dcsctp: Add data container
Represents data that is either received and extracted from a
DATA/I-DATA chunk, or data that is supposed to be sent, and
wrapped in a DATA/I-DATA chunk (depending on peer capabilities).
Bug: webrtc:12614
Change-Id: Iea831fa7ca939783a438f178740508e484920312
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/213346
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Reviewed-by: Tommi <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#33608}
diff --git a/net/dcsctp/packet/BUILD.gn b/net/dcsctp/packet/BUILD.gn
index 9a191d7..5189f2d 100644
--- a/net/dcsctp/packet/BUILD.gn
+++ b/net/dcsctp/packet/BUILD.gn
@@ -40,6 +40,15 @@
]
}
+rtc_source_set("data") {
+ deps = [
+ "../../../rtc_base",
+ "../../../rtc_base:checks",
+ "../../../rtc_base:rtc_base_approved",
+ ]
+ sources = [ "data.h" ]
+}
+
rtc_library("crc32c") {
deps = [
"../../../api:array_view",
diff --git a/net/dcsctp/packet/data.h b/net/dcsctp/packet/data.h
new file mode 100644
index 0000000..50f4552
--- /dev/null
+++ b/net/dcsctp/packet/data.h
@@ -0,0 +1,92 @@
+/*
+ * 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.
+ */
+#ifndef NET_DCSCTP_PACKET_DATA_H_
+#define NET_DCSCTP_PACKET_DATA_H_
+
+#include <cstdint>
+#include <utility>
+#include <vector>
+
+namespace dcsctp {
+
+// Represents data that is either received and extracted from a DATA/I-DATA
+// chunk, or data that is supposed to be sent, and wrapped in a DATA/I-DATA
+// chunk (depending on peer capabilities).
+//
+// The data wrapped in this structure is actually the same as the DATA/I-DATA
+// chunk (actually the union of them), but to avoid having all components be
+// aware of the implementation details of the different chunks, this abstraction
+// is used instead. A notable difference is also that it doesn't carry a
+// Transmission Sequence Number (TSN), as that is not known when a chunk is
+// created (assigned late, just when sending), and that the TSNs in DATA/I-DATA
+// are wrapped numbers, and within the library, unwrapped sequence numbers are
+// preferably used.
+struct Data {
+ Data(uint16_t stream_id,
+ uint16_t ssn,
+ uint32_t message_id,
+ uint32_t fsn,
+ uint32_t ppid,
+ std::vector<uint8_t> payload,
+ bool is_beginning,
+ bool is_end,
+ bool is_unordered)
+ : stream_id(stream_id),
+ ssn(ssn),
+ message_id(message_id),
+ fsn(fsn),
+ ppid(ppid),
+ payload(std::move(payload)),
+ is_beginning(is_beginning),
+ is_end(is_end),
+ is_unordered(is_unordered) {}
+
+ // Move-only, to avoid accidental copies.
+ Data(Data&& other) = default;
+ Data& operator=(Data&& other) = default;
+
+ // Creates a copy of this `Data` object.
+ Data Clone() {
+ return Data(stream_id, ssn, message_id, fsn, ppid, payload, is_beginning,
+ is_end, is_unordered);
+ }
+
+ // The size of this data, which translates to the size of its payload.
+ size_t size() const { return payload.size(); }
+
+ // Stream Identifier.
+ uint16_t stream_id;
+
+ // Stream Sequence Number (SSN), per stream, for ordered chunks. Defined by
+ // RFC4960 and used only in DATA chunks (not I-DATA).
+ uint16_t ssn;
+
+ // Message Identifier (MID) per stream and ordered/unordered. Defined by
+ // RFC8260, and used together with options.is_unordered and stream_id to
+ // uniquely identify a message. Used only in I-DATA chunks (not DATA).
+ uint32_t message_id;
+ // Fragment Sequence Number (FSN) per stream and ordered/unordered, as above.
+ uint32_t fsn;
+
+ // Payload Protocol Identifier (PPID).
+ uint32_t ppid;
+
+ // The actual data payload.
+ std::vector<uint8_t> payload;
+
+ // If this data represents the first, last or a middle chunk.
+ bool is_beginning;
+ bool is_end;
+ // If this data is sent/received unordered.
+ bool is_unordered;
+};
+} // namespace dcsctp
+
+#endif // NET_DCSCTP_PACKET_DATA_H_
