Switch to server status polling rather than pinging

Cargo.lock

@@ -181,17 +181,6 @@ dependencies = [
  "pin-utils",
 ]
 
-[[package]]
-name = "getrandom"
-version = "0.2.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7fcd999463524c52659517fe2cea98493cfe485d10565e7b0fb07dbba7ad2753"
-dependencies = [
- "cfg-if",
- "libc",
- "wasi",
-]
-
 [[package]]
 name = "hermit-abi"
 version = "0.1.19"
@@ -227,7 +216,6 @@ dependencies = [
  "log",
  "minecraft-protocol",
  "pretty_env_logger",
- "rand 0.8.4",
  "tokio",
 ]
 
@@ -261,7 +249,7 @@ checksum = "308cc39be01b73d0d18f82a0e7b2a3df85245f84af96fdddc5d202d27e47b86a"
 [[package]]
 name = "minecraft-protocol"
 version = "0.1.0"
-source = "git+https://github.com/timvisee/minecraft-protocol?rev=c578492#c57849246166add5ad45ef36b3bdebd8b744883d"
+source = "git+https://github.com/timvisee/minecraft-protocol?rev=c181117#c1811171c20a88bc7ecac1cda3257fbaa9f9c10c"
 dependencies = [
  "byteorder",
  "minecraft-protocol-derive",
@@ -274,7 +262,7 @@ dependencies = [
 [[package]]
 name = "minecraft-protocol-derive"
 version = "0.0.0"
-source = "git+https://github.com/timvisee/minecraft-protocol?rev=c578492#c57849246166add5ad45ef36b3bdebd8b744883d"
+source = "git+https://github.com/timvisee/minecraft-protocol?rev=c181117#c1811171c20a88bc7ecac1cda3257fbaa9f9c10c"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -361,12 +349,6 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8b870d8c151b6f2fb93e84a13146138f05d02ed11c7e7c54f8826aaaf7c9f184"
 
-[[package]]
-name = "ppv-lite86"
-version = "0.2.15"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ed0cfbc8191465bed66e1718596ee0b0b35d5ee1f41c5df2189d0fe8bde535ba"
-
 [[package]]
 name = "pretty_env_logger"
 version = "0.4.0"
@@ -409,9 +391,9 @@ checksum = "6d71dacdc3c88c1fde3885a3be3fbab9f35724e6ce99467f7d9c5026132184ca"
 dependencies = [
  "autocfg 0.1.7",
  "libc",
- "rand_chacha 0.1.1",
+ "rand_chacha",
  "rand_core 0.4.2",
- "rand_hc 0.1.0",
+ "rand_hc",
  "rand_isaac",
  "rand_jitter",
  "rand_os",
@@ -420,18 +402,6 @@ dependencies = [
  "winapi",
 ]
 
-[[package]]
-name = "rand"
-version = "0.8.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2e7573632e6454cf6b99d7aac4ccca54be06da05aca2ef7423d22d27d4d4bcd8"
-dependencies = [
- "libc",
- "rand_chacha 0.3.1",
- "rand_core 0.6.3",
- "rand_hc 0.3.1",
-]
-
 [[package]]
 name = "rand_chacha"
 version = "0.1.1"
@@ -442,16 +412,6 @@ dependencies = [
  "rand_core 0.3.1",
 ]
 
-[[package]]
-name = "rand_chacha"
-version = "0.3.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e6c10a63a0fa32252be49d21e7709d4d4baf8d231c2dbce1eaa8141b9b127d88"
-dependencies = [
- "ppv-lite86",
- "rand_core 0.6.3",
-]
-
 [[package]]
 name = "rand_core"
 version = "0.3.1"
@@ -467,15 +427,6 @@ version = "0.4.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9c33a3c44ca05fa6f1807d8e6743f3824e8509beca625669633be0acbdf509dc"
 
-[[package]]
-name = "rand_core"
-version = "0.6.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d34f1408f55294453790c48b2f1ebbb1c5b4b7563eb1f418bcfcfdbb06ebb4e7"
-dependencies = [
- "getrandom",
-]
-
 [[package]]
 name = "rand_hc"
 version = "0.1.0"
@@ -485,15 +436,6 @@ dependencies = [
  "rand_core 0.3.1",
 ]
 
-[[package]]
-name = "rand_hc"
-version = "0.3.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d51e9f596de227fda2ea6c84607f5558e196eeaf43c986b724ba4fb8fdf497e7"
-dependencies = [
- "rand_core 0.6.3",
-]
-
 [[package]]
 name = "rand_isaac"
 version = "0.1.1"
@@ -681,16 +623,10 @@ version = "0.7.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "90dbc611eb48397705a6b0f6e917da23ae517e4d127123d2cf7674206627d32a"
 dependencies = [
- "rand 0.6.5",
+ "rand",
  "serde",
 ]
 
-[[package]]
-name = "wasi"
-version = "0.10.2+wasi-snapshot-preview1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fd6fbd9a79829dd1ad0cc20627bf1ed606756a7f77edff7b66b7064f9cb327c6"
-
 [[package]]
 name = "winapi"
 version = "0.3.9"

Cargo.toml

@@ -22,8 +22,7 @@ edition = "2021"
 bytes = "1.1"
 futures = { version = "0.3", default-features = false }
 libc = "0.2"
-minecraft-protocol = { git = "https://github.com/timvisee/minecraft-protocol", rev = "c578492" }
+minecraft-protocol = { git = "https://github.com/timvisee/minecraft-protocol", rev = "c181117" }
-rand = "0.8"
 tokio = { version = "1", default-features = false, features = ["rt", "rt-multi-thread", "io-util", "net", "macros", "time", "process", "signal"] }
 
 dotenv = "0.15"

src/monitor.rs

@@ -5,11 +5,11 @@ use std::sync::Arc;
 use std::time::Duration;
 
 use bytes::BytesMut;
+use minecraft_protocol::data::server_status::ServerStatus;
 use minecraft_protocol::decoder::Decoder;
 use minecraft_protocol::encoder::Encoder;
 use minecraft_protocol::version::v1_14_4::handshake::Handshake;
-use minecraft_protocol::version::v1_14_4::status::{PingRequest, PingResponse};
+use minecraft_protocol::version::v1_14_4::status::StatusResponse;
-use rand::Rng;
 use tokio::io::AsyncWriteExt;
 use tokio::net::TcpStream;
 
@@ -22,42 +22,39 @@ const PROTOCOL_VERSION: i32 = 754;
 /// Monitor ping inverval in seconds.
 const MONITOR_PING_INTERVAL: u64 = 2;
 
-/// Ping timeout in seconds.
+/// Status request timeout in seconds.
-const PING_TIMEOUT: u64 = 8;
+const STATUS_TIMEOUT: u64 = 8;
-
-/// Poll server state.
-///
-/// Returns `true` if a ping succeeded.
-pub async fn poll_server(addr: SocketAddr) -> bool {
-    attempt_connect(addr).await.is_ok()
-}
 
 /// Monitor server.
 pub async fn monitor_server(addr: SocketAddr, state: Arc<ServerState>) {
     loop {
-        trace!("Polling {} ... ", addr);
+        trace!("Fetching status for {} ... ", addr);
-        let online = poll_server(addr).await;
+        let status = poll_server(addr).await;
 
-        state.set_online(online);
+        // Update server state
+        state.set_online(status.is_some());
+        if let Some(status) = status {
+            state.set_status(status);
+        }
 
         tokio::time::sleep(Duration::from_secs(MONITOR_PING_INTERVAL)).await;
     }
 }
 
-/// Attemp to connect to the given server.
+/// Poll server state.
-async fn attempt_connect(addr: SocketAddr) -> Result<(), ()> {
+///
+/// Returns server status if connection succeeded.
+pub async fn poll_server(addr: SocketAddr) -> Option<ServerStatus> {
+    fetch_status(addr).await.ok()
+}
+
+/// Attemp to fetch status from server.
+async fn fetch_status(addr: SocketAddr) -> Result<ServerStatus, ()> {
     let mut stream = TcpStream::connect(addr).await.map_err(|_| ())?;
 
-    // Send handshake
     send_handshake(&mut stream, addr).await?;
-
+    request_status(&mut stream).await?;
-    // Send ping request
+    wait_for_status_timeout(&mut stream).await
-    let token = send_ping(&mut stream).await?;
-
-    // Wait for ping with timeout
-    wait_for_ping_timeout(&mut stream, token).await?;
-
-    Ok(())
 }
 
 /// Send handshake.
@@ -81,29 +78,17 @@ async fn send_handshake(stream: &mut TcpStream, addr: SocketAddr) -> Result<(),
     Ok(())
 }
 
-/// Send ping requets.
+/// Send status request.
-///
+async fn request_status(stream: &mut TcpStream) -> Result<(), ()> {
-/// Returns sent ping time token on success.
+    let raw = RawPacket::new(proto::STATUS_PACKET_ID_STATUS, vec![])
-async fn send_ping(stream: &mut TcpStream) -> Result<u64, ()> {
-    // Generate a random ping token
-    let token = rand::thread_rng().gen();
-
-    let ping = PingRequest { time: token };
-
-    let mut packet = Vec::new();
-    ping.encode(&mut packet).map_err(|_| ())?;
-
-    let raw = RawPacket::new(proto::STATUS_PACKET_ID_PING, packet)
         .encode()
         .map_err(|_| ())?;
-
     stream.write_all(&raw).await.map_err(|_| ())?;
-
+    Ok(())
-    Ok(token)
 }
 
-/// Wait for a ping response.
+/// Wait for a status response.
-async fn wait_for_ping(stream: &mut TcpStream, token: u64) -> Result<(), ()> {
+async fn wait_for_status(stream: &mut TcpStream) -> Result<ServerStatus, ()> {
     // Get stream reader, set up buffer
     let (mut reader, mut _writer) = stream.split();
     let mut buf = BytesMut::new();
@@ -116,16 +101,10 @@ async fn wait_for_ping(stream: &mut TcpStream, token: u64) -> Result<(), ()> {
             Err(_) => continue,
         };
 
-        // Catch ping response
+        // Catch status response
-        if packet.id == proto::STATUS_PACKET_ID_PING {
+        if packet.id == proto::STATUS_PACKET_ID_STATUS {
-            let ping = PingResponse::decode(&mut packet.data.as_slice()).map_err(|_| ())?;
+            let status = StatusResponse::decode(&mut packet.data.as_slice()).map_err(|_| ())?;
-
+            return Ok(status.server_status);
-            // Ensure ping token is correct
-            if ping.time != token {
-                break;
-            }
-
-            return Ok(());
         }
     }
 
@@ -133,10 +112,10 @@ async fn wait_for_ping(stream: &mut TcpStream, token: u64) -> Result<(), ()> {
     Err(())
 }
 
-/// Wait for a ping response with timeout.
+/// Wait for a status response.
-async fn wait_for_ping_timeout(stream: &mut TcpStream, token: u64) -> Result<(), ()> {
+async fn wait_for_status_timeout(stream: &mut TcpStream) -> Result<ServerStatus, ()> {
-    let ping = wait_for_ping(stream, token);
+    let status = wait_for_status(stream);
-    tokio::time::timeout(Duration::from_secs(PING_TIMEOUT), ping)
+    tokio::time::timeout(Duration::from_secs(STATUS_TIMEOUT), status)
         .await
         .map_err(|_| ())?
 }

src/server.rs

@@ -1,6 +1,7 @@
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::{Arc, Mutex};
 
+use minecraft_protocol::data::server_status::ServerStatus;
 use tokio::process::Command;
 
 use crate::config::SERVER_CMD;
@@ -16,6 +17,11 @@ pub struct ServerState {
 
     /// Server PID.
     pid: Mutex<Option<u32>>,
+
+    /// Last known server status.
+    ///
+    /// Once set, this will remain set, and isn't cleared when the server goes offline.
+    status: Mutex<Option<ServerStatus>>,
 }
 
 impl ServerState {
@@ -54,6 +60,11 @@ impl ServerState {
     pub fn set_pid(&self, pid: Option<u32>) {
         *self.pid.lock().unwrap() = pid;
     }
+
+    /// Update the server status.
+    pub fn set_status(&self, status: ServerStatus) {
+        self.status.lock().unwrap().replace(status);
+    }
 }
 
 /// Start Minecraft server.