state_cookie.h - mozsearch

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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_SOCKET_STATE_COOKIE_H_

#define NET_DCSCTP_SOCKET_STATE_COOKIE_H_

#include <cstdint>

#include <optional>

#include <vector>

#include "api/array_view.h"

#include "net/dcsctp/common/internal_types.h"

#include "net/dcsctp/socket/capabilities.h"

namespace dcsctp {

// This is serialized as a state cookie and put in INIT_ACK. The client then

// responds with this in COOKIE_ECHO.

//

// NOTE: Expect that the client will modify it to try to exploit the library.

// Do not trust anything in it; no pointers or anything like that.

class StateCookie {

 public:

  static constexpr size_t kCookieSize = 44;

  StateCookie(VerificationTag peer_tag,

              VerificationTag my_tag,

              TSN peer_initial_tsn,

              TSN my_initial_tsn,

              uint32_t a_rwnd,

              TieTag tie_tag,

              Capabilities capabilities)

      : peer_tag_(peer_tag),

        my_tag_(my_tag),

        peer_initial_tsn_(peer_initial_tsn),

        my_initial_tsn_(my_initial_tsn),

        a_rwnd_(a_rwnd),

        tie_tag_(tie_tag),

        capabilities_(capabilities) {}

  // Returns a serialized version of this cookie.

  std::vector<uint8_t> Serialize();

  // Deserializes the cookie, and returns std::nullopt if that failed.

  static std::optional<StateCookie> Deserialize(

      rtc::ArrayView<const uint8_t> cookie);

  VerificationTag peer_tag() const { return peer_tag_; }

  VerificationTag my_tag() const { return my_tag_; }

  TSN peer_initial_tsn() const { return peer_initial_tsn_; }

  TSN my_initial_tsn() const { return my_initial_tsn_; }

  uint32_t a_rwnd() const { return a_rwnd_; }

  TieTag tie_tag() const { return tie_tag_; }

  const Capabilities& capabilities() const { return capabilities_; }

 private:

  // Also called "Tag_A" in RFC4960.

  const VerificationTag peer_tag_;

  // Also called "Tag_Z" in RFC4960.

  const VerificationTag my_tag_;

  const TSN peer_initial_tsn_;

  const TSN my_initial_tsn_;

  const uint32_t a_rwnd_;

  const TieTag tie_tag_;

  const Capabilities capabilities_;

};

}  // namespace dcsctp

#endif  // NET_DCSCTP_SOCKET_STATE_COOKIE_H_