2 * fsm.c - {Link, IP} Control Protocol Finite State Machine.
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43 #define RCSID "$Id: fsm.c,v 1.19 2002/12/04 23:03:32 paulus Exp $"
47 * Randomize fsm id on link/init.
48 * Deal with variable outgoing MTU.
53 #include <sys/types.h>
58 static const char rcsid[] = RCSID;
60 static void fsm_timeout __P((void *));
61 static void fsm_rconfreq __P((fsm *, int, u_char *, int));
62 static void fsm_rconfack __P((fsm *, int, u_char *, int));
63 static void fsm_rconfnakrej __P((fsm *, int, int, u_char *, int));
64 static void fsm_rtermreq __P((fsm *, int, u_char *, int));
65 static void fsm_rtermack __P((fsm *));
66 static void fsm_rcoderej __P((fsm *, u_char *, int));
67 static void fsm_sconfreq __P((fsm *, int));
69 #define PROTO_NAME(f) ((f)->callbacks->proto_name)
71 int peer_mru[NUM_PPP];
75 * fsm_init - Initialize fsm.
77 * Initialize fsm state.
85 f->id = 0; /* XXX Start with random id? */
86 f->timeouttime = DEFTIMEOUT;
87 f->maxconfreqtransmits = DEFMAXCONFREQS;
88 f->maxtermtransmits = DEFMAXTERMREQS;
89 f->maxnakloops = DEFMAXNAKLOOPS;
90 f->term_reason_len = 0;
95 * fsm_lowerup - The lower layer is up.
107 if( f->flags & OPT_SILENT )
110 /* Send an initial configure-request */
117 FSMDEBUG(("%s: Up event in state %d!", PROTO_NAME(f), f->state));
123 * fsm_lowerdown - The lower layer is down.
125 * Cancel all timeouts and inform upper layers.
138 if( f->callbacks->starting )
139 (*f->callbacks->starting)(f);
144 UNTIMEOUT(fsm_timeout, f); /* Cancel timeout */
152 UNTIMEOUT(fsm_timeout, f); /* Cancel timeout */
156 if( f->callbacks->down )
157 (*f->callbacks->down)(f);
162 FSMDEBUG(("%s: Down event in state %d!", PROTO_NAME(f), f->state));
168 * fsm_open - Link is allowed to come up.
177 if( f->callbacks->starting )
178 (*f->callbacks->starting)(f);
182 if( f->flags & OPT_SILENT )
185 /* Send an initial configure-request */
196 if( f->flags & OPT_RESTART ){
206 * fsm_close - Start closing connection.
208 * Cancel timeouts and either initiate close or possibly go directly to
216 f->term_reason = reason;
217 f->term_reason_len = (reason == NULL? 0: strlen(reason));
233 if( f->state != OPENED )
234 UNTIMEOUT(fsm_timeout, f); /* Cancel timeout */
235 else if( f->callbacks->down )
236 (*f->callbacks->down)(f); /* Inform upper layers we're down */
238 /* Init restart counter, send Terminate-Request */
239 f->retransmits = f->maxtermtransmits;
240 fsm_sdata(f, TERMREQ, f->reqid = ++f->id,
241 (u_char *) f->term_reason, f->term_reason_len);
242 TIMEOUT(fsm_timeout, f, f->timeouttime);
252 * fsm_timeout - Timeout expired.
258 fsm *f = (fsm *) arg;
263 if( f->retransmits <= 0 ){
265 * We've waited for an ack long enough. Peer probably heard us.
267 f->state = (f->state == CLOSING)? CLOSED: STOPPED;
268 if( f->callbacks->finished )
269 (*f->callbacks->finished)(f);
271 /* Send Terminate-Request */
272 fsm_sdata(f, TERMREQ, f->reqid = ++f->id,
273 (u_char *) f->term_reason, f->term_reason_len);
274 TIMEOUT(fsm_timeout, f, f->timeouttime);
282 if (f->retransmits <= 0) {
283 warn("%s: timeout sending Config-Requests\n", PROTO_NAME(f));
285 if( (f->flags & OPT_PASSIVE) == 0 && f->callbacks->finished )
286 (*f->callbacks->finished)(f);
289 /* Retransmit the configure-request */
290 if (f->callbacks->retransmit)
291 (*f->callbacks->retransmit)(f);
292 fsm_sconfreq(f, 1); /* Re-send Configure-Request */
293 if( f->state == ACKRCVD )
299 FSMDEBUG(("%s: Timeout event in state %d!", PROTO_NAME(f), f->state));
305 * fsm_input - Input packet.
308 fsm_input(f, inpacket, l)
318 * Parse header (code, id and length).
319 * If packet too short, drop it.
323 FSMDEBUG(("fsm_input(%x): Rcvd short header.", f->protocol));
329 if (len < HEADERLEN) {
330 FSMDEBUG(("fsm_input(%x): Rcvd illegal length.", f->protocol));
334 FSMDEBUG(("fsm_input(%x): Rcvd short packet.", f->protocol));
337 len -= HEADERLEN; /* subtract header length */
339 if( f->state == INITIAL || f->state == STARTING ){
340 FSMDEBUG(("fsm_input(%x): Rcvd packet in state %d.",
341 f->protocol, f->state));
346 * Action depends on code.
350 fsm_rconfreq(f, id, inp, len);
354 fsm_rconfack(f, id, inp, len);
359 fsm_rconfnakrej(f, code, id, inp, len);
363 fsm_rtermreq(f, id, inp, len);
371 fsm_rcoderej(f, inp, len);
375 if( !f->callbacks->extcode
376 || !(*f->callbacks->extcode)(f, code, id, inp, len) )
377 fsm_sdata(f, CODEREJ, ++f->id, inpacket, len + HEADERLEN);
384 * fsm_rconfreq - Receive Configure-Request.
387 fsm_rconfreq(f, id, inp, len)
393 int code, reject_if_disagree;
397 /* Go away, we're closed */
398 fsm_sdata(f, TERMACK, id, NULL, 0);
405 /* Go down and restart negotiation */
406 if( f->callbacks->down )
407 (*f->callbacks->down)(f); /* Inform upper layers */
408 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
412 /* Negotiation started by our peer */
413 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
419 * Pass the requested configuration options
420 * to protocol-specific code for checking.
422 if (f->callbacks->reqci){ /* Check CI */
423 reject_if_disagree = (f->nakloops >= f->maxnakloops);
424 code = (*f->callbacks->reqci)(f, inp, &len, reject_if_disagree);
426 code = CONFREJ; /* Reject all CI */
430 /* send the Ack, Nak or Rej to the peer */
431 fsm_sdata(f, code, id, inp, len);
433 if (code == CONFACK) {
434 if (f->state == ACKRCVD) {
435 UNTIMEOUT(fsm_timeout, f); /* Cancel timeout */
437 if (f->callbacks->up)
438 (*f->callbacks->up)(f); /* Inform upper layers */
444 /* we sent CONFACK or CONFREJ */
445 if (f->state != ACKRCVD)
447 if( code == CONFNAK )
454 * fsm_rconfack - Receive Configure-Ack.
457 fsm_rconfack(f, id, inp, len)
463 if (id != f->reqid || f->seen_ack) /* Expected id? */
464 return; /* Nope, toss... */
465 if( !(f->callbacks->ackci? (*f->callbacks->ackci)(f, inp, len):
467 /* Ack is bad - ignore it */
468 error("Received bad configure-ack: %P", inp, len);
476 fsm_sdata(f, TERMACK, id, NULL, 0);
481 f->retransmits = f->maxconfreqtransmits;
485 /* Huh? an extra valid Ack? oh well... */
486 UNTIMEOUT(fsm_timeout, f); /* Cancel timeout */
492 UNTIMEOUT(fsm_timeout, f); /* Cancel timeout */
494 f->retransmits = f->maxconfreqtransmits;
495 if (f->callbacks->up)
496 (*f->callbacks->up)(f); /* Inform upper layers */
500 /* Go down and restart negotiation */
501 if (f->callbacks->down)
502 (*f->callbacks->down)(f); /* Inform upper layers */
503 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
511 * fsm_rconfnakrej - Receive Configure-Nak or Configure-Reject.
514 fsm_rconfnakrej(f, code, id, inp, len)
520 int (*proc) __P((fsm *, u_char *, int));
523 if (id != f->reqid || f->seen_ack) /* Expected id? */
524 return; /* Nope, toss... */
525 proc = (code == CONFNAK)? f->callbacks->nakci: f->callbacks->rejci;
526 if (!proc || !(ret = proc(f, inp, len))) {
527 /* Nak/reject is bad - ignore it */
528 error("Received bad configure-nak/rej: %P", inp, len);
536 fsm_sdata(f, TERMACK, id, NULL, 0);
541 /* They didn't agree to what we wanted - try another request */
542 UNTIMEOUT(fsm_timeout, f); /* Cancel timeout */
544 f->state = STOPPED; /* kludge for stopping CCP */
546 fsm_sconfreq(f, 0); /* Send Configure-Request */
550 /* Got a Nak/reject when we had already had an Ack?? oh well... */
551 UNTIMEOUT(fsm_timeout, f); /* Cancel timeout */
557 /* Go down and restart negotiation */
558 if (f->callbacks->down)
559 (*f->callbacks->down)(f); /* Inform upper layers */
560 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
568 * fsm_rtermreq - Receive Terminate-Req.
571 fsm_rtermreq(f, id, p, len)
580 f->state = REQSENT; /* Start over but keep trying */
585 info("%s terminated by peer (%0.*v)", PROTO_NAME(f), len, p);
587 info("%s terminated by peer", PROTO_NAME(f));
590 if (f->callbacks->down)
591 (*f->callbacks->down)(f); /* Inform upper layers */
592 TIMEOUT(fsm_timeout, f, f->timeouttime);
596 fsm_sdata(f, TERMACK, id, NULL, 0);
601 * fsm_rtermack - Receive Terminate-Ack.
609 UNTIMEOUT(fsm_timeout, f);
611 if( f->callbacks->finished )
612 (*f->callbacks->finished)(f);
615 UNTIMEOUT(fsm_timeout, f);
617 if( f->callbacks->finished )
618 (*f->callbacks->finished)(f);
626 if (f->callbacks->down)
627 (*f->callbacks->down)(f); /* Inform upper layers */
635 * fsm_rcoderej - Receive an Code-Reject.
638 fsm_rcoderej(f, inp, len)
645 if (len < HEADERLEN) {
646 FSMDEBUG(("fsm_rcoderej: Rcvd short Code-Reject packet!"));
651 warn("%s: Rcvd Code-Reject for code %d, id %d", 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, f); /* Cancel timeout */
673 if( f->callbacks->finished )
674 (*f->callbacks->finished)(f);
681 UNTIMEOUT(fsm_timeout, 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, f, f->timeouttime);
704 FSMDEBUG(("%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, f, f->timeouttime);
759 * fsm_sdata - Send some data.
761 * Used for all packets sent to our peer by this module.
764 fsm_sdata(f, code, id, data, datalen)
773 /* Adjust length to be smaller than MTU */
774 outp = outpacket_buf;
775 if (datalen > peer_mru[f->unit] - HEADERLEN)
776 datalen = peer_mru[f->unit] - HEADERLEN;
777 if (datalen && data != outp + PPP_HDRLEN + HEADERLEN)
778 BCOPY(data, outp + PPP_HDRLEN + HEADERLEN, datalen);
779 outlen = datalen + HEADERLEN;
780 MAKEHEADER(outp, f->protocol);
783 PUTSHORT(outlen, outp);
784 output(f->unit, outpacket_buf, outlen + PPP_HDRLEN);