1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 1996 - 2001 Brian Somers <brian@Awfulhak.org>
5 *          based on work by Toshiharu OHNO <tony-o@iij.ad.jp>
6 *                           Internet Initiative Japan, Inc (IIJ)
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 *
30 * $FreeBSD$
31 */
32
33/*
34 *  State of machine
35 */
36#define	ST_INITIAL	0
37#define	ST_STARTING	1
38#define	ST_CLOSED	2
39#define	ST_STOPPED	3
40#define	ST_CLOSING	4
41#define	ST_STOPPING	5
42#define	ST_REQSENT	6
43#define	ST_ACKRCVD	7
44#define	ST_ACKSENT	8
45#define	ST_OPENED	9
46
47#define	ST_MAX		10
48#define	ST_UNDEF	-1
49
50#define	MODE_REQ	0
51#define	MODE_NAK	1
52#define	MODE_REJ	2
53#define	MODE_NOP	3
54#define	MODE_ACK	4	/* pseudo mode for ccp negotiations */
55
56#define	OPEN_PASSIVE	-1
57
58#define FSM_REQ_TIMER	1
59#define FSM_TRM_TIMER	2
60
61#define FSM_OPTLEN	100
62
63struct fsm;
64
65struct fsm_retry {
66  u_int timeout;                             /* FSM retry frequency */
67  u_int maxreq;                              /* Max Config REQ retries */
68  u_int maxtrm;                              /* Max Term REQ retries */
69};
70
71struct fsm_decode {
72  u_char ack[FSM_OPTLEN], *ackend;
73  u_char nak[FSM_OPTLEN], *nakend;
74  u_char rej[FSM_OPTLEN], *rejend;
75};
76
77struct fsm_callbacks {
78  int (*LayerUp)(struct fsm *);                 /* Layer is now up (tlu) */
79  void (*LayerDown)(struct fsm *);              /* About to come down (tld) */
80  void (*LayerStart)(struct fsm *);             /* Layer about to start (tls) */
81  void (*LayerFinish)(struct fsm *);            /* Layer now down (tlf) */
82  void (*InitRestartCounter)(struct fsm *, int);/* Set fsm timer load */
83  void (*SendConfigReq)(struct fsm *);          /* Send REQ please */
84  void (*SentTerminateReq)(struct fsm *);       /* Term REQ just sent */
85  void (*SendTerminateAck)(struct fsm *, u_char); /* Send Term ACK please */
86  void (*DecodeConfig)(struct fsm *, u_char *, u_char *, int,
87                       struct fsm_decode *);    /* Deal with incoming data */
88  int (*RecvResetReq)(struct fsm *fp);          /* Reset output */
89  void (*RecvResetAck)(struct fsm *fp, u_char); /* Reset input */
90};
91
92struct fsm_parent {
93  void (*LayerStart) (void *, struct fsm *);         /* tls */
94  void (*LayerUp) (void *, struct fsm *);            /* tlu */
95  void (*LayerDown) (void *, struct fsm *);          /* tld */
96  void (*LayerFinish) (void *, struct fsm *);        /* tlf */
97  void *object;
98};
99
100struct link;
101struct bundle;
102
103struct fsm {
104  const char *name;		/* Name of protocol */
105  u_short proto;		/* Protocol number */
106  u_short min_code;
107  u_short max_code;
108  int open_mode;		/* Delay before config REQ (-1 forever) */
109  unsigned state;		/* State of the machine */
110  u_char reqid;			/* Next request id */
111  int restart;			/* Restart counter value */
112
113  struct {
114    int reqs;			/* Max config REQs before a close() */
115    int naks;			/* Max config NAKs before a close() */
116    int rejs;			/* Max config REJs before a close() */
117  } more;
118
119  struct pppTimer FsmTimer;	/* Restart Timer */
120  struct pppTimer OpenTimer;	/* Delay before opening */
121
122  /*
123   * This timer times the ST_STOPPED state out after the given value
124   * (specified via "set stopped ...").  Although this isn't specified in the
125   * rfc, the rfc *does* say that "the application may use higher level
126   * timers to avoid deadlock". The StoppedTimer takes effect when the other
127   * side ABENDs rather than going into ST_ACKSENT (and sending the ACK),
128   * causing ppp to time out and drop into ST_STOPPED.  At this point,
129   * nothing will change this state :-(
130   */
131  struct pppTimer StoppedTimer;
132  int LogLevel;
133
134  /* The link layer active with this FSM (may be our bundle below) */
135  struct link *link;
136
137  /* Our high-level link */
138  struct bundle *bundle;
139
140  const struct fsm_parent *parent;
141  const struct fsm_callbacks *fn;
142};
143
144struct fsmheader {
145  u_char code;			/* Request code */
146  u_char id;			/* Identification */
147  u_short length;		/* Length of packet */
148};
149
150#define	CODE_CONFIGREQ	1
151#define	CODE_CONFIGACK	2
152#define	CODE_CONFIGNAK	3
153#define	CODE_CONFIGREJ	4
154#define	CODE_TERMREQ	5
155#define	CODE_TERMACK	6
156#define	CODE_CODEREJ	7
157#define	CODE_PROTOREJ	8
158#define	CODE_ECHOREQ	9	/* Used in LCP */
159#define	CODE_ECHOREP	10	/* Used in LCP */
160#define	CODE_DISCREQ	11
161#define	CODE_IDENT	12	/* Used in LCP Extension */
162#define	CODE_TIMEREM	13	/* Used in LCP Extension */
163#define	CODE_RESETREQ	14	/* Used in CCP */
164#define	CODE_RESETACK	15	/* Used in CCP */
165
166struct fsm_opt_hdr {
167  u_char id;
168  u_char len;
169} __packed;
170
171#define MAX_FSM_OPT_LEN 52
172struct fsm_opt {
173  struct fsm_opt_hdr hdr;
174  u_char data[MAX_FSM_OPT_LEN-2];
175};
176
177#define INC_FSM_OPT(ty, length, o)                      \
178  do {                                                  \
179    (o)->hdr.id = (ty);                                 \
180    (o)->hdr.len = (length);                            \
181    (o) = (struct fsm_opt *)((u_char *)(o) + (length)); \
182  } while (0)
183
184
185extern void fsm_Init(struct fsm *, const char *, u_short, int, int, int,
186                     struct bundle *, struct link *, const  struct fsm_parent *,
187                     struct fsm_callbacks *, const char * const [3]);
188extern void fsm_Output(struct fsm *, u_int, u_int, u_char *, unsigned, int);
189extern void fsm_Open(struct fsm *);
190extern void fsm_Up(struct fsm *);
191extern void fsm_Down(struct fsm *);
192extern void fsm_Input(struct fsm *, struct mbuf *);
193extern void fsm_Close(struct fsm *);
194extern int fsm_NullRecvResetReq(struct fsm *);
195extern void fsm_NullRecvResetAck(struct fsm *, u_char);
196extern void fsm_Reopen(struct fsm *);
197extern void fsm2initial(struct fsm *);
198extern const char *State2Nam(u_int);
199extern struct fsm_opt *fsm_readopt(u_char **);
200extern void fsm_rej(struct fsm_decode *, const struct fsm_opt *);
201extern void fsm_ack(struct fsm_decode *, const struct fsm_opt *);
202extern void fsm_nak(struct fsm_decode *, const struct fsm_opt *);
203extern void fsm_opt_normalise(struct fsm_decode *);
204