			.unwrap_or(current_config.forwarding_fee_base_msat),
+		cltv_expiry_delta,
+		max_dust_htlc_exposure,
+		force_close_avoidance_max_fee_satoshis: proto_channel_config
+			.force_close_avoidance_max_fee_satoshis
+			.unwrap_or(current_config.force_close_avoidance_max_fee_satoshis),
+		accept_underpaying_htlcs: proto_channel_config
+			.accept_underpaying_htlcs
+			.unwrap_or(current_config.accept_underpaying_htlcs),
+	}
+}

server/src/service.rs

@@ -25,6 +25,9 @@ use crate::api::list_payments::{handle_list_payments_request, LIST_PAYMENTS_PATH
 use crate::api::onchain_receive::{handle_onchain_receive_request, ONCHAIN_RECEIVE_PATH};
 use crate::api::onchain_send::{handle_onchain_send_request, ONCHAIN_SEND_PATH};
 use crate::api::open_channel::{handle_open_channel, OPEN_CHANNEL_PATH};
+use crate::api::update_channel_config::{
+	handle_update_channel_config_request, UPDATE_CHANNEL_CONFIG_PATH,
+};
 
 #[derive(Clone)]
 pub struct NodeService {
@@ -62,6 +65,9 @@ impl Service<Request<Incoming>> for NodeService {
 			OPEN_CHANNEL_PATH => Box::pin(handle_request(node, req, handle_open_channel)),
 			CLOSE_CHANNEL_PATH => Box::pin(handle_request(node, req, handle_close_channel_request)),
 			LIST_CHANNELS_PATH => Box::pin(handle_request(node, req, handle_list_channels_request)),
+			UPDATE_CHANNEL_CONFIG_PATH => {
+				Box::pin(handle_request(node, req, handle_update_channel_config_request))
+			},
 			GET_PAYMENT_DETAILS_PATH => {
 				Box::pin(handle_request(node, req, handle_get_payment_details_request))
 			},