dcsctp: add zero checksum acceptable chunk parameter

This will be included in INIT/INIT_ACK if the socket has
configured the "accept zero checksum" parameter, that will
be added in follow-up CLs.

Bug: webrtc:14997
Change-Id: I1a2823fbc77cfea8fe746b07c1c77593bc15efe9
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/298480
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Reviewed-by: Florent Castelli <orphis@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#39702}

net/dcsctp/packet/BUILD.gn

@@ -98,6 +98,8 @@ rtc_library("parameter") {
     "parameter/state_cookie_parameter.h",
     "parameter/supported_extensions_parameter.cc",
     "parameter/supported_extensions_parameter.h",
+    "parameter/zero_checksum_acceptable_chunk_parameter.cc",
+    "parameter/zero_checksum_acceptable_chunk_parameter.h",
   ]
   absl_deps = [
     "//third_party/abseil-cpp/absl/algorithm:container",
@@ -323,6 +325,7 @@ if (rtc_include_tests) {
       "parameter/ssn_tsn_reset_request_parameter_test.cc",
       "parameter/state_cookie_parameter_test.cc",
       "parameter/supported_extensions_parameter_test.cc",
+      "parameter/zero_checksum_acceptable_chunk_parameter_test.cc",
       "sctp_packet_test.cc",
       "tlv_trait_test.cc",
     ]

net/dcsctp/packet/parameter/zero_checksum_acceptable_chunk_parameter.cc

@@ -0,0 +1,46 @@
+/*
+ *  Copyright (c) 2023 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/parameter/zero_checksum_acceptable_chunk_parameter.h"
+
+#include <stdint.h>
+
+#include <vector>
+
+#include "absl/types/optional.h"
+#include "api/array_view.h"
+
+namespace dcsctp {
+
+// https://www.ietf.org/archive/id/draft-tuexen-tsvwg-sctp-zero-checksum-00.html#section-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 = 0x8001         |          Length = 4           |
+//  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+constexpr int ZeroChecksumAcceptableChunkParameter::kType;
+
+absl::optional<ZeroChecksumAcceptableChunkParameter>
+ZeroChecksumAcceptableChunkParameter::Parse(
+    rtc::ArrayView<const uint8_t> data) {
+  if (!ParseTLV(data).has_value()) {
+    return absl::nullopt;
+  }
+  return ZeroChecksumAcceptableChunkParameter();
+}
+
+void ZeroChecksumAcceptableChunkParameter::SerializeTo(
+    std::vector<uint8_t>& out) const {
+  AllocateTLV(out);
+}
+
+std::string ZeroChecksumAcceptableChunkParameter::ToString() const {
+  return "Zero Checksum Acceptable";
+}
+}  // namespace dcsctp

net/dcsctp/packet/parameter/zero_checksum_acceptable_chunk_parameter.h

@@ -0,0 +1,50 @@
+/*
+ *  Copyright (c) 2023 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_ZERO_CHECKSUM_ACCEPTABLE_CHUNK_PARAMETER_H_
+#define NET_DCSCTP_PACKET_PARAMETER_ZERO_CHECKSUM_ACCEPTABLE_CHUNK_PARAMETER_H_
+#include <stddef.h>
+#include <stdint.h>
+
+#include <string>
+#include <vector>
+
+#include "absl/strings/string_view.h"
+#include "api/array_view.h"
+#include "net/dcsctp/packet/parameter/parameter.h"
+#include "net/dcsctp/packet/tlv_trait.h"
+
+namespace dcsctp {
+
+// https://datatracker.ietf.org/doc/draft-tuexen-tsvwg-sctp-zero-checksum/
+struct ZeroChecksumAcceptableChunkParameterConfig : ParameterConfig {
+  static constexpr int kType = 0x8001;
+  static constexpr size_t kHeaderSize = 4;
+  static constexpr size_t kVariableLengthAlignment = 0;
+};
+
+class ZeroChecksumAcceptableChunkParameter
+    : public Parameter,
+      public TLVTrait<ZeroChecksumAcceptableChunkParameterConfig> {
+ public:
+  static constexpr int kType =
+      ZeroChecksumAcceptableChunkParameterConfig::kType;
+
+  ZeroChecksumAcceptableChunkParameter() {}
+
+  static absl::optional<ZeroChecksumAcceptableChunkParameter> Parse(
+      rtc::ArrayView<const uint8_t> data);
+
+  void SerializeTo(std::vector<uint8_t>& out) const override;
+  std::string ToString() const override;
+};
+
+}  // namespace dcsctp
+
+#endif  // NET_DCSCTP_PACKET_PARAMETER_ZERO_CHECKSUM_ACCEPTABLE_CHUNK_PARAMETER_H_

net/dcsctp/packet/parameter/zero_checksum_acceptable_chunk_parameter_test.cc

@@ -0,0 +1,53 @@
+/*
+ *  Copyright (c) 2023 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/parameter/zero_checksum_acceptable_chunk_parameter.h"
+
+#include <stdint.h>
+
+#include <type_traits>
+#include <vector>
+
+#include "net/dcsctp/testing/testing_macros.h"
+#include "rtc_base/gunit.h"
+#include "test/gmock.h"
+#include "test/gtest.h"
+
+namespace dcsctp {
+namespace {
+using ::testing::ElementsAre;
+
+TEST(ZeroChecksumAcceptableChunkParameterTest, SerializeAndDeserialize) {
+  ZeroChecksumAcceptableChunkParameter parameter;
+
+  std::vector<uint8_t> serialized;
+  parameter.SerializeTo(serialized);
+
+  EXPECT_THAT(serialized, ElementsAre(0x80, 0x01, 0x00, 0x04));
+
+  ASSERT_HAS_VALUE_AND_ASSIGN(
+      ZeroChecksumAcceptableChunkParameter deserialized,
+      ZeroChecksumAcceptableChunkParameter::Parse(serialized));
+}
+
+TEST(ZeroChecksumAcceptableChunkParameterTest, FailToDeserialize) {
+  std::vector<uint8_t> invalid = {0x00, 0x00, 0x00, 0x00};
+
+  EXPECT_FALSE(
+      ZeroChecksumAcceptableChunkParameter::Parse(invalid).has_value());
+}
+
+TEST(ZeroChecksumAcceptableChunkParameterTest, HasToString) {
+  ZeroChecksumAcceptableChunkParameter parameter;
+
+  EXPECT_EQ(parameter.ToString(), "Zero Checksum Acceptable");
+}
+
+}  // namespace
+}  // namespace dcsctp