8a13d2ca9f
This class handles the assembly of fragmented received messages (as DATA chunks) and manage per-stream queues. This class only handles non-interleaved messages as described in RFC4960, and is not used when message interleaving is enabled on the association, as described in RFC8260. This is also only part of the reassembly - a follow-up change will add the ReassemblyQueue that handle the other part as well. And an even further follow-up change will add a "interleaved reassembly stream". Bug: webrtc:12614 Change-Id: Iaf339fa215a2b14926f5cb74f15528392e273f99 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/214042 Commit-Queue: Victor Boivie <boivie@webrtc.org> Reviewed-by: Tommi <tommi@webrtc.org> Cr-Commit-Position: refs/heads/master@{#33677}
120 lines
4.1 KiB
C++
120 lines
4.1 KiB
C++
/*
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* Copyright (c) 2021 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef NET_DCSCTP_RX_TRADITIONAL_REASSEMBLY_STREAMS_H_
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#define NET_DCSCTP_RX_TRADITIONAL_REASSEMBLY_STREAMS_H_
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#include <stddef.h>
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#include <stdint.h>
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#include <map>
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#include <string>
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#include <unordered_map>
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#include "absl/strings/string_view.h"
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#include "api/array_view.h"
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#include "net/dcsctp/common/sequence_numbers.h"
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#include "net/dcsctp/packet/chunk/forward_tsn_common.h"
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#include "net/dcsctp/packet/data.h"
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#include "net/dcsctp/rx/reassembly_streams.h"
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namespace dcsctp {
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// Handles reassembly of incoming data when interleaved message sending
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// is not enabled on the association, i.e. when RFC8260 is not in use and
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// RFC4960 is to be followed.
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class TraditionalReassemblyStreams : public ReassemblyStreams {
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public:
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TraditionalReassemblyStreams(absl::string_view log_prefix,
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OnAssembledMessage on_assembled_message)
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: log_prefix_(log_prefix), on_assembled_message_(on_assembled_message) {}
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int Add(UnwrappedTSN tsn, Data data) override;
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size_t HandleForwardTsn(
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UnwrappedTSN new_cumulative_ack_tsn,
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rtc::ArrayView<const AnyForwardTsnChunk::SkippedStream> skipped_streams)
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override;
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void ResetStreams(rtc::ArrayView<const StreamID> stream_ids) override;
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private:
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using ChunkMap = std::map<UnwrappedTSN, Data>;
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// Base class for `UnorderedStream` and `OrderedStream`.
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class StreamBase {
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protected:
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explicit StreamBase(TraditionalReassemblyStreams* parent)
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: parent_(*parent) {}
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size_t AssembleMessage(const ChunkMap::iterator start,
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const ChunkMap::iterator end);
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TraditionalReassemblyStreams& parent_;
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};
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// Manages all received data for a specific unordered stream, and assembles
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// messages when possible.
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class UnorderedStream : StreamBase {
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public:
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explicit UnorderedStream(TraditionalReassemblyStreams* parent)
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: StreamBase(parent) {}
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int Add(UnwrappedTSN tsn, Data data);
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// Returns the number of bytes removed from the queue.
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size_t EraseTo(UnwrappedTSN tsn);
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private:
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// Given an iterator to any chunk within the map, try to assemble a message
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// into `reassembled_messages` containing it and - if successful - erase
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// those chunks from the stream chunks map.
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//
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// Returns the number of bytes that were assembled.
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size_t TryToAssembleMessage(ChunkMap::iterator iter);
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ChunkMap chunks_;
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};
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// Manages all received data for a specific ordered stream, and assembles
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// messages when possible.
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class OrderedStream : StreamBase {
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public:
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explicit OrderedStream(TraditionalReassemblyStreams* parent)
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: StreamBase(parent), next_ssn_(ssn_unwrapper_.Unwrap(SSN(0))) {}
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int Add(UnwrappedTSN tsn, Data data);
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size_t EraseTo(SSN ssn);
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void Reset() {
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ssn_unwrapper_.Reset();
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next_ssn_ = ssn_unwrapper_.Unwrap(SSN(0));
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}
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private:
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// Try to assemble one or several messages in order from the stream.
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// Returns the number of bytes assembled if a message was assembled.
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size_t TryToAssembleMessage();
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size_t TryToAssembleMessages();
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// This must be an ordered container to be able to iterate in SSN order.
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std::map<UnwrappedSSN, ChunkMap> chunks_by_ssn_;
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UnwrappedSSN::Unwrapper ssn_unwrapper_;
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UnwrappedSSN next_ssn_;
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};
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const std::string log_prefix_;
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// Callback for when a message has been assembled.
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const OnAssembledMessage on_assembled_message_;
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// All unordered and ordered streams, managing not-yet-assembled data.
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std::unordered_map<StreamID, UnorderedStream, StreamID::Hasher>
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unordered_streams_;
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std::unordered_map<StreamID, OrderedStream, StreamID::Hasher>
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ordered_streams_;
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};
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} // namespace dcsctp
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#endif // NET_DCSCTP_RX_TRADITIONAL_REASSEMBLY_STREAMS_H_
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