Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

10 files changed, 778 insertions, 0 deletions

diff --git a/third_party/libwebrtc/net/dcsctp/common/BUILD.gn b/third_party/libwebrtc/net/dcsctp/common/BUILD.gn
new file mode 100644
index 0000000000..78fa0d307e
--- /dev/null
+++ b/third_party/libwebrtc/net/dcsctp/common/BUILD.gn
@@ -0,0 +1,67 @@
+# 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.
+
+import("../../../webrtc.gni")
+
+rtc_source_set("internal_types") {
+  deps = [
+    "../../../rtc_base:strong_alias",
+    "../public:types",
+  ]
+  sources = [ "internal_types.h" ]
+}
+
+rtc_source_set("math") {
+  deps = []
+  sources = [ "math.h" ]
+}
+
+rtc_source_set("sequence_numbers") {
+  deps = [
+    ":internal_types",
+    "../../../rtc_base:rtc_numerics",
+  ]
+  sources = [ "sequence_numbers.h" ]
+}
+
+rtc_source_set("str_join") {
+  deps = [ "../../../rtc_base:stringutils" ]
+  sources = [ "str_join.h" ]
+  absl_deps = [ "//third_party/abseil-cpp/absl/strings" ]
+}
+
+if (rtc_include_tests) {
+  rtc_library("dcsctp_common_unittests") {
+    testonly = true
+
+    defines = []
+    deps = [
+      ":math",
+      ":sequence_numbers",
+      ":str_join",
+      "../../../api:array_view",
+      "../../../rtc_base:checks",
+      "../../../rtc_base:gunit_helpers",
+      "../../../test:test_support",
+    ]
+    sources = [
+      "math_test.cc",
+      "sequence_numbers_test.cc",
+      "str_join_test.cc",
+    ]
+  }
+}
+
+rtc_library("handover_testing") {
+  deps = [ "../public:socket" ]
+  testonly = true
+  sources = [
+    "handover_testing.cc",
+    "handover_testing.h",
+  ]
+}
diff --git a/third_party/libwebrtc/net/dcsctp/common/handover_testing.cc b/third_party/libwebrtc/net/dcsctp/common/handover_testing.cc
new file mode 100644
index 0000000000..1081766ea5
--- /dev/null
+++ b/third_party/libwebrtc/net/dcsctp/common/handover_testing.cc
@@ -0,0 +1,22 @@
+/*
+ *  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/common/handover_testing.h"
+
+namespace dcsctp {
+namespace {
+// Default transformer function does nothing - dcSCTP does not implement
+// state serialization that could be tested by setting
+// `g_handover_state_transformer_for_test`.
+void NoTransformation(DcSctpSocketHandoverState*) {}
+}  // namespace
+
+void (*g_handover_state_transformer_for_test)(DcSctpSocketHandoverState*) =
+    NoTransformation;
+}  // namespace dcsctp
diff --git a/third_party/libwebrtc/net/dcsctp/common/handover_testing.h b/third_party/libwebrtc/net/dcsctp/common/handover_testing.h
new file mode 100644
index 0000000000..396016afec
--- /dev/null
+++ b/third_party/libwebrtc/net/dcsctp/common/handover_testing.h
@@ -0,0 +1,29 @@
+/*
+ *  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_COMMON_HANDOVER_TESTING_H_
+#define NET_DCSCTP_COMMON_HANDOVER_TESTING_H_
+
+#include "net/dcsctp/public/dcsctp_handover_state.h"
+
+namespace dcsctp {
+// This global function is to facilitate testing of the socket handover state
+// (`DcSctpSocketHandoverState`) serialization. dcSCTP library users have to
+// implement state serialization if it's needed. To test the serialization one
+// can set a custom `g_handover_state_transformer_for_test` at startup, link to
+// the dcSCTP tests and run the resulting binary. Custom function can serialize
+// and deserialize the passed state. All dcSCTP handover tests call
+// `g_handover_state_transformer_for_test`. If some part of the state is
+// serialized incorrectly or is forgotten, high chance that it will fail the
+// tests.
+extern void (*g_handover_state_transformer_for_test)(
+    DcSctpSocketHandoverState*);
+}  // namespace dcsctp
+
+#endif  // NET_DCSCTP_COMMON_HANDOVER_TESTING_H_
diff --git a/third_party/libwebrtc/net/dcsctp/common/internal_types.h b/third_party/libwebrtc/net/dcsctp/common/internal_types.h
new file mode 100644
index 0000000000..4f3b1935a2
--- /dev/null
+++ b/third_party/libwebrtc/net/dcsctp/common/internal_types.h
@@ -0,0 +1,49 @@
+/*
+ *  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_COMMON_INTERNAL_TYPES_H_
+#define NET_DCSCTP_COMMON_INTERNAL_TYPES_H_
+
+#include <functional>
+#include <utility>
+
+#include "net/dcsctp/public/types.h"
+#include "rtc_base/strong_alias.h"
+
+namespace dcsctp {
+
+// Stream Sequence Number (SSN)
+using SSN = webrtc::StrongAlias<class SSNTag, uint16_t>;
+
+// Message Identifier (MID)
+using MID = webrtc::StrongAlias<class MIDTag, uint32_t>;
+
+// Fragment Sequence Number (FSN)
+using FSN = webrtc::StrongAlias<class FSNTag, uint32_t>;
+
+// Transmission Sequence Number (TSN)
+using TSN = webrtc::StrongAlias<class TSNTag, uint32_t>;
+
+// Reconfiguration Request Sequence Number
+using ReconfigRequestSN =
+    webrtc::StrongAlias<class ReconfigRequestSNTag, uint32_t>;
+
+// Verification Tag, used for packet validation.
+using VerificationTag = webrtc::StrongAlias<class VerificationTagTag, uint32_t>;
+
+// Tie Tag, used as a nonce when connecting.
+using TieTag = webrtc::StrongAlias<class TieTagTag, uint64_t>;
+
+// An ID for every outgoing message, to correlate outgoing data chunks with the
+// message it was carved from.
+using OutgoingMessageId =
+    webrtc::StrongAlias<class OutgoingMessageIdTag, uint32_t>;
+
+}  // namespace dcsctp
+#endif  // NET_DCSCTP_COMMON_INTERNAL_TYPES_H_
diff --git a/third_party/libwebrtc/net/dcsctp/common/math.h b/third_party/libwebrtc/net/dcsctp/common/math.h
new file mode 100644
index 0000000000..12f690ed57
--- /dev/null
+++ b/third_party/libwebrtc/net/dcsctp/common/math.h
@@ -0,0 +1,36 @@
+/*
+ *  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_COMMON_MATH_H_
+#define NET_DCSCTP_COMMON_MATH_H_
+
+namespace dcsctp {
+
+// Rounds up `val` to the nearest value that is divisible by four. Frequently
+// used to e.g. pad chunks or parameters to an even 32-bit offset.
+template <typename IntType>
+IntType RoundUpTo4(IntType val) {
+  return (val + 3) & ~3;
+}
+
+// Similarly, rounds down `val` to the nearest value that is divisible by four.
+template <typename IntType>
+IntType RoundDownTo4(IntType val) {
+  return val & ~3;
+}
+
+// Returns true if `val` is divisible by four.
+template <typename IntType>
+bool IsDivisibleBy4(IntType val) {
+  return (val & 3) == 0;
+}
+
+}  // namespace dcsctp
+
+#endif  // NET_DCSCTP_COMMON_MATH_H_
diff --git a/third_party/libwebrtc/net/dcsctp/common/math_test.cc b/third_party/libwebrtc/net/dcsctp/common/math_test.cc
new file mode 100644
index 0000000000..f95dfbdb55
--- /dev/null
+++ b/third_party/libwebrtc/net/dcsctp/common/math_test.cc
@@ -0,0 +1,116 @@
+/*
+ *  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/common/math.h"
+
+#include "test/gmock.h"
+
+namespace dcsctp {
+namespace {
+
+TEST(MathUtilTest, CanRoundUpTo4) {
+  // Signed numbers
+  EXPECT_EQ(RoundUpTo4(static_cast<int>(-5)), -4);
+  EXPECT_EQ(RoundUpTo4(static_cast<int>(-4)), -4);
+  EXPECT_EQ(RoundUpTo4(static_cast<int>(-3)), 0);
+  EXPECT_EQ(RoundUpTo4(static_cast<int>(-2)), 0);
+  EXPECT_EQ(RoundUpTo4(static_cast<int>(-1)), 0);
+  EXPECT_EQ(RoundUpTo4(static_cast<int>(0)), 0);
+  EXPECT_EQ(RoundUpTo4(static_cast<int>(1)), 4);
+  EXPECT_EQ(RoundUpTo4(static_cast<int>(2)), 4);
+  EXPECT_EQ(RoundUpTo4(static_cast<int>(3)), 4);
+  EXPECT_EQ(RoundUpTo4(static_cast<int>(4)), 4);
+  EXPECT_EQ(RoundUpTo4(static_cast<int>(5)), 8);
+  EXPECT_EQ(RoundUpTo4(static_cast<int>(6)), 8);
+  EXPECT_EQ(RoundUpTo4(static_cast<int>(7)), 8);
+  EXPECT_EQ(RoundUpTo4(static_cast<int>(8)), 8);
+  EXPECT_EQ(RoundUpTo4(static_cast<int64_t>(10000000000)), 10000000000);
+  EXPECT_EQ(RoundUpTo4(static_cast<int64_t>(10000000001)), 10000000004);
+
+  // Unsigned numbers
+  EXPECT_EQ(RoundUpTo4(static_cast<unsigned int>(0)), 0u);
+  EXPECT_EQ(RoundUpTo4(static_cast<unsigned int>(1)), 4u);
+  EXPECT_EQ(RoundUpTo4(static_cast<unsigned int>(2)), 4u);
+  EXPECT_EQ(RoundUpTo4(static_cast<unsigned int>(3)), 4u);
+  EXPECT_EQ(RoundUpTo4(static_cast<unsigned int>(4)), 4u);
+  EXPECT_EQ(RoundUpTo4(static_cast<unsigned int>(5)), 8u);
+  EXPECT_EQ(RoundUpTo4(static_cast<unsigned int>(6)), 8u);
+  EXPECT_EQ(RoundUpTo4(static_cast<unsigned int>(7)), 8u);
+  EXPECT_EQ(RoundUpTo4(static_cast<unsigned int>(8)), 8u);
+  EXPECT_EQ(RoundUpTo4(static_cast<uint64_t>(10000000000)), 10000000000u);
+  EXPECT_EQ(RoundUpTo4(static_cast<uint64_t>(10000000001)), 10000000004u);
+}
+
+TEST(MathUtilTest, CanRoundDownTo4) {
+  // Signed numbers
+  EXPECT_EQ(RoundDownTo4(static_cast<int>(-5)), -8);
+  EXPECT_EQ(RoundDownTo4(static_cast<int>(-4)), -4);
+  EXPECT_EQ(RoundDownTo4(static_cast<int>(-3)), -4);
+  EXPECT_EQ(RoundDownTo4(static_cast<int>(-2)), -4);
+  EXPECT_EQ(RoundDownTo4(static_cast<int>(-1)), -4);
+  EXPECT_EQ(RoundDownTo4(static_cast<int>(0)), 0);
+  EXPECT_EQ(RoundDownTo4(static_cast<int>(1)), 0);
+  EXPECT_EQ(RoundDownTo4(static_cast<int>(2)), 0);
+  EXPECT_EQ(RoundDownTo4(static_cast<int>(3)), 0);
+  EXPECT_EQ(RoundDownTo4(static_cast<int>(4)), 4);
+  EXPECT_EQ(RoundDownTo4(static_cast<int>(5)), 4);
+  EXPECT_EQ(RoundDownTo4(static_cast<int>(6)), 4);
+  EXPECT_EQ(RoundDownTo4(static_cast<int>(7)), 4);
+  EXPECT_EQ(RoundDownTo4(static_cast<int>(8)), 8);
+  EXPECT_EQ(RoundDownTo4(static_cast<int64_t>(10000000000)), 10000000000);
+  EXPECT_EQ(RoundDownTo4(static_cast<int64_t>(10000000001)), 10000000000);
+
+  // Unsigned numbers
+  EXPECT_EQ(RoundDownTo4(static_cast<unsigned int>(0)), 0u);
+  EXPECT_EQ(RoundDownTo4(static_cast<unsigned int>(1)), 0u);
+  EXPECT_EQ(RoundDownTo4(static_cast<unsigned int>(2)), 0u);
+  EXPECT_EQ(RoundDownTo4(static_cast<unsigned int>(3)), 0u);
+  EXPECT_EQ(RoundDownTo4(static_cast<unsigned int>(4)), 4u);
+  EXPECT_EQ(RoundDownTo4(static_cast<unsigned int>(5)), 4u);
+  EXPECT_EQ(RoundDownTo4(static_cast<unsigned int>(6)), 4u);
+  EXPECT_EQ(RoundDownTo4(static_cast<unsigned int>(7)), 4u);
+  EXPECT_EQ(RoundDownTo4(static_cast<unsigned int>(8)), 8u);
+  EXPECT_EQ(RoundDownTo4(static_cast<uint64_t>(10000000000)), 10000000000u);
+  EXPECT_EQ(RoundDownTo4(static_cast<uint64_t>(10000000001)), 10000000000u);
+}
+
+TEST(MathUtilTest, IsDivisibleBy4) {
+  // Signed numbers
+  EXPECT_EQ(IsDivisibleBy4(static_cast<int>(-4)), true);
+  EXPECT_EQ(IsDivisibleBy4(static_cast<int>(-3)), false);
+  EXPECT_EQ(IsDivisibleBy4(static_cast<int>(-2)), false);
+  EXPECT_EQ(IsDivisibleBy4(static_cast<int>(-1)), false);
+  EXPECT_EQ(IsDivisibleBy4(static_cast<int>(0)), true);
+  EXPECT_EQ(IsDivisibleBy4(static_cast<int>(1)), false);
+  EXPECT_EQ(IsDivisibleBy4(static_cast<int>(2)), false);
+  EXPECT_EQ(IsDivisibleBy4(static_cast<int>(3)), false);
+  EXPECT_EQ(IsDivisibleBy4(static_cast<int>(4)), true);
+  EXPECT_EQ(IsDivisibleBy4(static_cast<int>(5)), false);
+  EXPECT_EQ(IsDivisibleBy4(static_cast<int>(6)), false);
+  EXPECT_EQ(IsDivisibleBy4(static_cast<int>(7)), false);
+  EXPECT_EQ(IsDivisibleBy4(static_cast<int>(8)), true);
+  EXPECT_EQ(IsDivisibleBy4(static_cast<int64_t>(10000000000)), true);
+  EXPECT_EQ(IsDivisibleBy4(static_cast<int64_t>(10000000001)), false);
+
+  // Unsigned numbers
+  EXPECT_EQ(IsDivisibleBy4(static_cast<unsigned int>(0)), true);
+  EXPECT_EQ(IsDivisibleBy4(static_cast<unsigned int>(1)), false);
+  EXPECT_EQ(IsDivisibleBy4(static_cast<unsigned int>(2)), false);
+  EXPECT_EQ(IsDivisibleBy4(static_cast<unsigned int>(3)), false);
+  EXPECT_EQ(IsDivisibleBy4(static_cast<unsigned int>(4)), true);
+  EXPECT_EQ(IsDivisibleBy4(static_cast<unsigned int>(5)), false);
+  EXPECT_EQ(IsDivisibleBy4(static_cast<unsigned int>(6)), false);
+  EXPECT_EQ(IsDivisibleBy4(static_cast<unsigned int>(7)), false);
+  EXPECT_EQ(IsDivisibleBy4(static_cast<unsigned int>(8)), true);
+  EXPECT_EQ(IsDivisibleBy4(static_cast<uint64_t>(10000000000)), true);
+  EXPECT_EQ(IsDivisibleBy4(static_cast<uint64_t>(10000000001)), false);
+}
+
+}  // namespace
+}  // namespace dcsctp
diff --git a/third_party/libwebrtc/net/dcsctp/common/sequence_numbers.h b/third_party/libwebrtc/net/dcsctp/common/sequence_numbers.h
new file mode 100644
index 0000000000..d324fb223a
--- /dev/null
+++ b/third_party/libwebrtc/net/dcsctp/common/sequence_numbers.h
@@ -0,0 +1,156 @@
+/*
+ *  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_COMMON_SEQUENCE_NUMBERS_H_
+#define NET_DCSCTP_COMMON_SEQUENCE_NUMBERS_H_
+
+#include <cstdint>
+#include <limits>
+#include <utility>
+
+#include "net/dcsctp/common/internal_types.h"
+#include "rtc_base/numerics/sequence_number_unwrapper.h"
+
+namespace dcsctp {
+
+// UnwrappedSequenceNumber handles wrapping sequence numbers and unwraps them to
+// an int64_t value space, to allow wrapped sequence numbers to be easily
+// compared for ordering.
+//
+// Sequence numbers are expected to be monotonically increasing, but they do not
+// need to be unwrapped in order, as long as the difference to the previous one
+// is not larger than half the range of the wrapped sequence number.
+//
+// The WrappedType must be a webrtc::StrongAlias type.
+template <typename WrappedType>
+class UnwrappedSequenceNumber {
+ public:
+  static_assert(
+      !std::numeric_limits<typename WrappedType::UnderlyingType>::is_signed,
+      "The wrapped type must be unsigned");
+  static_assert(
+      std::numeric_limits<typename WrappedType::UnderlyingType>::max() <
+          std::numeric_limits<int64_t>::max(),
+      "The wrapped type must be less than the int64_t value space");
+
+  // The unwrapper is a sort of factory and converts wrapped sequence numbers to
+  // unwrapped ones.
+  class Unwrapper {
+   public:
+    Unwrapper() = default;
+    Unwrapper(const Unwrapper&) = default;
+    Unwrapper& operator=(const Unwrapper&) = default;
+
+    // Given a wrapped `value`, and with knowledge of its current last seen
+    // largest number, will return a value that can be compared using normal
+    // operators, such as less-than, greater-than etc.
+    //
+    // This will also update the Unwrapper's state, to track the last seen
+    // largest value.
+    UnwrappedSequenceNumber<WrappedType> Unwrap(WrappedType value) {
+      return UnwrappedSequenceNumber<WrappedType>(unwrapper_.Unwrap(*value));
+    }
+
+    // Similar to `Unwrap`, but will not update the Unwrappers's internal state.
+    UnwrappedSequenceNumber<WrappedType> PeekUnwrap(WrappedType value) const {
+      return UnwrappedSequenceNumber<WrappedType>(
+          unwrapper_.PeekUnwrap(*value));
+    }
+
+    // Resets the Unwrapper to its pristine state. Used when a sequence number
+    // is to be reset to zero.
+    void Reset() { unwrapper_.Reset(); }
+
+   private:
+    webrtc::SeqNumUnwrapper<typename WrappedType::UnderlyingType> unwrapper_;
+  };
+
+  // Returns the wrapped value this type represents.
+  WrappedType Wrap() const {
+    return static_cast<WrappedType>(value_ % kValueLimit);
+  }
+
+  template <typename H>
+  friend H AbslHashValue(H state,
+                         const UnwrappedSequenceNumber<WrappedType>& hash) {
+    return H::combine(std::move(state), hash.value_);
+  }
+
+  bool operator==(const UnwrappedSequenceNumber<WrappedType>& other) const {
+    return value_ == other.value_;
+  }
+  bool operator!=(const UnwrappedSequenceNumber<WrappedType>& other) const {
+    return value_ != other.value_;
+  }
+  bool operator<(const UnwrappedSequenceNumber<WrappedType>& other) const {
+    return value_ < other.value_;
+  }
+  bool operator>(const UnwrappedSequenceNumber<WrappedType>& other) const {
+    return value_ > other.value_;
+  }
+  bool operator>=(const UnwrappedSequenceNumber<WrappedType>& other) const {
+    return value_ >= other.value_;
+  }
+  bool operator<=(const UnwrappedSequenceNumber<WrappedType>& other) const {
+    return value_ <= other.value_;
+  }
+
+  // Const accessors for underlying value.
+  constexpr const int64_t* operator->() const { return &value_; }
+  constexpr const int64_t& operator*() const& { return value_; }
+  constexpr const int64_t&& operator*() const&& { return std::move(value_); }
+  constexpr const int64_t& value() const& { return value_; }
+  constexpr const int64_t&& value() const&& { return std::move(value_); }
+  constexpr explicit operator const int64_t&() const& { return value_; }
+
+  // Increments the value.
+  void Increment() { ++value_; }
+
+  // Returns the next value relative to this sequence number.
+  UnwrappedSequenceNumber<WrappedType> next_value() const {
+    return UnwrappedSequenceNumber<WrappedType>(value_ + 1);
+  }
+
+  // Returns a new sequence number based on `value`, and adding `delta` (which
+  // may be negative).
+  static UnwrappedSequenceNumber<WrappedType> AddTo(
+      UnwrappedSequenceNumber<WrappedType> value,
+      int delta) {
+    return UnwrappedSequenceNumber<WrappedType>(value.value_ + delta);
+  }
+
+  // Returns the absolute difference between `lhs` and `rhs`.
+  static typename WrappedType::UnderlyingType Difference(
+      UnwrappedSequenceNumber<WrappedType> lhs,
+      UnwrappedSequenceNumber<WrappedType> rhs) {
+    return (lhs.value_ > rhs.value_) ? (lhs.value_ - rhs.value_)
+                                     : (rhs.value_ - lhs.value_);
+  }
+
+ private:
+  explicit UnwrappedSequenceNumber(int64_t value) : value_(value) {}
+  static constexpr int64_t kValueLimit =
+      static_cast<int64_t>(1)
+      << std::numeric_limits<typename WrappedType::UnderlyingType>::digits;
+
+  int64_t value_;
+};
+
+// Unwrapped Transmission Sequence Numbers (TSN)
+using UnwrappedTSN = UnwrappedSequenceNumber<TSN>;
+
+// Unwrapped Stream Sequence Numbers (SSN)
+using UnwrappedSSN = UnwrappedSequenceNumber<SSN>;
+
+// Unwrapped Message Identifier (MID)
+using UnwrappedMID = UnwrappedSequenceNumber<MID>;
+
+}  // namespace dcsctp
+
+#endif  // NET_DCSCTP_COMMON_SEQUENCE_NUMBERS_H_
diff --git a/third_party/libwebrtc/net/dcsctp/common/sequence_numbers_test.cc b/third_party/libwebrtc/net/dcsctp/common/sequence_numbers_test.cc
new file mode 100644
index 0000000000..c4842f089e
--- /dev/null
+++ b/third_party/libwebrtc/net/dcsctp/common/sequence_numbers_test.cc
@@ -0,0 +1,202 @@
+/*
+ *  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/common/sequence_numbers.h"
+
+#include "test/gmock.h"
+
+namespace dcsctp {
+namespace {
+
+using Wrapped = webrtc::StrongAlias<class WrappedTag, uint16_t>;
+using TestSequence = UnwrappedSequenceNumber<Wrapped>;
+
+TEST(SequenceNumbersTest, SimpleUnwrapping) {
+  TestSequence::Unwrapper unwrapper;
+
+  TestSequence s0 = unwrapper.Unwrap(Wrapped(0));
+  TestSequence s1 = unwrapper.Unwrap(Wrapped(1));
+  TestSequence s2 = unwrapper.Unwrap(Wrapped(2));
+  TestSequence s3 = unwrapper.Unwrap(Wrapped(3));
+
+  EXPECT_LT(s0, s1);
+  EXPECT_LT(s0, s2);
+  EXPECT_LT(s0, s3);
+  EXPECT_LT(s1, s2);
+  EXPECT_LT(s1, s3);
+  EXPECT_LT(s2, s3);
+
+  EXPECT_EQ(TestSequence::Difference(s1, s0), 1);
+  EXPECT_EQ(TestSequence::Difference(s2, s0), 2);
+  EXPECT_EQ(TestSequence::Difference(s3, s0), 3);
+
+  EXPECT_GT(s1, s0);
+  EXPECT_GT(s2, s0);
+  EXPECT_GT(s3, s0);
+  EXPECT_GT(s2, s1);
+  EXPECT_GT(s3, s1);
+  EXPECT_GT(s3, s2);
+
+  s0.Increment();
+  EXPECT_EQ(s0, s1);
+  s1.Increment();
+  EXPECT_EQ(s1, s2);
+  s2.Increment();
+  EXPECT_EQ(s2, s3);
+
+  EXPECT_EQ(TestSequence::AddTo(s0, 2), s3);
+}
+
+TEST(SequenceNumbersTest, MidValueUnwrapping) {
+  TestSequence::Unwrapper unwrapper;
+
+  TestSequence s0 = unwrapper.Unwrap(Wrapped(0x7FFE));
+  TestSequence s1 = unwrapper.Unwrap(Wrapped(0x7FFF));
+  TestSequence s2 = unwrapper.Unwrap(Wrapped(0x8000));
+  TestSequence s3 = unwrapper.Unwrap(Wrapped(0x8001));
+
+  EXPECT_LT(s0, s1);
+  EXPECT_LT(s0, s2);
+  EXPECT_LT(s0, s3);
+  EXPECT_LT(s1, s2);
+  EXPECT_LT(s1, s3);
+  EXPECT_LT(s2, s3);
+
+  EXPECT_EQ(TestSequence::Difference(s1, s0), 1);
+  EXPECT_EQ(TestSequence::Difference(s2, s0), 2);
+  EXPECT_EQ(TestSequence::Difference(s3, s0), 3);
+
+  EXPECT_GT(s1, s0);
+  EXPECT_GT(s2, s0);
+  EXPECT_GT(s3, s0);
+  EXPECT_GT(s2, s1);
+  EXPECT_GT(s3, s1);
+  EXPECT_GT(s3, s2);
+
+  s0.Increment();
+  EXPECT_EQ(s0, s1);
+  s1.Increment();
+  EXPECT_EQ(s1, s2);
+  s2.Increment();
+  EXPECT_EQ(s2, s3);
+
+  EXPECT_EQ(TestSequence::AddTo(s0, 2), s3);
+}
+
+TEST(SequenceNumbersTest, WrappedUnwrapping) {
+  TestSequence::Unwrapper unwrapper;
+
+  TestSequence s0 = unwrapper.Unwrap(Wrapped(0xFFFE));
+  TestSequence s1 = unwrapper.Unwrap(Wrapped(0xFFFF));
+  TestSequence s2 = unwrapper.Unwrap(Wrapped(0x0000));
+  TestSequence s3 = unwrapper.Unwrap(Wrapped(0x0001));
+
+  EXPECT_LT(s0, s1);
+  EXPECT_LT(s0, s2);
+  EXPECT_LT(s0, s3);
+  EXPECT_LT(s1, s2);
+  EXPECT_LT(s1, s3);
+  EXPECT_LT(s2, s3);
+
+  EXPECT_EQ(TestSequence::Difference(s1, s0), 1);
+  EXPECT_EQ(TestSequence::Difference(s2, s0), 2);
+  EXPECT_EQ(TestSequence::Difference(s3, s0), 3);
+
+  EXPECT_GT(s1, s0);
+  EXPECT_GT(s2, s0);
+  EXPECT_GT(s3, s0);
+  EXPECT_GT(s2, s1);
+  EXPECT_GT(s3, s1);
+  EXPECT_GT(s3, s2);
+
+  s0.Increment();
+  EXPECT_EQ(s0, s1);
+  s1.Increment();
+  EXPECT_EQ(s1, s2);
+  s2.Increment();
+  EXPECT_EQ(s2, s3);
+
+  EXPECT_EQ(TestSequence::AddTo(s0, 2), s3);
+}
+
+TEST(SequenceNumbersTest, WrapAroundAFewTimes) {
+  TestSequence::Unwrapper unwrapper;
+
+  TestSequence s0 = unwrapper.Unwrap(Wrapped(0));
+  TestSequence prev = s0;
+
+  for (uint32_t i = 1; i < 65536 * 3; i++) {
+    uint16_t wrapped = static_cast<uint16_t>(i);
+    TestSequence si = unwrapper.Unwrap(Wrapped(wrapped));
+
+    EXPECT_LT(s0, si);
+    EXPECT_LT(prev, si);
+    prev = si;
+  }
+}
+
+TEST(SequenceNumbersTest, IncrementIsSameAsWrapped) {
+  TestSequence::Unwrapper unwrapper;
+
+  TestSequence s0 = unwrapper.Unwrap(Wrapped(0));
+
+  for (uint32_t i = 1; i < 65536 * 2; i++) {
+    uint16_t wrapped = static_cast<uint16_t>(i);
+    TestSequence si = unwrapper.Unwrap(Wrapped(wrapped));
+
+    s0.Increment();
+    EXPECT_EQ(s0, si);
+  }
+}
+
+TEST(SequenceNumbersTest, UnwrappingLargerNumberIsAlwaysLarger) {
+  TestSequence::Unwrapper unwrapper;
+
+  for (uint32_t i = 1; i < 65536 * 2; i++) {
+    uint16_t wrapped = static_cast<uint16_t>(i);
+    TestSequence si = unwrapper.Unwrap(Wrapped(wrapped));
+
+    EXPECT_GT(unwrapper.Unwrap(Wrapped(wrapped + 1)), si);
+    EXPECT_GT(unwrapper.Unwrap(Wrapped(wrapped + 5)), si);
+    EXPECT_GT(unwrapper.Unwrap(Wrapped(wrapped + 10)), si);
+    EXPECT_GT(unwrapper.Unwrap(Wrapped(wrapped + 100)), si);
+  }
+}
+
+TEST(SequenceNumbersTest, UnwrappingSmallerNumberIsAlwaysSmaller) {
+  TestSequence::Unwrapper unwrapper;
+
+  for (uint32_t i = 1; i < 65536 * 2; i++) {
+    uint16_t wrapped = static_cast<uint16_t>(i);
+    TestSequence si = unwrapper.Unwrap(Wrapped(wrapped));
+
+    EXPECT_LT(unwrapper.Unwrap(Wrapped(wrapped - 1)), si);
+    EXPECT_LT(unwrapper.Unwrap(Wrapped(wrapped - 5)), si);
+    EXPECT_LT(unwrapper.Unwrap(Wrapped(wrapped - 10)), si);
+    EXPECT_LT(unwrapper.Unwrap(Wrapped(wrapped - 100)), si);
+  }
+}
+
+TEST(SequenceNumbersTest, DifferenceIsAbsolute) {
+  TestSequence::Unwrapper unwrapper;
+
+  TestSequence this_value = unwrapper.Unwrap(Wrapped(10));
+  TestSequence other_value = TestSequence::AddTo(this_value, 100);
+
+  EXPECT_EQ(TestSequence::Difference(this_value, other_value), 100);
+  EXPECT_EQ(TestSequence::Difference(other_value, this_value), 100);
+
+  TestSequence minus_value = TestSequence::AddTo(this_value, -100);
+
+  EXPECT_EQ(TestSequence::Difference(this_value, minus_value), 100);
+  EXPECT_EQ(TestSequence::Difference(minus_value, this_value), 100);
+}
+
+}  // namespace
+}  // namespace dcsctp
diff --git a/third_party/libwebrtc/net/dcsctp/common/str_join.h b/third_party/libwebrtc/net/dcsctp/common/str_join.h
new file mode 100644
index 0000000000..04517827b7
--- /dev/null
+++ b/third_party/libwebrtc/net/dcsctp/common/str_join.h
@@ -0,0 +1,56 @@
+/*
+ *  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_COMMON_STR_JOIN_H_
+#define NET_DCSCTP_COMMON_STR_JOIN_H_
+
+#include <string>
+
+#include "absl/strings/string_view.h"
+#include "rtc_base/strings/string_builder.h"
+
+namespace dcsctp {
+
+template <typename Range>
+std::string StrJoin(const Range& seq, absl::string_view delimiter) {
+  rtc::StringBuilder sb;
+  int idx = 0;
+
+  for (const typename Range::value_type& elem : seq) {
+    if (idx > 0) {
+      sb << delimiter;
+    }
+    sb << elem;
+
+    ++idx;
+  }
+  return sb.Release();
+}
+
+template <typename Range, typename Functor>
+std::string StrJoin(const Range& seq,
+                    absl::string_view delimiter,
+                    const Functor& fn) {
+  rtc::StringBuilder sb;
+  int idx = 0;
+
+  for (const typename Range::value_type& elem : seq) {
+    if (idx > 0) {
+      sb << delimiter;
+    }
+    fn(sb, elem);
+
+    ++idx;
+  }
+  return sb.Release();
+}
+
+}  // namespace dcsctp
+
+#endif  // NET_DCSCTP_COMMON_STR_JOIN_H_
diff --git a/third_party/libwebrtc/net/dcsctp/common/str_join_test.cc b/third_party/libwebrtc/net/dcsctp/common/str_join_test.cc
new file mode 100644
index 0000000000..dbfd92c1cf
--- /dev/null
+++ b/third_party/libwebrtc/net/dcsctp/common/str_join_test.cc
@@ -0,0 +1,45 @@
+/*
+ *  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/common/str_join.h"
+
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "test/gmock.h"
+
+namespace dcsctp {
+namespace {
+
+TEST(StrJoinTest, CanJoinStringsFromVector) {
+  std::vector<std::string> strings = {"Hello", "World"};
+  std::string s = StrJoin(strings, " ");
+  EXPECT_EQ(s, "Hello World");
+}
+
+TEST(StrJoinTest, CanJoinNumbersFromArray) {
+  std::array<int, 3> numbers = {1, 2, 3};
+  std::string s = StrJoin(numbers, ",");
+  EXPECT_EQ(s, "1,2,3");
+}
+
+TEST(StrJoinTest, CanFormatElementsWhileJoining) {
+  std::vector<std::pair<std::string, std::string>> pairs = {
+      {"hello", "world"}, {"foo", "bar"}, {"fum", "gazonk"}};
+  std::string s = StrJoin(pairs, ",",
+                          [&](rtc::StringBuilder& sb,
+                              const std::pair<std::string, std::string>& p) {
+                            sb << p.first << "=" << p.second;
+                          });
+  EXPECT_EQ(s, "hello=world,foo=bar,fum=gazonk");
+}
+
+}  // namespace
+}  // namespace dcsctp