ee0270b67c
MID is a RFC8260 property on an I-DATA chunk, replacing the SSN property on the DATA chunk in non-interleaved message. The MID stands for "Message Identifier", and it was frequently named "message_id" in the source code, but sometimes "mid". To be consistent and using the same terminology as is most common in the RFC, use "mid" everywhere. This was triggered by the need to introduce yet another "message identifier" - but for now, this is just a refacotring CL. Bug: None Change-Id: I9cca898d9f3a2f162d6f2e4508ec1b4bc8d7308f Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/322500 Reviewed-by: Harald Alvestrand <hta@webrtc.org> Commit-Queue: Victor Boivie <boivie@webrtc.org> Cr-Commit-Position: refs/heads/main@{#40876}
105 lines
4.1 KiB
C++
105 lines
4.1 KiB
C++
/*
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* Copyright (c) 2021 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "net/dcsctp/packet/chunk/iforward_tsn_chunk.h"
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#include <stddef.h>
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#include <stdint.h>
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#include <string>
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#include <utility>
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#include <vector>
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#include "absl/types/optional.h"
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#include "api/array_view.h"
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#include "net/dcsctp/packet/bounded_byte_reader.h"
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#include "net/dcsctp/packet/bounded_byte_writer.h"
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#include "net/dcsctp/packet/chunk/forward_tsn_common.h"
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#include "net/dcsctp/packet/tlv_trait.h"
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#include "rtc_base/strings/string_builder.h"
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namespace dcsctp {
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// https://tools.ietf.org/html/rfc8260#section-2.3.1
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// 0 1 2 3
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// 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
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | Type = 194 | Flags = 0x00 | Length = Variable |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | New Cumulative TSN |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | Stream Identifier | Reserved |U|
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | Message Identifier |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// \ \
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// / /
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | Stream Identifier | Reserved |U|
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// | Message Identifier |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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constexpr int IForwardTsnChunk::kType;
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absl::optional<IForwardTsnChunk> IForwardTsnChunk::Parse(
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rtc::ArrayView<const uint8_t> data) {
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absl::optional<BoundedByteReader<kHeaderSize>> reader = ParseTLV(data);
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if (!reader.has_value()) {
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return absl::nullopt;
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}
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TSN new_cumulative_tsn(reader->Load32<4>());
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size_t streams_skipped =
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reader->variable_data_size() / kSkippedStreamBufferSize;
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std::vector<SkippedStream> skipped_streams;
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skipped_streams.reserve(streams_skipped);
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size_t offset = 0;
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for (size_t i = 0; i < streams_skipped; ++i) {
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BoundedByteReader<kSkippedStreamBufferSize> sub_reader =
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reader->sub_reader<kSkippedStreamBufferSize>(offset);
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StreamID stream_id(sub_reader.Load16<0>());
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IsUnordered unordered(sub_reader.Load8<3>() & 0x01);
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MID mid(sub_reader.Load32<4>());
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skipped_streams.emplace_back(unordered, stream_id, mid);
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offset += kSkippedStreamBufferSize;
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}
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RTC_DCHECK(offset == reader->variable_data_size());
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return IForwardTsnChunk(new_cumulative_tsn, std::move(skipped_streams));
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}
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void IForwardTsnChunk::SerializeTo(std::vector<uint8_t>& out) const {
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rtc::ArrayView<const SkippedStream> skipped = skipped_streams();
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size_t variable_size = skipped.size() * kSkippedStreamBufferSize;
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BoundedByteWriter<kHeaderSize> writer = AllocateTLV(out, variable_size);
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writer.Store32<4>(*new_cumulative_tsn());
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size_t offset = 0;
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for (size_t i = 0; i < skipped.size(); ++i) {
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BoundedByteWriter<kSkippedStreamBufferSize> sub_writer =
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writer.sub_writer<kSkippedStreamBufferSize>(offset);
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sub_writer.Store16<0>(*skipped[i].stream_id);
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sub_writer.Store8<3>(skipped[i].unordered ? 1 : 0);
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sub_writer.Store32<4>(*skipped[i].mid);
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offset += kSkippedStreamBufferSize;
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}
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RTC_DCHECK(offset == variable_size);
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}
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std::string IForwardTsnChunk::ToString() const {
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rtc::StringBuilder sb;
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sb << "I-FORWARD-TSN, new_cumulative_tsn=" << *new_cumulative_tsn();
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return sb.Release();
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}
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} // namespace dcsctp
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