coturn/src/client++/TurnMsgLib.h

/*
 * Copyright (C) 2011, 2012, 2013 Citrix Systems
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the project nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef __LIB_TURN_MSG_CPP__
#define __LIB_TURN_MSG_CPP__

#include "ns_turn_ioaddr.h"
#include "ns_turn_msg.h"

#include <string>

namespace turn {

class StunAttr;

/**
 * Exception "end of buffer"
 */
class EndOfStunMsgException {
public:
  EndOfStunMsgException() {}
  virtual ~EndOfStunMsgException() {}
};

/**
 * Exception "wrong format of StunAttr"
 */
class WrongStunAttrFormatException {
public:
  WrongStunAttrFormatException() {}
  virtual ~WrongStunAttrFormatException() {}
};

/**
 * Exception "wrong format of StunBuffer"
 */
class WrongStunBufferFormatException {
public:
  WrongStunBufferFormatException() {}
  virtual ~WrongStunBufferFormatException() {}
};

/**
 * Iterator class for attributes
 */
class StunAttrIterator {
public:
  /**
   * Iterator constructor: creates iterator on raw messagebuffer.
   */
  StunAttrIterator(uint8_t *buf, size_t sz) : _buf(buf), _sz(sz) {
    if (!stun_is_command_message_str(_buf, _sz)) {
      throw WrongStunBufferFormatException();
    }
    _sar = stun_attr_get_first_str(_buf, _sz);
  }

  /**
   * Iterator constructor: create iterator over message.
   */
  template <class T> StunAttrIterator(T &msg) : _buf(msg.getRawBuffer()), _sz(msg.getSize()) {
    if (!stun_is_command_message_str(_buf, _sz)) {
      throw WrongStunBufferFormatException();
    }
    _sar = stun_attr_get_first_str(_buf, _sz);
  }

  /**
   * Iterator constructor: creates iterator over raw buffer, starting from first
   * location of an attribute of particular type.
   */
  StunAttrIterator(uint8_t *buf, size_t sz, uint16_t attr_type) : _buf(buf), _sz(sz) {
    if (!stun_is_command_message_str(_buf, _sz)) {
      throw WrongStunBufferFormatException();
    }
    _sar = stun_attr_get_first_by_type_str(_buf, _sz, attr_type);
  }

  /**
   * Iterator constructor: creates iterator over message, starting from first
   * location of an attribute of particular type.
   */
  template <class T> StunAttrIterator(T &msg, uint16_t attr_type) : _buf(msg.getRawBuffer()), _sz(msg.getSize()) {
    if (!stun_is_command_message_str(_buf, _sz)) {
      throw WrongStunBufferFormatException();
    }
    _sar = stun_attr_get_first_by_type_str(_buf, _sz, attr_type);
  }

  /**
   * Moves iterator to next attribute location
   */
  void next() {
    if (!_sar) {
      throw EndOfStunMsgException();
    }
    _sar = stun_attr_get_next_str(_buf, _sz, _sar);
  }

  /**
   * Is the iterator finished
   */
  bool eof() const { return (!_sar); }

  /**
   * Is the iterator at an address attribute
   */
  bool isAddr() const { return stun_attr_is_addr(_sar); }

  /**
   * Return address family attribute value (if the iterator at the "address family" attribute.
   */
  int getAddressFamily() const { return stun_get_requested_address_family(_sar); }

  /**
   * Get attribute type
   */
  int getType() const { return stun_attr_get_type(_sar); }

  /**
   * Destructor
   */
  virtual ~StunAttrIterator() {}

  /**
   * Return raw memroy field of the attribute value.
   * If the attribute value length is zero (0), then return NULL.
   */
  const uint8_t *getRawBuffer(size_t &sz) const {
    int len = stun_attr_get_len(_sar);
    if (len < 0) {
      throw WrongStunAttrFormatException();
    }
    sz = (size_t)len;
    const uint8_t *value = stun_attr_get_value(_sar);
    return value;
  }
  friend class StunAttr;

private:
  uint8_t *_buf;
  size_t _sz;
  stun_attr_ref _sar;
};

/**
 * Root class of all STUN attributes.
 * Can be also used for a generic attribute object.
 */
class StunAttr {
public:
  /**
   * Empty constructor
   */
  StunAttr() : _attr_type(0), _value(0), _sz(0) {}

  /**
   * Constructs attribute from iterator
   */
  StunAttr(const StunAttrIterator &iter) {
    if (iter.eof()) {
      throw EndOfStunMsgException();
    }
    size_t sz = 0;
    const uint8_t *ptr = iter.getRawBuffer(sz);
    if (sz >= 0xFFFF) {
      throw WrongStunAttrFormatException();
    }
    int at = iter.getType();
    if (at < 0) {
      throw WrongStunAttrFormatException();
    }
    _attr_type = (uint16_t)at;
    _sz = sz;
    _value = (uint8_t *)malloc(_sz);
    if (ptr) {
      memcpy(_value, ptr, _sz);
    }
  }

  /**
   * Destructor
   */
  virtual ~StunAttr() {
    if (_value) {
      free(_value);
    }
  }

  /**
   * Return raw data representation of the attribute
   */
  const uint8_t *getRawValue(size_t &sz) const {
    sz = _sz;
    return _value;
  }

  /**
   * Set raw data value
   */
  void setRawValue(uint8_t *value, size_t sz) {
    if (sz > 0xFFFF) {
      throw WrongStunAttrFormatException();
    }
    if (_value) {
      free(_value);
    }
    _sz = sz;
    _value = (uint8_t *)malloc(_sz);
    if (value) {
      memcpy(_value, value, _sz);
    }
  }

  /**
   * Get attribute type
   */
  uint16_t getType() const { return _attr_type; }

  /**
   * Set attribute type
   */
  void setType(uint16_t at) { _attr_type = at; }

  /**
   * Add attribute to a message
   */
  template <class T> int addToMsg(T &msg) {
    if (!_attr_type) {
      throw WrongStunAttrFormatException();
    }
    uint8_t *buffer = msg.getRawBuffer();
    if (buffer) {
      size_t sz = msg.getSize();
      if (addToBuffer(buffer, sz) < 0) {
        throw WrongStunBufferFormatException();
      }
      msg.setSize(sz);
      return 0;
    }
    throw WrongStunBufferFormatException();
  }

protected:
  /**
   * Virtual function member to add attribute to a raw buffer
   */
  virtual int addToBuffer(uint8_t *buffer, size_t &sz) {
    if (buffer) {
      if (!_value) {
        throw WrongStunAttrFormatException();
      }
      if (!stun_attr_add_str(buffer, &sz, _attr_type, _value, _sz)) {
        throw WrongStunBufferFormatException();
      }
      return 0;
    }
    throw WrongStunBufferFormatException();
  }

  /**
   * Get low-level iterator object
   */
  static stun_attr_ref getSar(const StunAttrIterator &iter) { return iter._sar; }

private:
  uint16_t _attr_type;
  uint8_t *_value;
  size_t _sz;
};

/**
 * Channel number attribute class
 */
class StunAttrChannelNumber : public StunAttr {
public:
  StunAttrChannelNumber() : _cn(0) { setType(STUN_ATTRIBUTE_CHANNEL_NUMBER); }
  StunAttrChannelNumber(const StunAttrIterator &iter) : StunAttr(iter) {

    if (iter.eof()) {
      throw EndOfStunMsgException();
    }
    _cn = stun_attr_get_channel_number(getSar(iter));
    if (!_cn) {
      throw WrongStunAttrFormatException();
    }
  }
  virtual ~StunAttrChannelNumber() {}
  uint16_t getChannelNumber() const { return _cn; }
  void setChannelNumber(uint16_t cn) { _cn = cn; }

protected:
  virtual bool addToBuffer(uint8_t *buffer, size_t &sz) { return stun_attr_add_channel_number_str(buffer, &sz, _cn); }

private:
  uint16_t _cn;
};

/**
 * Even port attribute class
 */
class StunAttrEvenPort : public StunAttr {
public:
  StunAttrEvenPort() : _ep(0) { setType(STUN_ATTRIBUTE_EVEN_PORT); }
  StunAttrEvenPort(const StunAttrIterator &iter) : StunAttr(iter) {

    if (iter.eof()) {
      throw EndOfStunMsgException();
    }
    _ep = stun_attr_get_even_port(getSar(iter));
  }
  virtual ~StunAttrEvenPort() {}
  uint8_t getEvenPort() const { return _ep; }
  void setEvenPort(uint8_t ep) { _ep = ep; }

protected:
  virtual bool addToBuffer(uint8_t *buffer, size_t &sz) {
    return stun_attr_add_str(buffer, &sz, STUN_ATTRIBUTE_EVEN_PORT, &_ep, 1);
  }

private:
  uint8_t _ep;
};

/**
 * Reservation token attribute class
 */
class StunAttrReservationToken : public StunAttr {
public:
  StunAttrReservationToken() : _rt(0) { setType(STUN_ATTRIBUTE_RESERVATION_TOKEN); }
  StunAttrReservationToken(const StunAttrIterator &iter) : StunAttr(iter) {

    if (iter.eof()) {
      throw EndOfStunMsgException();
    }
    _rt = stun_attr_get_reservation_token_value(getSar(iter));
  }
  virtual ~StunAttrReservationToken() {}
  uint64_t getReservationToken() const { return _rt; }
  void setReservationToken(uint64_t rt) { _rt = rt; }

protected:
  virtual bool addToBuffer(uint8_t *buffer, size_t &sz) {
    uint64_t reservation_token = ioa_ntoh64(_rt);
    return stun_attr_add_str(buffer, &sz, STUN_ATTRIBUTE_RESERVATION_TOKEN, (uint8_t *)(&reservation_token), 8);
  }

private:
  uint64_t _rt;
};

/**
 * This attribute class is used for all address attributes
 */
class StunAttrAddr : public StunAttr {
public:
  StunAttrAddr(uint16_t attr_type = 0) {
    addr_set_any(&_addr);
    setType(attr_type);
  }
  StunAttrAddr(const StunAttrIterator &iter) : StunAttr(iter) {

    if (iter.eof()) {
      throw EndOfStunMsgException();
    }
    size_t sz = 0;
    const uint8_t *buf = iter.getRawBuffer(sz);
    if (!stun_attr_get_addr_str(buf, sz, getSar(iter), &_addr, NULL)) {
      throw WrongStunAttrFormatException();
    }
  }
  virtual ~StunAttrAddr() {}
  void getAddr(ioa_addr &addr) const { addr_cpy(&addr, &_addr); }
  void setAddr(ioa_addr &addr) { addr_cpy(&_addr, &addr); }

protected:
  virtual bool addToBuffer(uint8_t *buffer, size_t &sz) {
    return stun_attr_add_addr_str(buffer, &sz, getType(), &_addr);
  }

private:
  ioa_addr _addr;
};

/**
 * Change Request attribute class
 */
class StunAttrChangeRequest : public StunAttr {
public:
  StunAttrChangeRequest() : _changeIp(false), _changePort(false) { setType(STUN_ATTRIBUTE_CHANGE_REQUEST); }
  StunAttrChangeRequest(const StunAttrIterator &iter) : StunAttr(iter) {

    if (iter.eof()) {
      throw EndOfStunMsgException();
    }

    if (!stun_attr_get_change_request_str(getSar(iter), &_changeIp, &_changePort)) {
      throw WrongStunAttrFormatException();
    }
  }
  virtual ~StunAttrChangeRequest() {}
  bool getChangeIp() const { return _changeIp; }
  void setChangeIp(bool ci) { _changeIp = ci; }
  bool getChangePort() const { return _changePort; }
  void setChangePort(bool cp) { _changePort = cp; }

protected:
  virtual bool addToBuffer(uint8_t *buffer, size_t &sz) {
    return stun_attr_add_change_request_str(buffer, &sz, _changeIp, _changePort);
  }

private:
  bool _changeIp;
  bool _changePort;
};

/**
 * Change Request attribute class
 */
class StunAttrResponsePort : public StunAttr {
public:
  StunAttrResponsePort() : _rp(0) { setType(STUN_ATTRIBUTE_RESPONSE_PORT); }
  StunAttrResponsePort(const StunAttrIterator &iter) : StunAttr(iter) {

    if (iter.eof()) {
      throw EndOfStunMsgException();
    }

    int rp = stun_attr_get_response_port_str(getSar(iter));
    if (rp < 0) {
      throw WrongStunAttrFormatException();
    }
    _rp = (uint16_t)rp;
  }
  virtual ~StunAttrResponsePort() {}
  uint16_t getResponsePort() const { return _rp; }
  void setResponsePort(uint16_t p) { _rp = p; }

protected:
  virtual bool addToBuffer(uint8_t *buffer, size_t &sz) { return stun_attr_add_response_port_str(buffer, &sz, _rp); }

private:
  uint16_t _rp;
};

/**
 * Padding attribute class
 */
class StunAttrPadding : public StunAttr {
public:
  StunAttrPadding() : _p(0) { setType(STUN_ATTRIBUTE_PADDING); }
  StunAttrPadding(const StunAttrIterator &iter) : StunAttr(iter) {

    if (iter.eof()) {
      throw EndOfStunMsgException();
    }

    int p = stun_attr_get_padding_len_str(getSar(iter));
    if (p < 0) {
      throw WrongStunAttrFormatException();
    }
    _p = (uint16_t)p;
  }
  virtual ~StunAttrPadding() {}
  uint16_t getPadding() const { return _p; }
  /**
   * Set length of padding
   */
  void setPadding(uint16_t p) { _p = p; }

protected:
  virtual bool addToBuffer(uint8_t *buffer, size_t &sz) { return stun_attr_add_padding_str(buffer, &sz, _p); }

private:
  uint16_t _p;
};

/**
 * Generic "STUN Message" class, base class for all messages
 */
class StunMsg {
public:
  /**
   * Empty constructor
   */
  StunMsg() {
    _allocated_sz = 0xFFFF;
    _buffer = (uint8_t *)malloc(_allocated_sz);
    _deallocate = true;
    _sz = 0;
    _constructed = 0;
  }

  /**
   * Construct message over raw buffer.
   * Parameter "construct" is true if the buffer is initialized.
   */
  StunMsg(uint8_t *buffer, size_t total_sz, size_t sz, bool constructed)
      : _buffer(buffer), _deallocate(false), _allocated_sz(total_sz), _sz(sz), _constructed(constructed) {}

  /**
   * Destructor
   */
  virtual ~StunMsg() {
    if (_deallocate && _buffer) {
      free(_buffer);
    }
  }

  /**
   * Initialize buffer
   */
  void construct() { constructBuffer(); }

  /**
   * Checks if the message is properly constructed
   */
  bool isValid() { return check(); }

  /**
   * get raw buffer
   */
  uint8_t *getRawBuffer() { return _buffer; }

  /**
   * Get message size in the buffer (message can be mnuch smaller than the whole buffer)
   */
  size_t getSize() const { return _sz; }

  /**
   * Set message size
   */
  void setSize(size_t sz) {
    if (sz > _allocated_sz) {
      throw WrongStunBufferFormatException();
    }
    _sz = sz;
  }

  /**
   * Check if the raw buffer is a TURN "command" (request, response or indication).
   */
  static bool isCommand(uint8_t *buffer, size_t sz) { return stun_is_command_message_str(buffer, sz); }

  /**
   * Check if the current message object is a "command" (request, response, or indication).
   */
  bool isCommand() const { return stun_is_command_message_str(_buffer, _sz); }

  static bool isIndication(uint8_t *buffer, size_t sz) { return stun_is_indication_str(buffer, sz); }

  static bool isRequest(uint8_t *buffer, size_t sz) { return stun_is_request_str(buffer, sz); }

  static bool isSuccessResponse(uint8_t *buffer, size_t sz) { return stun_is_success_response_str(buffer, sz); }

  static bool isErrorResponse(uint8_t *buffer, size_t sz, int &err_code, uint8_t *err_msg, size_t err_msg_size) {
    return stun_is_error_response_str(buffer, sz, &err_code, err_msg, err_msg_size);
  }

  /**
   * Check if the raw buffer is a challenge response (the one with 401 error and realm and nonce values).
   */
  static bool isChallengeResponse(const uint8_t *buf, size_t sz, int &err_code, uint8_t *err_msg, size_t err_msg_size,
                                  uint8_t *realm, uint8_t *nonce, uint8_t *server_name, bool *oauth) {
    return stun_is_challenge_response_str(buf, sz, &err_code, err_msg, err_msg_size, realm, nonce, server_name, oauth);
  }

  /**
   * Check if the message is a channel message
   */
  static bool isChannel(uint8_t *buffer, size_t sz) { return is_channel_msg_str(buffer, sz); }

  /**
   * Check if the fingerprint is present.
   */
  static bool isFingerprintPresent(uint8_t *buffer, size_t sz) {
    if (!stun_is_command_message_str(buffer, sz)) {
      return false;
    }
    stun_attr_ref sar = stun_attr_get_first_by_type_str(buffer, sz, STUN_ATTRIBUTE_FINGERPRINT);
    if (!sar) {
      return false;
    }

    return true;
  }

  /**
   * Check the fingerprint
   */
  static bool checkFingerprint(uint8_t *buffer, size_t sz) {
    return stun_is_command_message_full_check_str(buffer, sz, 1, NULL);
  }

  /**
   * Add attribute to the message
   */
  int addAttr(StunAttr &attr) { return attr.addToMsg(*this); }

  /**
   * Get transaction ID
   */
  virtual stun_tid getTid() const {
    if (!_constructed || !isCommand()) {
      throw WrongStunBufferFormatException();
    }
    stun_tid tid;
    stun_tid_from_message_str(_buffer, _sz, &tid);
    return tid;
  }

  /**
   * Set transaction ID
   */
  virtual void setTid(stun_tid &tid) {
    if (!_constructed || !isCommand()) {
      throw WrongStunBufferFormatException();
    }
    stun_tid_message_cpy(_buffer, &tid);
  }

  /**
   * Add fingerprint to the message
   */
  void addFingerprint() {
    if (!_constructed || !isCommand()) {
      throw WrongStunBufferFormatException();
    }
    stun_attr_add_fingerprint_str(_buffer, &_sz);
  }

  /**
   * Check message integrity, in secure communications.
   */
  bool checkMessageIntegrity(turn_credential_type ct, std::string &uname, std::string &realm, std::string &upwd) const {
    if (!_constructed || !isCommand()) {
      throw WrongStunBufferFormatException();
    }
    uint8_t *suname = (uint8_t *)strdup(uname.c_str());
    uint8_t *srealm = (uint8_t *)strdup(realm.c_str());
    uint8_t *supwd = (uint8_t *)strdup(upwd.c_str());
    SHATYPE sht = SHATYPE_SHA1;
    bool ret = (0 < stun_check_message_integrity_str(ct, _buffer, _sz, suname, srealm, supwd, sht));
    free(suname);
    free(srealm);
    free(supwd);
    return ret;
  }

  /**
   * Adds long-term message integrity data to the message.
   */
  void addLTMessageIntegrity(std::string &uname, std::string &realm, std::string &upwd, std::string &nonce) {

    if (!_constructed || !isCommand()) {
      throw WrongStunBufferFormatException();
    }

    uint8_t *suname = (uint8_t *)strdup(uname.c_str());
    uint8_t *srealm = (uint8_t *)strdup(realm.c_str());
    uint8_t *supwd = (uint8_t *)strdup(upwd.c_str());
    uint8_t *snonce = (uint8_t *)strdup(nonce.c_str());

    stun_attr_add_integrity_by_user_str(_buffer, &_sz, suname, srealm, supwd, snonce, SHATYPE_SHA1);

    free(suname);
    free(srealm);
    free(supwd);
    free(snonce);
  }

  /**
   * Adds short-term message integrity data to the message.
   */
  void addSTMessageIntegrity(std::string &uname, std::string &upwd) {

    if (!_constructed || !isCommand()) {
      throw WrongStunBufferFormatException();
    }

    uint8_t *suname = (uint8_t *)strdup(uname.c_str());
    uint8_t *supwd = (uint8_t *)strdup(upwd.c_str());

    stun_attr_add_integrity_by_user_short_term_str(_buffer, &_sz, suname, supwd, SHATYPE_SHA1);

    free(suname);
    free(supwd);
  }

protected:
  virtual void constructBuffer() = 0;
  virtual bool check() = 0;

protected:
  uint8_t *_buffer;
  bool _deallocate;
  size_t _allocated_sz;
  size_t _sz;
  bool _constructed;
};

/**
 * Class that represents the "request" flavor of STUN/TURN messages.
 */
class StunMsgRequest : public StunMsg {
public:
  StunMsgRequest(uint16_t method) : _method(method){};
  StunMsgRequest(uint8_t *buffer, size_t total_sz, size_t sz, bool constructed)
      : StunMsg(buffer, total_sz, sz, constructed), _method(0) {

    if (constructed) {
      if (!stun_is_request_str(buffer, sz)) {
        throw WrongStunBufferFormatException();
      }
      _method = stun_get_method_str(buffer, sz);
    }
  }
  virtual ~StunMsgRequest() {}

  /**
   * Get request method
   */
  uint16_t getMethod() const { return _method; }

  /**
   * Set method
   */
  void setMethod(uint16_t method) { _method = method; }

  /**
   * Construct binding request
   */
  void constructBindingRequest() { stun_set_binding_request_str(_buffer, &_sz); }

  bool isBindingRequest() const { return stun_is_binding_request_str(_buffer, _sz, 0); }

  /**
   * Construct allocate request
   */
  void constructAllocateRequest(uint32_t lifetime, int af4, int af6, uint8_t transport, int mobile, const char *rt,
                                int ep) {
    stun_set_allocate_request_str(_buffer, &_sz, lifetime, af4, af6, transport, mobile, rt, ep);
  }

  /**
   * Construct channel bind request
   */
  void constructChannelBindRequest(const ioa_addr &peer_addr, uint16_t channel_number) {
    stun_set_channel_bind_request_str(_buffer, &_sz, &peer_addr, channel_number);
  }

protected:
  virtual void constructBuffer() {
    stun_init_request_str(_method, _buffer, &_sz);
    _constructed = true;
  }

  virtual bool check() {
    if (!_constructed) {
      return false;
    }
    if (!stun_is_request_str(_buffer, _sz)) {
      return false;
    }
    if (_method != stun_get_method_str(_buffer, _sz)) {
      return false;
    }
    return true;
  }

private:
  uint16_t _method;
};

/**
 * Class for STUN/TURN responses
 */
class StunMsgResponse : public StunMsg {
public:
  StunMsgResponse(uint16_t method, stun_tid &tid) : _method(method), _err(0), _reason(""), _tid(tid){};
  StunMsgResponse(uint16_t method, int error_code, std::string reason, stun_tid &tid)
      : _method(method), _err(error_code), _reason(reason), _tid(tid){

                                                            };
  StunMsgResponse(uint8_t *buffer, size_t total_sz, size_t sz, bool constructed)
      : StunMsg(buffer, total_sz, sz, constructed), _method(0), _err(0), _reason("") {

    if (constructed) {
      if (!stun_is_success_response_str(buffer, sz)) {
        uint8_t errtxt[0xFFFF];
        if (!stun_is_error_response_str(buffer, sz, &_err, errtxt, sizeof(errtxt))) {
          throw WrongStunBufferFormatException();
        }
        _reason = (char *)errtxt;
      }
      _method = stun_get_method_str(buffer, sz);
      stun_tid_from_message_str(_buffer, _sz, &_tid);
    }
  }

  uint16_t getMethod() const { return _method; }

  void setMethod(uint16_t method) { _method = method; }

  /**
   * Get error code
   */
  int getError() const { return _err; }

  /**
   * Set error code
   */
  void setError(int err) { _err = err; }

  /**
   * Get error message
   */
  std::string getReason() const { return _reason; }

  /**
   * Set error message
   */
  void setReason(std::string reason) { _reason = reason; }

  /**
   * Set transaction ID
   */
  void setTid(stun_tid &tid) { _tid = tid; }

  /**
   * Get transaction ID
   */
  virtual stun_tid getTid() const { return _tid; }

  /**
   * Check if this is a challenge response, and return realm and nonce
   */
  bool isChallenge(std::string &realm, std::string &nonce) const {
    bool ret = false;
    if (_constructed) {
      int err_code;
      uint8_t err_msg[1025];
      size_t err_msg_size = sizeof(err_msg);
      uint8_t srealm[0xFFFF];
      uint8_t snonce[0xFFFF];
      ret = stun_is_challenge_response_str(_buffer, _sz, &err_code, err_msg, err_msg_size, srealm, snonce, NULL, NULL);
      if (ret) {
        realm = (char *)srealm;
        nonce = (char *)snonce;
      }
    }
    return ret;
  }

  bool isChallenge() const {
    std::string realm, nonce;
    return isChallenge(realm, nonce);
  }

  /**
   * Check if this is a success response
   */
  bool isSuccess() const { return (_err == 0); }

  /**
   * Construct binding response
   */
  void constructBindingResponse(stun_tid &tid, const ioa_addr &reflexive_addr, int error_code, const uint8_t *reason) {

    stun_set_binding_response_str(_buffer, &_sz, &tid, &reflexive_addr, error_code, reason, 0, false, true);
  }

  bool isBindingResponse() const { return stun_is_binding_response_str(_buffer, _sz); }

  /**
   * Construct allocate response
   */
  void constructAllocateResponse(stun_tid &tid, const ioa_addr &relayed_addr1, const ioa_addr &relayed_addr2,
                                 const ioa_addr &reflexive_addr, uint32_t lifetime, int error_code,
                                 const uint8_t *reason, uint64_t reservation_token, char *mobile_id) {

    stun_set_allocate_response_str(_buffer, &_sz, &tid, &relayed_addr1, &relayed_addr2, &reflexive_addr, lifetime,
                                   STUN_DEFAULT_MAX_ALLOCATE_LIFETIME, error_code, reason, reservation_token,
                                   mobile_id);
  }

  /**
   * Construct channel bind response
   */
  void constructChannelBindResponse(stun_tid &tid, int error_code, const uint8_t *reason) {
    stun_set_channel_bind_response_str(_buffer, &_sz, &tid, error_code, reason);
  }

protected:
  virtual void constructBuffer() {
    if (_err) {
      stun_init_error_response_str(_method, _buffer, &_sz, _err, (const uint8_t *)_reason.c_str(), &_tid);
    } else {
      stun_init_success_response_str(_method, _buffer, &_sz, &_tid);
    }
    _constructed = true;
  }

  virtual bool check() {
    if (!_constructed) {
      return false;
    }
    if (!stun_is_success_response_str(_buffer, _sz)) {
      uint8_t errtxt[0xFFFF];
      int cerr = 0;
      if (!stun_is_error_response_str(_buffer, _sz, &cerr, errtxt, sizeof(errtxt))) {
        throw WrongStunBufferFormatException();
      }
      if (cerr != _err) {
        throw WrongStunBufferFormatException();
      }
    }
    if (_method != stun_get_method_str(_buffer, _sz)) {
      return false;
    }
    return true;
  }

private:
  uint16_t _method;
  int _err;
  std::string _reason;
  stun_tid _tid;
};

/**
 * Class for STUN/TURN indications
 */
class StunMsgIndication : public StunMsg {
public:
  StunMsgIndication(uint16_t method) : _method(method){};
  StunMsgIndication(uint8_t *buffer, size_t total_sz, size_t sz, bool constructed)
      : StunMsg(buffer, total_sz, sz, constructed), _method(0) {

    if (constructed) {
      if (!stun_is_indication_str(buffer, sz)) {
        throw WrongStunBufferFormatException();
      }
      _method = stun_get_method_str(buffer, sz);
    }
  }
  virtual ~StunMsgIndication() {}

  uint16_t getMethod() const { return _method; }

  void setMethod(uint16_t method) { _method = method; }

protected:
  virtual void constructBuffer() {
    stun_init_indication_str(_method, _buffer, &_sz);
    _constructed = true;
  }

  virtual bool check() {
    if (!_constructed) {
      return false;
    }
    if (!stun_is_indication_str(_buffer, _sz)) {
      return false;
    }
    if (_method != stun_get_method_str(_buffer, _sz)) {
      return false;
    }
    return true;
  }

private:
  uint16_t _method;
};

/**
 * Channel message
 */
class StunMsgChannel : public StunMsg {
public:
  StunMsgChannel(uint16_t cn, int length) : _cn(cn), _len(length){};
  StunMsgChannel(uint8_t *buffer, size_t total_sz, size_t sz, bool constructed)
      : StunMsg(buffer, total_sz, sz, constructed), _cn(0) {

    if (constructed) {
      if (!stun_is_channel_message_str(buffer, &_sz, &_cn, false)) {
        throw WrongStunBufferFormatException();
      }
      if (_sz > 0xFFFF || _sz < 4) {
        throw WrongStunBufferFormatException();
      }

      _len = _sz - 4;
    } else {
      if (total_sz > 0xFFFF || total_sz < 4) {
        throw WrongStunBufferFormatException();
      }

      _len = 0;
    }
  }
  virtual ~StunMsgChannel() {}

  uint16_t getChannelNumber() const { return _cn; }

  void setChannelNumber(uint16_t cn) { _cn = cn; }

  /**
   * Get length of message itself (excluding the 4 channel number bytes)
   */
  size_t getLength() const { return _len; }

  /**
   * Set length of message itself (excluding the 4 channel number bytes)
   */
  void setLength(size_t len) { _len = len; }

protected:
  virtual void constructBuffer() {
    stun_init_channel_message_str(_cn, _buffer, &_sz, (int)_len, 0);
    _constructed = true;
  }

  virtual bool check() {
    if (!_constructed) {
      return false;
    }
    uint16_t cn = 0;
    if (!stun_is_channel_message_str(_buffer, &_sz, &cn, false)) {
      return false;
    }
    if (_cn != cn) {
      return false;
    }
    return true;
  }

private:
  uint16_t _cn;
  size_t _len;
};

} // namespace turn
/* namespace */

#endif
/* __LIB_TURN_MSG_CPP__ */