But in this case, the same **FastAPI** application will handle the API and the authentication.

So, let's review it from that simplified point of view:

* The user types the `username` and `password` in the frontend, and hits `Enter`.
* The frontend (running in the user's browser) sends that `username` and `password` to a specific URL in our API (declared with `tokenUrl="token"`).

Mas nesse caso, a mesma aplicação **FastAPI** irá lidar com a API e a autenticação.

Então, vamos rever de um ponto de vista simplificado:

* O usuário digita o `username` e a `senha` no frontend e aperta `Enter`.
* O frontend (rodando no browser do usuário) manda o `username` e a `senha` para uma URL específica na sua API (declarada com `tokenUrl="token"`).

This is done by the [ZDS](../../pkg/zdsapi/zds.proto) API.
This will send some identifying information about the Pod to Ztunnel, and, importantly, the Pod's network namespace file descriptor.

Ztunnel will use this to enter the Pod network namespace and start various listeners (inbound, outbound, etc).

> [!NOTE]

Node Agent requires privileged node permissions, and will require allow-listing in constrained environments that block privileged workloads by default. If using sidecar repair mode or ambient mode, the node agent additionally needs permissions to enter pod network namespaces and perform networking configuration in them. If either sidecar repair or ambient mode are enabled, on startup the container will drop all Linux capabilities via (`drop:ALL`), and re-add back the ones sidecar repair/ambient explicitly...

	//
	// Privileged ISA
	//

	// 3.3.1: Environment Call and Breakpoint
	ECALL						// 73000000
	SCALL						// 73000000
	EBREAK						// 73001000
	SBREAK						// 73001000

	// Arbitrary bytes (entered in little-endian mode)
	WORD	$0x12345678	// WORD $305419896	// 78563412
	WORD	$0x9abcdef0	// WORD $2596069104	// f0debc9a

	// MOV pseudo-instructions
	MOV	X5, X6					// 13830200
	MOV	$2047, X5				// 9302f07f

      afe.initCause(ie);
      throw afe;
    }
  }

  /**
   * Spin-waits up to the specified number of milliseconds for the given thread to enter a wait
   * state: BLOCKED, WAITING, or TIMED_WAITING.
   */
  @SuppressWarnings("ThreadPriorityCheck") // TODO: b/175898629 - Consider onSpinWait.
  void waitForThreadToEnterWaitState(Thread thread, long timeoutMillis) {

Но в нашем случае одно и то же приложение **FastAPI** будет работать с API и аутентификацией.

Итак, рассмотрим его с этой упрощенной точки зрения:

* Пользователь вводит на фронтенде `имя пользователя` и `пароль` и нажимает `Enter`.
* Фронтенд (работающий в браузере пользователя) отправляет эти `имя пользователя` и `пароль` на определенный URL в нашем API (объявленный с помощью параметра `tokenUrl="token"`).

    if (approxCmp > 0) {
      /*
       * The code is written so that even completely incorrect approximations will still yield the
       * correct answer eventually, but in practice this branch should almost never be entered, and
       * even then the loop should not run more than once.
       */
      do {
        approxLog10--;
        approxPow = approxPow.divide(BigInteger.TEN);
        approxCmp = approxPow.compareTo(x);

Betrachten wir es also aus dieser vereinfachten Sicht:

* Der Benutzer gibt den `username` und das `password` im Frontend ein und drückt `Enter`.
* Das Frontend (das im Browser des Benutzers läuft) sendet diesen `username` und das `password` an eine bestimmte URL in unserer API (deklariert mit `tokenUrl="token"`).

        injector.discover(ProtoSession.class.getClassLoader());
        Session session = injector.getInstance(Session.class);
        SessionScope scope = new SessionScope();
        scope.enter();
        scope.seed(Session.class, session);
        injector.bindScope(SessionScoped.class, scope);
        return session;
    }