2 * fsm.c - {Link, IP} Control Protocol Finite State Machine.
4 * Copyright (c) 1989 Carnegie Mellon University.
7 * Redistribution and use in source and binary forms are permitted
8 * provided that the above copyright notice and this paragraph are
9 * duplicated in all such forms and that any documentation,
10 * advertising materials, and other materials related to such
11 * distribution and use acknowledge that the software was developed
12 * by Carnegie Mellon University. The name of the
13 * University may not be used to endorse or promote products derived
14 * from this software without specific prior written permission.
15 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
17 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
21 static char rcsid[] = "$Id: fsm.c,v 1.11 1996/04/04 03:37:01 paulus Exp $";
26 * Randomize fsm id on link/init.
27 * Deal with variable outgoing MTU.
32 #include <sys/types.h>
38 extern char *proto_name();
40 static void fsm_timeout __P((caddr_t));
41 static void fsm_rconfreq __P((fsm *, int, u_char *, int));
42 static void fsm_rconfack __P((fsm *, int, u_char *, int));
43 static void fsm_rconfnakrej __P((fsm *, int, int, u_char *, int));
44 static void fsm_rtermreq __P((fsm *, int));
45 static void fsm_rtermack __P((fsm *));
46 static void fsm_rcoderej __P((fsm *, u_char *, int));
47 static void fsm_sconfreq __P((fsm *, int));
49 #define PROTO_NAME(f) ((f)->callbacks->proto_name)
51 int peer_mru[NUM_PPP];
55 * fsm_init - Initialize fsm.
57 * Initialize fsm state.
65 f->id = 0; /* XXX Start with random id? */
66 f->timeouttime = DEFTIMEOUT;
67 f->maxconfreqtransmits = DEFMAXCONFREQS;
68 f->maxtermtransmits = DEFMAXTERMREQS;
69 f->maxnakloops = DEFMAXNAKLOOPS;
70 f->term_reason_len = 0;
75 * fsm_lowerup - The lower layer is up.
87 if( f->flags & OPT_SILENT )
90 /* Send an initial configure-request */
97 FSMDEBUG((LOG_INFO, "%s: Up event in state %d!",
98 PROTO_NAME(f), f->state));
104 * fsm_lowerdown - The lower layer is down.
106 * Cancel all timeouts and inform upper layers.
119 if( f->callbacks->starting )
120 (*f->callbacks->starting)(f);
125 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
133 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
137 if( f->callbacks->down )
138 (*f->callbacks->down)(f);
143 FSMDEBUG((LOG_INFO, "%s: Down event in state %d!",
144 PROTO_NAME(f), f->state));
150 * fsm_open - Link is allowed to come up.
159 if( f->callbacks->starting )
160 (*f->callbacks->starting)(f);
164 if( f->flags & OPT_SILENT )
167 /* Send an initial configure-request */
178 if( f->flags & OPT_RESTART ){
188 * fsm_close - Start closing connection.
190 * Cancel timeouts and either initiate close or possibly go directly to
198 f->term_reason = reason;
199 f->term_reason_len = (reason == NULL? 0: strlen(reason));
215 if( f->state != OPENED )
216 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
217 else if( f->callbacks->down )
218 (*f->callbacks->down)(f); /* Inform upper layers we're down */
220 /* Init restart counter, send Terminate-Request */
221 f->retransmits = f->maxtermtransmits;
222 fsm_sdata(f, TERMREQ, f->reqid = ++f->id,
223 (u_char *) f->term_reason, f->term_reason_len);
224 TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
234 * fsm_timeout - Timeout expired.
240 fsm *f = (fsm *) arg;
245 if( f->retransmits <= 0 ){
247 * We've waited for an ack long enough. Peer probably heard us.
249 f->state = (f->state == CLOSING)? CLOSED: STOPPED;
250 if( f->callbacks->finished )
251 (*f->callbacks->finished)(f);
253 /* Send Terminate-Request */
254 fsm_sdata(f, TERMREQ, f->reqid = ++f->id,
255 (u_char *) f->term_reason, f->term_reason_len);
256 TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
264 if (f->retransmits <= 0) {
265 syslog(LOG_WARNING, "%s: timeout sending Config-Requests",
268 if( (f->flags & OPT_PASSIVE) == 0 && f->callbacks->finished )
269 (*f->callbacks->finished)(f);
272 /* Retransmit the configure-request */
273 if (f->callbacks->retransmit)
274 (*f->callbacks->retransmit)(f);
275 fsm_sconfreq(f, 1); /* Re-send Configure-Request */
276 if( f->state == ACKRCVD )
282 FSMDEBUG((LOG_INFO, "%s: Timeout event in state %d!",
283 PROTO_NAME(f), f->state));
289 * fsm_input - Input packet.
292 fsm_input(f, inpacket, l)
302 * Parse header (code, id and length).
303 * If packet too short, drop it.
307 FSMDEBUG((LOG_WARNING, "fsm_input(%x): Rcvd short header.",
314 if (len < HEADERLEN) {
315 FSMDEBUG((LOG_INFO, "fsm_input(%x): Rcvd illegal length.",
320 FSMDEBUG((LOG_INFO, "fsm_input(%x): Rcvd short packet.",
324 len -= HEADERLEN; /* subtract header length */
326 if( f->state == INITIAL || f->state == STARTING ){
327 FSMDEBUG((LOG_INFO, "fsm_input(%x): Rcvd packet in state %d.",
328 f->protocol, f->state));
333 * Action depends on code.
337 fsm_rconfreq(f, id, inp, len);
341 fsm_rconfack(f, id, inp, len);
346 fsm_rconfnakrej(f, code, id, inp, len);
358 fsm_rcoderej(f, inp, len);
362 if( !f->callbacks->extcode
363 || !(*f->callbacks->extcode)(f, code, id, inp, len) )
364 fsm_sdata(f, CODEREJ, ++f->id, inpacket, len + HEADERLEN);
371 * fsm_rconfreq - Receive Configure-Request.
374 fsm_rconfreq(f, id, inp, len)
380 int code, reject_if_disagree;
382 FSMDEBUG((LOG_INFO, "fsm_rconfreq(%s): Rcvd id %d.", PROTO_NAME(f), id));
385 /* Go away, we're closed */
386 fsm_sdata(f, TERMACK, id, NULL, 0);
393 /* Go down and restart negotiation */
394 if( f->callbacks->down )
395 (*f->callbacks->down)(f); /* Inform upper layers */
396 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
400 /* Negotiation started by our peer */
401 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
407 * Pass the requested configuration options
408 * to protocol-specific code for checking.
410 if (f->callbacks->reqci){ /* Check CI */
411 reject_if_disagree = (f->nakloops >= f->maxnakloops);
412 code = (*f->callbacks->reqci)(f, inp, &len, reject_if_disagree);
414 code = CONFREJ; /* Reject all CI */
418 /* send the Ack, Nak or Rej to the peer */
419 fsm_sdata(f, code, id, inp, len);
421 if (code == CONFACK) {
422 if (f->state == ACKRCVD) {
423 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
425 if (f->callbacks->up)
426 (*f->callbacks->up)(f); /* Inform upper layers */
432 /* we sent CONFACK or CONFREJ */
433 if (f->state != ACKRCVD)
435 if( code == CONFNAK )
442 * fsm_rconfack - Receive Configure-Ack.
445 fsm_rconfack(f, id, inp, len)
451 FSMDEBUG((LOG_INFO, "fsm_rconfack(%s): Rcvd id %d.",
454 if (id != f->reqid || f->seen_ack) /* Expected id? */
455 return; /* Nope, toss... */
456 if( !(f->callbacks->ackci? (*f->callbacks->ackci)(f, inp, len):
458 /* Ack is bad - ignore it */
459 FSMDEBUG((LOG_INFO, "%s: received bad Ack (length %d)",
460 PROTO_NAME(f), len));
468 fsm_sdata(f, TERMACK, id, NULL, 0);
473 f->retransmits = f->maxconfreqtransmits;
477 /* Huh? an extra valid Ack? oh well... */
478 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
484 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
486 f->retransmits = f->maxconfreqtransmits;
487 if (f->callbacks->up)
488 (*f->callbacks->up)(f); /* Inform upper layers */
492 /* Go down and restart negotiation */
493 if (f->callbacks->down)
494 (*f->callbacks->down)(f); /* Inform upper layers */
495 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
503 * fsm_rconfnakrej - Receive Configure-Nak or Configure-Reject.
506 fsm_rconfnakrej(f, code, id, inp, len)
515 FSMDEBUG((LOG_INFO, "fsm_rconfnakrej(%s): Rcvd id %d.",
518 if (id != f->reqid || f->seen_ack) /* Expected id? */
519 return; /* Nope, toss... */
520 proc = (code == CONFNAK)? f->callbacks->nakci: f->callbacks->rejci;
521 if (!proc || !(ret = proc(f, inp, len))) {
522 /* Nak/reject is bad - ignore it */
523 FSMDEBUG((LOG_INFO, "%s: received bad %s (length %d)",
524 PROTO_NAME(f), (code==CONFNAK? "Nak": "reject"), len));
532 fsm_sdata(f, TERMACK, id, NULL, 0);
537 /* They didn't agree to what we wanted - try another request */
538 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
540 f->state = STOPPED; /* kludge for stopping CCP */
542 fsm_sconfreq(f, 0); /* Send Configure-Request */
546 /* Got a Nak/reject when we had already had an Ack?? oh well... */
547 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
553 /* Go down and restart negotiation */
554 if (f->callbacks->down)
555 (*f->callbacks->down)(f); /* Inform upper layers */
556 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
564 * fsm_rtermreq - Receive Terminate-Req.
571 FSMDEBUG((LOG_INFO, "fsm_rtermreq(%s): Rcvd id %d.",
577 f->state = REQSENT; /* Start over but keep trying */
581 syslog(LOG_INFO, "%s terminated at peer's request", PROTO_NAME(f));
582 if (f->callbacks->down)
583 (*f->callbacks->down)(f); /* Inform upper layers */
586 TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
590 fsm_sdata(f, TERMACK, id, NULL, 0);
595 * fsm_rtermack - Receive Terminate-Ack.
601 FSMDEBUG((LOG_INFO, "fsm_rtermack(%s).", PROTO_NAME(f)));
605 UNTIMEOUT(fsm_timeout, (caddr_t) f);
607 if( f->callbacks->finished )
608 (*f->callbacks->finished)(f);
611 UNTIMEOUT(fsm_timeout, (caddr_t) f);
613 if( f->callbacks->finished )
614 (*f->callbacks->finished)(f);
622 if (f->callbacks->down)
623 (*f->callbacks->down)(f); /* Inform upper layers */
631 * fsm_rcoderej - Receive an Code-Reject.
634 fsm_rcoderej(f, inp, len)
641 FSMDEBUG((LOG_INFO, "fsm_rcoderej(%s).", PROTO_NAME(f)));
643 if (len < HEADERLEN) {
644 FSMDEBUG((LOG_INFO, "fsm_rcoderej: Rcvd short Code-Reject packet!"));
649 syslog(LOG_WARNING, "%s: Rcvd Code-Reject for code %d, id %d",
650 PROTO_NAME(f), code, id);
652 if( f->state == ACKRCVD )
658 * fsm_protreject - Peer doesn't speak this protocol.
660 * Treat this as a catastrophic error (RXJ-).
668 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
672 if( f->callbacks->finished )
673 (*f->callbacks->finished)(f);
680 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
684 if( f->callbacks->finished )
685 (*f->callbacks->finished)(f);
689 if( f->callbacks->down )
690 (*f->callbacks->down)(f);
692 /* Init restart counter, send Terminate-Request */
693 f->retransmits = f->maxtermtransmits;
694 fsm_sdata(f, TERMREQ, f->reqid = ++f->id,
695 (u_char *) f->term_reason, f->term_reason_len);
696 TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
703 FSMDEBUG((LOG_INFO, "%s: Protocol-reject event in state %d!",
704 PROTO_NAME(f), f->state));
710 * fsm_sconfreq - Send a Configure-Request.
713 fsm_sconfreq(f, retransmit)
720 if( f->state != REQSENT && f->state != ACKRCVD && f->state != ACKSENT ){
721 /* Not currently negotiating - reset options */
722 if( f->callbacks->resetci )
723 (*f->callbacks->resetci)(f);
728 /* New request - reset retransmission counter, use new ID */
729 f->retransmits = f->maxconfreqtransmits;
736 * Make up the request packet
738 outp = outpacket_buf + PPP_HDRLEN + HEADERLEN;
739 if( f->callbacks->cilen && f->callbacks->addci ){
740 cilen = (*f->callbacks->cilen)(f);
741 if( cilen > peer_mru[f->unit] - HEADERLEN )
742 cilen = peer_mru[f->unit] - HEADERLEN;
743 if (f->callbacks->addci)
744 (*f->callbacks->addci)(f, outp, &cilen);
748 /* send the request to our peer */
749 fsm_sdata(f, CONFREQ, f->reqid, outp, cilen);
751 /* start the retransmit timer */
753 TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
755 FSMDEBUG((LOG_INFO, "%s: sending Configure-Request, id %d",
756 PROTO_NAME(f), f->reqid));
761 * fsm_sdata - Send some data.
763 * Used for all packets sent to our peer by this module.
766 fsm_sdata(f, code, id, data, datalen)
775 /* Adjust length to be smaller than MTU */
776 outp = outpacket_buf;
777 if (datalen > peer_mru[f->unit] - HEADERLEN)
778 datalen = peer_mru[f->unit] - HEADERLEN;
779 if (datalen && data != outp + PPP_HDRLEN + HEADERLEN)
780 BCOPY(data, outp + PPP_HDRLEN + HEADERLEN, datalen);
781 outlen = datalen + HEADERLEN;
782 MAKEHEADER(outp, f->protocol);
785 PUTSHORT(outlen, outp);
786 output(f->unit, outpacket_buf, outlen + PPP_HDRLEN);
788 FSMDEBUG((LOG_INFO, "fsm_sdata(%s): Sent code %d, id %d.",
789 PROTO_NAME(f), code, id));