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      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 
     26 namespace {
     27 
     28 const 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};
     31 const 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 
     35 size_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 
     43 namespace android {
     44 namespace hardware {
     45 namespace bluetooth {
     46 namespace hci {
     47 
     48 const hidl_vec<uint8_t>& HciPacketizer::GetPacket() const { return packet_; }
     49 
     50 void HciPacketizer::OnDataReady(int fd, HciPacketType packet_type) {
     51   switch (state_) {
     52     case HCI_PREAMBLE: {
     53       size_t bytes_read = TEMP_FAILURE_RETRY(
     54           read(fd, preamble_ + bytes_read_,
     55                preamble_size_for_type[packet_type] - bytes_read_));
     56       CHECK(bytes_read > 0);
     57       bytes_read_ += bytes_read;
     58       if (bytes_read_ == preamble_size_for_type[packet_type]) {
     59         size_t packet_length =
     60             HciGetPacketLengthForType(packet_type, preamble_);
     61         packet_.resize(preamble_size_for_type[packet_type] + packet_length);
     62         memcpy(packet_.data(), preamble_, preamble_size_for_type[packet_type]);
     63         bytes_remaining_ = packet_length;
     64         state_ = HCI_PAYLOAD;
     65         bytes_read_ = 0;
     66       }
     67       break;
     68     }
     69 
     70     case HCI_PAYLOAD: {
     71       size_t bytes_read = TEMP_FAILURE_RETRY(read(
     72           fd,
     73           packet_.data() + preamble_size_for_type[packet_type] + bytes_read_,
     74           bytes_remaining_));
     75       CHECK(bytes_read > 0);
     76       bytes_remaining_ -= bytes_read;
     77       bytes_read_ += bytes_read;
     78       if (bytes_remaining_ == 0) {
     79         packet_ready_cb_();
     80         state_ = HCI_PREAMBLE;
     81         bytes_read_ = 0;
     82       }
     83       break;
     84     }
     85   }
     86 }
     87 
     88 }  // namespace hci
     89 }  // namespace bluetooth
     90 }  // namespace hardware
     91 }  // namespace android
     92