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