src/connectivity/bluetooth/core/bt-host/host.cc

// Copyright 2023 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "host.h"

#include <fidl/fuchsia.hardware.bluetooth/cpp/wire.h>
#include <lib/fdio/directory.h>
#include <lib/inspect/component/cpp/component.h>

#include "fidl/host_server.h"
#include "fuchsia/hardware/bluetooth/cpp/fidl.h"
#include "lib/async/default.h"
#include "src/connectivity/bluetooth/core/bt-host/controllers/fidl_controller.h"
#include "src/connectivity/bluetooth/core/bt-host/public/pw_bluetooth_sapphire/internal/host/common/log.h"
#include "src/connectivity/bluetooth/core/bt-host/public/pw_bluetooth_sapphire/internal/host/common/random.h"

using namespace bt;

namespace bthost {

BtHostComponent::BtHostComponent(async_dispatcher_t* dispatcher, const std::string& device_path,
                                 bool initialize_rng)
    : pw_dispatcher_(dispatcher),
      device_path_(device_path),
      initialize_rng_(initialize_rng),
      inspector_(inspect::ComponentInspector(dispatcher, {})) {
  if (initialize_rng) {
    set_random_generator(&random_generator_);
  }
  inspector_.root().RecordString("name", device_path_);
}

BtHostComponent::~BtHostComponent() {
  if (initialize_rng_) {
    set_random_generator(nullptr);
  }
}

// static
std::unique_ptr<BtHostComponent> BtHostComponent::Create(async_dispatcher_t* dispatcher,
                                                         const std::string& device_path) {
  std::unique_ptr<BtHostComponent> host(
      new BtHostComponent(dispatcher, device_path, /*initialize_rng=*/true));
  return host;
}

// static
std::unique_ptr<BtHostComponent> BtHostComponent::CreateForTesting(async_dispatcher_t* dispatcher,
                                                                   const std::string& device_path) {
  std::unique_ptr<BtHostComponent> host(
      new BtHostComponent(dispatcher, device_path, /*initialize_rng=*/false));
  return host;
}

bool BtHostComponent::Initialize(fuchsia::hardware::bluetooth::VendorHandle vendor_handle,
                                 InitCallback init_cb, ErrorCallback error_cb) {
  std::unique_ptr<bt::controllers::FidlController> controller =
      std::make_unique<bt::controllers::FidlController>(std::move(vendor_handle),
                                                        async_get_default_dispatcher());

  bt_log(INFO, "bt-host", "Create HCI transport layer");
  hci_ = std::make_unique<hci::Transport>(std::move(controller), pw_dispatcher_);

  bt_log(INFO, "bt-host", "Create GATT layer");
  gatt_ = gatt::GATT::Create();

  gap_ = gap::Adapter::Create(pw_dispatcher_, hci_->GetWeakPtr(), gatt_->GetWeakPtr());
  if (!gap_) {
    bt_log(WARN, "bt-host", "GAP could not be created");
    return false;
  }
  gap_->AttachInspect(inspector_.root(), "adapter");

  // Called when the GAP layer is ready. We initialize the GATT profile after
  // initial setup in GAP. The data domain will be initialized by GAP because it
  // both sets up the HCI ACL data channel that L2CAP relies on and registers
  // L2CAP services.
  auto gap_init_callback = [callback = std::move(init_cb)](bool success) mutable {
    bt_log(DEBUG, "bt-host", "GAP init complete status: (%s)", (success ? "success" : "failure"));
    callback(success);
  };

  auto transport_closed_callback = [error_cb = std::move(error_cb)]() mutable {
    bt_log(WARN, "bt-host", "HCI transport has closed");
    error_cb();
  };

  bt_log(DEBUG, "bt-host", "Initializing GAP");
  return gap_->Initialize(std::move(gap_init_callback), std::move(transport_closed_callback));
}

void BtHostComponent::ShutDown() {
  bt_log(DEBUG, "bt-host", "Shutting down");

  if (!gap_) {
    bt_log(DEBUG, "bt-host", "Already shut down");
    return;
  }

  // Closes all FIDL channels owned by |host_server_|.
  host_server_ = nullptr;

  // Make sure that |gap_| gets shut down and destroyed on its creation thread
  // as it is not thread-safe.
  gap_->ShutDown();
  gap_ = nullptr;

  // This shuts down the GATT profile and all of its clients.
  gatt_ = nullptr;

  // Shuts down HCI command channel and ACL data channel.
  hci_ = nullptr;
}

void BtHostComponent::BindToHostInterface(
    fidl::ServerEnd<fuchsia_bluetooth_host::Host> host_client) {
  if (host_server_) {
    bt_log(WARN, "bt-host", "Host interface channel already open");
    return;
  }

  BT_DEBUG_ASSERT(gap_);
  BT_DEBUG_ASSERT(gatt_);

  zx::channel channel = host_client.TakeChannel();

  host_server_ =
      std::make_unique<HostServer>(std::move(channel), gap_->AsWeakPtr(), gatt_->GetWeakPtr());
  host_server_->set_error_handler([this](zx_status_t status) {
    BT_DEBUG_ASSERT(host_server_);
    bt_log(WARN, "bt-host", "Host interface disconnected");
    host_server_ = nullptr;
  });
}

}  // namespace bthost