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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 
21 #include <dlfcn.h>
22 #include <errno.h>
23 #include <fcntl.h>
24 #include <unistd.h>
25 #include <utils/Log.h>
26 
27 namespace {
28 
29 const size_t preamble_size_for_type[] = {
30     0, HCI_COMMAND_PREAMBLE_SIZE, HCI_ACL_PREAMBLE_SIZE, HCI_SCO_PREAMBLE_SIZE,
31     HCI_EVENT_PREAMBLE_SIZE};
32 const size_t packet_length_offset_for_type[] = {
33     0, HCI_LENGTH_OFFSET_CMD, HCI_LENGTH_OFFSET_ACL, HCI_LENGTH_OFFSET_SCO,
34     HCI_LENGTH_OFFSET_EVT};
35 
HciGetPacketLengthForType(HciPacketType type,const uint8_t * preamble)36 size_t HciGetPacketLengthForType(HciPacketType type, const uint8_t* preamble) {
37   size_t offset = packet_length_offset_for_type[type];
38   if (type != HCI_PACKET_TYPE_ACL_DATA) return preamble[offset];
39   return (((preamble[offset + 1]) << 8) | preamble[offset]);
40 }
41 
42 }  // namespace
43 
44 namespace android {
45 namespace hardware {
46 namespace bluetooth {
47 namespace hci {
48 
GetPacket() const49 const hidl_vec<uint8_t>& HciPacketizer::GetPacket() const {
50   return packet_;
51 }
52 
OnDataReady(int fd,HciPacketType packet_type)53 void HciPacketizer::OnDataReady(int fd, HciPacketType packet_type) {
54   switch (state_) {
55     case HCI_PREAMBLE: {
56       ssize_t bytes_read = TEMP_FAILURE_RETRY(
57           read(fd, preamble_ + bytes_read_,
58                preamble_size_for_type[packet_type] - bytes_read_));
59       if (bytes_read == 0) {
60         // This is only expected if the UART got closed when shutting down.
61         ALOGE("%s: Unexpected EOF reading the header!", __func__);
62         sleep(5);  // Expect to be shut down within 5 seconds.
63         return;
64       }
65       if (bytes_read < 0) {
66         LOG_ALWAYS_FATAL("%s: Read header error: %s", __func__,
67                          strerror(errno));
68       }
69       bytes_read_ += bytes_read;
70       if (bytes_read_ == preamble_size_for_type[packet_type]) {
71         size_t packet_length =
72             HciGetPacketLengthForType(packet_type, preamble_);
73         packet_.resize(preamble_size_for_type[packet_type] + packet_length);
74         memcpy(packet_.data(), preamble_, preamble_size_for_type[packet_type]);
75         bytes_remaining_ = packet_length;
76         state_ = HCI_PAYLOAD;
77         bytes_read_ = 0;
78       }
79       break;
80     }
81 
82     case HCI_PAYLOAD: {
83       ssize_t bytes_read = TEMP_FAILURE_RETRY(read(
84           fd,
85           packet_.data() + preamble_size_for_type[packet_type] + bytes_read_,
86           bytes_remaining_));
87       if (bytes_read == 0) {
88         // This is only expected if the UART got closed when shutting down.
89         ALOGE("%s: Unexpected EOF reading the payload!", __func__);
90         sleep(5);  // Expect to be shut down within 5 seconds.
91         return;
92       }
93       if (bytes_read < 0) {
94         LOG_ALWAYS_FATAL("%s: Read payload error: %s", __func__,
95                          strerror(errno));
96       }
97       bytes_remaining_ -= bytes_read;
98       bytes_read_ += bytes_read;
99       if (bytes_remaining_ == 0) {
100         packet_ready_cb_();
101         state_ = HCI_PREAMBLE;
102         bytes_read_ = 0;
103       }
104       break;
105     }
106   }
107 }
108 
109 }  // namespace hci
110 }  // namespace bluetooth
111 }  // namespace hardware
112 }  // namespace android
113