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/*
* 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/data_chunk.h"
#include <stdint.h>
#include <string>
#include <type_traits>
#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/data_common.h"
#include "rtc_base/strings/string_builder.h"
namespace dcsctp {
// https://tools.ietf.org/html/rfc4960#section-3.3.1
// 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 = 0 | Reserved|U|B|E| Length |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | TSN |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Stream Identifier S | Stream Sequence Number n |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Payload Protocol Identifier |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// \ \
// / User Data (seq n of Stream S) /
// \ \
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
constexpr int DataChunk::kType;
absl::optional<DataChunk> DataChunk::Parse(rtc::ArrayView<const uint8_t> data) {
absl::optional<BoundedByteReader<kHeaderSize>> reader = ParseTLV(data);
if (!reader.has_value()) {
return absl::nullopt;
}
uint8_t flags = reader->Load8<1>();
TSN tsn(reader->Load32<4>());
StreamID stream_identifier(reader->Load16<8>());
SSN ssn(reader->Load16<10>());
PPID ppid(reader->Load32<12>());
Options options;
options.is_end = Data::IsEnd((flags & (1 << kFlagsBitEnd)) != 0);
options.is_beginning =
Data::IsBeginning((flags & (1 << kFlagsBitBeginning)) != 0);
options.is_unordered = IsUnordered((flags & (1 << kFlagsBitUnordered)) != 0);
options.immediate_ack =
ImmediateAckFlag((flags & (1 << kFlagsBitImmediateAck)) != 0);
return DataChunk(tsn, stream_identifier, ssn, ppid,
std::vector<uint8_t>(reader->variable_data().begin(),
reader->variable_data().end()),
options);
}
void DataChunk::SerializeTo(std::vector<uint8_t>& out) const {
BoundedByteWriter<kHeaderSize> writer = AllocateTLV(out, payload().size());
writer.Store8<1>(
(*options().is_end ? (1 << kFlagsBitEnd) : 0) |
(*options().is_beginning ? (1 << kFlagsBitBeginning) : 0) |
(*options().is_unordered ? (1 << kFlagsBitUnordered) : 0) |
(*options().immediate_ack ? (1 << kFlagsBitImmediateAck) : 0));
writer.Store32<4>(*tsn());
writer.Store16<8>(*stream_id());
writer.Store16<10>(*ssn());
writer.Store32<12>(*ppid());
writer.CopyToVariableData(payload());
}
std::string DataChunk::ToString() const {
rtc::StringBuilder sb;
sb << "DATA, type=" << (options().is_unordered ? "unordered" : "ordered")
<< "::"
<< (*options().is_beginning && *options().is_end
? "complete"
: *options().is_beginning ? "first"
: *options().is_end ? "last" : "middle")
<< ", tsn=" << *tsn() << ", sid=" << *stream_id() << ", ssn=" << *ssn()
<< ", ppid=" << *ppid() << ", length=" << payload().size();
return sb.Release();
}
} // namespace dcsctp
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