// Copyright Joyent, Inc. and other Node contributors.

//

// Permission is hereby granted, free of charge, to any person obtaining a

// copy of this software and associated documentation files (the

// "Software"), to deal in the Software without restriction, including

// without limitation the rights to use, copy, modify, merge, publish,

// distribute, sublicense, and/or sell copies of the Software, and to permit

// persons to whom the Software is furnished to do so, subject to the

// following conditions:

//

// The above copyright notice and this permission notice shall be included

// in all copies or substantial portions of the Software.

//

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS

// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN

// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,

// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR

// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE

// USE OR OTHER DEALINGS IN THE SOFTWARE.

#ifndef SRC_CRYPTO_CRYPTO_CLIENTHELLO_H_

#define SRC_CRYPTO_CRYPTO_CLIENTHELLO_H_

#if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS

#include <cstddef>  // size_t

#include <cstdint>

namespace node {

namespace crypto {

// Parse the client hello so we can do async session resumption. OpenSSL's

// session resumption uses synchronous callbacks, see SSL_CTX_sess_set_get_cb

// and get_session_cb.

//

// TLS1.3 handshakes masquerade as TLS1.2 session resumption, and to do this,

// they always include a session_id in the ClientHello, making up a bogus value

// if necessary. The parser can't know if its a bogus id, and will cause a

// 'newSession' event to be emitted. This should do no harm, the id won't be

// found, and the handshake will continue.

class ClientHelloParser {

 public:

  inline ClientHelloParser();

  class ClientHello {

   public:

    inline uint8_t session_size() const { return session_size_; }

    inline const uint8_t* session_id() const { return session_id_; }

    inline bool has_ticket() const { return has_ticket_; }

    inline uint8_t servername_size() const { return servername_size_; }

    inline const uint8_t* servername() const { return servername_; }

   private:

    uint8_t session_size_;

    const uint8_t* session_id_;

    bool has_ticket_;

    uint8_t servername_size_;

    const uint8_t* servername_;

    friend class ClientHelloParser;

  };

  typedef void (*OnHelloCb)(void* arg, const ClientHello& hello);

  typedef void (*OnEndCb)(void* arg);

  void Parse(const uint8_t* data, size_t avail);

  inline void Reset();

  inline void Start(OnHelloCb onhello_cb, OnEndCb onend_cb, void* cb_arg);

  inline void End();

  inline bool IsPaused() const;

  inline bool IsEnded() const;

 private:

  static const size_t kMaxTLSFrameLen = 16 * 1024 + 5;

  static const size_t kMaxSSLExFrameLen = 32 * 1024;

  static const uint8_t kServernameHostname = 0;

  static const size_t kMinStatusRequestSize = 5;

  enum ParseState {

    kWaiting,

    kTLSHeader,

    kPaused,

    kEnded

  };

  enum FrameType {

    kChangeCipherSpec = 20,

    kAlert = 21,

    kHandshake = 22,

    kApplicationData = 23,

    kOther = 255

  };

  enum HandshakeType {

    kClientHello = 1

  };

  enum ExtensionType {

    kServerName = 0,

    kTLSSessionTicket = 35

  };

  bool ParseRecordHeader(const uint8_t* data, size_t avail);

  void ParseHeader(const uint8_t* data, size_t avail);

  void ParseExtension(const uint16_t type,

                      const uint8_t* data,

                      size_t len);

  bool ParseTLSClientHello(const uint8_t* data, size_t avail);

  ParseState state_;

  OnHelloCb onhello_cb_;

  OnEndCb onend_cb_;

  void* cb_arg_;

  size_t frame_len_ = 0;

  size_t body_offset_ = 0;

  size_t extension_offset_ = 0;

  uint8_t session_size_ = 0;

  const uint8_t* session_id_ = nullptr;

  uint16_t servername_size_ = 0;

  const uint8_t* servername_ = nullptr;

  uint16_t tls_ticket_size_ = -1;

  const uint8_t* tls_ticket_ = nullptr;

};

}  // namespace crypto

}  // namespace node

#endif  // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS

#endif  // SRC_CRYPTO_CRYPTO_CLIENTHELLO_H_