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 1.1 1993/11/11 03:54:25 paulus Exp $";
26 * Randomize fsm id on link/init.
27 * Deal with variable outgoing MTU.
31 #include <sys/types.h>
32 /*#include <malloc.h>*/
39 extern char *proto_name();
41 static void fsm_timeout __ARGS((caddr_t));
42 static void fsm_rconfreq __ARGS((fsm *, int, u_char *, int));
43 static void fsm_rconfack __ARGS((fsm *, int, u_char *, int));
44 static void fsm_rconfnakrej __ARGS((fsm *, int, int, u_char *, int));
45 static void fsm_rtermreq __ARGS((fsm *, int));
46 static void fsm_rtermack __ARGS((fsm *));
47 static void fsm_rcoderej __ARGS((fsm *, u_char *, int));
48 static void fsm_sconfreq __ARGS((fsm *, int));
50 #define PROTO_NAME(f) ((f)->callbacks->proto_name)
56 * fsm_init - Initialize fsm.
58 * Initialize fsm state.
66 f->id = 0; /* XXX Start with random id? */
67 f->timeouttime = DEFTIMEOUT;
68 f->maxconfreqtransmits = DEFMAXCONFREQS;
69 f->maxtermtransmits = DEFMAXTERMREQS;
70 f->maxnakloops = DEFMAXNAKLOOPS;
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
212 if( f->state != OPENED )
213 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
214 else if( f->callbacks->down )
215 (*f->callbacks->down)(f); /* Inform upper layers we're down */
217 /* Init restart counter, send Terminate-Request */
218 f->retransmits = f->maxtermtransmits;
219 fsm_sdata(f, TERMREQ, f->reqid = ++f->id, NULL, 0);
220 TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
230 * fsm_timeout - Timeout expired.
236 fsm *f = (fsm *) arg;
241 if( f->retransmits <= 0 ){
243 * We've waited for an ack long enough. Peer probably heard us.
245 f->state = (f->state == CLOSING)? CLOSED: STOPPED;
246 if( f->callbacks->finished )
247 (*f->callbacks->finished)(f);
249 /* Send Terminate-Request */
250 fsm_sdata(f, TERMREQ, f->reqid = ++f->id, NULL, 0);
251 TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
259 if (f->retransmits <= 0) {
260 syslog(LOG_WARNING, "%s: timeout sending Config-Requests",
263 if( (f->flags & OPT_PASSIVE) == 0 && f->callbacks->finished )
264 (*f->callbacks->finished)(f);
267 /* Retransmit the configure-request */
268 if (f->callbacks->retransmit)
269 (*f->callbacks->retransmit)(f);
270 fsm_sconfreq(f, 1); /* Re-send Configure-Request */
271 if( f->state == ACKRCVD )
277 FSMDEBUG((LOG_INFO, "%s: Timeout event in state %d!",
278 PROTO_NAME(f), f->state));
284 * fsm_input - Input packet.
287 fsm_input(f, inpacket, l)
297 * Parse header (code, id and length).
298 * If packet too short, drop it.
302 FSMDEBUG((LOG_WARNING, "fsm_input(%x): Rcvd short header.",
309 if (len < HEADERLEN) {
310 FSMDEBUG((LOG_INFO, "fsm_input(%x): Rcvd illegal length.",
315 FSMDEBUG((LOG_INFO, "fsm_input(%x): Rcvd short packet.",
319 len -= HEADERLEN; /* subtract header length */
321 if( f->state == INITIAL || f->state == STARTING ){
322 FSMDEBUG((LOG_INFO, "fsm_input(%x): Rcvd packet in state %d.",
323 f->protocol, f->state));
328 * Action depends on code.
332 fsm_rconfreq(f, id, inp, len);
336 fsm_rconfack(f, id, inp, len);
341 fsm_rconfnakrej(f, code, id, inp, len);
353 fsm_rcoderej(f, inp, len);
357 if( !f->callbacks->extcode
358 || !(*f->callbacks->extcode)(f, code, id, inp, len) )
359 fsm_sdata(f, CODEREJ, ++f->id, inpacket, len + HEADERLEN);
366 * fsm_rconfreq - Receive Configure-Request.
369 fsm_rconfreq(f, id, inp, len)
376 int code, reject_if_disagree;
378 FSMDEBUG((LOG_INFO, "fsm_rconfreq(%s): Rcvd id %d.", PROTO_NAME(f), id));
381 /* Go away, we're closed */
382 fsm_sdata(f, TERMACK, id, NULL, 0);
389 /* Go down and restart negotiation */
390 if( f->callbacks->down )
391 (*f->callbacks->down)(f); /* Inform upper layers */
392 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
396 /* Negotiation started by our peer */
397 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
403 * Pass the requested configuration options
404 * to protocol-specific code for checking.
406 if (f->callbacks->reqci){ /* Check CI */
407 reject_if_disagree = (f->nakloops >= f->maxnakloops);
408 code = (*f->callbacks->reqci)(f, inp, &len, reject_if_disagree);
410 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) /* Expected id? */
449 return; /* Nope, toss... */
450 if( !(f->callbacks->ackci? (*f->callbacks->ackci)(f, inp, len): (len == 0)) ){
451 /* Ack is bad - ignore it */
452 FSMDEBUG((LOG_INFO, "%s: received bad Ack (length %d)",
453 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));
521 fsm_sdata(f, TERMACK, id, NULL, 0);
526 /* They didn't agree to what we wanted - try another request */
527 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
528 fsm_sconfreq(f, 0); /* Send Configure-Request */
532 /* Got a Nak/reject when we had already had an Ack?? oh well... */
538 /* Go down and restart negotiation */
539 if (f->callbacks->down)
540 (*f->callbacks->down)(f); /* Inform upper layers */
541 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
549 * fsm_rtermreq - Receive Terminate-Req.
556 FSMDEBUG((LOG_INFO, "fsm_rtermreq(%s): Rcvd id %d.",
559 fsm_sdata(f, TERMACK, id, NULL, 0);
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);
579 * fsm_rtermack - Receive Terminate-Ack.
585 FSMDEBUG((LOG_INFO, "fsm_rtermack(%s).", PROTO_NAME(f)));
590 if( f->callbacks->finished )
591 (*f->callbacks->finished)(f);
595 if( f->callbacks->finished )
596 (*f->callbacks->finished)(f);
604 if (f->callbacks->down)
605 (*f->callbacks->down)(f); /* Inform upper layers */
613 * fsm_rcoderej - Receive an Code-Reject.
616 fsm_rcoderej(f, inp, len)
623 FSMDEBUG((LOG_INFO, "fsm_rcoderej(%s).", PROTO_NAME(f)));
625 if (len < HEADERLEN) {
626 FSMDEBUG((LOG_INFO, "fsm_rcoderej: Rcvd short Code-Reject packet!"));
631 syslog(LOG_WARNING, "%s: Rcvd Code-Reject for code %d, id %d",
632 PROTO_NAME(f), code, id);
634 if( f->state == ACKRCVD )
640 * fsm_protreject - Peer doesn't speak this protocol.
642 * Treat this as a catastrophic error (RXJ-).
650 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
654 if( f->callbacks->finished )
655 (*f->callbacks->finished)(f);
662 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
666 if( f->callbacks->finished )
667 (*f->callbacks->finished)(f);
671 if( f->callbacks->down )
672 (*f->callbacks->down)(f);
674 /* Init restart counter, send Terminate-Request */
675 f->retransmits = f->maxtermtransmits;
676 fsm_sdata(f, TERMREQ, f->reqid = ++f->id, NULL, 0);
677 TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
684 FSMDEBUG((LOG_INFO, "%s: Protocol-reject event in state %d!",
685 PROTO_NAME(f), f->state));
691 * fsm_sconfreq - Send a Configure-Request.
694 fsm_sconfreq(f, retransmit)
701 if( f->state != REQSENT && f->state != ACKRCVD && f->state != ACKSENT ){
702 /* Not currently negotiating - reset options */
703 if( f->callbacks->resetci )
704 (*f->callbacks->resetci)(f);
709 /* New request - reset retransmission counter, use new ID */
710 f->retransmits = f->maxconfreqtransmits;
715 * Make up the request packet
717 if( f->callbacks->cilen && f->callbacks->addci ){
718 cilen = (*f->callbacks->cilen)(f);
719 if( cilen > peer_mru[f->unit] - HEADERLEN )
720 cilen = peer_mru[f->unit] - HEADERLEN;
721 outp = outpacket_buf + DLLHEADERLEN + HEADERLEN;
722 if (f->callbacks->addci)
723 (*f->callbacks->addci)(f, outp, &cilen);
727 /* send the request to our peer */
728 fsm_sdata(f, CONFREQ, f->reqid, outp, cilen);
730 /* start the retransmit timer */
732 TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
734 FSMDEBUG((LOG_INFO, "%s: sending Configure-Request, id %d",
735 PROTO_NAME(f), f->reqid));
740 * fsm_sdata - Send some data.
742 * Used for all packets sent to our peer by this module.
745 fsm_sdata(f, code, id, data, datalen)
754 /* Adjust length to be smaller than MTU */
755 outp = outpacket_buf;
756 if (datalen > peer_mru[f->unit] - HEADERLEN)
757 datalen = peer_mru[f->unit] - HEADERLEN;
758 if (datalen && data != outp + DLLHEADERLEN + HEADERLEN)
759 BCOPY(data, outp + DLLHEADERLEN + HEADERLEN, datalen);
760 outlen = datalen + HEADERLEN;
761 MAKEHEADER(outp, f->protocol);
764 PUTSHORT(outlen, outp);
765 output(f->unit, outpacket_buf, outlen + DLLHEADERLEN);
767 FSMDEBUG((LOG_INFO, "fsm_sdata(%s): Sent code %d, id %d.",
768 PROTO_NAME(f), code, id));