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 1.13 1997/04/30 05:52:17 paulus Exp $";
26 * Randomize fsm id on link/init.
27 * Deal with variable outgoing MTU.
32 #include <sys/types.h>
38 static void fsm_timeout __P((void *));
39 static void fsm_rconfreq __P((fsm *, int, u_char *, int));
40 static void fsm_rconfack __P((fsm *, int, u_char *, int));
41 static void fsm_rconfnakrej __P((fsm *, int, int, u_char *, int));
42 static void fsm_rtermreq __P((fsm *, int, u_char *, int));
43 static void fsm_rtermack __P((fsm *));
44 static void fsm_rcoderej __P((fsm *, u_char *, int));
45 static void fsm_sconfreq __P((fsm *, int));
47 #define PROTO_NAME(f) ((f)->callbacks->proto_name)
49 int peer_mru[NUM_PPP];
53 * fsm_init - Initialize fsm.
55 * Initialize fsm state.
63 f->id = 0; /* XXX Start with random id? */
64 f->timeouttime = DEFTIMEOUT;
65 f->maxconfreqtransmits = DEFMAXCONFREQS;
66 f->maxtermtransmits = DEFMAXTERMREQS;
67 f->maxnakloops = DEFMAXNAKLOOPS;
68 f->term_reason_len = 0;
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, f); /* Cancel timeout */
131 UNTIMEOUT(fsm_timeout, 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
196 f->term_reason = reason;
197 f->term_reason_len = (reason == NULL? 0: strlen(reason));
213 if( f->state != OPENED )
214 UNTIMEOUT(fsm_timeout, f); /* Cancel timeout */
215 else if( f->callbacks->down )
216 (*f->callbacks->down)(f); /* Inform upper layers we're down */
218 /* Init restart counter, send Terminate-Request */
219 f->retransmits = f->maxtermtransmits;
220 fsm_sdata(f, TERMREQ, f->reqid = ++f->id,
221 (u_char *) f->term_reason, f->term_reason_len);
222 TIMEOUT(fsm_timeout, f, f->timeouttime);
232 * fsm_timeout - Timeout expired.
238 fsm *f = (fsm *) arg;
243 if( f->retransmits <= 0 ){
245 * We've waited for an ack long enough. Peer probably heard us.
247 f->state = (f->state == CLOSING)? CLOSED: STOPPED;
248 if( f->callbacks->finished )
249 (*f->callbacks->finished)(f);
251 /* Send Terminate-Request */
252 fsm_sdata(f, TERMREQ, f->reqid = ++f->id,
253 (u_char *) f->term_reason, f->term_reason_len);
254 TIMEOUT(fsm_timeout, f, f->timeouttime);
262 if (f->retransmits <= 0) {
263 syslog(LOG_WARNING, "%s: timeout sending Config-Requests",
266 if( (f->flags & OPT_PASSIVE) == 0 && f->callbacks->finished )
267 (*f->callbacks->finished)(f);
270 /* Retransmit the configure-request */
271 if (f->callbacks->retransmit)
272 (*f->callbacks->retransmit)(f);
273 fsm_sconfreq(f, 1); /* Re-send Configure-Request */
274 if( f->state == ACKRCVD )
280 FSMDEBUG((LOG_INFO, "%s: Timeout event in state %d!",
281 PROTO_NAME(f), f->state));
287 * fsm_input - Input packet.
290 fsm_input(f, inpacket, l)
300 * Parse header (code, id and length).
301 * If packet too short, drop it.
305 FSMDEBUG((LOG_WARNING, "fsm_input(%x): Rcvd short header.",
312 if (len < HEADERLEN) {
313 FSMDEBUG((LOG_INFO, "fsm_input(%x): Rcvd illegal length.",
318 FSMDEBUG((LOG_INFO, "fsm_input(%x): Rcvd short packet.",
322 len -= HEADERLEN; /* subtract header length */
324 if( f->state == INITIAL || f->state == STARTING ){
325 FSMDEBUG((LOG_INFO, "fsm_input(%x): Rcvd packet in state %d.",
326 f->protocol, f->state));
331 * Action depends on code.
335 fsm_rconfreq(f, id, inp, len);
339 fsm_rconfack(f, id, inp, len);
344 fsm_rconfnakrej(f, code, id, inp, len);
348 fsm_rtermreq(f, id, inp, len);
356 fsm_rcoderej(f, inp, len);
360 if( !f->callbacks->extcode
361 || !(*f->callbacks->extcode)(f, code, id, inp, len) )
362 fsm_sdata(f, CODEREJ, ++f->id, inpacket, len + HEADERLEN);
369 * fsm_rconfreq - Receive Configure-Request.
372 fsm_rconfreq(f, id, inp, len)
378 int code, reject_if_disagree;
380 FSMDEBUG((LOG_INFO, "fsm_rconfreq(%s): Rcvd id %d.", PROTO_NAME(f), id));
383 /* Go away, we're closed */
384 fsm_sdata(f, TERMACK, id, NULL, 0);
391 /* Go down and restart negotiation */
392 if( f->callbacks->down )
393 (*f->callbacks->down)(f); /* Inform upper layers */
394 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
398 /* Negotiation started by our peer */
399 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
405 * Pass the requested configuration options
406 * to protocol-specific code for checking.
408 if (f->callbacks->reqci){ /* Check CI */
409 reject_if_disagree = (f->nakloops >= f->maxnakloops);
410 code = (*f->callbacks->reqci)(f, inp, &len, reject_if_disagree);
412 code = CONFREJ; /* Reject all CI */
416 /* send the Ack, Nak or Rej to the peer */
417 fsm_sdata(f, code, id, inp, len);
419 if (code == CONFACK) {
420 if (f->state == ACKRCVD) {
421 UNTIMEOUT(fsm_timeout, f); /* Cancel timeout */
423 if (f->callbacks->up)
424 (*f->callbacks->up)(f); /* Inform upper layers */
430 /* we sent CONFACK or CONFREJ */
431 if (f->state != ACKRCVD)
433 if( code == CONFNAK )
440 * fsm_rconfack - Receive Configure-Ack.
443 fsm_rconfack(f, id, inp, len)
449 FSMDEBUG((LOG_INFO, "fsm_rconfack(%s): Rcvd id %d.",
452 if (id != f->reqid || f->seen_ack) /* Expected id? */
453 return; /* Nope, toss... */
454 if( !(f->callbacks->ackci? (*f->callbacks->ackci)(f, inp, len):
456 /* Ack is bad - ignore it */
457 log_packet(inp, len, "Received bad configure-ack: ", LOG_ERR);
458 FSMDEBUG((LOG_INFO, "%s: received bad Ack (length %d)",
459 PROTO_NAME(f), len));
467 fsm_sdata(f, TERMACK, id, NULL, 0);
472 f->retransmits = f->maxconfreqtransmits;
476 /* Huh? an extra valid Ack? oh well... */
477 UNTIMEOUT(fsm_timeout, f); /* Cancel timeout */
483 UNTIMEOUT(fsm_timeout, f); /* Cancel timeout */
485 f->retransmits = f->maxconfreqtransmits;
486 if (f->callbacks->up)
487 (*f->callbacks->up)(f); /* Inform upper layers */
491 /* Go down and restart negotiation */
492 if (f->callbacks->down)
493 (*f->callbacks->down)(f); /* Inform upper layers */
494 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
502 * fsm_rconfnakrej - Receive Configure-Nak or Configure-Reject.
505 fsm_rconfnakrej(f, code, id, inp, len)
511 int (*proc) __P((fsm *, u_char *, int));
514 FSMDEBUG((LOG_INFO, "fsm_rconfnakrej(%s): Rcvd id %d.",
517 if (id != f->reqid || f->seen_ack) /* Expected id? */
518 return; /* Nope, toss... */
519 proc = (code == CONFNAK)? f->callbacks->nakci: f->callbacks->rejci;
520 if (!proc || !(ret = proc(f, inp, len))) {
521 /* Nak/reject is bad - ignore it */
522 log_packet(inp, len, "Received bad configure-nak/rej: ", LOG_ERR);
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, 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, 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.
567 fsm_rtermreq(f, id, p, len)
575 FSMDEBUG((LOG_INFO, "fsm_rtermreq(%s): Rcvd id %d.",
581 f->state = REQSENT; /* Start over but keep trying */
586 fmtmsg(str, sizeof(str), "%0.*v", len, p);
587 syslog(LOG_INFO, "%s terminated by peer (%s)", PROTO_NAME(f), str);
589 syslog(LOG_INFO, "%s terminated by peer", PROTO_NAME(f));
590 if (f->callbacks->down)
591 (*f->callbacks->down)(f); /* Inform upper layers */
594 TIMEOUT(fsm_timeout, f, f->timeouttime);
598 fsm_sdata(f, TERMACK, id, NULL, 0);
603 * fsm_rtermack - Receive Terminate-Ack.
609 FSMDEBUG((LOG_INFO, "fsm_rtermack(%s).", PROTO_NAME(f)));
613 UNTIMEOUT(fsm_timeout, f);
615 if( f->callbacks->finished )
616 (*f->callbacks->finished)(f);
619 UNTIMEOUT(fsm_timeout, f);
621 if( f->callbacks->finished )
622 (*f->callbacks->finished)(f);
630 if (f->callbacks->down)
631 (*f->callbacks->down)(f); /* Inform upper layers */
639 * fsm_rcoderej - Receive an Code-Reject.
642 fsm_rcoderej(f, inp, len)
649 FSMDEBUG((LOG_INFO, "fsm_rcoderej(%s).", PROTO_NAME(f)));
651 if (len < HEADERLEN) {
652 FSMDEBUG((LOG_INFO, "fsm_rcoderej: Rcvd short Code-Reject packet!"));
657 syslog(LOG_WARNING, "%s: Rcvd Code-Reject for code %d, id %d",
658 PROTO_NAME(f), code, id);
660 if( f->state == ACKRCVD )
666 * fsm_protreject - Peer doesn't speak this protocol.
668 * Treat this as a catastrophic error (RXJ-).
676 UNTIMEOUT(fsm_timeout, f); /* Cancel timeout */
680 if( f->callbacks->finished )
681 (*f->callbacks->finished)(f);
688 UNTIMEOUT(fsm_timeout, f); /* Cancel timeout */
692 if( f->callbacks->finished )
693 (*f->callbacks->finished)(f);
697 if( f->callbacks->down )
698 (*f->callbacks->down)(f);
700 /* Init restart counter, send Terminate-Request */
701 f->retransmits = f->maxtermtransmits;
702 fsm_sdata(f, TERMREQ, f->reqid = ++f->id,
703 (u_char *) f->term_reason, f->term_reason_len);
704 TIMEOUT(fsm_timeout, f, f->timeouttime);
711 FSMDEBUG((LOG_INFO, "%s: Protocol-reject event in state %d!",
712 PROTO_NAME(f), f->state));
718 * fsm_sconfreq - Send a Configure-Request.
721 fsm_sconfreq(f, retransmit)
728 if( f->state != REQSENT && f->state != ACKRCVD && f->state != ACKSENT ){
729 /* Not currently negotiating - reset options */
730 if( f->callbacks->resetci )
731 (*f->callbacks->resetci)(f);
736 /* New request - reset retransmission counter, use new ID */
737 f->retransmits = f->maxconfreqtransmits;
744 * Make up the request packet
746 outp = outpacket_buf + PPP_HDRLEN + HEADERLEN;
747 if( f->callbacks->cilen && f->callbacks->addci ){
748 cilen = (*f->callbacks->cilen)(f);
749 if( cilen > peer_mru[f->unit] - HEADERLEN )
750 cilen = peer_mru[f->unit] - HEADERLEN;
751 if (f->callbacks->addci)
752 (*f->callbacks->addci)(f, outp, &cilen);
756 /* send the request to our peer */
757 fsm_sdata(f, CONFREQ, f->reqid, outp, cilen);
759 /* start the retransmit timer */
761 TIMEOUT(fsm_timeout, f, f->timeouttime);
763 FSMDEBUG((LOG_INFO, "%s: sending Configure-Request, id %d",
764 PROTO_NAME(f), f->reqid));
769 * fsm_sdata - Send some data.
771 * Used for all packets sent to our peer by this module.
774 fsm_sdata(f, code, id, data, datalen)
783 /* Adjust length to be smaller than MTU */
784 outp = outpacket_buf;
785 if (datalen > peer_mru[f->unit] - HEADERLEN)
786 datalen = peer_mru[f->unit] - HEADERLEN;
787 if (datalen && data != outp + PPP_HDRLEN + HEADERLEN)
788 BCOPY(data, outp + PPP_HDRLEN + HEADERLEN, datalen);
789 outlen = datalen + HEADERLEN;
790 MAKEHEADER(outp, f->protocol);
793 PUTSHORT(outlen, outp);
794 output(f->unit, outpacket_buf, outlen + PPP_HDRLEN);
796 FSMDEBUG((LOG_INFO, "fsm_sdata(%s): Sent code %d, id %d.",
797 PROTO_NAME(f), code, id));