Update Rust crate tokio-tungstenite to 0.20

Cargo.toml

@@ -366,7 +366,7 @@ tofino = { git = "http://github.com/oxidecomputer/tofino", branch = "main" }
 tokio = "1.33.0"
 tokio-postgres = { version = "0.7", features = [ "with-chrono-0_4", "with-uuid-1" ] }
 tokio-stream = "0.1.14"
-tokio-tungstenite = "0.18"
+tokio-tungstenite = "0.20"
 tokio-util = "0.7.10"
 toml = "0.8.8"
 toml_edit = "0.21.0"

gateway/src/serial_console.rs

@@ -48,8 +48,12 @@ pub(crate) async fn run(
     log: Logger,
 ) -> WebsocketChannelResult {
     let upgraded = conn.into_inner();
-    let config =
-        WebSocketConfig { max_send_queue: Some(4096), ..Default::default() };
+    let config = WebSocketConfig {
+        // Maintain a max write buffer size of 2 MB (this is only relevant if
+        // writes are failing).
+        max_write_buffer_size: 1 << 21,
+        ..Default::default()
+    };
     let ws_stream =
         WebSocketStream::from_raw_socket(upgraded, Role::Server, Some(config))
             .await;

gateway/tests/integration_tests/serial_console.rs

@@ -100,11 +100,12 @@ async fn serial_console_detach() {
         }
         tungstenite::Error::ConnectionClosed
         | tungstenite::Error::AlreadyClosed
+        | tungstenite::Error::AttackAttempt
         | tungstenite::Error::Io(_)
         | tungstenite::Error::Tls(_)
         | tungstenite::Error::Capacity(_)
         | tungstenite::Error::Protocol(_)
-        | tungstenite::Error::SendQueueFull(_)
+        | tungstenite::Error::WriteBufferFull(_)
         | tungstenite::Error::Utf8
         | tungstenite::Error::Url(_)
         | tungstenite::Error::HttpFormat(_) => panic!("unexpected error"),