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 1.5 1994/09/21 06:47:37 paulus Exp $";
26 * Randomize fsm id on link/init.
27 * Deal with variable outgoing MTU.
31 #include <sys/types.h>
37 extern char *proto_name();
39 static void fsm_timeout __P((caddr_t));
40 static void fsm_rconfreq __P((fsm *, int, u_char *, int));
41 static void fsm_rconfack __P((fsm *, int, u_char *, int));
42 static void fsm_rconfnakrej __P((fsm *, int, int, u_char *, int));
43 static void fsm_rtermreq __P((fsm *, int));
44 static void fsm_rtermack __P((fsm *));
45 static void fsm_rcoderej __P((fsm *, u_char *, int));
46 static void fsm_sconfreq __P((fsm *, int));
48 #define PROTO_NAME(f) ((f)->callbacks->proto_name)
54 * fsm_init - Initialize fsm.
56 * Initialize fsm state.
64 f->id = 0; /* XXX Start with random id? */
65 f->timeouttime = DEFTIMEOUT;
66 f->maxconfreqtransmits = DEFMAXCONFREQS;
67 f->maxtermtransmits = DEFMAXTERMREQS;
68 f->maxnakloops = DEFMAXNAKLOOPS;
73 * fsm_lowerup - The lower layer is up.
85 if( f->flags & OPT_SILENT )
88 /* Send an initial configure-request */
95 FSMDEBUG((LOG_INFO, "%s: Up event in state %d!",
96 PROTO_NAME(f), f->state));
102 * fsm_lowerdown - The lower layer is down.
104 * Cancel all timeouts and inform upper layers.
117 if( f->callbacks->starting )
118 (*f->callbacks->starting)(f);
123 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
131 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
135 if( f->callbacks->down )
136 (*f->callbacks->down)(f);
141 FSMDEBUG((LOG_INFO, "%s: Down event in state %d!",
142 PROTO_NAME(f), f->state));
148 * fsm_open - Link is allowed to come up.
157 if( f->callbacks->starting )
158 (*f->callbacks->starting)(f);
162 if( f->flags & OPT_SILENT )
165 /* Send an initial configure-request */
176 if( f->flags & OPT_RESTART ){
186 * fsm_close - Start closing connection.
188 * Cancel timeouts and either initiate close or possibly go directly to
210 if( f->state != OPENED )
211 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
212 else if( f->callbacks->down )
213 (*f->callbacks->down)(f); /* Inform upper layers we're down */
215 /* Init restart counter, send Terminate-Request */
216 f->retransmits = f->maxtermtransmits;
217 fsm_sdata(f, TERMREQ, f->reqid = ++f->id, NULL, 0);
218 TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
228 * fsm_timeout - Timeout expired.
234 fsm *f = (fsm *) arg;
239 if( f->retransmits <= 0 ){
241 * We've waited for an ack long enough. Peer probably heard us.
243 f->state = (f->state == CLOSING)? CLOSED: STOPPED;
244 if( f->callbacks->finished )
245 (*f->callbacks->finished)(f);
247 /* Send Terminate-Request */
248 fsm_sdata(f, TERMREQ, f->reqid = ++f->id, NULL, 0);
249 TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
257 if (f->retransmits <= 0) {
258 syslog(LOG_WARNING, "%s: timeout sending Config-Requests",
261 if( (f->flags & OPT_PASSIVE) == 0 && f->callbacks->finished )
262 (*f->callbacks->finished)(f);
265 /* Retransmit the configure-request */
266 if (f->callbacks->retransmit)
267 (*f->callbacks->retransmit)(f);
268 fsm_sconfreq(f, 1); /* Re-send Configure-Request */
269 if( f->state == ACKRCVD )
275 FSMDEBUG((LOG_INFO, "%s: Timeout event in state %d!",
276 PROTO_NAME(f), f->state));
282 * fsm_input - Input packet.
285 fsm_input(f, inpacket, l)
295 * Parse header (code, id and length).
296 * If packet too short, drop it.
300 FSMDEBUG((LOG_WARNING, "fsm_input(%x): Rcvd short header.",
307 if (len < HEADERLEN) {
308 FSMDEBUG((LOG_INFO, "fsm_input(%x): Rcvd illegal length.",
313 FSMDEBUG((LOG_INFO, "fsm_input(%x): Rcvd short packet.",
317 len -= HEADERLEN; /* subtract header length */
319 if( f->state == INITIAL || f->state == STARTING ){
320 FSMDEBUG((LOG_INFO, "fsm_input(%x): Rcvd packet in state %d.",
321 f->protocol, f->state));
326 * Action depends on code.
330 fsm_rconfreq(f, id, inp, len);
334 fsm_rconfack(f, id, inp, len);
339 fsm_rconfnakrej(f, code, id, inp, len);
351 fsm_rcoderej(f, inp, len);
355 if( !f->callbacks->extcode
356 || !(*f->callbacks->extcode)(f, code, id, inp, len) )
357 fsm_sdata(f, CODEREJ, ++f->id, inpacket, len + HEADERLEN);
364 * fsm_rconfreq - Receive Configure-Request.
367 fsm_rconfreq(f, id, inp, len)
374 int code, reject_if_disagree;
376 FSMDEBUG((LOG_INFO, "fsm_rconfreq(%s): Rcvd id %d.", PROTO_NAME(f), id));
379 /* Go away, we're closed */
380 fsm_sdata(f, TERMACK, id, NULL, 0);
387 /* Go down and restart negotiation */
388 if( f->callbacks->down )
389 (*f->callbacks->down)(f); /* Inform upper layers */
390 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
394 /* Negotiation started by our peer */
395 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
401 * Pass the requested configuration options
402 * to protocol-specific code for checking.
404 if (f->callbacks->reqci){ /* Check CI */
405 reject_if_disagree = (f->nakloops >= f->maxnakloops);
406 code = (*f->callbacks->reqci)(f, inp, &len, reject_if_disagree);
408 code = CONFREJ; /* Reject all CI */
412 /* send the Ack, Nak or Rej to the peer */
413 fsm_sdata(f, code, id, inp, len);
415 if (code == CONFACK) {
416 if (f->state == ACKRCVD) {
417 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
419 if (f->callbacks->up)
420 (*f->callbacks->up)(f); /* Inform upper layers */
426 /* we sent CONFACK or CONFREJ */
427 if (f->state != ACKRCVD)
429 if( code == CONFNAK )
436 * fsm_rconfack - Receive Configure-Ack.
439 fsm_rconfack(f, id, inp, len)
445 FSMDEBUG((LOG_INFO, "fsm_rconfack(%s): Rcvd id %d.",
448 if (id != f->reqid || f->seen_ack) /* Expected id? */
449 return; /* Nope, toss... */
450 if( !(f->callbacks->ackci? (*f->callbacks->ackci)(f, inp, len):
452 /* Ack is bad - ignore it */
453 FSMDEBUG((LOG_INFO, "%s: received bad Ack (length %d)",
454 PROTO_NAME(f), len));
462 fsm_sdata(f, TERMACK, id, NULL, 0);
467 f->retransmits = f->maxconfreqtransmits;
471 /* Huh? an extra valid Ack? oh well... */
477 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
479 f->retransmits = f->maxconfreqtransmits;
480 if (f->callbacks->up)
481 (*f->callbacks->up)(f); /* Inform upper layers */
485 /* Go down and restart negotiation */
486 if (f->callbacks->down)
487 (*f->callbacks->down)(f); /* Inform upper layers */
488 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
496 * fsm_rconfnakrej - Receive Configure-Nak or Configure-Reject.
499 fsm_rconfnakrej(f, code, id, inp, len)
507 FSMDEBUG((LOG_INFO, "fsm_rconfnakrej(%s): Rcvd id %d.",
510 if (id != f->reqid || f->seen_ack) /* Expected id? */
511 return; /* Nope, toss... */
512 proc = (code == CONFNAK)? f->callbacks->nakci: f->callbacks->rejci;
513 if (!proc || !proc(f, inp, len)) {
514 /* Nak/reject is bad - ignore it */
515 FSMDEBUG((LOG_INFO, "%s: received bad %s (length %d)",
516 PROTO_NAME(f), (code==CONFNAK? "Nak": "reject"), len));
524 fsm_sdata(f, TERMACK, id, NULL, 0);
529 /* They didn't agree to what we wanted - try another request */
530 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
531 fsm_sconfreq(f, 0); /* Send Configure-Request */
535 /* Got a Nak/reject when we had already had an Ack?? oh well... */
541 /* Go down and restart negotiation */
542 if (f->callbacks->down)
543 (*f->callbacks->down)(f); /* Inform upper layers */
544 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
552 * fsm_rtermreq - Receive Terminate-Req.
559 FSMDEBUG((LOG_INFO, "fsm_rtermreq(%s): Rcvd id %d.",
565 f->state = REQSENT; /* Start over but keep trying */
569 syslog(LOG_INFO, "%s terminated at peer's request", PROTO_NAME(f));
570 if (f->callbacks->down)
571 (*f->callbacks->down)(f); /* Inform upper layers */
574 TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
578 fsm_sdata(f, TERMACK, id, NULL, 0);
583 * fsm_rtermack - Receive Terminate-Ack.
589 FSMDEBUG((LOG_INFO, "fsm_rtermack(%s).", PROTO_NAME(f)));
594 if( f->callbacks->finished )
595 (*f->callbacks->finished)(f);
599 if( f->callbacks->finished )
600 (*f->callbacks->finished)(f);
608 if (f->callbacks->down)
609 (*f->callbacks->down)(f); /* Inform upper layers */
617 * fsm_rcoderej - Receive an Code-Reject.
620 fsm_rcoderej(f, inp, len)
627 FSMDEBUG((LOG_INFO, "fsm_rcoderej(%s).", PROTO_NAME(f)));
629 if (len < HEADERLEN) {
630 FSMDEBUG((LOG_INFO, "fsm_rcoderej: Rcvd short Code-Reject packet!"));
635 syslog(LOG_WARNING, "%s: Rcvd Code-Reject for code %d, id %d",
636 PROTO_NAME(f), code, id);
638 if( f->state == ACKRCVD )
644 * fsm_protreject - Peer doesn't speak this protocol.
646 * Treat this as a catastrophic error (RXJ-).
654 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
658 if( f->callbacks->finished )
659 (*f->callbacks->finished)(f);
666 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
670 if( f->callbacks->finished )
671 (*f->callbacks->finished)(f);
675 if( f->callbacks->down )
676 (*f->callbacks->down)(f);
678 /* Init restart counter, send Terminate-Request */
679 f->retransmits = f->maxtermtransmits;
680 fsm_sdata(f, TERMREQ, f->reqid = ++f->id, NULL, 0);
681 TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
688 FSMDEBUG((LOG_INFO, "%s: Protocol-reject event in state %d!",
689 PROTO_NAME(f), f->state));
695 * fsm_sconfreq - Send a Configure-Request.
698 fsm_sconfreq(f, retransmit)
705 if( f->state != REQSENT && f->state != ACKRCVD && f->state != ACKSENT ){
706 /* Not currently negotiating - reset options */
707 if( f->callbacks->resetci )
708 (*f->callbacks->resetci)(f);
713 /* New request - reset retransmission counter, use new ID */
714 f->retransmits = f->maxconfreqtransmits;
721 * Make up the request packet
723 outp = outpacket_buf + PPP_HDRLEN + HEADERLEN;
724 if( f->callbacks->cilen && f->callbacks->addci ){
725 cilen = (*f->callbacks->cilen)(f);
726 if( cilen > peer_mru[f->unit] - HEADERLEN )
727 cilen = peer_mru[f->unit] - HEADERLEN;
728 if (f->callbacks->addci)
729 (*f->callbacks->addci)(f, outp, &cilen);
733 /* send the request to our peer */
734 fsm_sdata(f, CONFREQ, f->reqid, outp, cilen);
736 /* start the retransmit timer */
738 TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
740 FSMDEBUG((LOG_INFO, "%s: sending Configure-Request, id %d",
741 PROTO_NAME(f), f->reqid));
746 * fsm_sdata - Send some data.
748 * Used for all packets sent to our peer by this module.
751 fsm_sdata(f, code, id, data, datalen)
760 /* Adjust length to be smaller than MTU */
761 outp = outpacket_buf;
762 if (datalen > peer_mru[f->unit] - HEADERLEN)
763 datalen = peer_mru[f->unit] - HEADERLEN;
764 if (datalen && data != outp + PPP_HDRLEN + HEADERLEN)
765 BCOPY(data, outp + PPP_HDRLEN + HEADERLEN, datalen);
766 outlen = datalen + HEADERLEN;
767 MAKEHEADER(outp, f->protocol);
770 PUTSHORT(outlen, outp);
771 output(f->unit, outpacket_buf, outlen + PPP_HDRLEN);
773 FSMDEBUG((LOG_INFO, "fsm_sdata(%s): Sent code %d, id %d.",
774 PROTO_NAME(f), code, id));