xref: /aosp_15_r20/external/webrtc/net/dcsctp/packet/parameter/outgoing_ssn_reset_request_parameter.cc (revision d9f758449e529ab9291ac668be2861e7a55c2422) 
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/parameter/outgoing_ssn_reset_request_parameter.h"
11 
12 #include <stddef.h>
13 
14 #include <cstdint>
15 #include <string>
16 #include <utility>
17 #include <vector>
18 
19 #include "absl/types/optional.h"
20 #include "api/array_view.h"
21 #include "net/dcsctp/common/internal_types.h"
22 #include "net/dcsctp/packet/bounded_byte_reader.h"
23 #include "net/dcsctp/packet/bounded_byte_writer.h"
24 #include "net/dcsctp/packet/tlv_trait.h"
25 #include "net/dcsctp/public/types.h"
26 #include "rtc_base/strings/string_builder.h"
27 
28 namespace dcsctp {
29 
30 // https://tools.ietf.org/html/rfc6525#section-4.1
31 
32 //   0                   1                   2                   3
33 //   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
34 //  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
35 //  |     Parameter Type = 13       | Parameter Length = 16 + 2 * N |
36 //  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
37 //  |           Re-configuration Request Sequence Number            |
38 //  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
39 //  |           Re-configuration Response Sequence Number           |
40 //  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
41 //  |                Sender's Last Assigned TSN                     |
42 //  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
43 //  |  Stream Number 1 (optional)   |    Stream Number 2 (optional) |
44 //  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
45 //  /                            ......                             /
46 //  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
47 //  |  Stream Number N-1 (optional) |    Stream Number N (optional) |
48 //  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
49 constexpr int OutgoingSSNResetRequestParameter::kType;
50 
51 absl::optional<OutgoingSSNResetRequestParameter>
Parse(rtc::ArrayView<const uint8_t> data)52 OutgoingSSNResetRequestParameter::Parse(rtc::ArrayView<const uint8_t> data) {
53   absl::optional<BoundedByteReader<kHeaderSize>> reader = ParseTLV(data);
54   if (!reader.has_value()) {
55     return absl::nullopt;
56   }
57 
58   ReconfigRequestSN request_sequence_number(reader->Load32<4>());
59   ReconfigRequestSN response_sequence_number(reader->Load32<8>());
60   TSN sender_last_assigned_tsn(reader->Load32<12>());
61 
62   size_t stream_count = reader->variable_data_size() / kStreamIdSize;
63   std::vector<StreamID> stream_ids;
64   stream_ids.reserve(stream_count);
65   for (size_t i = 0; i < stream_count; ++i) {
66     BoundedByteReader<kStreamIdSize> sub_reader =
67         reader->sub_reader<kStreamIdSize>(i * kStreamIdSize);
68 
69     stream_ids.push_back(StreamID(sub_reader.Load16<0>()));
70   }
71 
72   return OutgoingSSNResetRequestParameter(
73       request_sequence_number, response_sequence_number,
74       sender_last_assigned_tsn, std::move(stream_ids));
75 }
76 
SerializeTo(std::vector<uint8_t> & out) const77 void OutgoingSSNResetRequestParameter::SerializeTo(
78     std::vector<uint8_t>& out) const {
79   size_t variable_size = stream_ids_.size() * kStreamIdSize;
80   BoundedByteWriter<kHeaderSize> writer = AllocateTLV(out, variable_size);
81 
82   writer.Store32<4>(*request_sequence_number_);
83   writer.Store32<8>(*response_sequence_number_);
84   writer.Store32<12>(*sender_last_assigned_tsn_);
85 
86   for (size_t i = 0; i < stream_ids_.size(); ++i) {
87     BoundedByteWriter<kStreamIdSize> sub_writer =
88         writer.sub_writer<kStreamIdSize>(i * kStreamIdSize);
89     sub_writer.Store16<0>(*stream_ids_[i]);
90   }
91 }
92 
ToString() const93 std::string OutgoingSSNResetRequestParameter::ToString() const {
94   rtc::StringBuilder sb;
95   sb << "Outgoing SSN Reset Request, req_seq_nbr=" << *request_sequence_number()
96      << ", resp_seq_nbr=" << *response_sequence_number()
97      << ", sender_last_asg_tsn=" << *sender_last_assigned_tsn();
98   return sb.Release();
99 }
100 
101 }  // namespace dcsctp
102