feat: broadcast node announcement with set alias

What this commit does:
Broadcasts node announcement with the user-provided alias, if set,
else, uses the default [0u8;32].

Additionally, adds a random node alias generating function for use
in the generation of random configuration.

src/lib.rs

@@ -603,6 +603,7 @@ impl Node {
 		let bcast_logger = Arc::clone(&self.logger);
 		let bcast_ann_timestamp = Arc::clone(&self.latest_node_announcement_broadcast_timestamp);
 		let mut stop_bcast = self.stop_sender.subscribe();
+		let node_alias = self.config().node_alias;
 		runtime.spawn(async move {
 			// We check every 30 secs whether our last broadcast is NODE_ANN_BCAST_INTERVAL away.
 			#[cfg(not(test))]
@@ -652,7 +653,16 @@ impl Node {
 								continue;
 							}
 
-							bcast_pm.broadcast_node_announcement([0; 3], [0; 32], addresses);
+							// Extract alias if set, else select the default
+							let alias = if let Some(ref alias) = node_alias {
+								let mut buf = [0_u8; 32];
+								buf[..alias.as_bytes().len()].copy_from_slice(alias.as_bytes());
+								buf
+							} else {
+								[0; 32]
+							};
+
+							bcast_pm.broadcast_node_announcement([0; 3], alias, addresses);
 
 							let unix_time_secs_opt =
 								SystemTime::now().duration_since(UNIX_EPOCH).ok().map(|d| d.as_secs());

tests/common/mod.rs

@@ -193,6 +193,15 @@ pub(crate) fn random_listening_addresses() -> Vec<SocketAddress> {
 	listening_addresses
 }
 
+pub(crate) fn random_node_alias() -> Option<String> {
+	let mut rng = thread_rng();
+	let ranged_val = rng.gen_range(0..10);
+	match ranged_val {
+		0 => None,
+		val => Some(format!("ldk-node-{}", val)),
+	}
+}
+
 pub(crate) fn random_config(anchor_channels: bool) -> Config {
 	let mut config = Config::default();
 
@@ -213,6 +222,10 @@ pub(crate) fn random_config(anchor_channels: bool) -> Config {
 	println!("Setting random LDK listening addresses: {:?}", rand_listening_addresses);
 	config.listening_addresses = Some(rand_listening_addresses);
 
+	let alias = random_node_alias();
+	println!("Setting random LDK node alias: {:?}", alias);
+	config.node_alias = alias;
+
 	config.log_level = LogLevel::Gossip;
 
 	config