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