Merge pull request #209 from radstevee/feat/lan_pinging

feat: lan pinging

Author: ReCore-sys

src/bin/src/game_loop.rs

@@ -2,6 +2,7 @@ use crate::errors::BinaryError;
 use crate::packet_handlers::{play_packets, register_player_systems};
 use crate::register_events::register_events;
 use crate::register_resources::register_resources;
+use crate::systems::lan_pinger::LanPinger;
 use crate::systems::register_game_systems;
 use crate::systems::shutdown_systems::register_shutdown_systems;
 use bevy_ecs::prelude::World;
@@ -19,6 +20,7 @@ use ferrumc_utils::formatting::format_duration;
 use play_packets::register_packet_handlers;
 use std::sync::Arc;
 use std::time::{Duration, Instant};
+use tokio::time::sleep;
 use tracing::{debug, error, info, info_span, trace, warn, Instrument};
 
 pub fn start_game_loop(global_state: GlobalState) -> Result<(), BinaryError> {
@@ -214,6 +216,17 @@ fn tcp_conn_acceptor(
                 .enable_all()
                 .thread_name("Tokio-Async-Network")
                 .build()?;
+            async_runtime.spawn(async move {
+                let Ok(mut pinger) = LanPinger::new().await else {
+                    error!("Failed creating LAN pinger");
+                    return
+                };
+
+                loop {
+                    pinger.send().await;
+                    sleep(Duration::from_millis(1500)).await;
+                }
+            });
             async_runtime.block_on({
                 let state = Arc::clone(&state);
                 async move {

src/bin/src/systems/lan_pinger.rs

@@ -0,0 +1,42 @@
+use ferrumc_config::server_config::get_global_config;
+use rand::prelude::IndexedRandom;
+use std::net::{Ipv4Addr, SocketAddrV4};
+use tokio::net::UdpSocket;
+use tracing::error;
+
+pub struct LanPinger {
+    socket: UdpSocket,
+    addr: SocketAddrV4,
+}
+
+impl LanPinger {
+    pub async fn new() -> std::io::Result<Self> {
+        const ADDR: Ipv4Addr = Ipv4Addr::new(224, 0, 2, 60); // mojang's UDP multicast address
+        const PORT: u16 = 4445;
+
+        Ok(Self {
+            socket: UdpSocket::bind("0.0.0.0:0").await?,
+            addr: SocketAddrV4::new(ADDR, PORT),
+        })
+    }
+
+    pub fn announcement(&self) -> String {
+        let cfg = get_global_config();
+        let motd = cfg.motd.choose(&mut rand::rng()).unwrap();
+        let port = cfg.port;
+
+        format!("[MOTD]{motd}[/MOTD][AD]{port}[/AD]")
+    }
+
+    pub async fn send(&mut self) {
+        let announcement = self.announcement();
+
+        if let Err(err) = self
+            .socket
+            .send_to(announcement.as_bytes(), self.addr)
+            .await
+        {
+            error!("Failed sending LAN UDP Packet: {err}")
+        }
+    }
+}

src/bin/src/systems/mod.rs

@@ -1,6 +1,7 @@
 pub mod connection_killer;
 mod cross_chunk_boundary;
 pub mod keep_alive_system;
+pub mod lan_pinger;
 mod mq;
 pub mod new_connections;
 pub mod player_count_update;