1 files changed, 78 insertions, 0 deletions
diff --git a/server/registry/src/conn_test.rs b/server/registry/src/conn_test.rs
new file mode 100644
index 00000000..2fda288c
--- /dev/null
+++ b/server/registry/src/conn_test.rs
@@ -0,0 +1,78 @@
+/*
+    Hurry Curry! - a game about cooking
+    Copyright 2024 metamuffin
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published by
+    the Free Software Foundation, version 3 of the License only.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+*/
+use crate::MAX_ADDR_CACHE;
+use anyhow::{bail, Result};
+use hurrycurry_client_lib::network::tokio::Network;
+use hurrycurry_protocol::PacketC;
+use log::info;
+use std::{
+    collections::BTreeMap,
+    net::SocketAddr,
+    time::{Duration, Instant},
+};
+use tokio::{net::TcpStream, sync::RwLock, time::timeout};
+
+#[derive(Debug, Clone, Copy)]
+struct ConnectTest {
+    verified_at: Instant,
+    version: (u32, u32),
+}
+
+static CONNECT_OK: RwLock<BTreeMap<SocketAddr, ConnectTest>> = RwLock::const_new(BTreeMap::new());
+
+pub(crate) async fn test_connect(addr: SocketAddr, uri: &str) -> Result<(u32, u32), &'static str> {
+    let r = CONNECT_OK.read().await.get(&addr).copied();
+    if let Some(r) = r {
+        Ok(r.version)
+    } else {
+        // TODO locks to prevent parallel tests for same addr and dos attempts
+        let res = timeout(Duration::from_secs(10), test_connect_inner(addr, uri))
+            .await
+            .map_err(|_| "connect timeout")?;
+        info!("connect result: {res:?}");
+        let version = res.map_err(|_| "server unreachable")?;
+        {
+            let mut g = CONNECT_OK.write().await;
+            g.insert(
+                addr,
+                ConnectTest {
+                    verified_at: Instant::now(),
+                    version,
+                },
+            );
+            while g.len() > MAX_ADDR_CACHE {
+                // TODO perf maybe later
+                if let Some(key) = g.iter().min_by_key(|(_, v)| v.verified_at).map(|(k, _)| *k) {
+                    g.remove(&key);
+                }
+            }
+        }
+        info!("cache updated");
+        Ok(version)
+    }
+}
+async fn test_connect_inner(addr: SocketAddr, uri: &str) -> Result<(u32, u32)> {
+    info!("test connect {addr} {uri:?}");
+    let stream = TcpStream::connect(addr).await?;
+    let net = Network::connect_raw(stream, uri).await?;
+    let packet = net.receive().await?;
+    match packet {
+        Some(PacketC::Version { minor, major, .. }) => return Ok((major, minor)),
+        _ => bail!("bad initial packet"),
+    }
+}