dcsctp: Add parameters, error causes and chunks

Quite a large commit, but mostly trivial. It adds all the (in dcSCTP)
supported parameters, error causes and chunks as an object model, with
serializers and deserializers. They are verified with packet captures
where available, that have been captured with Wireshark against a
reference implementation.

This _could_ be split in parameter/ as one commit, error_cause/ in the
following, and chunk/ as the third, but as each chunk/parameter is
completely isolated from the other, reviewing it should be linear with
the number of chunks/parameters and having them in more commits wouldn't
change that, taken all those three commits into account.

Bug: webrtc:12614
Change-Id: Ie83c9a22cae6e3a39e35ef26fd532837a6387a08
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/213347
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Reviewed-by: Tommi <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#33625}

net/dcsctp/packet/parameter/reconfiguration_response_parameter.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_PARAMETER_RECONFIGURATION_RESPONSE_PARAMETER_H_
+#define NET_DCSCTP_PACKET_PARAMETER_RECONFIGURATION_RESPONSE_PARAMETER_H_
+#include <stddef.h>
+
+#include <cstdint>
+#include <string>
+#include <vector>
+
+#include "absl/strings/string_view.h"
+#include "absl/types/optional.h"
+#include "api/array_view.h"
+#include "net/dcsctp/common/internal_types.h"
+#include "net/dcsctp/packet/parameter/parameter.h"
+#include "net/dcsctp/packet/tlv_trait.h"
+
+namespace dcsctp {
+
+// https://tools.ietf.org/html/rfc6525#section-4.4
+struct ReconfigurationResponseParameterConfig : ParameterConfig {
+  static constexpr int kType = 16;
+  static constexpr size_t kHeaderSize = 12;
+  static constexpr size_t kVariableLengthAlignment = 4;
+};
+
+class ReconfigurationResponseParameter
+    : public Parameter,
+      public TLVTrait<ReconfigurationResponseParameterConfig> {
+ public:
+  static constexpr int kType = ReconfigurationResponseParameterConfig::kType;
+
+  enum class Result {
+    kSuccessNothingToDo = 0,
+    kSuccessPerformed = 1,
+    kDenied = 2,
+    kErrorWrongSSN = 3,
+    kErrorRequestAlreadyInProgress = 4,
+    kErrorBadSequenceNumber = 5,
+    kInProgress = 6,
+  };
+
+  ReconfigurationResponseParameter(ReconfigResponseSN response_sequence_number,
+                                   Result result)
+      : response_sequence_number_(response_sequence_number),
+        result_(result),
+        sender_next_tsn_(absl::nullopt),
+        receiver_next_tsn_(absl::nullopt) {}
+
+  explicit ReconfigurationResponseParameter(
+      ReconfigResponseSN response_sequence_number,
+      Result result,
+      TSN sender_next_tsn,
+      TSN receiver_next_tsn)
+      : response_sequence_number_(response_sequence_number),
+        result_(result),
+        sender_next_tsn_(sender_next_tsn),
+        receiver_next_tsn_(receiver_next_tsn) {}
+
+  static absl::optional<ReconfigurationResponseParameter> Parse(
+      rtc::ArrayView<const uint8_t> data);
+
+  void SerializeTo(std::vector<uint8_t>& out) const override;
+  std::string ToString() const override;
+
+  ReconfigResponseSN response_sequence_number() const {
+    return response_sequence_number_;
+  }
+  Result result() const { return result_; }
+  absl::optional<TSN> sender_next_tsn() const { return sender_next_tsn_; }
+  absl::optional<TSN> receiver_next_tsn() const { return receiver_next_tsn_; }
+
+ private:
+  static constexpr size_t kNextTsnHeaderSize = 8;
+  ReconfigResponseSN response_sequence_number_;
+  Result result_;
+  absl::optional<TSN> sender_next_tsn_;
+  absl::optional<TSN> receiver_next_tsn_;
+};
+
+absl::string_view ToString(ReconfigurationResponseParameter::Result result);
+
+}  // namespace dcsctp
+
+#endif  // NET_DCSCTP_PACKET_PARAMETER_RECONFIGURATION_RESPONSE_PARAMETER_H_