hci/src/hci_packet_parser.cc

/******************************************************************************
 *
 *  Copyright (C) 2014 Google, Inc.
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at:
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 ******************************************************************************/

#define LOG_TAG "bt_hci"

#include "hci_packet_parser.h"

#include <base/logging.h>

#include "buffer_allocator.h"
#include "hci_layer.h"
#include "hcimsgs.h"
#include "osi/include/log.h"

static const command_opcode_t NO_OPCODE_CHECKING = 0;

static const allocator_t* buffer_allocator;

static uint8_t* read_command_complete_header(BT_HDR* response,
                                             command_opcode_t expected_opcode,
                                             size_t minimum_bytes_after);

static void parse_generic_command_complete(BT_HDR* response) {
  read_command_complete_header(response, NO_OPCODE_CHECKING,
                               0 /* bytes after */);

  buffer_allocator->free(response);
}

static void parse_read_buffer_size_response(BT_HDR* response,
                                            uint16_t* data_size_ptr,
                                            uint16_t* acl_buffer_count_ptr) {
  uint8_t* stream = read_command_complete_header(response, HCI_READ_BUFFER_SIZE,
                                                 5 /* bytes after */);
  CHECK(stream != NULL);
  STREAM_TO_UINT16(*data_size_ptr, stream);
  STREAM_SKIP_UINT8(stream);  // skip the sco packet length
  STREAM_TO_UINT16(*acl_buffer_count_ptr, stream);

  buffer_allocator->free(response);
}

static void parse_read_local_version_info_response(BT_HDR* response,
                                                   bt_version_t* bt_version) {
  uint8_t* stream = read_command_complete_header(
      response, HCI_READ_LOCAL_VERSION_INFO, 8 /* bytes after */);
  CHECK(stream != NULL);
  STREAM_TO_UINT8(bt_version->hci_version, stream);
  STREAM_TO_UINT16(bt_version->hci_revision, stream);
  STREAM_TO_UINT8(bt_version->lmp_version, stream);
  STREAM_TO_UINT16(bt_version->manufacturer, stream);
  STREAM_TO_UINT16(bt_version->lmp_subversion, stream);

  buffer_allocator->free(response);
}

static void parse_read_local_supported_codecs_response(
    BT_HDR* response, uint8_t* number_of_local_supported_codecs,
    uint8_t* local_supported_codecs) {
  uint8_t* stream = read_command_complete_header(
      response, HCI_READ_LOCAL_SUPPORTED_CODECS, 0 /* bytes after */);
  if (stream) {
    STREAM_TO_UINT8(*number_of_local_supported_codecs, stream);
    for (uint8_t i = 0; i < *number_of_local_supported_codecs; i++) {
      STREAM_TO_UINT8(*local_supported_codecs, stream);
      local_supported_codecs++;
    }
  }

  buffer_allocator->free(response);
}

static void parse_read_bd_addr_response(BT_HDR* response,
                                        bt_bdaddr_t* address_ptr) {
  uint8_t* stream = read_command_complete_header(
      response, HCI_READ_BD_ADDR, sizeof(bt_bdaddr_t) /* bytes after */);
  CHECK(stream != NULL);
  STREAM_TO_BDADDR(address_ptr->address, stream);

  buffer_allocator->free(response);
}

static void parse_read_local_supported_commands_response(
    BT_HDR* response, uint8_t* supported_commands_ptr,
    size_t supported_commands_length) {
  uint8_t* stream =
      read_command_complete_header(response, HCI_READ_LOCAL_SUPPORTED_CMDS,
                                   supported_commands_length /* bytes after */);
  CHECK(stream != NULL);
  STREAM_TO_ARRAY(supported_commands_ptr, stream,
                  (int)supported_commands_length);

  buffer_allocator->free(response);
}

static void parse_read_local_extended_features_response(
    BT_HDR* response, uint8_t* page_number_ptr, uint8_t* max_page_number_ptr,
    bt_device_features_t* feature_pages, size_t feature_pages_count) {
  uint8_t* stream = read_command_complete_header(
      response, HCI_READ_LOCAL_EXT_FEATURES,
      2 + sizeof(bt_device_features_t) /* bytes after */);
  CHECK(stream != NULL);

  STREAM_TO_UINT8(*page_number_ptr, stream);
  STREAM_TO_UINT8(*max_page_number_ptr, stream);

  CHECK(*page_number_ptr < feature_pages_count);
  STREAM_TO_ARRAY(feature_pages[*page_number_ptr].as_array, stream,
                  (int)sizeof(bt_device_features_t));

  buffer_allocator->free(response);
}

static void parse_ble_read_white_list_size_response(
    BT_HDR* response, uint8_t* white_list_size_ptr) {
  uint8_t* stream = read_command_complete_header(
      response, HCI_BLE_READ_WHITE_LIST_SIZE, 1 /* byte after */);
  CHECK(stream != NULL);
  STREAM_TO_UINT8(*white_list_size_ptr, stream);

  buffer_allocator->free(response);
}

static void parse_ble_read_buffer_size_response(BT_HDR* response,
                                                uint16_t* data_size_ptr,
                                                uint8_t* acl_buffer_count_ptr) {
  uint8_t* stream = read_command_complete_header(
      response, HCI_BLE_READ_BUFFER_SIZE, 3 /* bytes after */);
  CHECK(stream != NULL);
  STREAM_TO_UINT16(*data_size_ptr, stream);
  STREAM_TO_UINT8(*acl_buffer_count_ptr, stream);

  buffer_allocator->free(response);
}

static void parse_ble_read_supported_states_response(
    BT_HDR* response, uint8_t* supported_states, size_t supported_states_size) {
  uint8_t* stream =
      read_command_complete_header(response, HCI_BLE_READ_SUPPORTED_STATES,
                                   supported_states_size /* bytes after */);
  CHECK(stream != NULL);
  STREAM_TO_ARRAY(supported_states, stream, (int)supported_states_size);

  buffer_allocator->free(response);
}

static void parse_ble_read_local_supported_features_response(
    BT_HDR* response, bt_device_features_t* supported_features) {
  uint8_t* stream = read_command_complete_header(
      response, HCI_BLE_READ_LOCAL_SPT_FEAT,
      sizeof(bt_device_features_t) /* bytes after */);
  CHECK(stream != NULL);
  STREAM_TO_ARRAY(supported_features->as_array, stream,
                  (int)sizeof(bt_device_features_t));

  buffer_allocator->free(response);
}

static void parse_ble_read_resolving_list_size_response(
    BT_HDR* response, uint8_t* resolving_list_size_ptr) {
  uint8_t* stream = read_command_complete_header(
      response, HCI_BLE_READ_RESOLVING_LIST_SIZE, 1 /* bytes after */);
  STREAM_TO_UINT8(*resolving_list_size_ptr, stream);

  buffer_allocator->free(response);
}

static void parse_ble_read_suggested_default_data_length_response(
    BT_HDR* response, uint16_t* ble_default_packet_length_ptr) {
  uint8_t* stream = read_command_complete_header(
      response, HCI_BLE_READ_DEFAULT_DATA_LENGTH, 2 /* bytes after */);
  STREAM_TO_UINT8(*ble_default_packet_length_ptr, stream);
}

static void parse_ble_read_maximum_advertising_data_length(
    BT_HDR* response, uint16_t* ble_maximum_advertising_data_length_ptr) {
  uint8_t* stream = read_command_complete_header(
      response, HCI_LE_READ_MAXIMUM_ADVERTISING_DATA_LENGTH,
      2 /* bytes after */);
  STREAM_TO_UINT16(*ble_maximum_advertising_data_length_ptr, stream);

  buffer_allocator->free(response);
}

static void parse_ble_read_number_of_supported_advertising_sets(
    BT_HDR* response, uint8_t* ble_number_of_supported_advertising_sets_ptr) {
  uint8_t* stream = read_command_complete_header(
      response, HCI_LE_READ_NUMBER_OF_SUPPORTED_ADVERTISING_SETS,
      1 /* bytes after */);
  STREAM_TO_UINT8(*ble_number_of_supported_advertising_sets_ptr, stream);

  buffer_allocator->free(response);
}

// Internal functions

static uint8_t* read_command_complete_header(BT_HDR* response,
                                             command_opcode_t expected_opcode,
                                             size_t minimum_bytes_after) {
  uint8_t* stream = response->data + response->offset;

  // Read the event header
  uint8_t event_code;
  uint8_t parameter_length;
  STREAM_TO_UINT8(event_code, stream);
  STREAM_TO_UINT8(parameter_length, stream);

  const size_t parameter_bytes_we_read_here = 4;

  // Check the event header values against what we expect
  CHECK(event_code == HCI_COMMAND_COMPLETE_EVT);
  CHECK(parameter_length >=
        (parameter_bytes_we_read_here + minimum_bytes_after));

  // Read the command complete header
  command_opcode_t opcode;
  uint8_t status;
  STREAM_SKIP_UINT8(stream);  // skip the number of hci command packets field
  STREAM_TO_UINT16(opcode, stream);

  // Check the command complete header values against what we expect
  if (expected_opcode != NO_OPCODE_CHECKING) {
    CHECK(opcode == expected_opcode);
  }

  // Assume the next field is the status field
  STREAM_TO_UINT8(status, stream);

  if (status != HCI_SUCCESS) {
    LOG_ERROR(LOG_TAG, "%s: return status - 0x%x", __func__, status);
    return NULL;
  }

  return stream;
}

static const hci_packet_parser_t interface = {
    parse_generic_command_complete,
    parse_read_buffer_size_response,
    parse_read_local_version_info_response,
    parse_read_bd_addr_response,
    parse_read_local_supported_commands_response,
    parse_read_local_extended_features_response,
    parse_ble_read_white_list_size_response,
    parse_ble_read_buffer_size_response,
    parse_ble_read_supported_states_response,
    parse_ble_read_local_supported_features_response,
    parse_ble_read_resolving_list_size_response,
    parse_ble_read_suggested_default_data_length_response,
    parse_ble_read_maximum_advertising_data_length,
    parse_ble_read_number_of_supported_advertising_sets,
    parse_read_local_supported_codecs_response};

const hci_packet_parser_t* hci_packet_parser_get_interface() {
  buffer_allocator = buffer_allocator_get_interface();
  return &interface;
}

const hci_packet_parser_t* hci_packet_parser_get_test_interface(
    allocator_t* buffer_allocator_interface) {
  buffer_allocator = buffer_allocator_interface;
  return &interface;
}