text: /*****************************************************************************
  * fsm.h - Network Control Protocol Finite State Machine header file.
  *
  * Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
  * Copyright (c) 1997 Global Election Systems Inc.
  *
  * The authors hereby grant permission to use, copy, modify, distribute,
  * and license this software and its documentation for any purpose, provided
  * that existing copyright notices are retained in all copies and that this
  * notice and the following disclaimer are included verbatim in any
  * distributions. No written agreement, license, or royalty fee is required
  * for any of the authorized uses.
  *
  * THIS SOFTWARE IS PROVIDED BY THE 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 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.
  *
  ******************************************************************************
  * REVISION HISTORY
  *
  * 03-01-01 Marc Boucher <marc@mbsi.ca>
  *   Ported to lwIP.
  * 97-11-05 Guy Lancaster <glanca@gesn.com>, Global Election Systems Inc.
  *   Original based on BSD code.
  *****************************************************************************/
  /*
   * fsm.h - {Link, IP} Control Protocol Finite State Machine definitions.
   *
   * Copyright (c) 1989 Carnegie Mellon University.
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms are permitted
   * provided that the above copyright notice and this paragraph are
   * duplicated in all such forms and that any documentation,
   * advertising materials, and other materials related to such
   * distribution and use acknowledge that the software was developed
   * by Carnegie Mellon University.  The name of the
   * University may not be used to endorse or promote products derived
   * from this software without specific prior written permission.
   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
   * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
   * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
   *
   * $Id: fsm.h,v 1.5 2009/12/31 17:08:08 goldsimon Exp $
   */
  
  #ifndef FSM_H
  #define FSM_H
  
  /*
   * LCP Packet header = Code, id, length.
   */
  #define HEADERLEN (sizeof (u_char) + sizeof (u_char) + sizeof (u_short))
  
  
  /*
   *  CP (LCP, IPCP, etc.) codes.
   */
  #define CONFREQ     1 /* Configuration Request */
  #define CONFACK     2 /* Configuration Ack */
  #define CONFNAK     3 /* Configuration Nak */
  #define CONFREJ     4 /* Configuration Reject */
  #define TERMREQ     5 /* Termination Request */
  #define TERMACK     6 /* Termination Ack */
  #define CODEREJ     7 /* Code Reject */
  
  
  /*
   * Each FSM is described by an fsm structure and fsm callbacks.
   */
  typedef struct fsm {
      int unit;                        /* Interface unit number */
      u_short protocol;                /* Data Link Layer Protocol field value */
      int state;                       /* State */
      int flags;                       /* Contains option bits */
      u_char id;                       /* Current id */
      u_char reqid;                    /* Current request id */
      u_char seen_ack;                 /* Have received valid Ack/Nak/Rej to Req */
      int timeouttime;                 /* Timeout time in milliseconds */
      int maxconfreqtransmits;         /* Maximum Configure-Request transmissions */
      int retransmits;                 /* Number of retransmissions left */
      int maxtermtransmits;            /* Maximum Terminate-Request transmissions */
      int nakloops;                    /* Number of nak loops since last ack */
      int maxnakloops;                 /* Maximum number of nak loops tolerated */
      struct fsm_callbacks* callbacks; /* Callback routines */
      char* term_reason;               /* Reason for closing protocol */
      int term_reason_len;             /* Length of term_reason */
  } fsm;
  
  
  typedef struct fsm_callbacks {
      void (*resetci)(fsm*);                            /* Reset our Configuration Information */
      int  (*cilen)(fsm*);                              /* Length of our Configuration Information */
      void (*addci)(fsm*, u_char*, int*);               /* Add our Configuration Information */
      int  (*ackci)(fsm*, u_char*, int);                /* ACK our Configuration Information */
      int  (*nakci)(fsm*, u_char*, int);                /* NAK our Configuration Information */
      int  (*rejci)(fsm*, u_char*, int);                /* Reject our Configuration Information */
      int  (*reqci)(fsm*, u_char*, int*, int);          /* Request peer's Configuration Information */
      void (*up)(fsm*);                                 /* Called when fsm reaches LS_OPENED state */
      void (*down)(fsm*);                               /* Called when fsm leaves LS_OPENED state */
      void (*starting)(fsm*);                           /* Called when we want the lower layer */
      void (*finished)(fsm*);                           /* Called when we don't want the lower layer */
      void (*protreject)(int);                          /* Called when Protocol-Reject received */
      void (*retransmit)(fsm*);                         /* Retransmission is necessary */
      int  (*extcode)(fsm*, int, u_char, u_char*, int); /* Called when unknown code received */
      char *proto_name;                                 /* String name for protocol (for messages) */
  } fsm_callbacks;
  
  
  /*
   * Link states.
   */
  #define LS_INITIAL  0 /* Down, hasn't been opened */
  #define LS_STARTING 1 /* Down, been opened */
  #define LS_CLOSED   2 /* Up, hasn't been opened */
  #define LS_STOPPED  3 /* Open, waiting for down event */
  #define LS_CLOSING  4 /* Terminating the connection, not open */
  #define LS_STOPPING 5 /* Terminating, but open */
  #define LS_REQSENT  6 /* We've sent a Config Request */
  #define LS_ACKRCVD  7 /* We've received a Config Ack */
  #define LS_ACKSENT  8 /* We've sent a Config Ack */
  #define LS_OPENED   9 /* Connection available */
  
  /*
   * Flags - indicate options controlling FSM operation
   */
  #define OPT_PASSIVE 1 /* Don't die if we don't get a response */
  #define OPT_RESTART 2 /* Treat 2nd OPEN as DOWN, UP */
  #define OPT_SILENT  4 /* Wait for peer to speak first */
  
  
  /*
   * Prototypes
   */
  void fsm_init (fsm*);
  void fsm_lowerup (fsm*);
  void fsm_lowerdown (fsm*);
  void fsm_open (fsm*);
  void fsm_close (fsm*, char*);
  void fsm_input (fsm*, u_char*, int);
  void fsm_protreject (fsm*);
  void fsm_sdata (fsm*, u_char, u_char, u_char*, int);
  
  
  /*
   * Variables
   */
  extern int peer_mru[]; /* currently negotiated peer MRU (per unit) */
  
  #endif /* FSM_H */
  