[移动开发]Android 11 BT配对流程[2]

上面讲到Android JAVA层的调用，这里开始学习Bluedroid协议栈处理create_bond 的流程

system/bt/btif/src/bluetooth.cc


static int create_bond(const RawAddress* bd_addr, int transport) {
  /* sanity check */
  if (!interface_ready()) return BT_STATUS_NOT_READY;

  return btif_dm_create_bond(bd_addr, transport);
}

system/bt/btif/src/btif_dm.cc

/*******************************************************************************
 *
 * Function         btif_dm_create_bond
 *
 * Description      Initiate bonding with the specified device
 *
 * Returns          bt_status_t
 *
 ******************************************************************************/
bt_status_t btif_dm_create_bond(const RawAddress* bd_addr, int transport) {
  btif_dm_create_bond_cb_t create_bond_cb;
  create_bond_cb.transport = transport;
  create_bond_cb.bdaddr = *bd_addr;

这里把设备地址bd_addr和transport打包到create_bond_cb发送到

  BTIF_TRACE_EVENT("%s: bd_addr=%s, transport=%d", __func__,
                   bd_addr->ToString().c_str(), transport);
  if (pairing_cb.state != BT_BOND_STATE_NONE) return BT_STATUS_BUSY;

  btif_stats_add_bond_event(*bd_addr, BTIF_DM_FUNC_CREATE_BOND,
                            pairing_cb.state);


发送消息BTIF_DM_CB_CREATE_BOND处理配对流程
  btif_transfer_context(btif_dm_generic_evt, BTIF_DM_CB_CREATE_BOND,
                        (char*)&create_bond_cb,
                        sizeof(btif_dm_create_bond_cb_t), NULL);

  return BT_STATUS_SUCCESS;
}


bt_status_t btif_transfer_context(tBTIF_CBACK* p_cback, uint16_t event,
                                  char* p_params, int param_len,
                                  tBTIF_COPY_CBACK* p_copy_cback) {
  tBTIF_CONTEXT_SWITCH_CBACK* p_msg = (tBTIF_CONTEXT_SWITCH_CBACK*)osi_malloc(
      sizeof(tBTIF_CONTEXT_SWITCH_CBACK) + param_len);

  BTIF_TRACE_VERBOSE("btif_transfer_context event %d, len %d", event,
                     param_len);

  /* allocate and send message that will be executed in btif context */
  p_msg->hdr.event = BT_EVT_CONTEXT_SWITCH_EVT; /* internal event */
  p_msg->p_cb = p_cback;

  p_msg->event = event; /* callback event */

  /* check if caller has provided a copy callback to do the deep copy */
  if (p_copy_cback) {

这里相当于执行了btif_dm_generic_evt -> BTIF_DM_CB_CREATE_BOND
    p_copy_cback(event, p_msg->p_param, p_params);
  } else if (p_params) {
    memcpy(p_msg->p_param, p_params, param_len); /* callback parameter data */
  }

  btif_sendmsg(p_msg);

  return BT_STATUS_SUCCESS;
}



/*******************************************************************************
 *
 * Function         btif_dm_generic_evt
 *
 * Description      Executes non-BTA upstream events in BTIF context
 *
 * Returns          void
 *
 ******************************************************************************/
static void btif_dm_generic_evt(uint16_t event, char* p_param) {
  BTIF_TRACE_EVENT("%s: event=%d", __func__, event);
  switch (event) {
    case BTIF_DM_CB_DISCOVERY_STARTED: {
      HAL_CBACK(bt_hal_cbacks, discovery_state_changed_cb,
                BT_DISCOVERY_STARTED);
    } break;

    case BTIF_DM_CB_CREATE_BOND: {
      pairing_cb.timeout_retries = NUM_TIMEOUT_RETRIES;
      btif_dm_create_bond_cb_t* create_bond_cb =
          (btif_dm_create_bond_cb_t*)p_param;

//-->btif_dm_cb_create_bond

      btif_dm_cb_create_bond(create_bond_cb->bdaddr, create_bond_cb->transport);
    } break;

    case BTIF_DM_CB_REMOVE_BOND: {
      btif_dm_cb_remove_bond((RawAddress*)p_param);
    } break;

    case BTIF_DM_CB_HID_REMOTE_NAME: {
      btif_dm_cb_hid_remote_name((tBTM_REMOTE_DEV_NAME*)p_param);
    } break;

    case BTIF_DM_CB_BOND_STATE_BONDING: {
      bond_state_changed(BT_STATUS_SUCCESS, *((RawAddress*)p_param),
                         BT_BOND_STATE_BONDING);
    } break;
    case BTIF_DM_CB_LE_TX_TEST:
    case BTIF_DM_CB_LE_RX_TEST: {
      uint8_t status;
      STREAM_TO_UINT8(status, p_param);
      HAL_CBACK(bt_hal_cbacks, le_test_mode_cb,
                (status == 0) ? BT_STATUS_SUCCESS : BT_STATUS_FAIL, 0);
    } break;
    case BTIF_DM_CB_LE_TEST_END: {
      uint8_t status;
      uint16_t count = 0;
      STREAM_TO_UINT8(status, p_param);
      if (status == 0) STREAM_TO_UINT16(count, p_param);
      HAL_CBACK(bt_hal_cbacks, le_test_mode_cb,
                (status == 0) ? BT_STATUS_SUCCESS : BT_STATUS_FAIL, count);
    } break;
    default: {
      BTIF_TRACE_WARNING("%s : Unknown event 0x%x", __func__, event);
    } break;
  }
}


/*******************************************************************************
 *
 * Function         btif_dm_cb_create_bond
 *
 * Description      Create bond initiated from the BTIF thread context
 *                  Special handling for HID devices
 *
 * Returns          void
 *
 ******************************************************************************/
static void btif_dm_cb_create_bond(const RawAddress& bd_addr,
                                   tBTA_TRANSPORT transport) {
  bool is_hid = check_cod(&bd_addr, COD_HID_POINTING);
  bond_state_changed(BT_STATUS_SUCCESS, bd_addr, BT_BOND_STATE_BONDING);

  int device_type = 0;
  int addr_type;
  std::string addrstr = bd_addr.ToString();
  const char* bdstr = addrstr.c_str();
  if (transport == BT_TRANSPORT_LE) {
    if (!btif_config_get_int(bdstr, "DevType", &device_type)) {
      btif_config_set_int(bdstr, "DevType", BT_DEVICE_TYPE_BLE);
    }
    if (btif_storage_get_remote_addr_type(&bd_addr, &addr_type) !=
        BT_STATUS_SUCCESS) {
      // Try to read address type. OOB pairing might have set it earlier, but
      // didn't store it, it defaults to BLE_ADDR_PUBLIC
      uint8_t tmp_dev_type;
      uint8_t tmp_addr_type;
      BTM_ReadDevInfo(bd_addr, &tmp_dev_type, &tmp_addr_type);
      addr_type = tmp_addr_type;

      btif_storage_set_remote_addr_type(&bd_addr, addr_type);
    }
  }
  if ((btif_config_get_int(bdstr, "DevType", &device_type) &&
       (btif_storage_get_remote_addr_type(&bd_addr, &addr_type) ==
        BT_STATUS_SUCCESS) &&
       (device_type & BT_DEVICE_TYPE_BLE) == BT_DEVICE_TYPE_BLE) ||
      (transport == BT_TRANSPORT_LE)) {
    BTA_DmAddBleDevice(bd_addr, addr_type, device_type);
  }

  if (is_hid && (device_type & BT_DEVICE_TYPE_BLE) == 0) {
    bt_status_t status;
    status = (bt_status_t)btif_hh_connect(&bd_addr);
    if (status != BT_STATUS_SUCCESS)
      bond_state_changed(status, bd_addr, BT_BOND_STATE_NONE);
  } else {
    BTA_DmBond(bd_addr, addr_type, transport);
  }
  /*  Track  originator of bond creation  */
  pairing_cb.is_local_initiated = true;
}