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[] = {0,
30 HCI_COMMAND_PREAMBLE_SIZE,
31 HCI_ACL_PREAMBLE_SIZE,
32 HCI_SCO_PREAMBLE_SIZE,
33 HCI_EVENT_PREAMBLE_SIZE,
34 HCI_ISO_PREAMBLE_SIZE};
35 const size_t packet_length_offset_for_type[] = {0,
36 HCI_LENGTH_OFFSET_CMD,
37 HCI_LENGTH_OFFSET_ACL,
38 HCI_LENGTH_OFFSET_SCO,
39 HCI_LENGTH_OFFSET_EVT,
40 HCI_LENGTH_OFFSET_ISO};
41
HciGetPacketLengthForType(HciPacketType type,const uint8_t * preamble)42 size_t HciGetPacketLengthForType(HciPacketType type, const uint8_t* preamble) {
43 size_t offset = packet_length_offset_for_type[type];
44 if (type == HCI_PACKET_TYPE_ACL_DATA) {
45 return (((preamble[offset + 1]) << 8) | preamble[offset]);
46 } else if (type == HCI_PACKET_TYPE_ISO_DATA) {
47 return ((((preamble[offset + 1]) & 0x3f) << 8) | preamble[offset]);
48 }
49 return preamble[offset];
50 }
51
52 } // namespace
53
54 namespace android {
55 namespace hardware {
56 namespace bluetooth {
57 namespace hci {
58
GetPacket() const59 const hidl_vec<uint8_t>& HciPacketizer::GetPacket() const { return packet_; }
60
OnDataReady(int fd,HciPacketType packet_type)61 void HciPacketizer::OnDataReady(int fd, HciPacketType packet_type) {
62 switch (state_) {
63 case HCI_PREAMBLE: {
64 ssize_t bytes_read = TEMP_FAILURE_RETRY(
65 read(fd, preamble_ + bytes_read_,
66 preamble_size_for_type[packet_type] - bytes_read_));
67 if (bytes_read == 0) {
68 // This is only expected if the UART got closed when shutting down.
69 ALOGE("%s: Unexpected EOF reading the header!", __func__);
70 sleep(5); // Expect to be shut down within 5 seconds.
71 return;
72 }
73 if (bytes_read < 0) {
74 LOG_ALWAYS_FATAL("%s: Read header error: %s", __func__,
75 strerror(errno));
76 }
77 bytes_read_ += bytes_read;
78 if (bytes_read_ == preamble_size_for_type[packet_type]) {
79 size_t packet_length =
80 HciGetPacketLengthForType(packet_type, preamble_);
81 packet_.resize(preamble_size_for_type[packet_type] + packet_length);
82 memcpy(packet_.data(), preamble_, preamble_size_for_type[packet_type]);
83 bytes_remaining_ = packet_length;
84 state_ = HCI_PAYLOAD;
85 bytes_read_ = 0;
86 }
87 break;
88 }
89
90 case HCI_PAYLOAD: {
91 ssize_t bytes_read = TEMP_FAILURE_RETRY(read(
92 fd,
93 packet_.data() + preamble_size_for_type[packet_type] + bytes_read_,
94 bytes_remaining_));
95 if (bytes_read == 0) {
96 // This is only expected if the UART got closed when shutting down.
97 ALOGE("%s: Unexpected EOF reading the payload!", __func__);
98 sleep(5); // Expect to be shut down within 5 seconds.
99 return;
100 }
101 if (bytes_read < 0) {
102 LOG_ALWAYS_FATAL("%s: Read payload error: %s", __func__,
103 strerror(errno));
104 }
105 bytes_remaining_ -= bytes_read;
106 bytes_read_ += bytes_read;
107 if (bytes_remaining_ == 0) {
108 packet_ready_cb_();
109 state_ = HCI_PREAMBLE;
110 bytes_read_ = 0;
111 }
112 break;
113 }
114 }
115 }
116
117 } // namespace hci
118 } // namespace bluetooth
119 } // namespace hardware
120 } // namespace android
121