feat(s2n-quic-platform): add unstable option for multiple sockets

quic/s2n-quic-platform/src/io/tokio.rs

@@ -168,11 +168,21 @@ impl Io {
 
             let mut consumers = vec![];
 
-            let (producer, consumer) = socket::ring::pair(entries, payload_len);
-            consumers.push(consumer);
-
-            // spawn a task that actually reads from the socket into the ring buffer
-            handle.spawn(task::rx(rx_socket, producer));
+            let rx_socket_count = parse_env("S2N_QUIC_UNSTABLE_RX_SOCKET_COUNT").unwrap_or(1);
+
+            for idx in 0usize..rx_socket_count {
+                let (producer, consumer) = socket::ring::pair(entries, payload_len);
+                consumers.push(consumer);
+
+                // spawn a task that actually reads from the socket into the ring buffer
+                if idx + 1 == rx_socket_count {
+                    handle.spawn(task::rx(rx_socket, producer));
+                    break;
+                } else {
+                    let rx_socket = rx_socket.try_clone()?;
+                    handle.spawn(task::rx(rx_socket, producer));
+                }
+            }
 
             // construct the RX side for the endpoint event loop
             let max_mtu = MaxMtu::try_from(payload_len as u16).unwrap();
@@ -201,11 +211,21 @@ impl Io {
 
             let mut producers = vec![];
 
-            let (producer, consumer) = socket::ring::pair(entries, payload_len);
-            producers.push(producer);
+            let tx_socket_count = parse_env("S2N_QUIC_UNSTABLE_TX_SOCKET_COUNT").unwrap_or(1);
+
+            for idx in 0usize..tx_socket_count {
+                let (producer, consumer) = socket::ring::pair(entries, payload_len);
+                producers.push(producer);
 
-            // spawn a task that actually flushes the ring buffer to the socket
-            handle.spawn(task::tx(tx_socket, consumer, gso.clone()));
+                // spawn a task that actually flushes the ring buffer to the socket
+                if idx + 1 == tx_socket_count {
+                    handle.spawn(task::tx(tx_socket, consumer, gso.clone()));
+                    break;
+                } else {
+                    let tx_socket = tx_socket.try_clone()?;
+                    handle.spawn(task::tx(tx_socket, consumer, gso.clone()));
+                }
+            }
 
             // construct the TX side for the endpoint event loop
             socket::io::tx::Tx::new(producers, gso, max_mtu)
@@ -234,3 +254,7 @@ fn convert_addr_to_std(addr: socket2::SockAddr) -> io::Result<std::net::SocketAd
     addr.as_socket()
         .ok_or_else(|| io::Error::new(io::ErrorKind::InvalidInput, "invalid domain for socket"))
 }
+
+fn parse_env<T: core::str::FromStr>(name: &str) -> Option<T> {
+    std::env::var(name).ok().and_then(|v| v.parse().ok())
+}