1//
2// Copyright 2017 The Android Open Source Project
3//
4// Licensed under the Apache License, Version 2.0 (the "License");
5// you may not use this file except in compliance with the License.
6// You may obtain a copy of the License at
7//
8// http://www.apache.org/licenses/LICENSE-2.0
9//
10// Unless required by applicable law or agreed to in writing, software
11// distributed under the License is distributed on an "AS IS" BASIS,
12// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13// See the License for the specific language governing permissions and
14// limitations under the License.
15//
16
17#include "hci_packetizer.h"
18
19#define LOG_TAG "android.hardware.bluetooth.hci_packetizer"
20#include <android-base/logging.h>
21#include <utils/Log.h>
22
23#include <dlfcn.h>
24#include <fcntl.h>
25
26namespace {
27
28const size_t preamble_size_for_type[] = {
29    0, HCI_COMMAND_PREAMBLE_SIZE, HCI_ACL_PREAMBLE_SIZE, HCI_SCO_PREAMBLE_SIZE,
30    HCI_EVENT_PREAMBLE_SIZE};
31const size_t packet_length_offset_for_type[] = {
32    0, HCI_LENGTH_OFFSET_CMD, HCI_LENGTH_OFFSET_ACL, HCI_LENGTH_OFFSET_SCO,
33    HCI_LENGTH_OFFSET_EVT};
34
35size_t HciGetPacketLengthForType(HciPacketType type, const uint8_t* preamble) {
36  size_t offset = packet_length_offset_for_type[type];
37  if (type != HCI_PACKET_TYPE_ACL_DATA) return preamble[offset];
38  return (((preamble[offset + 1]) << 8) | preamble[offset]);
39}
40
41}  // namespace
42
43namespace android {
44namespace hardware {
45namespace bluetooth {
46namespace hci {
47
48const hidl_vec<uint8_t>& HciPacketizer::GetPacket() const { return packet_; }
49
50void HciPacketizer::CbHciPacket(uint8_t *data, size_t len) {
51    packet_.setToExternal(data, len);
52    packet_ready_cb_();
53}
54
55void HciPacketizer::OnDataReady(int fd, HciPacketType packet_type) {
56  switch (state_) {
57    case HCI_PREAMBLE: {
58      size_t bytes_read = TEMP_FAILURE_RETRY(
59          read(fd, preamble_ + bytes_read_,
60               preamble_size_for_type[packet_type] - bytes_read_));
61      CHECK(bytes_read > 0);
62      bytes_read_ += bytes_read;
63      if (bytes_read_ == preamble_size_for_type[packet_type]) {
64        size_t packet_length =
65            HciGetPacketLengthForType(packet_type, preamble_);
66        packet_.resize(preamble_size_for_type[packet_type] + packet_length);
67        memcpy(packet_.data(), preamble_, preamble_size_for_type[packet_type]);
68        bytes_remaining_ = packet_length;
69        state_ = HCI_PAYLOAD;
70        bytes_read_ = 0;
71      }
72      break;
73    }
74
75    case HCI_PAYLOAD: {
76      size_t bytes_read = TEMP_FAILURE_RETRY(read(
77          fd,
78          packet_.data() + preamble_size_for_type[packet_type] + bytes_read_,
79          bytes_remaining_));
80      CHECK(bytes_read > 0);
81      bytes_remaining_ -= bytes_read;
82      bytes_read_ += bytes_read;
83      if (bytes_remaining_ == 0) {
84        packet_ready_cb_();
85        state_ = HCI_PREAMBLE;
86        bytes_read_ = 0;
87      }
88      break;
89    }
90  }
91}
92
93}  // namespace hci
94}  // namespace bluetooth
95}  // namespace hardware
96}  // namespace android
97