104 lines
3.5 KiB
C++
104 lines
3.5 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_PACKET_DATA_H_
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#define NET_DCSCTP_PACKET_DATA_H_
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#include <cstdint>
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#include <utility>
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#include <vector>
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#include "net/dcsctp/common/internal_types.h"
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#include "net/dcsctp/public/types.h"
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namespace dcsctp {
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// Represents data that is either received and extracted from a DATA/I-DATA
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// chunk, or data that is supposed to be sent, and wrapped in a DATA/I-DATA
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// chunk (depending on peer capabilities).
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//
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// The data wrapped in this structure is actually the same as the DATA/I-DATA
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// chunk (actually the union of them), but to avoid having all components be
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// aware of the implementation details of the different chunks, this abstraction
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// is used instead. A notable difference is also that it doesn't carry a
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// Transmission Sequence Number (TSN), as that is not known when a chunk is
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// created (assigned late, just when sending), and that the TSNs in DATA/I-DATA
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// are wrapped numbers, and within the library, unwrapped sequence numbers are
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// preferably used.
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struct Data {
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// Indicates if a chunk is the first in a fragmented message and maps to the
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// "beginning" flag in DATA/I-DATA chunk.
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using IsBeginning = webrtc::StrongAlias<class IsBeginningTag, bool>;
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// Indicates if a chunk is the last in a fragmented message and maps to the
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// "end" flag in DATA/I-DATA chunk.
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using IsEnd = webrtc::StrongAlias<class IsEndTag, bool>;
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Data(StreamID stream_id,
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SSN ssn,
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MID message_id,
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FSN fsn,
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PPID ppid,
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std::vector<uint8_t> payload,
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IsBeginning is_beginning,
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IsEnd is_end,
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IsUnordered is_unordered)
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: stream_id(stream_id),
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ssn(ssn),
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message_id(message_id),
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fsn(fsn),
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ppid(ppid),
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payload(std::move(payload)),
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is_beginning(is_beginning),
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is_end(is_end),
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is_unordered(is_unordered) {}
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// Move-only, to avoid accidental copies.
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Data(Data&& other) = default;
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Data& operator=(Data&& other) = default;
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// Creates a copy of this `Data` object.
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Data Clone() const {
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return Data(stream_id, ssn, message_id, fsn, ppid, payload, is_beginning,
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is_end, is_unordered);
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}
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// The size of this data, which translates to the size of its payload.
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size_t size() const { return payload.size(); }
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// Stream Identifier.
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StreamID stream_id;
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// Stream Sequence Number (SSN), per stream, for ordered chunks. Defined by
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// RFC4960 and used only in DATA chunks (not I-DATA).
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SSN ssn;
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// Message Identifier (MID) per stream and ordered/unordered. Defined by
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// RFC8260, and used together with options.is_unordered and stream_id to
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// uniquely identify a message. Used only in I-DATA chunks (not DATA).
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MID message_id;
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// Fragment Sequence Number (FSN) per stream and ordered/unordered, as above.
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FSN fsn;
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// Payload Protocol Identifier (PPID).
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PPID ppid;
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// The actual data payload.
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std::vector<uint8_t> payload;
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// If this data represents the first, last or a middle chunk.
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IsBeginning is_beginning;
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IsEnd is_end;
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// If this data is sent/received unordered.
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IsUnordered is_unordered;
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};
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} // namespace dcsctp
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#endif // NET_DCSCTP_PACKET_DATA_H_
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