fsm.h

/*
 * 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.
 *
 * $Id$
 */

/*
 * Packet header = Code, id, length.
 */
#define HEADERLEN   4


/*
 *  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 */
    int 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)     /* Reset our Configuration Information */
        (fsm *);
    int  (*cilen)       /* Length of our Configuration Information */
        (fsm *);
    void (*addci)       /* Add our Configuration Information */
        (fsm *, u_char *, int *);
    int  (*ackci)       /* ACK our Configuration Information */
        (fsm *, u_char *, int);
    int  (*nakci)       /* NAK our Configuration Information */
        (fsm *, u_char *, int);
    int  (*rejci)       /* Reject our Configuration Information */
        (fsm *, u_char *, int);
    int  (*reqci)       /* Request peer's Configuration Information */
        (fsm *, u_char *, int *, int);
    void (*up)          /* Called when fsm reaches OPENED state */
        (fsm *);
    void (*down)        /* Called when fsm leaves OPENED state */
        (fsm *);
    void (*starting)        /* Called when we want the lower layer */
        (fsm *);
    void (*finished)        /* Called when we don't want the lower layer */
        (fsm *);
    void (*protreject)      /* Called when Protocol-Reject received */
        (int);
    void (*retransmit)      /* Retransmission is necessary */
        (fsm *);
    int  (*extcode)     /* Called when unknown code received */
        (fsm *, int, int, u_char *, int);
    char *proto_name;       /* String name for protocol (for messages) */
} fsm_callbacks;


/*
 * Link states.
 */
#define INITIAL     0   /* Down, hasn't been opened */
#define STARTING    1   /* Down, been opened */
#define CLOSED      2   /* Up, hasn't been opened */
#define STOPPED     3   /* Open, waiting for down event */
#define CLOSING     4   /* Terminating the connection, not open */
#define STOPPING    5   /* Terminating, but open */
#define REQSENT     6   /* We've sent a Config Request */
#define ACKRCVD     7   /* We've received a Config Ack */
#define ACKSENT     8   /* We've sent a Config Ack */
#define 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 */


/*
 * Timeouts.
 */
#define DEFTIMEOUT  5   /* Timeout time in seconds */
#define DEFMAXTERMREQS  2   /* Maximum Terminate-Request transmissions */
#define DEFMAXCONFREQS  10  /* Maximum Configure-Request transmissions */
#define DEFMAXNAKLOOPS  5   /* Maximum number of nak loops */


/*
 * 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) */