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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/idata_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/rfc8260#section-2.1
// 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 = 64 | Res |I|U|B|E| Length = Variable |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | TSN |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Stream Identifier | Reserved |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Message Identifier |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Payload Protocol Identifier / Fragment Sequence Number |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// \ \
// / User Data /
// \ \
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
constexpr int IDataChunk::kType;
absl::optional<IDataChunk> IDataChunk::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>());
MID mid(reader->Load32<12>());
uint32_t ppid_or_fsn = reader->Load32<16>();
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 IDataChunk(tsn, stream_identifier, mid,
PPID(options.is_beginning ? ppid_or_fsn : 0),
FSN(options.is_beginning ? 0 : ppid_or_fsn),
std::vector<uint8_t>(reader->variable_data().begin(),
reader->variable_data().end()),
options);
}
void IDataChunk::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.Store32<12>(*mid());
writer.Store32<16>(options().is_beginning ? *ppid() : *fsn());
writer.CopyToVariableData(payload());
}
std::string IDataChunk::ToString() const {
rtc::StringBuilder sb;
sb << "I-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() << ", stream_id=" << *stream_id()
<< ", mid=" << *mid();
if (*options().is_beginning) {
sb << ", ppid=" << *ppid();
} else {
sb << ", fsn=" << *fsn();
}
sb << ", length=" << payload().size();
return sb.Release();
}
} // namespace dcsctp
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