1 files changed, 121 insertions, 0 deletions
diff --git a/third_party/libwebrtc/net/dcsctp/packet/sctp_packet.h b/third_party/libwebrtc/net/dcsctp/packet/sctp_packet.h
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+++ b/third_party/libwebrtc/net/dcsctp/packet/sctp_packet.h
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+/*
+ *  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_SCTP_PACKET_H_
+#define NET_DCSCTP_PACKET_SCTP_PACKET_H_
+
+#include <stddef.h>
+
+#include <cstdint>
+#include <functional>
+#include <memory>
+#include <utility>
+#include <vector>
+
+#include "api/array_view.h"
+#include "net/dcsctp/common/internal_types.h"
+#include "net/dcsctp/packet/chunk/chunk.h"
+#include "net/dcsctp/public/dcsctp_options.h"
+
+namespace dcsctp {
+
+// The "Common Header", which every SCTP packet starts with, and is described in
+// https://tools.ietf.org/html/rfc4960#section-3.1.
+struct CommonHeader {
+  uint16_t source_port;
+  uint16_t destination_port;
+  VerificationTag verification_tag;
+  uint32_t checksum;
+};
+
+// Represents an immutable (received or to-be-sent) SCTP packet.
+class SctpPacket {
+ public:
+  static constexpr size_t kHeaderSize = 12;
+
+  struct ChunkDescriptor {
+    ChunkDescriptor(uint8_t type,
+                    uint8_t flags,
+                    rtc::ArrayView<const uint8_t> data)
+        : type(type), flags(flags), data(data) {}
+    uint8_t type;
+    uint8_t flags;
+    rtc::ArrayView<const uint8_t> data;
+  };
+
+  SctpPacket(SctpPacket&& other) = default;
+  SctpPacket& operator=(SctpPacket&& other) = default;
+  SctpPacket(const SctpPacket&) = delete;
+  SctpPacket& operator=(const SctpPacket&) = delete;
+
+  // Used for building SctpPacket, as those are immutable.
+  class Builder {
+   public:
+    Builder(VerificationTag verification_tag, const DcSctpOptions& options);
+
+    Builder(Builder&& other) = default;
+    Builder& operator=(Builder&& other) = default;
+
+    // Adds a chunk to the to-be-built SCTP packet.
+    Builder& Add(const Chunk& chunk);
+
+    // The number of bytes remaining in the packet for chunk storage until the
+    // packet reaches its maximum size.
+    size_t bytes_remaining() const;
+
+    // Indicates if any packets have been added to the builder.
+    bool empty() const { return out_.empty(); }
+
+    // Returns the payload of the build SCTP packet. The Builder will be cleared
+    // after having called this function, and can be used to build a new packet.
+    std::vector<uint8_t> Build();
+
+   private:
+    VerificationTag verification_tag_;
+    uint16_t source_port_;
+    uint16_t dest_port_;
+    // The maximum packet size is always even divisible by four, as chunks are
+    // always padded to a size even divisible by four.
+    size_t max_packet_size_;
+    std::vector<uint8_t> out_;
+  };
+
+  // Parses `data` as an SCTP packet and returns it if it validates.
+  static absl::optional<SctpPacket> Parse(
+      rtc::ArrayView<const uint8_t> data,
+      bool disable_checksum_verification = false);
+
+  // Returns the SCTP common header.
+  const CommonHeader& common_header() const { return common_header_; }
+
+  // Returns the chunks (types and offsets) within the packet.
+  rtc::ArrayView<const ChunkDescriptor> descriptors() const {
+    return descriptors_;
+  }
+
+ private:
+  SctpPacket(const CommonHeader& common_header,
+             std::vector<uint8_t> data,
+             std::vector<ChunkDescriptor> descriptors)
+      : common_header_(common_header),
+        data_(std::move(data)),
+        descriptors_(std::move(descriptors)) {}
+
+  CommonHeader common_header_;
+
+  // As the `descriptors_` refer to offset within data, and since SctpPacket is
+  // movable, `data` needs to be pointer stable, which it is according to
+  // http://www.open-std.org/JTC1/SC22/WG21/docs/lwg-active.html#2321
+  std::vector<uint8_t> data_;
+  // The chunks and their offsets within `data_ `.
+  std::vector<ChunkDescriptor> descriptors_;
+};
+}  // namespace dcsctp
+
+#endif  // NET_DCSCTP_PACKET_SCTP_PACKET_H_