lsps: Add service implementation for LSPS0

Implements the LSPS0 service plugin for core lightning

Changelog-Added: lsps-plugin: lsps0 service support

Signed-off-by: Peter Neuroth <pet.v.ne@gmail.com>

plugins/.gitignore

@@ -21,3 +21,4 @@ recklessrpc
 exposesecret
 cln-xpay
 cln-lsps-client
+cln-lsps-service

plugins/Makefile

@@ -149,8 +149,10 @@ plugins/clnrest: target/${RUST_PROFILE}/clnrest
 	@cp $< $@
 plugins/cln-lsps-client: target/${RUST_PROFILE}/cln-lsps-client
 	@cp $< $@
+plugins/cln-lsps-service: target/${RUST_PROFILE}/cln-lsps-service
+	@cp $< $@
 
-PLUGINS += plugins/cln-grpc plugins/clnrest plugins/cln-lsps-client
+PLUGINS += plugins/cln-grpc plugins/clnrest plugins/cln-lsps-client plugins/cln-lsps-service
 endif
 
 PLUGIN_COMMON_OBJS :=				\
@@ -310,10 +312,12 @@ target/${RUST_PROFILE}/clnrest: ${CLN_REST_PLUGIN_SRC}
 	cargo build ${CARGO_OPTS} --bin clnrest
 target/${RUST_PROFILE}/cln-lsps-client: ${CLN_LSPS_PLUGIN_SRC}
 	cargo build ${CARGO_OPTS} --bin cln-lsps-client
+target/${RUST_PROFILE}/cln-lsps-service: ${CLN_LSPS_PLUGIN_SRC}
+	cargo build ${CARGO_OPTS} --bin cln-lsps-service
 
 ifneq ($(RUST),0)
 include plugins/rest-plugin/Makefile
-DEFAULT_TARGETS += $(CLN_PLUGIN_EXAMPLES) plugins/cln-grpc plugins/clnrest plugins/cln-lsps-client
+DEFAULT_TARGETS += $(CLN_PLUGIN_EXAMPLES) plugins/cln-grpc plugins/clnrest plugins/cln-lsps-client plugins/cln-lsps-service
 endif
 
 clean: plugins-clean

plugins/lsps-plugin/Cargo.toml

@@ -7,6 +7,10 @@ edition = "2021"
 name = "cln-lsps-client"
 path = "src/client.rs"
 
+[[bin]]
+name = "cln-lsps-service"
+path = "src/service.rs"
+
 [dependencies]
 anyhow = "1.0"
 async-trait = "0.1"

plugins/lsps-plugin/src/service.rs

@@ -0,0 +1,126 @@
+use anyhow::anyhow;
+use async_trait::async_trait;
+use cln_lsps::jsonrpc::server::{JsonRpcResponseWriter, RequestHandler};
+use cln_lsps::jsonrpc::{server::JsonRpcServer, JsonRpcRequest};
+use cln_lsps::jsonrpc::{JsonRpcResponse, RequestObject, RpcError, TransportError};
+use cln_lsps::lsps0;
+use cln_lsps::lsps0::model::{Lsps0listProtocolsRequest, Lsps0listProtocolsResponse};
+use cln_lsps::lsps0::transport::{self, CustomMsg};
+use cln_plugin::options::ConfigOption;
+use cln_plugin::{options, Plugin};
+use cln_rpc::notifications::CustomMsgNotification;
+use cln_rpc::primitives::PublicKey;
+use log::debug;
+use std::path::{Path, PathBuf};
+use std::str::FromStr;
+use std::sync::Arc;
+
+/// An option to enable this service. It defaults to `false` as we don't want a
+/// node to be an LSP per default.
+/// If a user want's to run an LSP service on their node this has to explicitly
+/// set to true. We keep this as a dev option for now until it actually does
+/// something.
+const OPTION_ENABLED: options::DefaultBooleanConfigOption = ConfigOption::new_bool_with_default(
+    "dev-lsps-service",
+    false,
+    "Enables an LSPS service on the node.",
+);
+
+#[derive(Clone)]
+struct State {
+    lsps_service: JsonRpcServer,
+}
+
+#[tokio::main]
+async fn main() -> Result<(), anyhow::Error> {
+    let lsps_service = JsonRpcServer::builder()
+        .with_handler(
+            Lsps0listProtocolsRequest::METHOD.to_string(),
+            Arc::new(Lsps0ListProtocolsHandler),
+        )
+        .build();
+    let state = State { lsps_service };
+
+    if let Some(plugin) = cln_plugin::Builder::new(tokio::io::stdin(), tokio::io::stdout())
+        .option(OPTION_ENABLED)
+        .hook("custommsg", on_custommsg)
+        .configure()
+        .await?
+    {
+        if !plugin.option(&OPTION_ENABLED)? {
+            return plugin
+                .disable(&format!("`{}` not enabled", OPTION_ENABLED.name))
+                .await;
+        }
+
+        let plugin = plugin.start(state).await?;
+        plugin.join().await
+    } else {
+        Ok(())
+    }
+}
+
+async fn on_custommsg(
+    p: Plugin<State>,
+    v: serde_json::Value,
+) -> Result<serde_json::Value, anyhow::Error> {
+    // All of this could be done async if needed.
+    let continue_response = Ok(serde_json::json!({
+      "result": "continue"
+    }));
+    let msg: CustomMsgNotification =
+        serde_json::from_value(v).map_err(|e| anyhow!("invalid custommsg: {e}"))?;
+
+    let req = CustomMsg::from_str(&msg.payload).map_err(|e| anyhow!("invalid payload {e}"))?;
+    if req.message_type != lsps0::transport::LSPS0_MESSAGE_TYPE {
+        // We don't care if this is not for us!
+        return continue_response;
+    }
+
+    let dir = p.configuration().lightning_dir;
+    let rpc_path = Path::new(&dir).join(&p.configuration().rpc_file);
+    let mut writer = LspsResponseWriter {
+        peer_id: msg.peer_id,
+        rpc_path: rpc_path.try_into()?,
+    };
+
+    let service = p.state().lsps_service.clone();
+    match service.handle_message(&req.payload, &mut writer).await {
+        Ok(_) => continue_response,
+        Err(e) => {
+            debug!("failed to handle lsps message: {}", e);
+            continue_response
+        }
+    }
+}
+
+pub struct LspsResponseWriter {
+    peer_id: PublicKey,
+    rpc_path: PathBuf,
+}
+
+#[async_trait]
+impl JsonRpcResponseWriter for LspsResponseWriter {
+    async fn write(&mut self, payload: &[u8]) -> cln_lsps::jsonrpc::Result<()> {
+        let mut client = cln_rpc::ClnRpc::new(&self.rpc_path).await.map_err(|e| {
+            cln_lsps::jsonrpc::Error::Transport(TransportError::Other(e.to_string()))
+        })?;
+        transport::send_custommsg(&mut client, payload.to_vec(), self.peer_id).await
+    }
+}
+
+pub struct Lsps0ListProtocolsHandler;
+
+#[async_trait]
+impl RequestHandler for Lsps0ListProtocolsHandler {
+    async fn handle(&self, payload: &[u8]) -> core::result::Result<Vec<u8>, RpcError> {
+        let req: RequestObject<Lsps0listProtocolsRequest> =
+            serde_json::from_slice(payload).unwrap();
+        if let Some(id) = req.id {
+            let res = Lsps0listProtocolsResponse { protocols: vec![] }.into_response(id);
+            let res_vec = serde_json::to_vec(&res).unwrap();
+            return Ok(res_vec);
+        }
+        Ok(vec![])
+    }
+}