fix: add timeouts to UdpClient operations

The generic UDP client does not have timeouts. When the server is down
it waits forever for responses. This client has been using only for
testing where the server was always up, but now it's using in production
code by the Tracker Checker.

For the time being, I keep the panicking behavior of the UdpClient when
something is wrong. However we should return an error when the operation
times out.

For the Tracker Checker, it means that when the checker can't connect to
a UDP server the checker is going to panic after 5 seconds. That is not
the intended behavior for the checker. It should always return a full
reprot of all checks. In order to implement that behavior we need to
change the UdpClient to return errors. Since that's a bug refactor I
open a new issue.

Author: josecelano

src/shared/bit_torrent/tracker/udp/client.rs

@@ -10,10 +10,18 @@ use tokio::time;
 
 use crate::shared::bit_torrent::tracker::udp::{source_address, MAX_PACKET_SIZE};
 
+/// Default timeout for sending and receiving packets. And waiting for sockets
+/// to be readable and writable.
+const DEFAULT_TIMEOUT: Duration = Duration::from_secs(5);
+
 #[allow(clippy::module_name_repetitions)]
 #[derive(Debug)]
 pub struct UdpClient {
+    /// The socket to connect to
     pub socket: Arc<UdpSocket>,
+
+    /// Timeout for sending and receiving packets
+    pub timeout: Duration,
 }
 
 impl UdpClient {
@@ -29,6 +37,7 @@ impl UdpClient {
 
         Self {
             socket: Arc::new(socket),
+            timeout: DEFAULT_TIMEOUT,
         }
     }
 
@@ -53,10 +62,23 @@ impl UdpClient {
     /// - Can't write to the socket.
     /// - Can't send data.
     pub async fn send(&self, bytes: &[u8]) -> usize {
-        debug!(target: "UDP client", "send {bytes:?}");
+        debug!(target: "UDP client", "sending {bytes:?} ...");
+
+        match time::timeout(self.timeout, self.socket.writable()).await {
+            Ok(writable_result) => match writable_result {
+                Ok(()) => (),
+                Err(e) => panic!("{}", format!("IO error waiting for the socket to become readable: {e:?}")),
+            },
+            Err(e) => panic!("{}", format!("Timeout waiting for the socket to become readable: {e:?}")),
+        };
 
-        self.socket.writable().await.unwrap();
-        self.socket.send(bytes).await.unwrap()
+        match time::timeout(self.timeout, self.socket.send(bytes)).await {
+            Ok(send_result) => match send_result {
+                Ok(size) => size,
+                Err(e) => panic!("{}", format!("IO error during send: {e:?}")),
+            },
+            Err(e) => panic!("{}", format!("Send operation timed out: {e:?}")),
+        }
     }
 
     /// # Panics
@@ -68,9 +90,21 @@ impl UdpClient {
     pub async fn receive(&self, bytes: &mut [u8]) -> usize {
         debug!(target: "UDP client", "receiving ...");
 
-        self.socket.readable().await.unwrap();
+        match time::timeout(self.timeout, self.socket.readable()).await {
+            Ok(readable_result) => match readable_result {
+                Ok(()) => (),
+                Err(e) => panic!("{}", format!("IO error waiting for the socket to become readable: {e:?}")),
+            },
+            Err(e) => panic!("{}", format!("Timeout waiting for the socket to become readable: {e:?}")),
+        };
 
-        let size = self.socket.recv(bytes).await.unwrap();
+        let size = match time::timeout(self.timeout, self.socket.recv(bytes)).await {
+            Ok(recv_result) => match recv_result {
+                Ok(size) => size,
+                Err(e) => panic!("{}", format!("IO error during send: {e:?}")),
+            },
+            Err(e) => panic!("{}", format!("Receive operation timed out: {e:?}")),
+        };
 
         debug!(target: "UDP client", "{size} bytes received {bytes:?}");