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 1.10 1995/12/18 03:44:42 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)
381 int code, reject_if_disagree;
383 FSMDEBUG((LOG_INFO, "fsm_rconfreq(%s): Rcvd id %d.", PROTO_NAME(f), id));
386 /* Go away, we're closed */
387 fsm_sdata(f, TERMACK, id, NULL, 0);
394 /* Go down and restart negotiation */
395 if( f->callbacks->down )
396 (*f->callbacks->down)(f); /* Inform upper layers */
397 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
401 /* Negotiation started by our peer */
402 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
408 * Pass the requested configuration options
409 * to protocol-specific code for checking.
411 if (f->callbacks->reqci){ /* Check CI */
412 reject_if_disagree = (f->nakloops >= f->maxnakloops);
413 code = (*f->callbacks->reqci)(f, inp, &len, reject_if_disagree);
415 code = CONFREJ; /* Reject all CI */
419 /* send the Ack, Nak or Rej to the peer */
420 fsm_sdata(f, code, id, inp, len);
422 if (code == CONFACK) {
423 if (f->state == ACKRCVD) {
424 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
426 if (f->callbacks->up)
427 (*f->callbacks->up)(f); /* Inform upper layers */
433 /* we sent CONFACK or CONFREJ */
434 if (f->state != ACKRCVD)
436 if( code == CONFNAK )
443 * fsm_rconfack - Receive Configure-Ack.
446 fsm_rconfack(f, id, inp, len)
452 FSMDEBUG((LOG_INFO, "fsm_rconfack(%s): Rcvd id %d.",
455 if (id != f->reqid || f->seen_ack) /* Expected id? */
456 return; /* Nope, toss... */
457 if( !(f->callbacks->ackci? (*f->callbacks->ackci)(f, inp, len):
459 /* Ack is bad - ignore it */
460 FSMDEBUG((LOG_INFO, "%s: received bad Ack (length %d)",
461 PROTO_NAME(f), len));
469 fsm_sdata(f, TERMACK, id, NULL, 0);
474 f->retransmits = f->maxconfreqtransmits;
478 /* Huh? an extra valid Ack? oh well... */
479 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
485 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
487 f->retransmits = f->maxconfreqtransmits;
488 if (f->callbacks->up)
489 (*f->callbacks->up)(f); /* Inform upper layers */
493 /* Go down and restart negotiation */
494 if (f->callbacks->down)
495 (*f->callbacks->down)(f); /* Inform upper layers */
496 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
504 * fsm_rconfnakrej - Receive Configure-Nak or Configure-Reject.
507 fsm_rconfnakrej(f, code, id, inp, len)
516 FSMDEBUG((LOG_INFO, "fsm_rconfnakrej(%s): Rcvd id %d.",
519 if (id != f->reqid || f->seen_ack) /* Expected id? */
520 return; /* Nope, toss... */
521 proc = (code == CONFNAK)? f->callbacks->nakci: f->callbacks->rejci;
522 if (!proc || !(ret = proc(f, inp, len))) {
523 /* Nak/reject is bad - ignore it */
524 FSMDEBUG((LOG_INFO, "%s: received bad %s (length %d)",
525 PROTO_NAME(f), (code==CONFNAK? "Nak": "reject"), len));
533 fsm_sdata(f, TERMACK, id, NULL, 0);
538 /* They didn't agree to what we wanted - try another request */
539 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
541 f->state = STOPPED; /* kludge for stopping CCP */
543 fsm_sconfreq(f, 0); /* Send Configure-Request */
547 /* Got a Nak/reject when we had already had an Ack?? oh well... */
548 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
554 /* Go down and restart negotiation */
555 if (f->callbacks->down)
556 (*f->callbacks->down)(f); /* Inform upper layers */
557 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
565 * fsm_rtermreq - Receive Terminate-Req.
572 FSMDEBUG((LOG_INFO, "fsm_rtermreq(%s): Rcvd id %d.",
578 f->state = REQSENT; /* Start over but keep trying */
582 syslog(LOG_INFO, "%s terminated at peer's request", PROTO_NAME(f));
583 if (f->callbacks->down)
584 (*f->callbacks->down)(f); /* Inform upper layers */
587 TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
591 fsm_sdata(f, TERMACK, id, NULL, 0);
596 * fsm_rtermack - Receive Terminate-Ack.
602 FSMDEBUG((LOG_INFO, "fsm_rtermack(%s).", PROTO_NAME(f)));
606 UNTIMEOUT(fsm_timeout, (caddr_t) f);
608 if( f->callbacks->finished )
609 (*f->callbacks->finished)(f);
612 UNTIMEOUT(fsm_timeout, (caddr_t) f);
614 if( f->callbacks->finished )
615 (*f->callbacks->finished)(f);
623 if (f->callbacks->down)
624 (*f->callbacks->down)(f); /* Inform upper layers */
632 * fsm_rcoderej - Receive an Code-Reject.
635 fsm_rcoderej(f, inp, len)
642 FSMDEBUG((LOG_INFO, "fsm_rcoderej(%s).", PROTO_NAME(f)));
644 if (len < HEADERLEN) {
645 FSMDEBUG((LOG_INFO, "fsm_rcoderej: Rcvd short Code-Reject packet!"));
650 syslog(LOG_WARNING, "%s: Rcvd Code-Reject for code %d, id %d",
651 PROTO_NAME(f), code, id);
653 if( f->state == ACKRCVD )
659 * fsm_protreject - Peer doesn't speak this protocol.
661 * Treat this as a catastrophic error (RXJ-).
669 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
673 if( f->callbacks->finished )
674 (*f->callbacks->finished)(f);
681 UNTIMEOUT(fsm_timeout, (caddr_t) f); /* Cancel timeout */
685 if( f->callbacks->finished )
686 (*f->callbacks->finished)(f);
690 if( f->callbacks->down )
691 (*f->callbacks->down)(f);
693 /* Init restart counter, send Terminate-Request */
694 f->retransmits = f->maxtermtransmits;
695 fsm_sdata(f, TERMREQ, f->reqid = ++f->id,
696 (u_char *) f->term_reason, f->term_reason_len);
697 TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
704 FSMDEBUG((LOG_INFO, "%s: Protocol-reject event in state %d!",
705 PROTO_NAME(f), f->state));
711 * fsm_sconfreq - Send a Configure-Request.
714 fsm_sconfreq(f, retransmit)
721 if( f->state != REQSENT && f->state != ACKRCVD && f->state != ACKSENT ){
722 /* Not currently negotiating - reset options */
723 if( f->callbacks->resetci )
724 (*f->callbacks->resetci)(f);
729 /* New request - reset retransmission counter, use new ID */
730 f->retransmits = f->maxconfreqtransmits;
737 * Make up the request packet
739 outp = outpacket_buf + PPP_HDRLEN + HEADERLEN;
740 if( f->callbacks->cilen && f->callbacks->addci ){
741 cilen = (*f->callbacks->cilen)(f);
742 if( cilen > peer_mru[f->unit] - HEADERLEN )
743 cilen = peer_mru[f->unit] - HEADERLEN;
744 if (f->callbacks->addci)
745 (*f->callbacks->addci)(f, outp, &cilen);
749 /* send the request to our peer */
750 fsm_sdata(f, CONFREQ, f->reqid, outp, cilen);
752 /* start the retransmit timer */
754 TIMEOUT(fsm_timeout, (caddr_t) f, f->timeouttime);
756 FSMDEBUG((LOG_INFO, "%s: sending Configure-Request, id %d",
757 PROTO_NAME(f), f->reqid));
762 * fsm_sdata - Send some data.
764 * Used for all packets sent to our peer by this module.
767 fsm_sdata(f, code, id, data, datalen)
776 /* Adjust length to be smaller than MTU */
777 outp = outpacket_buf;
778 if (datalen > peer_mru[f->unit] - HEADERLEN)
779 datalen = peer_mru[f->unit] - HEADERLEN;
780 if (datalen && data != outp + PPP_HDRLEN + HEADERLEN)
781 BCOPY(data, outp + PPP_HDRLEN + HEADERLEN, datalen);
782 outlen = datalen + HEADERLEN;
783 MAKEHEADER(outp, f->protocol);
786 PUTSHORT(outlen, outp);
787 output(f->unit, outpacket_buf, outlen + PPP_HDRLEN);
789 FSMDEBUG((LOG_INFO, "fsm_sdata(%s): Sent code %d, id %d.",
790 PROTO_NAME(f), code, id));