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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/iforward_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/rfc8260#section-2.3.1
// 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 = 194 | Flags = 0x00 | Length = Variable |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | New Cumulative TSN |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Stream Identifier | Reserved |U|
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Message Identifier |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// \ \
// / /
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Stream Identifier | Reserved |U|
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Message Identifier |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
constexpr int IForwardTsnChunk::kType;
absl::optional<IForwardTsnChunk> IForwardTsnChunk::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);
size_t offset = 0;
for (size_t i = 0; i < streams_skipped; ++i) {
BoundedByteReader<kSkippedStreamBufferSize> sub_reader =
reader->sub_reader<kSkippedStreamBufferSize>(offset);
StreamID stream_id(sub_reader.Load16<0>());
IsUnordered unordered(sub_reader.Load8<3>() & 0x01);
MID message_id(sub_reader.Load32<4>());
skipped_streams.emplace_back(unordered, stream_id, message_id);
offset += kSkippedStreamBufferSize;
}
RTC_DCHECK(offset == reader->variable_data_size());
return IForwardTsnChunk(new_cumulative_tsn, std::move(skipped_streams));
}
void IForwardTsnChunk::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());
size_t offset = 0;
for (size_t i = 0; i < skipped.size(); ++i) {
BoundedByteWriter<kSkippedStreamBufferSize> sub_writer =
writer.sub_writer<kSkippedStreamBufferSize>(offset);
sub_writer.Store16<0>(*skipped[i].stream_id);
sub_writer.Store8<3>(skipped[i].unordered ? 1 : 0);
sub_writer.Store32<4>(*skipped[i].message_id);
offset += kSkippedStreamBufferSize;
}
RTC_DCHECK(offset == variable_size);
}
std::string IForwardTsnChunk::ToString() const {
rtc::StringBuilder sb;
sb << "I-FORWARD-TSN, new_cumulative_tsn=" << *new_cumulative_tsn();
return sb.Release();
}
} // namespace dcsctp
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