fix: keep client tunnels open when one of their connections fails (Support#1417)

electron/main.cjs

@@ -2187,11 +2187,6 @@ async function openC2SRelay(
     targetHost,
     targetPort,
   });
-  setC2STunnelStatus(tunnelName, {
-    connected: false,
-    status: "CONNECTING",
-    reason: `Opening relay to ${targetHost}:${targetPort}`,
-  });
   const ws = new WebSocket(
     relayUrl,
     getWebSocketOptions(relayUrl, { headers }),
@@ -2226,13 +2221,16 @@ async function openC2SRelay(
 
   socket.on("data", sendChunk);
   socket.on("close", cleanup);
+  // One connection failing must not stop the tunnel: the listener refuses
+  // new connections while the tunnel is not connected, and a browser opens
+  // many at once.
   socket.on("error", (error) => {
-    setC2STunnelError(tunnelName, error.message || "Local socket error");
+    logToFile(`[c2s] ${tunnelName} local socket error:`, error.message);
     cleanup();
   });
   ws.on("close", cleanup);
   ws.on("error", (error) => {
-    setC2STunnelError(tunnelName, error.message || "Relay connection failed");
+    logToFile(`[c2s] ${tunnelName} relay error:`, error.message);
     cleanup();
   });
 
@@ -2259,10 +2257,6 @@ async function openC2SRelay(
       if (message.type === "ready") {
         ready = true;
         logToFile(`[c2s] relay ready for ${tunnelName}`);
-        setC2STunnelStatus(tunnelName, {
-          connected: true,
-          status: "CONNECTED",
-        });
         if (initialData?.length) {
           ws.send(initialData);
         }
@@ -2275,12 +2269,13 @@ async function openC2SRelay(
           "Relay rejected the client tunnel",
         );
         logToFile("[c2s] relay error:", relayError);
-        setC2STunnelError(tunnelName, relayError);
+        if (relayError === C2S_REMOTE_SESSION_EXPIRED_ERROR) {
+          setC2STunnelError(tunnelName, relayError);
+        }
         cleanup();
       }
     } catch (error) {
       logToFile("[c2s] invalid relay message:", error.message);
-      setC2STunnelError(tunnelName, error.message || "Invalid relay response");
       cleanup();
     }
   });
@@ -2506,7 +2501,9 @@ function handleC2SLocalConnection(tunnel, socket, authToken) {
       "Local relay failed",
     );
     logToFile("[c2s] local relay failed:", message);
-    setC2STunnelError(tunnelName, message);
+    if (message === C2S_REMOTE_SESSION_EXPIRED_ERROR) {
+      setC2STunnelError(tunnelName, message);
+    }
     socket.destroy();
   });
 }

src/backend/tests/electron/c2s-runtime.test.ts

@@ -72,9 +72,12 @@ function setup() {
       runtimes.get(name).status = { connected: false, reason: error };
     },
     createC2SFailure: (error: string) => ({ success: false, error }),
+    normalizeC2SErrorMessage: (message: string) => message,
+    C2S_REMOTE_SESSION_EXPIRED_ERROR: "expired",
   });
   vm.runInContext(
-    section("async function testC2SRelay(", "async function testC2STunnel(") +
+    section("async function openC2SRelay(", "async function testC2SRelay(") +
+      section("async function testC2SRelay(", "async function testC2STunnel(") +
       section("async function startC2STunnel(", "function stopAllC2STunnels("),
     context,
   );
@@ -140,4 +143,37 @@ describe("client tunnel runtime authentication", () => {
     ).toEqual({ success: false, error: "Tunnel stopped" });
     expect(sockets).toHaveLength(1);
   });
+
+  it("keeps the tunnel connected when one of its connections fails", async () => {
+    const { context, runtimes, sockets } = setup();
+    runtimes.set("web", { status: { connected: true, status: "CONNECTED" } });
+    const local = () =>
+      Object.assign(new EventEmitter(), {
+        destroy: vi.fn(),
+        write: vi.fn(),
+      });
+
+    const first = local();
+    await context.openC2SRelay({ name: "web" }, "127.0.0.1", 8006, first);
+    await vi.waitFor(() => expect(sockets).toHaveLength(1));
+    first.emit("error", new Error("ECONNRESET"));
+    sockets[0].emit(
+      "message",
+      Buffer.from(JSON.stringify({ type: "error", error: "refused" })),
+      false,
+    );
+    expect(runtimes.get("web").status.connected).toBe(true);
+
+    await context.openC2SRelay({ name: "web" }, "127.0.0.1", 8006, local());
+    await vi.waitFor(() => expect(sockets).toHaveLength(2));
+    sockets[1].emit(
+      "message",
+      Buffer.from(JSON.stringify({ type: "error", error: "expired" })),
+      false,
+    );
+    expect(runtimes.get("web").status).toMatchObject({
+      connected: false,
+      reason: "expired",
+    });
+  });
 });