1 files changed, 80 insertions, 0 deletions
diff --git a/third_party/libwebrtc/net/dcsctp/packet/chunk/sack_chunk.h b/third_party/libwebrtc/net/dcsctp/packet/chunk/sack_chunk.h
new file mode 100644
index 0000000000..e6758fa332
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+++ b/third_party/libwebrtc/net/dcsctp/packet/chunk/sack_chunk.h
@@ -0,0 +1,80 @@
+/*
+ *  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_CHUNK_SACK_CHUNK_H_
+#define NET_DCSCTP_PACKET_CHUNK_SACK_CHUNK_H_
+#include <stddef.h>
+
+#include <cstdint>
+#include <set>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "absl/strings/string_view.h"
+#include "api/array_view.h"
+#include "net/dcsctp/packet/chunk/chunk.h"
+#include "net/dcsctp/packet/tlv_trait.h"
+
+namespace dcsctp {
+
+// https://tools.ietf.org/html/rfc4960#section-3.3.4
+struct SackChunkConfig : ChunkConfig {
+  static constexpr int kType = 3;
+  static constexpr size_t kHeaderSize = 16;
+  static constexpr size_t kVariableLengthAlignment = 4;
+};
+
+class SackChunk : public Chunk, public TLVTrait<SackChunkConfig> {
+ public:
+  static constexpr int kType = SackChunkConfig::kType;
+
+  struct GapAckBlock {
+    GapAckBlock(uint16_t start, uint16_t end) : start(start), end(end) {}
+
+    uint16_t start;
+    uint16_t end;
+
+    bool operator==(const GapAckBlock& other) const {
+      return start == other.start && end == other.end;
+    }
+  };
+
+  SackChunk(TSN cumulative_tsn_ack,
+            uint32_t a_rwnd,
+            std::vector<GapAckBlock> gap_ack_blocks,
+            std::set<TSN> duplicate_tsns)
+      : cumulative_tsn_ack_(cumulative_tsn_ack),
+        a_rwnd_(a_rwnd),
+        gap_ack_blocks_(std::move(gap_ack_blocks)),
+        duplicate_tsns_(std::move(duplicate_tsns)) {}
+  static absl::optional<SackChunk> Parse(rtc::ArrayView<const uint8_t> data);
+
+  void SerializeTo(std::vector<uint8_t>& out) const override;
+  std::string ToString() const override;
+
+  TSN cumulative_tsn_ack() const { return cumulative_tsn_ack_; }
+  uint32_t a_rwnd() const { return a_rwnd_; }
+  rtc::ArrayView<const GapAckBlock> gap_ack_blocks() const {
+    return gap_ack_blocks_;
+  }
+  const std::set<TSN>& duplicate_tsns() const { return duplicate_tsns_; }
+
+ private:
+  static constexpr size_t kGapAckBlockSize = 4;
+  static constexpr size_t kDupTsnBlockSize = 4;
+
+  const TSN cumulative_tsn_ack_;
+  const uint32_t a_rwnd_;
+  std::vector<GapAckBlock> gap_ack_blocks_;
+  std::set<TSN> duplicate_tsns_;
+};
+}  // namespace dcsctp
+
+#endif  // NET_DCSCTP_PACKET_CHUNK_SACK_CHUNK_H_