1 files changed, 104 insertions, 0 deletions
diff --git a/third_party/libwebrtc/net/dcsctp/packet/chunk/iforward_tsn_chunk.cc b/third_party/libwebrtc/net/dcsctp/packet/chunk/iforward_tsn_chunk.cc
new file mode 100644
index 0000000000..a647a8bf8a
--- /dev/null
+++ b/third_party/libwebrtc/net/dcsctp/packet/chunk/iforward_tsn_chunk.cc
@@ -0,0 +1,104 @@
+/*
+ *  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/iforward_tsn_chunk.h"
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "absl/types/optional.h"
+#include "api/array_view.h"
+#include "net/dcsctp/packet/bounded_byte_reader.h"
+#include "net/dcsctp/packet/bounded_byte_writer.h"
+#include "net/dcsctp/packet/chunk/forward_tsn_common.h"
+#include "net/dcsctp/packet/tlv_trait.h"
+#include "rtc_base/strings/string_builder.h"
+
+namespace dcsctp {
+
+// https://tools.ietf.org/html/rfc8260#section-2.3.1
+
+//   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 = 194  | Flags = 0x00  |      Length = Variable        |
+//  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//  |                       New Cumulative TSN                      |
+//  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//  |       Stream Identifier       |          Reserved           |U|
+//  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//  |                       Message Identifier                      |
+//  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//  \                                                               \
+//  /                                                               /
+//  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//  |       Stream Identifier       |          Reserved           |U|
+//  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//  |                       Message Identifier                      |
+//  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+constexpr int IForwardTsnChunk::kType;
+
+absl::optional<IForwardTsnChunk> IForwardTsnChunk::Parse(
+    rtc::ArrayView<const uint8_t> data) {
+  absl::optional<BoundedByteReader<kHeaderSize>> reader = ParseTLV(data);
+  if (!reader.has_value()) {
+    return absl::nullopt;
+  }
+
+  TSN new_cumulative_tsn(reader->Load32<4>());
+
+  size_t streams_skipped =
+      reader->variable_data_size() / kSkippedStreamBufferSize;
+  std::vector<SkippedStream> skipped_streams;
+  skipped_streams.reserve(streams_skipped);
+  size_t offset = 0;
+  for (size_t i = 0; i < streams_skipped; ++i) {
+    BoundedByteReader<kSkippedStreamBufferSize> sub_reader =
+        reader->sub_reader<kSkippedStreamBufferSize>(offset);
+
+    StreamID stream_id(sub_reader.Load16<0>());
+    IsUnordered unordered(sub_reader.Load8<3>() & 0x01);
+    MID message_id(sub_reader.Load32<4>());
+    skipped_streams.emplace_back(unordered, stream_id, message_id);
+    offset += kSkippedStreamBufferSize;
+  }
+  RTC_DCHECK(offset == reader->variable_data_size());
+  return IForwardTsnChunk(new_cumulative_tsn, std::move(skipped_streams));
+}
+
+void IForwardTsnChunk::SerializeTo(std::vector<uint8_t>& out) const {
+  rtc::ArrayView<const SkippedStream> skipped = skipped_streams();
+  size_t variable_size = skipped.size() * kSkippedStreamBufferSize;
+  BoundedByteWriter<kHeaderSize> writer = AllocateTLV(out, variable_size);
+
+  writer.Store32<4>(*new_cumulative_tsn());
+  size_t offset = 0;
+  for (size_t i = 0; i < skipped.size(); ++i) {
+    BoundedByteWriter<kSkippedStreamBufferSize> sub_writer =
+        writer.sub_writer<kSkippedStreamBufferSize>(offset);
+
+    sub_writer.Store16<0>(*skipped[i].stream_id);
+    sub_writer.Store8<3>(skipped[i].unordered ? 1 : 0);
+    sub_writer.Store32<4>(*skipped[i].message_id);
+    offset += kSkippedStreamBufferSize;
+  }
+  RTC_DCHECK(offset == variable_size);
+}
+
+std::string IForwardTsnChunk::ToString() const {
+  rtc::StringBuilder sb;
+  sb << "I-FORWARD-TSN, new_cumulative_tsn=" << *new_cumulative_tsn();
+  return sb.Release();
+}
+
+}  // namespace dcsctp