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 1.2 1994/04/18 04:01:50 paulus Exp $";
26 * Randomize fsm id on link/init.
27 * Deal with variable outgoing MTU.
31 #include <sys/types.h>
38 extern char *proto_name();
40 static void fsm_timeout __ARGS((caddr_t));
41 static void fsm_rconfreq __ARGS((fsm *, int, u_char *, int));
42 static void fsm_rconfack __ARGS((fsm *, int, u_char *, int));
43 static void fsm_rconfnakrej __ARGS((fsm *, int, int, u_char *, int));
44 static void fsm_rtermreq __ARGS((fsm *, int));
45 static void fsm_rtermack __ARGS((fsm *));
46 static void fsm_rcoderej __ARGS((fsm *, u_char *, int));
47 static void fsm_sconfreq __ARGS((fsm *, int));
49 #define PROTO_NAME(f) ((f)->callbacks->proto_name)
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;
74 * fsm_lowerup - The lower layer is up.
86 if( f->flags & OPT_SILENT )
89 /* Send an initial configure-request */
96 FSMDEBUG((LOG_INFO, "%s: Up event in state %d!",
97 PROTO_NAME(f), f->state));
103 * fsm_lowerdown - The lower layer is down.
105 * Cancel all timeouts and inform upper layers.
118 if( f->callbacks->starting )
119 (*f->callbacks->starting)(f);
124 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
132 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
136 if( f->callbacks->down )
137 (*f->callbacks->down)(f);
142 FSMDEBUG((LOG_INFO, "%s: Down event in state %d!",
143 PROTO_NAME(f), f->state));
149 * fsm_open - Link is allowed to come up.
158 if( f->callbacks->starting )
159 (*f->callbacks->starting)(f);
163 if( f->flags & OPT_SILENT )
166 /* Send an initial configure-request */
177 if( f->flags & OPT_RESTART ){
187 * fsm_close - Start closing connection.
189 * Cancel timeouts and either initiate close or possibly go directly to
211 if( f->state != OPENED )
212 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
213 else if( f->callbacks->down )
214 (*f->callbacks->down)(f); /* Inform upper layers we're down */
216 /* Init restart counter, send Terminate-Request */
217 f->retransmits = f->maxtermtransmits;
218 fsm_sdata(f, TERMREQ, f->reqid = ++f->id, NULL, 0);
219 TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
229 * fsm_timeout - Timeout expired.
235 fsm *f = (fsm *) arg;
240 if( f->retransmits <= 0 ){
242 * We've waited for an ack long enough. Peer probably heard us.
244 f->state = (f->state == CLOSING)? CLOSED: STOPPED;
245 if( f->callbacks->finished )
246 (*f->callbacks->finished)(f);
248 /* Send Terminate-Request */
249 fsm_sdata(f, TERMREQ, f->reqid = ++f->id, NULL, 0);
250 TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
258 if (f->retransmits <= 0) {
259 syslog(LOG_WARNING, "%s: timeout sending Config-Requests",
262 if( (f->flags & OPT_PASSIVE) == 0 && f->callbacks->finished )
263 (*f->callbacks->finished)(f);
266 /* Retransmit the configure-request */
267 if (f->callbacks->retransmit)
268 (*f->callbacks->retransmit)(f);
269 fsm_sconfreq(f, 1); /* Re-send Configure-Request */
270 if( f->state == ACKRCVD )
276 FSMDEBUG((LOG_INFO, "%s: Timeout event in state %d!",
277 PROTO_NAME(f), f->state));
283 * fsm_input - Input packet.
286 fsm_input(f, inpacket, l)
296 * Parse header (code, id and length).
297 * If packet too short, drop it.
301 FSMDEBUG((LOG_WARNING, "fsm_input(%x): Rcvd short header.",
308 if (len < HEADERLEN) {
309 FSMDEBUG((LOG_INFO, "fsm_input(%x): Rcvd illegal length.",
314 FSMDEBUG((LOG_INFO, "fsm_input(%x): Rcvd short packet.",
318 len -= HEADERLEN; /* subtract header length */
320 if( f->state == INITIAL || f->state == STARTING ){
321 FSMDEBUG((LOG_INFO, "fsm_input(%x): Rcvd packet in state %d.",
322 f->protocol, f->state));
327 * Action depends on code.
331 fsm_rconfreq(f, id, inp, len);
335 fsm_rconfack(f, id, inp, len);
340 fsm_rconfnakrej(f, code, id, inp, len);
352 fsm_rcoderej(f, inp, len);
356 if( !f->callbacks->extcode
357 || !(*f->callbacks->extcode)(f, code, id, inp, len) )
358 fsm_sdata(f, CODEREJ, ++f->id, inpacket, len + HEADERLEN);
365 * fsm_rconfreq - Receive Configure-Request.
368 fsm_rconfreq(f, id, inp, len)
375 int code, reject_if_disagree;
377 FSMDEBUG((LOG_INFO, "fsm_rconfreq(%s): Rcvd id %d.", PROTO_NAME(f), id));
380 /* Go away, we're closed */
381 fsm_sdata(f, TERMACK, id, NULL, 0);
388 /* Go down and restart negotiation */
389 if( f->callbacks->down )
390 (*f->callbacks->down)(f); /* Inform upper layers */
391 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
395 /* Negotiation started by our peer */
396 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
402 * Pass the requested configuration options
403 * to protocol-specific code for checking.
405 if (f->callbacks->reqci){ /* Check CI */
406 reject_if_disagree = (f->nakloops >= f->maxnakloops);
407 code = (*f->callbacks->reqci)(f, inp, &len, reject_if_disagree);
409 code = CONFREJ; /* Reject all CI */
411 /* send the Ack, Nak or Rej to the peer */
412 fsm_sdata(f, code, id, inp, len);
414 if (code == CONFACK) {
415 if (f->state == ACKRCVD) {
416 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
418 if (f->callbacks->up)
419 (*f->callbacks->up)(f); /* Inform upper layers */
425 /* we sent CONFACK or CONFREJ */
426 if (f->state != ACKRCVD)
428 if( code == CONFNAK )
435 * fsm_rconfack - Receive Configure-Ack.
438 fsm_rconfack(f, id, inp, len)
444 FSMDEBUG((LOG_INFO, "fsm_rconfack(%s): Rcvd id %d.",
447 if (id != f->reqid) /* Expected id? */
448 return; /* Nope, toss... */
449 if( !(f->callbacks->ackci? (*f->callbacks->ackci)(f, inp, len): (len == 0)) ){
450 /* Ack is bad - ignore it */
451 FSMDEBUG((LOG_INFO, "%s: received bad Ack (length %d)",
452 PROTO_NAME(f), len));
460 fsm_sdata(f, TERMACK, id, NULL, 0);
465 f->retransmits = f->maxconfreqtransmits;
469 /* Huh? an extra Ack? oh well... */
475 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
477 f->retransmits = f->maxconfreqtransmits;
478 if (f->callbacks->up)
479 (*f->callbacks->up)(f); /* Inform upper layers */
483 /* Go down and restart negotiation */
484 if (f->callbacks->down)
485 (*f->callbacks->down)(f); /* Inform upper layers */
486 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
494 * fsm_rconfnakrej - Receive Configure-Nak or Configure-Reject.
497 fsm_rconfnakrej(f, code, id, inp, len)
505 FSMDEBUG((LOG_INFO, "fsm_rconfnakrej(%s): Rcvd id %d.",
508 if (id != f->reqid) /* Expected id? */
509 return; /* Nope, toss... */
510 proc = (code == CONFNAK)? f->callbacks->nakci: f->callbacks->rejci;
511 if( !proc || !proc(f, inp, len) ){
512 /* Nak/reject is bad - ignore it */
513 FSMDEBUG((LOG_INFO, "%s: received bad %s (length %d)",
514 PROTO_NAME(f), (code==CONFNAK? "Nak": "reject"), len));
522 fsm_sdata(f, TERMACK, id, NULL, 0);
527 /* They didn't agree to what we wanted - try another request */
528 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
529 fsm_sconfreq(f, 0); /* Send Configure-Request */
533 /* Got a Nak/reject when we had already had an Ack?? oh well... */
539 /* Go down and restart negotiation */
540 if (f->callbacks->down)
541 (*f->callbacks->down)(f); /* Inform upper layers */
542 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
550 * fsm_rtermreq - Receive Terminate-Req.
557 FSMDEBUG((LOG_INFO, "fsm_rtermreq(%s): Rcvd id %d.",
563 f->state = REQSENT; /* Start over but keep trying */
567 syslog(LOG_INFO, "%s terminated at peer's request", PROTO_NAME(f));
568 if (f->callbacks->down)
569 (*f->callbacks->down)(f); /* Inform upper layers */
572 TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
576 fsm_sdata(f, TERMACK, id, NULL, 0);
581 * fsm_rtermack - Receive Terminate-Ack.
587 FSMDEBUG((LOG_INFO, "fsm_rtermack(%s).", PROTO_NAME(f)));
592 if( f->callbacks->finished )
593 (*f->callbacks->finished)(f);
597 if( f->callbacks->finished )
598 (*f->callbacks->finished)(f);
606 if (f->callbacks->down)
607 (*f->callbacks->down)(f); /* Inform upper layers */
615 * fsm_rcoderej - Receive an Code-Reject.
618 fsm_rcoderej(f, inp, len)
625 FSMDEBUG((LOG_INFO, "fsm_rcoderej(%s).", PROTO_NAME(f)));
627 if (len < HEADERLEN) {
628 FSMDEBUG((LOG_INFO, "fsm_rcoderej: Rcvd short Code-Reject packet!"));
633 syslog(LOG_WARNING, "%s: Rcvd Code-Reject for code %d, id %d",
634 PROTO_NAME(f), code, id);
636 if( f->state == ACKRCVD )
642 * fsm_protreject - Peer doesn't speak this protocol.
644 * Treat this as a catastrophic error (RXJ-).
652 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
656 if( f->callbacks->finished )
657 (*f->callbacks->finished)(f);
664 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
668 if( f->callbacks->finished )
669 (*f->callbacks->finished)(f);
673 if( f->callbacks->down )
674 (*f->callbacks->down)(f);
676 /* Init restart counter, send Terminate-Request */
677 f->retransmits = f->maxtermtransmits;
678 fsm_sdata(f, TERMREQ, f->reqid = ++f->id, NULL, 0);
679 TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
686 FSMDEBUG((LOG_INFO, "%s: Protocol-reject event in state %d!",
687 PROTO_NAME(f), f->state));
693 * fsm_sconfreq - Send a Configure-Request.
696 fsm_sconfreq(f, retransmit)
703 if( f->state != REQSENT && f->state != ACKRCVD && f->state != ACKSENT ){
704 /* Not currently negotiating - reset options */
705 if( f->callbacks->resetci )
706 (*f->callbacks->resetci)(f);
711 /* New request - reset retransmission counter, use new ID */
712 f->retransmits = f->maxconfreqtransmits;
717 * Make up the request packet
719 if( f->callbacks->cilen && f->callbacks->addci ){
720 cilen = (*f->callbacks->cilen)(f);
721 if( cilen > peer_mru[f->unit] - HEADERLEN )
722 cilen = peer_mru[f->unit] - HEADERLEN;
723 outp = outpacket_buf + DLLHEADERLEN + HEADERLEN;
724 if (f->callbacks->addci)
725 (*f->callbacks->addci)(f, outp, &cilen);
729 /* send the request to our peer */
730 fsm_sdata(f, CONFREQ, f->reqid, outp, cilen);
732 /* start the retransmit timer */
734 TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
736 FSMDEBUG((LOG_INFO, "%s: sending Configure-Request, id %d",
737 PROTO_NAME(f), f->reqid));
742 * fsm_sdata - Send some data.
744 * Used for all packets sent to our peer by this module.
747 fsm_sdata(f, code, id, data, datalen)
756 /* Adjust length to be smaller than MTU */
757 outp = outpacket_buf;
758 if (datalen > peer_mru[f->unit] - HEADERLEN)
759 datalen = peer_mru[f->unit] - HEADERLEN;
760 if (datalen && data != outp + DLLHEADERLEN + HEADERLEN)
761 BCOPY(data, outp + DLLHEADERLEN + HEADERLEN, datalen);
762 outlen = datalen + HEADERLEN;
763 MAKEHEADER(outp, f->protocol);
766 PUTSHORT(outlen, outp);
767 output(f->unit, outpacket_buf, outlen + DLLHEADERLEN);
769 FSMDEBUG((LOG_INFO, "fsm_sdata(%s): Sent code %d, id %d.",
770 PROTO_NAME(f), code, id));