1 /*
2 * Copyright 2021 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_sniffer.h"
18
19 #include "hci/pcap_filter.h"
20 #include "pcap.h"
21
22 namespace rootcanal {
23
HciSniffer(std::shared_ptr<HciTransport> transport,std::shared_ptr<std::ostream> outputStream,std::shared_ptr<PcapFilter> filter)24 HciSniffer::HciSniffer(std::shared_ptr<HciTransport> transport,
25 std::shared_ptr<std::ostream> outputStream,
26 std::shared_ptr<PcapFilter> filter)
27 : transport_(transport), filter_(filter) {
28 SetOutputStream(outputStream);
29 }
30
SetPcapFilter(std::shared_ptr<PcapFilter> filter)31 void HciSniffer::SetPcapFilter(std::shared_ptr<PcapFilter> filter) {
32 filter_ = filter;
33 }
34
SetOutputStream(std::shared_ptr<std::ostream> outputStream)35 void HciSniffer::SetOutputStream(std::shared_ptr<std::ostream> outputStream) {
36 output_ = outputStream;
37 if (output_) {
38 uint32_t linktype = 201; // http://www.tcpdump.org/linktypes.html
39 // LINKTYPE_BLUETOOTH_HCI_H4_WITH_PHDR
40
41 pcap::WriteHeader(*output_, linktype);
42 }
43 }
44
AppendRecord(PacketDirection packet_direction,PacketType packet_type,const std::vector<uint8_t> & packet)45 void HciSniffer::AppendRecord(PacketDirection packet_direction,
46 PacketType packet_type,
47 const std::vector<uint8_t>& packet) {
48 if (output_ == nullptr) {
49 return;
50 }
51
52 pcap::WriteRecordHeader(*output_, 4 + 1 + packet.size());
53
54 // http://www.tcpdump.org/linktypes.html LINKTYPE_BLUETOOTH_HCI_H4_WITH_PHDR
55 // Note: the description given for the direction bit by tcpdump
56 // is in opposition with the implementation in wireshark.
57 // The values match wireshark's implementation here.
58 char direction[4] = {0, 0, 0, static_cast<char>(packet_direction)};
59 uint8_t idc = static_cast<uint8_t>(packet_type);
60 output_->write(direction, sizeof(direction));
61 output_->write((char*)&idc, 1);
62
63 // Apply the PCAP filter when provided.
64 if (filter_ != nullptr) {
65 std::vector<uint8_t> filtered_packet =
66 filter_->FilterHciPacket(packet, idc);
67 output_->write((char*)filtered_packet.data(), filtered_packet.size());
68 } else {
69 output_->write((char*)packet.data(), packet.size());
70 }
71
72 // Flush packet.
73 output_->flush();
74 }
75
RegisterCallbacks(PacketCallback packet_callback,CloseCallback close_callback)76 void HciSniffer::RegisterCallbacks(PacketCallback packet_callback,
77 CloseCallback close_callback) {
78 transport_->RegisterCallbacks(
79 [this, packet_callback](
80 PacketType packet_type,
81 const std::shared_ptr<std::vector<uint8_t>> packet) {
82 AppendRecord(PacketDirection::HOST_TO_CONTROLLER, packet_type, *packet);
83 packet_callback(packet_type, packet);
84 },
85 close_callback);
86 }
87
Tick()88 void HciSniffer::Tick() { transport_->Tick(); }
89
Close()90 void HciSniffer::Close() {
91 transport_->Close();
92 if (output_ != nullptr) {
93 output_->flush();
94 }
95 }
96
Send(PacketType packet_type,const std::vector<uint8_t> & packet)97 void HciSniffer::Send(PacketType packet_type,
98 const std::vector<uint8_t>& packet) {
99 AppendRecord(PacketDirection::CONTROLLER_TO_HOST, packet_type, packet);
100 transport_->Send(packet_type, packet);
101 }
102
103 } // namespace rootcanal
104