/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=2 et sw=2 tw=80: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this file,

 * You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef tls_parser_h_

#define tls_parser_h_

#include <memory>

#include <cstdint>

#include <cstring>

#include <arpa/inet.h>

#include "databuffer.h"

namespace nss_test {

const uint8_t kTlsChangeCipherSpecType = 20;

const uint8_t kTlsAlertType = 21;

const uint8_t kTlsHandshakeType = 22;

const uint8_t kTlsHandshakeClientHello = 1;

const uint8_t kTlsHandshakeServerHello = 2;

const uint8_t kTlsHandshakeCertificate = 11;

const uint8_t kTlsHandshakeServerKeyExchange = 12;

const uint8_t kTlsAlertWarning = 1;

const uint8_t kTlsAlertFatal = 2;

const uint8_t kTlsAlertUnexpectedMessage = 10;

const uint8_t kTlsAlertHandshakeFailure = 40;

const uint8_t kTlsAlertIllegalParameter = 47;

const uint8_t kTlsAlertDecodeError = 50;

const uint8_t kTlsAlertUnsupportedExtension = 110;

const uint8_t kTlsAlertNoApplicationProtocol = 120;

const uint8_t kTlsFakeChangeCipherSpec[] = {

    kTlsChangeCipherSpecType,        // Type

    0xfe,                     0xff,  // Version

    0x00,                     0x00, 0x00, 0x00,

    0x00,                     0x00, 0x00, 0x10,  // Fictitious sequence #

    0x00,                     0x01,              // Length

    0x01                                         // Value

};

inline bool IsDtls(uint16_t version) {

  return (version & 0x8000) == 0x8000;

}

inline uint16_t NormalizeTlsVersion(uint16_t version) {

  if (version == 0xfeff) {

    return 0x0302; // special: DTLS 1.0 == TLS 1.1

  }

  if (IsDtls(version)) {

    return (version ^ 0xffff) + 0x0201;

  }

  return version;

}

inline void WriteVariable(DataBuffer* target, size_t index,

                          const DataBuffer& buf, size_t len_size) {

  target->Write(index, static_cast<uint32_t>(buf.len()), len_size);

  target->Write(index + len_size, buf.data(), buf.len());

}

class TlsParser {

 public:

  TlsParser(const uint8_t* data, size_t len)

      : buffer_(data, len), offset_(0) {}

  explicit TlsParser(const DataBuffer& buf)

      : buffer_(buf), offset_(0) {}

  bool Read(uint8_t* val);

  // Read an integral type of specified width.

  bool Read(uint32_t* val, size_t size);

  // Reads len bytes into dest buffer, overwriting it.

  bool Read(DataBuffer* dest, size_t len);

  // Reads bytes into dest buffer, overwriting it.  The number of bytes is

  // determined by reading from len_size bytes from the stream first.

  bool ReadVariable(DataBuffer* dest, size_t len_size);

  bool Skip(size_t len);

  bool SkipVariable(size_t len_size);

  size_t consumed() const { return offset_; }

  size_t remaining() const { return buffer_.len() - offset_; }

 private:

  void consume(size_t len) { offset_ += len; }

  const uint8_t* ptr() const { return buffer_.data() + offset_; }

  DataBuffer buffer_;

  size_t offset_;

};

} // namespace nss_test

#endif