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Diffstat (limited to 'third_party/libwebrtc/net/dcsctp/packet/chunk/sack_chunk.cc')
| -rw-r--r-- | third_party/libwebrtc/net/dcsctp/packet/chunk/sack_chunk.cc | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/third_party/libwebrtc/net/dcsctp/packet/chunk/sack_chunk.cc b/third_party/libwebrtc/net/dcsctp/packet/chunk/sack_chunk.cc new file mode 100644 index 0000000000..d80e430082 --- /dev/null +++ b/third_party/libwebrtc/net/dcsctp/packet/chunk/sack_chunk.cc @@ -0,0 +1,155 @@ +/* + * 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/sack_chunk.h" + +#include <stddef.h> + +#include <cstdint> +#include <string> +#include <type_traits> +#include <vector> + +#include "absl/types/optional.h" +#include "api/array_view.h" +#include "net/dcsctp/common/str_join.h" +#include "net/dcsctp/packet/bounded_byte_reader.h" +#include "net/dcsctp/packet/bounded_byte_writer.h" +#include "net/dcsctp/packet/tlv_trait.h" +#include "rtc_base/logging.h" +#include "rtc_base/strings/string_builder.h" + +namespace dcsctp { + +// https://tools.ietf.org/html/rfc4960#section-3.3.4 + +// 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 = 3 |Chunk Flags | Chunk Length | +// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +// | Cumulative TSN Ack | +// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +// | Advertised Receiver Window Credit (a_rwnd) | +// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +// | Number of Gap Ack Blocks = N | Number of Duplicate TSNs = X | +// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +// | Gap Ack Block #1 Start | Gap Ack Block #1 End | +// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +// / / +// \ ... \ +// / / +// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +// | Gap Ack Block #N Start | Gap Ack Block #N End | +// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +// | Duplicate TSN 1 | +// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +// / / +// \ ... \ +// / / +// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +// | Duplicate TSN X | +// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +constexpr int SackChunk::kType; + +absl::optional<SackChunk> SackChunk::Parse(rtc::ArrayView<const uint8_t> data) { + absl::optional<BoundedByteReader<kHeaderSize>> reader = ParseTLV(data); + if (!reader.has_value()) { + return absl::nullopt; + } + + TSN tsn_ack(reader->Load32<4>()); + uint32_t a_rwnd = reader->Load32<8>(); + uint16_t nbr_of_gap_blocks = reader->Load16<12>(); + uint16_t nbr_of_dup_tsns = reader->Load16<14>(); + + if (reader->variable_data_size() != nbr_of_gap_blocks * kGapAckBlockSize + + nbr_of_dup_tsns * kDupTsnBlockSize) { + RTC_DLOG(LS_WARNING) << "Invalid number of gap blocks or duplicate TSNs"; + return absl::nullopt; + } + + std::vector<GapAckBlock> gap_ack_blocks; + gap_ack_blocks.reserve(nbr_of_gap_blocks); + size_t offset = 0; + for (int i = 0; i < nbr_of_gap_blocks; ++i) { + BoundedByteReader<kGapAckBlockSize> sub_reader = + reader->sub_reader<kGapAckBlockSize>(offset); + + uint16_t start = sub_reader.Load16<0>(); + uint16_t end = sub_reader.Load16<2>(); + gap_ack_blocks.emplace_back(start, end); + offset += kGapAckBlockSize; + } + + std::set<TSN> duplicate_tsns; + for (int i = 0; i < nbr_of_dup_tsns; ++i) { + BoundedByteReader<kDupTsnBlockSize> sub_reader = + reader->sub_reader<kDupTsnBlockSize>(offset); + + duplicate_tsns.insert(TSN(sub_reader.Load32<0>())); + offset += kDupTsnBlockSize; + } + RTC_DCHECK(offset == reader->variable_data_size()); + + return SackChunk(tsn_ack, a_rwnd, gap_ack_blocks, duplicate_tsns); +} + +void SackChunk::SerializeTo(std::vector<uint8_t>& out) const { + int nbr_of_gap_blocks = gap_ack_blocks_.size(); + int nbr_of_dup_tsns = duplicate_tsns_.size(); + size_t variable_size = + nbr_of_gap_blocks * kGapAckBlockSize + nbr_of_dup_tsns * kDupTsnBlockSize; + BoundedByteWriter<kHeaderSize> writer = AllocateTLV(out, variable_size); + + writer.Store32<4>(*cumulative_tsn_ack_); + writer.Store32<8>(a_rwnd_); + writer.Store16<12>(nbr_of_gap_blocks); + writer.Store16<14>(nbr_of_dup_tsns); + + size_t offset = 0; + for (int i = 0; i < nbr_of_gap_blocks; ++i) { + BoundedByteWriter<kGapAckBlockSize> sub_writer = + writer.sub_writer<kGapAckBlockSize>(offset); + + sub_writer.Store16<0>(gap_ack_blocks_[i].start); + sub_writer.Store16<2>(gap_ack_blocks_[i].end); + offset += kGapAckBlockSize; + } + + for (TSN tsn : duplicate_tsns_) { + BoundedByteWriter<kDupTsnBlockSize> sub_writer = + writer.sub_writer<kDupTsnBlockSize>(offset); + + sub_writer.Store32<0>(*tsn); + offset += kDupTsnBlockSize; + } + + RTC_DCHECK(offset == variable_size); +} + +std::string SackChunk::ToString() const { + rtc::StringBuilder sb; + sb << "SACK, cum_ack_tsn=" << *cumulative_tsn_ack() + << ", a_rwnd=" << a_rwnd(); + for (const GapAckBlock& gap : gap_ack_blocks_) { + uint32_t first = *cumulative_tsn_ack_ + gap.start; + uint32_t last = *cumulative_tsn_ack_ + gap.end; + sb << ", gap=" << first << "--" << last; + } + if (!duplicate_tsns_.empty()) { + sb << ", dup_tsns=" + << StrJoin(duplicate_tsns(), ",", + [](rtc::StringBuilder& sb, TSN tsn) { sb << *tsn; }); + } + + return sb.Release(); +} + +} // namespace dcsctp |