telnetio.java

java telnet 服务器实现 .

        case ECHO:
          if (DO_ECHO) {
            DO_ECHO = false;
          } else {
            DO_ECHO = true;
          }
          break;
        case NAWS:
          if (DO_NAWS) {
            DO_NAWS = false;
          } else {
            DO_NAWS = true;
          }
          break;
        case TTYPE:
          if (DO_TTYPE) {
            DO_TTYPE = false;
          } else {
            DO_TTYPE = true;
            getTTYPE();
          }
          break;
        case LINEMODE:
          if (DO_LINEMODE) {
            DO_LINEMODE = false;
            //set false in connection data, so the application knows.
            m_ConnectionData.setLineMode(false);
          } else {
            DO_LINEMODE = true;
            negotiateLineMode();
          }
          break;
        case NEWENV:
          if (DO_NEWENV) {
            DO_NEWENV = false;
          } else {
            DO_NEWENV = true;
            negotiateEnvironment();
          }
          break;
      }
    }//enable

    /**
     * Method that informs internally about the status of the supported
     * Negotiation Options.
     *
     * @param i int that represents requested the Option
     * @return Boolean that represents the enabled status
     */
    private boolean isEnabled(int i) {
      switch (i) {
        case SUPGA:
          return DO_SUPGA;
        case ECHO:
          return DO_ECHO;
        case NAWS:
          return DO_NAWS;
        case TTYPE:
          return DO_TTYPE;
        case LINEMODE:
          return DO_LINEMODE;
        case NEWENV:
          return DO_NEWENV;
        default:
          return false;
      }
    }//isEnabled

    /**
     * Method that informs internally about the WILL wait status
     * of an option.
     *
     * @param i that represents requested the Option
     * @return Boolean that represents WILL wait status of the Option
     */
    private boolean waitWILLreply(int i) {
      switch (i) {
        case SUPGA:
          return WAIT_WILL_REPLY_SUPGA;
        case ECHO:
          return WAIT_WILL_REPLY_ECHO;
        case NAWS:
          return WAIT_WILL_REPLY_NAWS;
        case TTYPE:
          return WAIT_WILL_REPLY_TTYPE;
        default:
          return false;
      }
    }//waitWILLreply

    /**
     * Method that informs internally about the DO wait status
     * of an option.
     *
     * @param i Integer that represents requested the Option
     * @return Boolean that represents DO wait status of the Option
     */
    private boolean waitDOreply(int i) {
      switch (i) {
        case SUPGA:
          return WAIT_DO_REPLY_SUPGA;
        case ECHO:
          return WAIT_DO_REPLY_ECHO;
        case NAWS:
          return WAIT_DO_REPLY_NAWS;
        case TTYPE:
          return WAIT_DO_REPLY_TTYPE;
        case LINEMODE:
          return WAIT_DO_REPLY_LINEMODE;
        case NEWENV:
          return WAIT_DO_REPLY_NEWENV;
        default:
          return false;
      }
    }//waitDOreply

    /**
     * Method that mutates the wait status of an option in
     * negotiation. We need the wait status to keep track of
     * negotiation in process. So we cant miss if we started out
     * or the other and so on.
     *
     * @param WHAT   Integer values of  DO or WILL
     * @param OPTION Integer that represents the Option
     * @param WAIT   Boolean that represents the status of wait that should be set
     */
    private void setWait(int WHAT, int OPTION, boolean WAIT) {
      switch (WHAT) {
        case DO:
          switch (OPTION) {
            case SUPGA:
              WAIT_DO_REPLY_SUPGA = WAIT;
              break;
            case ECHO:
              WAIT_DO_REPLY_ECHO = WAIT;
              break;
            case NAWS:
              WAIT_DO_REPLY_NAWS = WAIT;
              break;
            case TTYPE:
              WAIT_DO_REPLY_TTYPE = WAIT;
              break;
            case LINEMODE:
              WAIT_DO_REPLY_LINEMODE = WAIT;
              break;
            case NEWENV:
              WAIT_DO_REPLY_NEWENV = WAIT;
              break;
          }
          break;
        case WILL:
          switch (OPTION) {
            case SUPGA:
              WAIT_WILL_REPLY_SUPGA = WAIT;
              break;
            case ECHO:
              WAIT_WILL_REPLY_ECHO = WAIT;
              break;
            case NAWS:
              WAIT_WILL_REPLY_NAWS = WAIT;
              break;
            case TTYPE:
              WAIT_WILL_REPLY_TTYPE = WAIT;
              break;
          }
          break;
      }
    }//setWait

  }//inner class IACHandler



  /** Constants declaration ***********************************************/

//Telnet Protocoll Constants

  /**
   * Interpret As Command
   */
  protected static final int IAC = 255;

  /**
   * Go Ahead <BR> Newer Telnets do not make use of this option
   * that allows a specific communication mode.
   */
  protected static final int GA = 249;

  /**
   * Negotiation: Will do option
   */
  protected static final int WILL = 251;

  /**
   * Negotiation: Wont do option
   */
  protected static final int WONT = 252;

  /**
   * Negotiation: Do option
   */
  protected static final int DO = 253;

  /**
   * Negotiation:  Dont do option
   */
  protected static final int DONT = 254;

  /**
   * Marks start of a subnegotiation.
   */
  protected static final int SB = 250;

  /**
   * Marks end of subnegotiation.
   */
  protected static final int SE = 240;

  /**
   * No operation
   */
  protected static final int NOP = 241;

  /**
   * Data mark its the data part of a SYNCH which helps to clean up the buffers between
   * Telnet Server &lt;-&gt; Telnet Client. <BR>
   * It should work like this we send a TCP urgent package and &lt;IAC&gt; &lt;DM&gt; the receiver
   * should get the urgent package (SYNCH) and just discard everything until he receives
   * our &lt;IAC&gt; &lt;DM&gt;.<BR>
   * <EM>Remark</EM>:
   * <OL>
   * <LI>can we send a TCP urgent package?
   * <LI>can we make use of the thing at all?
   * </OL>
   */
  protected static final int DM = 242;

  /**
   * Break
   */
  protected static final int BRK = 243;

  /**
   * The following implement the NVT (network virtual terminal) which offers the concept
   * of a simple "printer". They are the basical meanings of control possibilities
   * on a standard telnet implementation.
   */

  /**
   * Interrupt Process
   */
  protected static final int IP = 244;

  /**
   * Abort Output
   */
  protected static final int AO = 245;

  /**
   * Are You There
   */
  protected static final int AYT = 246;

  /**
   * Erase Char
   */
  protected static final int EC = 247;

  /**
   * Erase Line
   */
  protected static final int EL = 248;

  /**
   * The following are constants for supported options,
   * which can be negotiated based upon the telnet protocol
   * specification.
   */

  /**
   * Telnet Option: ECHO
   */
  protected static final int ECHO = 1;

  /**
   * Telnet Option: SUPress Go Ahead<br>
   * This will be negotiated, all new telnet protocol implementations are
   * recommended to do this.
   */
  protected static final int SUPGA = 3;

  /**
   * The following options are options for which we also support subnegotiation
   * based upon the telnet protocol specification.
   */

  /**
   * Telnet Option: Negotiate About Window Size<br>
   * <ul>
   * <li>Server request is IAC DO NAWS
   * <li>Client response contains subnegotiation with data (columns, rows).
   * </ul>
   */
  protected static final int NAWS = 31;

  /**
   * Telnet Option: Terminal TYPE <br>
   * <ul>
   * <li>Server request contains subnegotiation SEND
   * <li>Client response contains subnegotiation with data IS,terminal type string
   * </ul>
   */
  protected static final int TTYPE = 24;

  /**
   * TTYPE subnegotiation: IS
   */
  protected static final int IS = 0;

  /**
   * TTYPE subnegotiation: SEND
   */
  protected static final int SEND = 1;

  /**
   * Telnet Option: Logout<br>
   * This allows nice goodbye to time-outed or unwanted clients.
   */
  protected static final int LOGOUT = 18;

  /**
   * Telnet Option: Linemode
   * <p/>
   * The infamous line mode option.
   */
  protected static final int LINEMODE = 34;
  protected static final int LM_MODE = 1;
  protected static final int LM_EDIT = 1;
  protected static final int LM_TRAPSIG = 2;
  protected static final int LM_MODEACK = 4;
  protected static final int LM_FORWARDMASK = 2;

  protected static final int LM_SLC = 3;
  protected static final int LM_SLC_NOSUPPORT = 0;
  protected static final int LM_SLC_DEFAULT = 3;
  protected static final int LM_SLC_VALUE = 2;
  protected static final int LM_SLC_CANTCHANGE = 1;
  protected static final int LM_SLC_LEVELBITS = 3;
  protected static final int LM_SLC_ACK = 128;
  protected static final int LM_SLC_FLUSHIN = 64;
  protected static final int LM_SLC_FLUSHOUT = 32;

  protected static final int LM_SLC_SYNCH = 1;
  protected static final int LM_SLC_BRK = 2;
  protected static final int LM_SLC_IP = 3;
  protected static final int LM_SLC_AO = 4;
  protected static final int LM_SLC_AYT = 5;
  protected static final int LM_SLC_EOR = 6;
  protected static final int LM_SLC_ABORT = 7;
  protected static final int LM_SLC_EOF = 8;
  protected static final int LM_SLC_SUSP = 9;

  /**
   * Telnet Option: Environment
   */
  protected static final int NEWENV = 39;
  protected static final int NE_INFO = 2;
  protected static final int NE_VAR = 0;
  protected static final int NE_VALUE = 1;
  protected static final int NE_ESC = 2;
  protected static final int NE_USERVAR = 3;

  protected static final int NE_VAR_OK = 2;
  protected static final int NE_VAR_DEFINED = 1;
  protected static final int NE_VAR_DEFINED_EMPTY = 0;
  protected static final int NE_VAR_UNDEFINED = -1;
  protected static final int NE_IN_ERROR = -2;
  protected static final int NE_IN_END = -3;
  protected static final int NE_VAR_NAME_MAXLENGTH = 50;
  protected static final int NE_VAR_VALUE_MAXLENGTH = 1000;

  /**
   * The following options are options which might be of interest, but are not
   * yet implemented or in use.
   */

  /**
   * Unused
   */
  protected static final int EXT_ASCII = 17;		//Defines Extended ASCII
  protected static final int SEND_LOC = 23;		//Defines Send Location
  protected static final int AUTHENTICATION = 37;	//Defines Authentication
  protected static final int ENCRYPT = 38;			//Defines Encryption


  /**
   * Window Size Constants
   */
  private static final int SMALLEST_BELIEVABLE_WIDTH = 20;
  private static final int SMALLEST_BELIEVABLE_HEIGHT = 6;
  private static final int DEFAULT_WIDTH = 80;
  private static final int DEFAULT_HEIGHT = 25;

  /** end Constants declaration **************************************************/

}//class TelnetIO