1 /*
2 * Copyright (c) 2021 The WebRTC project authors. All Rights Reserved.
3 *
4 * Use of this source code is governed by a BSD-style license
5 * that can be found in the LICENSE file in the root of the source
6 * tree. An additional intellectual property rights grant can be found
7 * in the file PATENTS. All contributing project authors may
8 * be found in the AUTHORS file in the root of the source tree.
9 */
10 #include "net/dcsctp/packet/chunk/idata_chunk.h"
11
12 #include <stdint.h>
13
14 #include <string>
15 #include <type_traits>
16 #include <vector>
17
18 #include "absl/types/optional.h"
19 #include "api/array_view.h"
20 #include "net/dcsctp/packet/bounded_byte_reader.h"
21 #include "net/dcsctp/packet/bounded_byte_writer.h"
22 #include "net/dcsctp/packet/chunk/data_common.h"
23 #include "rtc_base/strings/string_builder.h"
24
25 namespace dcsctp {
26
27 // https://tools.ietf.org/html/rfc8260#section-2.1
28
29 // 0 1 2 3
30 // 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
31 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
32 // | Type = 64 | Res |I|U|B|E| Length = Variable |
33 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
34 // | TSN |
35 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
36 // | Stream Identifier | Reserved |
37 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
38 // | Message Identifier |
39 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
40 // | Payload Protocol Identifier / Fragment Sequence Number |
41 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
42 // \ \
43 // / User Data /
44 // \ \
45 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
46 constexpr int IDataChunk::kType;
47
Parse(rtc::ArrayView<const uint8_t> data)48 absl::optional<IDataChunk> IDataChunk::Parse(
49 rtc::ArrayView<const uint8_t> data) {
50 absl::optional<BoundedByteReader<kHeaderSize>> reader = ParseTLV(data);
51 if (!reader.has_value()) {
52 return absl::nullopt;
53 }
54 uint8_t flags = reader->Load8<1>();
55 TSN tsn(reader->Load32<4>());
56 StreamID stream_identifier(reader->Load16<8>());
57 MID message_id(reader->Load32<12>());
58 uint32_t ppid_or_fsn = reader->Load32<16>();
59
60 Options options;
61 options.is_end = Data::IsEnd((flags & (1 << kFlagsBitEnd)) != 0);
62 options.is_beginning =
63 Data::IsBeginning((flags & (1 << kFlagsBitBeginning)) != 0);
64 options.is_unordered = IsUnordered((flags & (1 << kFlagsBitUnordered)) != 0);
65 options.immediate_ack =
66 ImmediateAckFlag((flags & (1 << kFlagsBitImmediateAck)) != 0);
67
68 return IDataChunk(tsn, stream_identifier, message_id,
69 PPID(options.is_beginning ? ppid_or_fsn : 0),
70 FSN(options.is_beginning ? 0 : ppid_or_fsn),
71 std::vector<uint8_t>(reader->variable_data().begin(),
72 reader->variable_data().end()),
73 options);
74 }
75
SerializeTo(std::vector<uint8_t> & out) const76 void IDataChunk::SerializeTo(std::vector<uint8_t>& out) const {
77 BoundedByteWriter<kHeaderSize> writer = AllocateTLV(out, payload().size());
78
79 writer.Store8<1>(
80 (*options().is_end ? (1 << kFlagsBitEnd) : 0) |
81 (*options().is_beginning ? (1 << kFlagsBitBeginning) : 0) |
82 (*options().is_unordered ? (1 << kFlagsBitUnordered) : 0) |
83 (*options().immediate_ack ? (1 << kFlagsBitImmediateAck) : 0));
84 writer.Store32<4>(*tsn());
85 writer.Store16<8>(*stream_id());
86 writer.Store32<12>(*message_id());
87 writer.Store32<16>(options().is_beginning ? *ppid() : *fsn());
88 writer.CopyToVariableData(payload());
89 }
90
ToString() const91 std::string IDataChunk::ToString() const {
92 rtc::StringBuilder sb;
93 sb << "I-DATA, type=" << (options().is_unordered ? "unordered" : "ordered")
94 << "::"
95 << (*options().is_beginning && *options().is_end
96 ? "complete"
97 : *options().is_beginning ? "first"
98 : *options().is_end ? "last" : "middle")
99 << ", tsn=" << *tsn() << ", stream_id=" << *stream_id()
100 << ", message_id=" << *message_id();
101
102 if (*options().is_beginning) {
103 sb << ", ppid=" << *ppid();
104 } else {
105 sb << ", fsn=" << *fsn();
106 }
107 sb << ", length=" << payload().size();
108 return sb.Release();
109 }
110
111 } // namespace dcsctp
112