| /* |
| * Copyright (c) 2021 The WebRTC project authors. All Rights Reserved. |
| * |
| * Use of this source code is governed by a BSD-style license |
| * that can be found in the LICENSE file in the root of the source |
| * tree. An additional intellectual property rights grant can be found |
| * in the file PATENTS. All contributing project authors may |
| * be found in the AUTHORS file in the root of the source tree. |
| */ |
| #include "net/dcsctp/packet/chunk/forward_tsn_chunk.h" |
| |
| #include <stddef.h> |
| #include <stdint.h> |
| |
| #include <string> |
| #include <utility> |
| #include <vector> |
| |
| #include "absl/types/optional.h" |
| #include "api/array_view.h" |
| #include "net/dcsctp/packet/bounded_byte_reader.h" |
| #include "net/dcsctp/packet/bounded_byte_writer.h" |
| #include "net/dcsctp/packet/chunk/forward_tsn_common.h" |
| #include "net/dcsctp/packet/tlv_trait.h" |
| #include "rtc_base/strings/string_builder.h" |
| |
| namespace dcsctp { |
| |
| // https://tools.ietf.org/html/rfc3758#section-3.2 |
| |
| // 0 1 2 3 |
| // 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 |
| // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| // | Type = 192 | Flags = 0x00 | Length = Variable | |
| // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| // | New Cumulative TSN | |
| // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| // | Stream-1 | Stream Sequence-1 | |
| // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| // \ / |
| // / \ |
| // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| // | Stream-N | Stream Sequence-N | |
| // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| constexpr int ForwardTsnChunk::kType; |
| |
| absl::optional<ForwardTsnChunk> ForwardTsnChunk::Parse( |
| rtc::ArrayView<const uint8_t> data) { |
| absl::optional<BoundedByteReader<kHeaderSize>> reader = ParseTLV(data); |
| if (!reader.has_value()) { |
| return absl::nullopt; |
| } |
| TSN new_cumulative_tsn(reader->Load32<4>()); |
| |
| size_t streams_skipped = |
| reader->variable_data_size() / kSkippedStreamBufferSize; |
| |
| std::vector<SkippedStream> skipped_streams; |
| skipped_streams.reserve(streams_skipped); |
| for (size_t i = 0; i < streams_skipped; ++i) { |
| BoundedByteReader<kSkippedStreamBufferSize> sub_reader = |
| reader->sub_reader<kSkippedStreamBufferSize>(i * |
| kSkippedStreamBufferSize); |
| |
| StreamID stream_id(sub_reader.Load16<0>()); |
| SSN ssn(sub_reader.Load16<2>()); |
| skipped_streams.emplace_back(stream_id, ssn); |
| } |
| return ForwardTsnChunk(new_cumulative_tsn, std::move(skipped_streams)); |
| } |
| |
| void ForwardTsnChunk::SerializeTo(std::vector<uint8_t>& out) const { |
| rtc::ArrayView<const SkippedStream> skipped = skipped_streams(); |
| size_t variable_size = skipped.size() * kSkippedStreamBufferSize; |
| BoundedByteWriter<kHeaderSize> writer = AllocateTLV(out, variable_size); |
| |
| writer.Store32<4>(*new_cumulative_tsn()); |
| for (size_t i = 0; i < skipped.size(); ++i) { |
| BoundedByteWriter<kSkippedStreamBufferSize> sub_writer = |
| writer.sub_writer<kSkippedStreamBufferSize>(i * |
| kSkippedStreamBufferSize); |
| sub_writer.Store16<0>(*skipped[i].stream_id); |
| sub_writer.Store16<2>(*skipped[i].ssn); |
| } |
| } |
| |
| std::string ForwardTsnChunk::ToString() const { |
| rtc::StringBuilder sb; |
| sb << "FORWARD-TSN, new_cumulative_tsn=" << *new_cumulative_tsn(); |
| return sb.str(); |
| } |
| } // namespace dcsctp |