| /* |
| * 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/rx/reassembly_queue.h" |
| |
| #include <stddef.h> |
| |
| #include <algorithm> |
| #include <cstdint> |
| #include <memory> |
| #include <set> |
| #include <string> |
| #include <utility> |
| #include <vector> |
| |
| #include "absl/strings/string_view.h" |
| #include "absl/types/optional.h" |
| #include "api/array_view.h" |
| #include "net/dcsctp/common/sequence_numbers.h" |
| #include "net/dcsctp/common/str_join.h" |
| #include "net/dcsctp/packet/chunk/forward_tsn_common.h" |
| #include "net/dcsctp/packet/data.h" |
| #include "net/dcsctp/packet/parameter/outgoing_ssn_reset_request_parameter.h" |
| #include "net/dcsctp/packet/parameter/reconfiguration_response_parameter.h" |
| #include "net/dcsctp/public/dcsctp_message.h" |
| #include "net/dcsctp/public/types.h" |
| #include "net/dcsctp/rx/interleaved_reassembly_streams.h" |
| #include "net/dcsctp/rx/reassembly_streams.h" |
| #include "net/dcsctp/rx/traditional_reassembly_streams.h" |
| #include "rtc_base/logging.h" |
| |
| namespace dcsctp { |
| namespace { |
| std::unique_ptr<ReassemblyStreams> CreateStreams( |
| absl::string_view log_prefix, |
| ReassemblyStreams::OnAssembledMessage on_assembled_message, |
| bool use_message_interleaving) { |
| if (use_message_interleaving) { |
| return std::make_unique<InterleavedReassemblyStreams>( |
| log_prefix, std::move(on_assembled_message)); |
| } |
| return std::make_unique<TraditionalReassemblyStreams>( |
| log_prefix, std::move(on_assembled_message)); |
| } |
| } // namespace |
| |
| ReassemblyQueue::ReassemblyQueue(absl::string_view log_prefix, |
| TSN peer_initial_tsn, |
| size_t max_size_bytes, |
| bool use_message_interleaving) |
| : log_prefix_(log_prefix), |
| max_size_bytes_(max_size_bytes), |
| watermark_bytes_(max_size_bytes * kHighWatermarkLimit), |
| last_assembled_tsn_watermark_( |
| tsn_unwrapper_.Unwrap(TSN(*peer_initial_tsn - 1))), |
| last_completed_reset_req_seq_nbr_(ReconfigRequestSN(0)), |
| streams_(CreateStreams( |
| log_prefix_, |
| [this](rtc::ArrayView<const UnwrappedTSN> tsns, |
| DcSctpMessage message) { |
| AddReassembledMessage(tsns, std::move(message)); |
| }, |
| use_message_interleaving)) {} |
| |
| void ReassemblyQueue::Add(TSN tsn, Data data) { |
| RTC_DLOG(LS_VERBOSE) << log_prefix_ << "added tsn=" << *tsn |
| << ", stream=" << *data.stream_id << ":" << *data.mid |
| << ":" << *data.fsn << ", type=" |
| << (data.is_beginning && data.is_end ? "complete" |
| : data.is_beginning ? "first" |
| : data.is_end ? "last" |
| : "middle"); |
| |
| UnwrappedTSN unwrapped_tsn = tsn_unwrapper_.Unwrap(tsn); |
| |
| // If a stream reset has been received with a "sender's last assigned tsn" in |
| // the future, the socket is in "deferred reset processing" mode and must |
| // buffer chunks until it's exited. |
| if (deferred_reset_streams_.has_value() && |
| unwrapped_tsn > deferred_reset_streams_->sender_last_assigned_tsn && |
| deferred_reset_streams_->streams.contains(data.stream_id)) { |
| RTC_DLOG(LS_VERBOSE) |
| << log_prefix_ << "Deferring chunk with tsn=" << *tsn |
| << ", sid=" << *data.stream_id << " until tsn=" |
| << *deferred_reset_streams_->sender_last_assigned_tsn.Wrap(); |
| // https://tools.ietf.org/html/rfc6525#section-5.2.2 |
| // "In this mode, any data arriving with a TSN larger than the |
| // Sender's Last Assigned TSN for the affected stream(s) MUST be queued |
| // locally and held until the cumulative acknowledgment point reaches the |
| // Sender's Last Assigned TSN." |
| queued_bytes_ += data.size(); |
| deferred_reset_streams_->deferred_actions.push_back( |
| [this, tsn, data = std::move(data)]() mutable { |
| queued_bytes_ -= data.size(); |
| Add(tsn, std::move(data)); |
| }); |
| } else { |
| queued_bytes_ += streams_->Add(unwrapped_tsn, std::move(data)); |
| } |
| |
| // https://tools.ietf.org/html/rfc4960#section-6.9 |
| // "Note: If the data receiver runs out of buffer space while still |
| // waiting for more fragments to complete the reassembly of the message, it |
| // should dispatch part of its inbound message through a partial delivery |
| // API (see Section 10), freeing some of its receive buffer space so that |
| // the rest of the message may be received." |
| |
| // TODO(boivie): Support EOR flag and partial delivery? |
| RTC_DCHECK(IsConsistent()); |
| } |
| |
| void ReassemblyQueue::ResetStreamsAndLeaveDeferredReset( |
| rtc::ArrayView<const StreamID> stream_ids) { |
| RTC_DLOG(LS_VERBOSE) << log_prefix_ << "Resetting streams: [" |
| << StrJoin(stream_ids, ",", |
| [](rtc::StringBuilder& sb, StreamID sid) { |
| sb << *sid; |
| }) |
| << "]"; |
| |
| // https://tools.ietf.org/html/rfc6525#section-5.2.2 |
| // "... streams MUST be reset to 0 as the next expected SSN." |
| streams_->ResetStreams(stream_ids); |
| |
| if (deferred_reset_streams_.has_value()) { |
| RTC_DLOG(LS_VERBOSE) << log_prefix_ |
| << "Leaving deferred reset processing, feeding back " |
| << deferred_reset_streams_->deferred_actions.size() |
| << " actions"; |
| // https://tools.ietf.org/html/rfc6525#section-5.2.2 |
| // "Any queued TSNs (queued at step E2) MUST now be released and processed |
| // normally." |
| auto deferred_actions = |
| std::move(deferred_reset_streams_->deferred_actions); |
| deferred_reset_streams_ = absl::nullopt; |
| |
| for (auto& action : deferred_actions) { |
| action(); |
| } |
| } |
| |
| RTC_DCHECK(IsConsistent()); |
| } |
| |
| void ReassemblyQueue::EnterDeferredReset( |
| TSN sender_last_assigned_tsn, |
| rtc::ArrayView<const StreamID> streams) { |
| if (!deferred_reset_streams_.has_value()) { |
| RTC_DLOG(LS_VERBOSE) << log_prefix_ |
| << "Entering deferred reset; sender_last_assigned_tsn=" |
| << *sender_last_assigned_tsn; |
| deferred_reset_streams_ = absl::make_optional<DeferredResetStreams>( |
| tsn_unwrapper_.Unwrap(sender_last_assigned_tsn), |
| webrtc::flat_set<StreamID>(streams.begin(), streams.end())); |
| } |
| RTC_DCHECK(IsConsistent()); |
| } |
| |
| std::vector<DcSctpMessage> ReassemblyQueue::FlushMessages() { |
| std::vector<DcSctpMessage> ret; |
| reassembled_messages_.swap(ret); |
| return ret; |
| } |
| |
| void ReassemblyQueue::AddReassembledMessage( |
| rtc::ArrayView<const UnwrappedTSN> tsns, |
| DcSctpMessage message) { |
| RTC_DLOG(LS_VERBOSE) << log_prefix_ << "Assembled message from TSN=[" |
| << StrJoin(tsns, ",", |
| [](rtc::StringBuilder& sb, UnwrappedTSN tsn) { |
| sb << *tsn.Wrap(); |
| }) |
| << "], message; stream_id=" << *message.stream_id() |
| << ", ppid=" << *message.ppid() |
| << ", payload=" << message.payload().size() << " bytes"; |
| |
| for (const UnwrappedTSN tsn : tsns) { |
| if (tsn == last_assembled_tsn_watermark_.next_value()) { |
| // Update watermark, or insert into delivered_tsns_ |
| last_assembled_tsn_watermark_.Increment(); |
| } else { |
| delivered_tsns_.insert(tsn); |
| } |
| } |
| |
| // With new TSNs in delivered_tsns, gaps might be filled. |
| MaybeMoveLastAssembledWatermarkFurther(); |
| |
| reassembled_messages_.emplace_back(std::move(message)); |
| } |
| |
| void ReassemblyQueue::MaybeMoveLastAssembledWatermarkFurther() { |
| // `delivered_tsns_` contain TSNS when there is a gap between ranges of |
| // assembled TSNs. `last_assembled_tsn_watermark_` should not be adjacent to |
| // that list, because if so, it can be moved. |
| while (!delivered_tsns_.empty() && |
| *delivered_tsns_.begin() == |
| last_assembled_tsn_watermark_.next_value()) { |
| last_assembled_tsn_watermark_.Increment(); |
| delivered_tsns_.erase(delivered_tsns_.begin()); |
| } |
| } |
| |
| void ReassemblyQueue::HandleForwardTsn( |
| TSN new_cumulative_tsn, |
| rtc::ArrayView<const AnyForwardTsnChunk::SkippedStream> skipped_streams) { |
| UnwrappedTSN tsn = tsn_unwrapper_.Unwrap(new_cumulative_tsn); |
| |
| if (deferred_reset_streams_.has_value() && |
| tsn > deferred_reset_streams_->sender_last_assigned_tsn) { |
| RTC_DLOG(LS_VERBOSE) << log_prefix_ << "ForwardTSN to " << *tsn.Wrap() |
| << "- deferring."; |
| deferred_reset_streams_->deferred_actions.emplace_back( |
| [this, new_cumulative_tsn, |
| streams = std::vector<AnyForwardTsnChunk::SkippedStream>( |
| skipped_streams.begin(), skipped_streams.end())] { |
| HandleForwardTsn(new_cumulative_tsn, streams); |
| }); |
| RTC_DCHECK(IsConsistent()); |
| return; |
| } |
| |
| RTC_DLOG(LS_VERBOSE) << log_prefix_ << "ForwardTSN to " << *tsn.Wrap() |
| << " - performing."; |
| last_assembled_tsn_watermark_ = std::max(last_assembled_tsn_watermark_, tsn); |
| delivered_tsns_.erase(delivered_tsns_.begin(), |
| delivered_tsns_.upper_bound(tsn)); |
| MaybeMoveLastAssembledWatermarkFurther(); |
| queued_bytes_ -= streams_->HandleForwardTsn(tsn, skipped_streams); |
| RTC_DCHECK(IsConsistent()); |
| } |
| |
| bool ReassemblyQueue::IsConsistent() const { |
| // `delivered_tsns_` and `last_assembled_tsn_watermark_` mustn't overlap or be |
| // adjacent. |
| if (!delivered_tsns_.empty() && |
| last_assembled_tsn_watermark_.next_value() >= *delivered_tsns_.begin()) { |
| return false; |
| } |
| |
| // Allow queued_bytes_ to be larger than max_size_bytes, as it's not actively |
| // enforced in this class. This comparison will still trigger if queued_bytes_ |
| // became "negative". |
| return (queued_bytes_ >= 0 && queued_bytes_ <= 2 * max_size_bytes_); |
| } |
| |
| HandoverReadinessStatus ReassemblyQueue::GetHandoverReadiness() const { |
| HandoverReadinessStatus status = streams_->GetHandoverReadiness(); |
| if (!delivered_tsns_.empty()) { |
| status.Add(HandoverUnreadinessReason::kReassemblyQueueDeliveredTSNsGap); |
| } |
| if (deferred_reset_streams_.has_value()) { |
| status.Add(HandoverUnreadinessReason::kStreamResetDeferred); |
| } |
| return status; |
| } |
| |
| void ReassemblyQueue::AddHandoverState(DcSctpSocketHandoverState& state) { |
| state.rx.last_assembled_tsn = last_assembled_tsn_watermark_.Wrap().value(); |
| state.rx.last_completed_deferred_reset_req_sn = |
| last_completed_reset_req_seq_nbr_.value(); |
| streams_->AddHandoverState(state); |
| } |
| |
| void ReassemblyQueue::RestoreFromState(const DcSctpSocketHandoverState& state) { |
| // Validate that the component is in pristine state. |
| RTC_DCHECK(last_completed_reset_req_seq_nbr_ == ReconfigRequestSN(0)); |
| |
| last_assembled_tsn_watermark_ = |
| tsn_unwrapper_.Unwrap(TSN(state.rx.last_assembled_tsn)); |
| last_completed_reset_req_seq_nbr_ = |
| ReconfigRequestSN(state.rx.last_completed_deferred_reset_req_sn); |
| streams_->RestoreFromState(state); |
| } |
| } // namespace dcsctp |
