2 * fsm.c - {Link, IP} Control Protocol Finite State Machine.
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43 #include "netif/ppp/ppp_opts.h"
44 #if PPP_SUPPORT /* don't build if not configured for use in lwipopts.h */
48 * Randomize fsm id on link/init.
49 * Deal with variable outgoing MTU.
55 #include <sys/types.h>
58 #include "netif/ppp/ppp_impl.h"
60 #include "netif/ppp/fsm.h"
62 static void fsm_timeout (void *);
63 static void fsm_rconfreq(fsm *f, u_char id, u_char *inp, int len);
64 static void fsm_rconfack(fsm *f, int id, u_char *inp, int len);
65 static void fsm_rconfnakrej(fsm *f, int code, int id, u_char *inp, int len);
66 static void fsm_rtermreq(fsm *f, int id, u_char *p, int len);
67 static void fsm_rtermack(fsm *f);
68 static void fsm_rcoderej(fsm *f, u_char *inp, int len);
69 static void fsm_sconfreq(fsm *f, int retransmit);
71 #define PROTO_NAME(f) ((f)->callbacks->proto_name)
74 * fsm_init - Initialize fsm.
76 * Initialize fsm state.
78 void fsm_init(fsm *f) {
79 ppp_pcb *pcb = f->pcb;
80 f->state = PPP_FSM_INITIAL;
82 f->id = 0; /* XXX Start with random id? */
83 f->maxnakloops = pcb->settings.fsm_max_nak_loops;
84 f->term_reason_len = 0;
89 * fsm_lowerup - The lower layer is up.
91 void fsm_lowerup(fsm *f) {
94 f->state = PPP_FSM_CLOSED;
97 case PPP_FSM_STARTING:
98 if( f->flags & OPT_SILENT )
99 f->state = PPP_FSM_STOPPED;
101 /* Send an initial configure-request */
103 f->state = PPP_FSM_REQSENT;
108 FSMDEBUG(("%s: Up event in state %d!", PROTO_NAME(f), f->state));
115 * fsm_lowerdown - The lower layer is down.
117 * Cancel all timeouts and inform upper layers.
119 void fsm_lowerdown(fsm *f) {
122 f->state = PPP_FSM_INITIAL;
125 case PPP_FSM_STOPPED:
126 f->state = PPP_FSM_STARTING;
127 if( f->callbacks->starting )
128 (*f->callbacks->starting)(f);
131 case PPP_FSM_CLOSING:
132 f->state = PPP_FSM_INITIAL;
133 UNTIMEOUT(fsm_timeout, f); /* Cancel timeout */
136 case PPP_FSM_STOPPING:
137 case PPP_FSM_REQSENT:
138 case PPP_FSM_ACKRCVD:
139 case PPP_FSM_ACKSENT:
140 f->state = PPP_FSM_STARTING;
141 UNTIMEOUT(fsm_timeout, f); /* Cancel timeout */
145 if( f->callbacks->down )
146 (*f->callbacks->down)(f);
147 f->state = PPP_FSM_STARTING;
151 FSMDEBUG(("%s: Down event in state %d!", PROTO_NAME(f), f->state));
158 * fsm_open - Link is allowed to come up.
160 void fsm_open(fsm *f) {
162 case PPP_FSM_INITIAL:
163 f->state = PPP_FSM_STARTING;
164 if( f->callbacks->starting )
165 (*f->callbacks->starting)(f);
169 if( f->flags & OPT_SILENT )
170 f->state = PPP_FSM_STOPPED;
172 /* Send an initial configure-request */
174 f->state = PPP_FSM_REQSENT;
178 case PPP_FSM_CLOSING:
179 f->state = PPP_FSM_STOPPING;
182 case PPP_FSM_STOPPED:
184 if( f->flags & OPT_RESTART ){
195 * terminate_layer - Start process of shutting down the FSM
197 * Cancel any timeout running, notify upper layers we're done, and
198 * send a terminate-request message as configured.
200 static void terminate_layer(fsm *f, int nextstate) {
201 ppp_pcb *pcb = f->pcb;
203 if( f->state != PPP_FSM_OPENED )
204 UNTIMEOUT(fsm_timeout, f); /* Cancel timeout */
205 else if( f->callbacks->down )
206 (*f->callbacks->down)(f); /* Inform upper layers we're down */
208 /* Init restart counter and send Terminate-Request */
209 f->retransmits = pcb->settings.fsm_max_term_transmits;
210 fsm_sdata(f, TERMREQ, f->reqid = ++f->id,
211 (const u_char *) f->term_reason, f->term_reason_len);
213 if (f->retransmits == 0) {
215 * User asked for no terminate requests at all; just close it.
216 * We've already fired off one Terminate-Request just to be nice
217 * to the peer, but we're not going to wait for a reply.
219 f->state = nextstate == PPP_FSM_CLOSING ? PPP_FSM_CLOSED : PPP_FSM_STOPPED;
220 if( f->callbacks->finished )
221 (*f->callbacks->finished)(f);
225 TIMEOUT(fsm_timeout, f, pcb->settings.fsm_timeout_time);
228 f->state = nextstate;
232 * fsm_close - Start closing connection.
234 * Cancel timeouts and either initiate close or possibly go directly to
235 * the PPP_FSM_CLOSED state.
237 void fsm_close(fsm *f, const char *reason) {
238 f->term_reason = reason;
239 f->term_reason_len = (reason == NULL? 0: LWIP_MIN(strlen(reason), 0xFF) );
241 case PPP_FSM_STARTING:
242 f->state = PPP_FSM_INITIAL;
244 case PPP_FSM_STOPPED:
245 f->state = PPP_FSM_CLOSED;
247 case PPP_FSM_STOPPING:
248 f->state = PPP_FSM_CLOSING;
251 case PPP_FSM_REQSENT:
252 case PPP_FSM_ACKRCVD:
253 case PPP_FSM_ACKSENT:
255 terminate_layer(f, PPP_FSM_CLOSING);
264 * fsm_timeout - Timeout expired.
266 static void fsm_timeout(void *arg) {
267 fsm *f = (fsm *) arg;
268 ppp_pcb *pcb = f->pcb;
271 case PPP_FSM_CLOSING:
272 case PPP_FSM_STOPPING:
273 if( f->retransmits <= 0 ){
275 * We've waited for an ack long enough. Peer probably heard us.
277 f->state = (f->state == PPP_FSM_CLOSING)? PPP_FSM_CLOSED: PPP_FSM_STOPPED;
278 if( f->callbacks->finished )
279 (*f->callbacks->finished)(f);
281 /* Send Terminate-Request */
282 fsm_sdata(f, TERMREQ, f->reqid = ++f->id,
283 (const u_char *) f->term_reason, f->term_reason_len);
284 TIMEOUT(fsm_timeout, f, pcb->settings.fsm_timeout_time);
289 case PPP_FSM_REQSENT:
290 case PPP_FSM_ACKRCVD:
291 case PPP_FSM_ACKSENT:
292 if (f->retransmits <= 0) {
293 ppp_warn("%s: timeout sending Config-Requests", PROTO_NAME(f));
294 f->state = PPP_FSM_STOPPED;
295 if( (f->flags & OPT_PASSIVE) == 0 && f->callbacks->finished )
296 (*f->callbacks->finished)(f);
299 /* Retransmit the configure-request */
300 if (f->callbacks->retransmit)
301 (*f->callbacks->retransmit)(f);
302 fsm_sconfreq(f, 1); /* Re-send Configure-Request */
303 if( f->state == PPP_FSM_ACKRCVD )
304 f->state = PPP_FSM_REQSENT;
309 FSMDEBUG(("%s: Timeout event in state %d!", PROTO_NAME(f), f->state));
316 * fsm_input - Input packet.
318 void fsm_input(fsm *f, u_char *inpacket, int l) {
324 * Parse header (code, id and length).
325 * If packet too short, drop it.
329 FSMDEBUG(("fsm_input(%x): Rcvd short header.", f->protocol));
335 if (len < HEADERLEN) {
336 FSMDEBUG(("fsm_input(%x): Rcvd illegal length.", f->protocol));
340 FSMDEBUG(("fsm_input(%x): Rcvd short packet.", f->protocol));
343 len -= HEADERLEN; /* subtract header length */
345 if( f->state == PPP_FSM_INITIAL || f->state == PPP_FSM_STARTING ){
346 FSMDEBUG(("fsm_input(%x): Rcvd packet in state %d.",
347 f->protocol, f->state));
352 * Action depends on code.
356 fsm_rconfreq(f, id, inp, len);
360 fsm_rconfack(f, id, inp, len);
365 fsm_rconfnakrej(f, code, id, inp, len);
369 fsm_rtermreq(f, id, inp, len);
377 fsm_rcoderej(f, inp, len);
381 if( !f->callbacks->extcode
382 || !(*f->callbacks->extcode)(f, code, id, inp, len) )
383 fsm_sdata(f, CODEREJ, ++f->id, inpacket, len + HEADERLEN);
390 * fsm_rconfreq - Receive Configure-Request.
392 static void fsm_rconfreq(fsm *f, u_char id, u_char *inp, int len) {
393 int code, reject_if_disagree;
397 /* Go away, we're closed */
398 fsm_sdata(f, TERMACK, id, NULL, 0);
400 case PPP_FSM_CLOSING:
401 case PPP_FSM_STOPPING:
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 */
409 f->state = PPP_FSM_REQSENT;
412 case PPP_FSM_STOPPED:
413 /* Negotiation started by our peer */
414 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
415 f->state = PPP_FSM_REQSENT;
422 * Pass the requested configuration options
423 * to protocol-specific code for checking.
425 if (f->callbacks->reqci){ /* Check CI */
426 reject_if_disagree = (f->nakloops >= f->maxnakloops);
427 code = (*f->callbacks->reqci)(f, inp, &len, reject_if_disagree);
429 code = CONFREJ; /* Reject all CI */
433 /* send the Ack, Nak or Rej to the peer */
434 fsm_sdata(f, code, id, inp, len);
436 if (code == CONFACK) {
437 if (f->state == PPP_FSM_ACKRCVD) {
438 UNTIMEOUT(fsm_timeout, f); /* Cancel timeout */
439 f->state = PPP_FSM_OPENED;
440 if (f->callbacks->up)
441 (*f->callbacks->up)(f); /* Inform upper layers */
443 f->state = PPP_FSM_ACKSENT;
447 /* we sent CONFACK or CONFREJ */
448 if (f->state != PPP_FSM_ACKRCVD)
449 f->state = PPP_FSM_REQSENT;
450 if( code == CONFNAK )
457 * fsm_rconfack - Receive Configure-Ack.
459 static void fsm_rconfack(fsm *f, int id, u_char *inp, int len) {
460 ppp_pcb *pcb = f->pcb;
462 if (id != f->reqid || f->seen_ack) /* Expected id? */
463 return; /* Nope, toss... */
464 if( !(f->callbacks->ackci? (*f->callbacks->ackci)(f, inp, len):
466 /* Ack is bad - ignore it */
467 ppp_error("Received bad configure-ack: %P", inp, len);
475 case PPP_FSM_STOPPED:
476 fsm_sdata(f, TERMACK, id, NULL, 0);
479 case PPP_FSM_REQSENT:
480 f->state = PPP_FSM_ACKRCVD;
481 f->retransmits = pcb->settings.fsm_max_conf_req_transmits;
484 case PPP_FSM_ACKRCVD:
485 /* Huh? an extra valid Ack? oh well... */
486 UNTIMEOUT(fsm_timeout, f); /* Cancel timeout */
488 f->state = PPP_FSM_REQSENT;
491 case PPP_FSM_ACKSENT:
492 UNTIMEOUT(fsm_timeout, f); /* Cancel timeout */
493 f->state = PPP_FSM_OPENED;
494 f->retransmits = pcb->settings.fsm_max_conf_req_transmits;
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 */
504 f->state = PPP_FSM_REQSENT;
513 * fsm_rconfnakrej - Receive Configure-Nak or Configure-Reject.
515 static void fsm_rconfnakrej(fsm *f, int code, int id, u_char *inp, int len) {
519 if (id != f->reqid || f->seen_ack) /* Expected id? */
520 return; /* Nope, toss... */
522 if (code == CONFNAK) {
524 treat_as_reject = (f->rnakloops >= f->maxnakloops);
525 if (f->callbacks->nakci == NULL
526 || !(ret = f->callbacks->nakci(f, inp, len, treat_as_reject))) {
527 ppp_error("Received bad configure-nak: %P", inp, len);
532 if (f->callbacks->rejci == NULL
533 || !(ret = f->callbacks->rejci(f, inp, len))) {
534 ppp_error("Received bad configure-rej: %P", inp, len);
543 case PPP_FSM_STOPPED:
544 fsm_sdata(f, TERMACK, id, NULL, 0);
547 case PPP_FSM_REQSENT:
548 case PPP_FSM_ACKSENT:
549 /* They didn't agree to what we wanted - try another request */
550 UNTIMEOUT(fsm_timeout, f); /* Cancel timeout */
552 f->state = PPP_FSM_STOPPED; /* kludge for stopping CCP */
554 fsm_sconfreq(f, 0); /* Send Configure-Request */
557 case PPP_FSM_ACKRCVD:
558 /* Got a Nak/reject when we had already had an Ack?? oh well... */
559 UNTIMEOUT(fsm_timeout, f); /* Cancel timeout */
561 f->state = PPP_FSM_REQSENT;
565 /* Go down and restart negotiation */
566 if (f->callbacks->down)
567 (*f->callbacks->down)(f); /* Inform upper layers */
568 fsm_sconfreq(f, 0); /* Send initial Configure-Request */
569 f->state = PPP_FSM_REQSENT;
578 * fsm_rtermreq - Receive Terminate-Req.
580 static void fsm_rtermreq(fsm *f, int id, u_char *p, int len) {
581 ppp_pcb *pcb = f->pcb;
584 case PPP_FSM_ACKRCVD:
585 case PPP_FSM_ACKSENT:
586 f->state = PPP_FSM_REQSENT; /* Start over but keep trying */
591 ppp_info("%s terminated by peer (%0.*v)", PROTO_NAME(f), len, p);
593 ppp_info("%s terminated by peer", PROTO_NAME(f));
595 f->state = PPP_FSM_STOPPING;
596 if (f->callbacks->down)
597 (*f->callbacks->down)(f); /* Inform upper layers */
598 TIMEOUT(fsm_timeout, f, pcb->settings.fsm_timeout_time);
604 fsm_sdata(f, TERMACK, id, NULL, 0);
609 * fsm_rtermack - Receive Terminate-Ack.
611 static void fsm_rtermack(fsm *f) {
613 case PPP_FSM_CLOSING:
614 UNTIMEOUT(fsm_timeout, f);
615 f->state = PPP_FSM_CLOSED;
616 if( f->callbacks->finished )
617 (*f->callbacks->finished)(f);
619 case PPP_FSM_STOPPING:
620 UNTIMEOUT(fsm_timeout, f);
621 f->state = PPP_FSM_STOPPED;
622 if( f->callbacks->finished )
623 (*f->callbacks->finished)(f);
626 case PPP_FSM_ACKRCVD:
627 f->state = PPP_FSM_REQSENT;
631 if (f->callbacks->down)
632 (*f->callbacks->down)(f); /* Inform upper layers */
634 f->state = PPP_FSM_REQSENT;
643 * fsm_rcoderej - Receive an Code-Reject.
645 static void fsm_rcoderej(fsm *f, u_char *inp, int len) {
648 if (len < HEADERLEN) {
649 FSMDEBUG(("fsm_rcoderej: Rcvd short Code-Reject packet!"));
654 ppp_warn("%s: Rcvd Code-Reject for code %d, id %d", PROTO_NAME(f), code, id);
656 if( f->state == PPP_FSM_ACKRCVD )
657 f->state = PPP_FSM_REQSENT;
662 * fsm_protreject - Peer doesn't speak this protocol.
664 * Treat this as a catastrophic error (RXJ-).
666 void fsm_protreject(fsm *f) {
668 case PPP_FSM_CLOSING:
669 UNTIMEOUT(fsm_timeout, f); /* Cancel timeout */
673 f->state = PPP_FSM_CLOSED;
674 if( f->callbacks->finished )
675 (*f->callbacks->finished)(f);
678 case PPP_FSM_STOPPING:
679 case PPP_FSM_REQSENT:
680 case PPP_FSM_ACKRCVD:
681 case PPP_FSM_ACKSENT:
682 UNTIMEOUT(fsm_timeout, f); /* Cancel timeout */
685 case PPP_FSM_STOPPED:
686 f->state = PPP_FSM_STOPPED;
687 if( f->callbacks->finished )
688 (*f->callbacks->finished)(f);
692 terminate_layer(f, PPP_FSM_STOPPING);
696 FSMDEBUG(("%s: Protocol-reject event in state %d!",
697 PROTO_NAME(f), f->state));
704 * fsm_sconfreq - Send a Configure-Request.
706 static void fsm_sconfreq(fsm *f, int retransmit) {
707 ppp_pcb *pcb = f->pcb;
712 if( f->state != PPP_FSM_REQSENT && f->state != PPP_FSM_ACKRCVD && f->state != PPP_FSM_ACKSENT ){
713 /* Not currently negotiating - reset options */
714 if( f->callbacks->resetci )
715 (*f->callbacks->resetci)(f);
721 /* New request - reset retransmission counter, use new ID */
722 f->retransmits = pcb->settings.fsm_max_conf_req_transmits;
729 * Make up the request packet
731 if( f->callbacks->cilen && f->callbacks->addci ){
732 cilen = (*f->callbacks->cilen)(f);
733 if( cilen > pcb->peer_mru - HEADERLEN )
734 cilen = pcb->peer_mru - HEADERLEN;
738 p = pbuf_alloc(PBUF_RAW, (u16_t)(cilen + HEADERLEN + PPP_HDRLEN), PPP_CTRL_PBUF_TYPE);
741 if(p->tot_len != p->len) {
746 /* send the request to our peer */
747 outp = (u_char*)p->payload;
748 MAKEHEADER(outp, f->protocol);
749 PUTCHAR(CONFREQ, outp);
750 PUTCHAR(f->reqid, outp);
751 PUTSHORT(cilen + HEADERLEN, outp);
753 (*f->callbacks->addci)(f, outp, &cilen);
754 LWIP_ASSERT("cilen == p->len - HEADERLEN - PPP_HDRLEN", cilen == p->len - HEADERLEN - PPP_HDRLEN);
759 /* start the retransmit timer */
761 TIMEOUT(fsm_timeout, f, pcb->settings.fsm_timeout_time);
766 * fsm_sdata - Send some data.
768 * Used for all packets sent to our peer by this module.
770 void fsm_sdata(fsm *f, u_char code, u_char id, const u_char *data, int datalen) {
771 ppp_pcb *pcb = f->pcb;
776 /* Adjust length to be smaller than MTU */
777 if (datalen > pcb->peer_mru - HEADERLEN)
778 datalen = pcb->peer_mru - HEADERLEN;
779 outlen = datalen + HEADERLEN;
781 p = pbuf_alloc(PBUF_RAW, (u16_t)(outlen + PPP_HDRLEN), PPP_CTRL_PBUF_TYPE);
784 if(p->tot_len != p->len) {
789 outp = (u_char*)p->payload;
790 if (datalen) /* && data != outp + PPP_HDRLEN + HEADERLEN) -- was only for fsm_sconfreq() */
791 MEMCPY(outp + PPP_HDRLEN + HEADERLEN, data, datalen);
792 MAKEHEADER(outp, f->protocol);
795 PUTSHORT(outlen, outp);
799 #endif /* PPP_SUPPORT */