Expose graph node announcement features

Include the feature map from LDK's NodeAnnouncementInfo in
GraphNodeAnnouncement. Features are part of the BOLT 7 node_announcement
payload, so exposing them makes the graph node announcement proto match the
underlying gossip data more completely.

Reuse the existing bit-keyed Feature representation and conversion helper, and
cover the new field in the graph-get-node e2e test. This also supports callers
such as sim-ln that need to inspect other nodes' advertised capabilities.

For context:
bitcoin-dev-project/sim-ln#307
https://github.com/bitcoin-dev-project/sim-ln/pull/307/changes#r3481510079

Author: enigbe

e2e-tests/tests/e2e.rs

@@ -1111,11 +1111,47 @@ async fn test_cli_graph_with_channel() {
 	assert!(node_ids.contains(&server_a.node_id()), "Expected server_a in graph nodes");
 	assert!(node_ids.contains(&server_b.node_id()), "Expected server_b in graph nodes");
 
-	// Test GraphGetNode: should return node info with at least one channel.
-	let output = run_cli(&server_a, &["graph-get-node", server_b.node_id()]);
+	// Test GraphGetNode: should return node info with at least one channel and
+	// node announcement features once the node announcement reaches the graph.
+	let output = {
+		let start = std::time::Instant::now();
+		loop {
+			let output = run_cli(&server_a, &["graph-get-node", server_b.node_id()]);
+			let node = &output["node"];
+			let has_channel =
+				node["channels"].as_array().is_some_and(|channels| !channels.is_empty());
+			let has_announcement_features = node["announcement_info"]["features"]
+				.as_object()
+				.is_some_and(|features| !features.is_empty());
+
+			if has_channel && has_announcement_features {
+				break output;
+			}
+			if start.elapsed() > Duration::from_secs(30) {
+				panic!("Timed out waiting for node announcement features in network graph");
+			}
+			tokio::time::sleep(Duration::from_secs(1)).await;
+		}
+	};
 	let node = &output["node"];
 	let channels = node["channels"].as_array().unwrap();
 	assert!(!channels.is_empty(), "Expected node to have at least one channel");
+
+	let announcement_info = &node["announcement_info"];
+	let features = announcement_info["features"].as_object().unwrap();
+	assert!(!features.is_empty(), "Expected node announcement features");
+
+	// Every entry should be keyed by the signaled bit and expose the decoded name
+	// plus whether that bit is required.
+	for (bit, feature) in features {
+		assert!(bit.parse::<u32>().is_ok(), "Feature key is not a bit number: {bit}");
+		assert!(feature.get("name").is_some(), "Feature missing name field");
+		assert!(feature.get("is_required").is_some(), "Feature missing is_required field");
+	}
+
+	let keysend = &features["55"];
+	assert_eq!(keysend["name"], "Keysend");
+	assert_eq!(keysend["is_required"], false);
 }
 
 #[tokio::test]

ldk-server-grpc/build.rs

@@ -40,6 +40,7 @@ fn generate_protos() {
 			"api.GetNodeInfoResponse.features",
 			"api.DecodeInvoiceResponse.features",
 			"api.DecodeOfferResponse.features",
+			"types.GraphNodeAnnouncement.features",
 		])
 		.type_attribute(
 			".",

ldk-server-grpc/src/proto/types.proto

@@ -798,6 +798,9 @@ message GraphNodeAnnouncement {
 
   // List of addresses on which this node is reachable.
   repeated string addresses = 4;
+
+  // Features signaled in this node announcement, keyed by feature bit.
+  map<uint32, Feature> features = 5;
 }
 
 // Details of a known Lightning peer.

ldk-server-grpc/src/types.rs

@@ -1019,6 +1019,9 @@ pub struct GraphNodeAnnouncement {
 	/// List of addresses on which this node is reachable.
 	#[prost(string, repeated, tag = "4")]
 	pub addresses: ::prost::alloc::vec::Vec<::prost::alloc::string::String>,
+	/// Features signaled in this node announcement, keyed by feature bit.
+	#[prost(btree_map = "uint32, message", tag = "5")]
+	pub features: ::prost::alloc::collections::BTreeMap<u32, Feature>,
 }
 /// Details of a known Lightning peer.
 /// See more: <https://docs.rs/ldk-node/latest/ldk_node/struct.Node.html#method.list_peers>

ldk-server/src/util/proto_adapter.rs

@@ -7,10 +7,10 @@
 // You may not use this file except in accordance with one or both of these
 // licenses.
 
-use bytes::Bytes;
-use hex::prelude::*;
 use std::collections::BTreeMap;
 
+use bytes::Bytes;
+use hex::prelude::*;
 use ldk_node::bitcoin::hashes::sha256;
 use ldk_node::bitcoin::Network;
 use ldk_node::config::{ChannelConfig, MaxDustHTLCExposure};
@@ -19,6 +19,7 @@ use ldk_node::lightning::routing::gossip::{
 	ChannelInfo, ChannelUpdateInfo, NodeAnnouncementInfo, NodeInfo, RoutingFees,
 };
 use ldk_node::lightning_invoice::{Bolt11InvoiceDescription, Description, Sha256};
+use ldk_node::lightning_types::features::NodeFeatures;
 use ldk_node::payment::{
 	ConfirmationStatus, PaymentDetails, PaymentDirection, PaymentKind, PaymentStatus,
 };
@@ -472,11 +473,16 @@ pub(crate) fn graph_node_announcement_to_proto(
 	announcement: NodeAnnouncementInfo,
 ) -> ldk_server_grpc::types::GraphNodeAnnouncement {
 	let rgb = announcement.rgb();
+	let features = features_to_proto(announcement.features().le_flags(), |bytes| {
+		NodeFeatures::from_le_bytes(bytes).to_string()
+	});
+
 	ldk_server_grpc::types::GraphNodeAnnouncement {
 		last_update: announcement.last_update(),
 		alias: announcement.alias().to_string(),
 		rgb: format!("{:02x}{:02x}{:02x}", rgb[0], rgb[1], rgb[2]),
 		addresses: announcement.addresses().iter().map(|a| a.to_string()).collect(),
+		features,
 	}
 }