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      1 /*	$NetBSD: fsm.h,v 1.6 2025/01/08 19:59:39 christos Exp $	*/
      2 
      3 /*
      4  * fsm.h - {Link, IP} Control Protocol Finite State Machine definitions.
      5  *
      6  * Copyright (c) 1984-2000 Carnegie Mellon University. All rights reserved.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  *
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  *
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in
     17  *    the documentation and/or other materials provided with the
     18  *    distribution.
     19  *
     20  * 3. The name "Carnegie Mellon University" must not be used to
     21  *    endorse or promote products derived from this software without
     22  *    prior written permission. For permission or any legal
     23  *    details, please contact
     24  *      Office of Technology Transfer
     25  *      Carnegie Mellon University
     26  *      5000 Forbes Avenue
     27  *      Pittsburgh, PA  15213-3890
     28  *      (412) 268-4387, fax: (412) 268-7395
     29  *      tech-transfer (at) andrew.cmu.edu
     30  *
     31  * 4. Redistributions of any form whatsoever must retain the following
     32  *    acknowledgment:
     33  *    "This product includes software developed by Computing Services
     34  *     at Carnegie Mellon University (http://www.cmu.edu/computing/)."
     35  *
     36  * CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
     37  * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
     38  * AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
     39  * FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
     40  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
     41  * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
     42  * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
     43  */
     44 #ifndef PPP_FSM_H
     45 #define PPP_FSM_H
     46 
     47 #include "pppdconf.h"
     48 
     49 #ifdef __cplusplus
     50 extern "C" {
     51 #endif
     52 
     53 /*
     54  * Packet header = Code, id, length.
     55  */
     56 #define HEADERLEN	4
     57 
     58 /*
     59  *  CP (LCP, IPCP, etc.) codes.
     60  */
     61 #define CONFREQ		1	/* Configuration Request */
     62 #define CONFACK		2	/* Configuration Ack */
     63 #define CONFNAK		3	/* Configuration Nak */
     64 #define CONFREJ		4	/* Configuration Reject */
     65 #define TERMREQ		5	/* Termination Request */
     66 #define TERMACK		6	/* Termination Ack */
     67 #define CODEREJ		7	/* Code Reject */
     68 
     69 
     70 /*
     71  * Each FSM is described by an fsm structure and fsm callbacks.
     72  */
     73 typedef struct fsm {
     74     int unit;			/* Interface unit number */
     75     int protocol;		/* Data Link Layer Protocol field value */
     76     int state;			/* State */
     77     int flags;			/* Contains option bits */
     78     unsigned char id;			/* Current id */
     79     unsigned char reqid;		/* Current request id */
     80     unsigned char seen_ack;		/* Have received valid Ack/Nak/Rej to Req */
     81     int timeouttime;		/* Timeout time in milliseconds */
     82     int maxconfreqtransmits;	/* Maximum Configure-Request transmissions */
     83     int retransmits;		/* Number of retransmissions left */
     84     int maxtermtransmits;	/* Maximum Terminate-Request transmissions */
     85     int nakloops;		/* Number of nak loops since last ack */
     86     int rnakloops;		/* Number of naks received */
     87     int maxnakloops;		/* Maximum number of nak loops tolerated */
     88     struct fsm_callbacks *callbacks;	/* Callback routines */
     89     char *term_reason;		/* Reason for closing protocol */
     90     int term_reason_len;	/* Length of term_reason */
     91 } fsm;
     92 
     93 
     94 typedef struct fsm_callbacks {
     95     void (*resetci)(fsm *);	/* Reset our Configuration Information */
     96     int  (*cilen)(fsm *);	/* Length of our Configuration Information */
     97     void (*addci) 		/* Add our Configuration Information */
     98 		(fsm *, unsigned char *, int *);
     99     int  (*ackci)		/* ACK our Configuration Information */
    100 		(fsm *, unsigned char *, int);
    101     int  (*nakci)		/* NAK our Configuration Information */
    102 		(fsm *, unsigned char *, int, int);
    103     int  (*rejci)		/* Reject our Configuration Information */
    104 		(fsm *, unsigned char *, int);
    105     int  (*reqci)		/* Request peer's Configuration Information */
    106 		(fsm *, unsigned char *, int *, int);
    107     void (*up)(fsm *);		/* Called when fsm reaches OPENED state */
    108     void (*down)(fsm *);	/* Called when fsm leaves OPENED state */
    109     void (*starting)(fsm *);	/* Called when we want the lower layer */
    110     void (*finished)(fsm *);	/* Called when we don't want the lower layer */
    111     void (*protreject)(int);	/* Called when Protocol-Reject received */
    112     void (*retransmit)(fsm *);	/* Retransmission is necessary */
    113     int  (*extcode)		/* Called when unknown code received */
    114 		(fsm *, int, int, unsigned char *, int);
    115     char *proto_name;		/* String name for protocol (for messages) */
    116 } fsm_callbacks;
    117 
    118 
    119 /*
    120  * Link states.
    121  */
    122 #define INITIAL		0	/* Down, hasn't been opened */
    123 #define STARTING	1	/* Down, been opened */
    124 #define CLOSED		2	/* Up, hasn't been opened */
    125 #define STOPPED		3	/* Open, waiting for down event */
    126 #define CLOSING		4	/* Terminating the connection, not open */
    127 #define STOPPING	5	/* Terminating, but open */
    128 #define REQSENT		6	/* We've sent a Config Request */
    129 #define ACKRCVD		7	/* We've received a Config Ack */
    130 #define ACKSENT		8	/* We've sent a Config Ack */
    131 #define OPENED		9	/* Connection available */
    132 
    133 
    134 /*
    135  * Flags - indicate options controlling FSM operation
    136  */
    137 #define OPT_PASSIVE	1	/* Don't die if we don't get a response */
    138 #define OPT_RESTART	2	/* Treat 2nd OPEN as DOWN, UP */
    139 #define OPT_SILENT	4	/* Wait for peer to speak first */
    140 
    141 
    142 /*
    143  * Timeouts.
    144  */
    145 #define DEFTIMEOUT	3	/* Timeout time in seconds */
    146 #define DEFMAXTERMREQS	2	/* Maximum Terminate-Request transmissions */
    147 #define DEFMAXCONFREQS	10	/* Maximum Configure-Request transmissions */
    148 #define DEFMAXNAKLOOPS	5	/* Maximum number of nak loops */
    149 
    150 
    151 /*
    152  * Prototypes
    153  */
    154 void fsm_init (fsm *);
    155 void fsm_lowerup (fsm *);
    156 void fsm_lowerdown (fsm *);
    157 void fsm_open (fsm *);
    158 void fsm_close (fsm *, char *);
    159 void fsm_input (fsm *, unsigned char *, int);
    160 void fsm_protreject (fsm *);
    161 void fsm_sdata (fsm *, int, int, unsigned char *, int);
    162 
    163 
    164 /*
    165  * Variables
    166  */
    167 extern int peer_mru[];		/* currently negotiated peer MRU (per unit) */
    168 
    169 #ifdef __cplusplus
    170 }
    171 #endif
    172 
    173 #endif // PPP_FSM_H
    174