1 files changed, 82 insertions, 0 deletions
diff --git a/third_party/libwebrtc/net/dcsctp/socket/state_cookie.cc b/third_party/libwebrtc/net/dcsctp/socket/state_cookie.cc
new file mode 100644
index 0000000000..86be77aa34
--- /dev/null
+++ b/third_party/libwebrtc/net/dcsctp/socket/state_cookie.cc
@@ -0,0 +1,82 @@
+/*
+ *  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/socket/state_cookie.h"
+
+#include <cstdint>
+#include <vector>
+
+#include "absl/types/optional.h"
+#include "api/array_view.h"
+#include "net/dcsctp/packet/bounded_byte_reader.h"
+#include "net/dcsctp/packet/bounded_byte_writer.h"
+#include "net/dcsctp/socket/capabilities.h"
+#include "rtc_base/logging.h"
+
+namespace dcsctp {
+
+// Magic values, which the state cookie is prefixed with.
+constexpr uint32_t kMagic1 = 1684230979;
+constexpr uint32_t kMagic2 = 1414541360;
+constexpr size_t StateCookie::kCookieSize;
+
+std::vector<uint8_t> StateCookie::Serialize() {
+  std::vector<uint8_t> cookie;
+  cookie.resize(kCookieSize);
+  BoundedByteWriter<kCookieSize> buffer(cookie);
+  buffer.Store32<0>(kMagic1);
+  buffer.Store32<4>(kMagic2);
+  buffer.Store32<8>(*initiate_tag_);
+  buffer.Store32<12>(*initial_tsn_);
+  buffer.Store32<16>(a_rwnd_);
+  buffer.Store32<20>(static_cast<uint32_t>(*tie_tag_ >> 32));
+  buffer.Store32<24>(static_cast<uint32_t>(*tie_tag_));
+  buffer.Store8<28>(capabilities_.partial_reliability);
+  buffer.Store8<29>(capabilities_.message_interleaving);
+  buffer.Store8<30>(capabilities_.reconfig);
+  buffer.Store16<32>(capabilities_.negotiated_maximum_incoming_streams);
+  buffer.Store16<34>(capabilities_.negotiated_maximum_outgoing_streams);
+  return cookie;
+}
+
+absl::optional<StateCookie> StateCookie::Deserialize(
+    rtc::ArrayView<const uint8_t> cookie) {
+  if (cookie.size() != kCookieSize) {
+    RTC_DLOG(LS_WARNING) << "Invalid state cookie: " << cookie.size()
+                         << " bytes";
+    return absl::nullopt;
+  }
+
+  BoundedByteReader<kCookieSize> buffer(cookie);
+  uint32_t magic1 = buffer.Load32<0>();
+  uint32_t magic2 = buffer.Load32<4>();
+  if (magic1 != kMagic1 || magic2 != kMagic2) {
+    RTC_DLOG(LS_WARNING) << "Invalid state cookie; wrong magic";
+    return absl::nullopt;
+  }
+
+  VerificationTag verification_tag(buffer.Load32<8>());
+  TSN initial_tsn(buffer.Load32<12>());
+  uint32_t a_rwnd = buffer.Load32<16>();
+  uint32_t tie_tag_upper = buffer.Load32<20>();
+  uint32_t tie_tag_lower = buffer.Load32<24>();
+  TieTag tie_tag(static_cast<uint64_t>(tie_tag_upper) << 32 |
+                 static_cast<uint64_t>(tie_tag_lower));
+  Capabilities capabilities;
+  capabilities.partial_reliability = buffer.Load8<28>() != 0;
+  capabilities.message_interleaving = buffer.Load8<29>() != 0;
+  capabilities.reconfig = buffer.Load8<30>() != 0;
+  capabilities.negotiated_maximum_incoming_streams = buffer.Load16<32>();
+  capabilities.negotiated_maximum_outgoing_streams = buffer.Load16<34>();
+
+  return StateCookie(verification_tag, initial_tsn, a_rwnd, tie_tag,
+                     capabilities);
+}
+
+}  // namespace dcsctp