diff options
Diffstat (limited to 'third_party/libwebrtc/net/dcsctp/packet/chunk/forward_tsn_chunk.cc')
-rw-r--r-- | third_party/libwebrtc/net/dcsctp/packet/chunk/forward_tsn_chunk.cc | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/third_party/libwebrtc/net/dcsctp/packet/chunk/forward_tsn_chunk.cc b/third_party/libwebrtc/net/dcsctp/packet/chunk/forward_tsn_chunk.cc new file mode 100644 index 0000000000..e432114c50 --- /dev/null +++ b/third_party/libwebrtc/net/dcsctp/packet/chunk/forward_tsn_chunk.cc @@ -0,0 +1,95 @@ +/* + * 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(); + for (const auto& skipped : skipped_streams()) { + sb << ", skip " << skipped.stream_id.value() << ":" << *skipped.ssn; + } + return sb.str(); +} +} // namespace dcsctp |