xref: /freebsd/usr.sbin/ppp/fsm.c (revision 9e8ec64b6b4ce05e891f1c4d21a40c57c57ae931)
1 /*
2  *		PPP Finite State Machine for LCP/IPCP
3  *
4  *	    Written by Toshiharu OHNO (tony-o@iij.ad.jp)
5  *
6  *   Copyright (C) 1993, Internet Initiative Japan, Inc. All rights reserverd.
7  *
8  * Redistribution and use in source and binary forms are permitted
9  * provided that the above copyright notice and this paragraph are
10  * duplicated in all such forms and that any documentation,
11  * advertising materials, and other materials related to such
12  * distribution and use acknowledge that the software was developed
13  * by the Internet Initiative Japan, Inc.  The name of the
14  * IIJ may not be used to endorse or promote products derived
15  * from this software without specific prior written permission.
16  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
17  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
18  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
19  *
20  * $Id: fsm.c,v 1.36 1998/08/01 01:02:41 brian Exp $
21  *
22  *  TODO:
23  */
24 
25 #include <sys/types.h>
26 #include <netinet/in.h>
27 #include <netinet/in_systm.h>
28 #include <netinet/ip.h>
29 #include <sys/un.h>
30 
31 #include <string.h>
32 #include <termios.h>
33 
34 #include "ua.h"
35 #include "mbuf.h"
36 #include "log.h"
37 #include "defs.h"
38 #include "timer.h"
39 #include "fsm.h"
40 #include "iplist.h"
41 #include "lqr.h"
42 #include "hdlc.h"
43 #include "throughput.h"
44 #include "slcompress.h"
45 #include "ipcp.h"
46 #include "filter.h"
47 #include "descriptor.h"
48 #include "lcp.h"
49 #include "ccp.h"
50 #include "link.h"
51 #include "mp.h"
52 #include "bundle.h"
53 #include "async.h"
54 #include "physical.h"
55 #include "lcpproto.h"
56 
57 static void FsmSendConfigReq(struct fsm *);
58 static void FsmSendTerminateReq(struct fsm *);
59 static void FsmInitRestartCounter(struct fsm *);
60 
61 typedef void (recvfn)(struct fsm *, struct fsmheader *, struct mbuf *);
62 static recvfn FsmRecvConfigReq, FsmRecvConfigAck, FsmRecvConfigNak,
63               FsmRecvConfigRej, FsmRecvTermReq, FsmRecvTermAck,
64               FsmRecvCodeRej, FsmRecvProtoRej, FsmRecvEchoReq,
65               FsmRecvEchoRep, FsmRecvDiscReq, FsmRecvIdent,
66               FsmRecvTimeRemain, FsmRecvResetReq, FsmRecvResetAck;
67 
68 static const struct fsmcodedesc {
69   recvfn *recv;
70   unsigned check_reqid : 1;
71   unsigned inc_reqid : 1;
72   const char *name;
73 } FsmCodes[] = {
74   { FsmRecvConfigReq, 0, 0, "ConfigReq"    },
75   { FsmRecvConfigAck, 1, 1, "ConfigAck"    },
76   { FsmRecvConfigNak, 1, 1, "ConfigNak"    },
77   { FsmRecvConfigRej, 1, 1, "ConfigRej"    },
78   { FsmRecvTermReq,   0, 0, "TerminateReq" },
79   { FsmRecvTermAck,   1, 1, "TerminateAck" },
80   { FsmRecvCodeRej,   0, 0, "CodeRej"      },
81   { FsmRecvProtoRej,  0, 0, "ProtocolRej"  },
82   { FsmRecvEchoReq,   0, 0, "EchoRequest"  },
83   { FsmRecvEchoRep,   0, 0, "EchoReply"    },
84   { FsmRecvDiscReq,   0, 0, "DiscardReq"   },
85   { FsmRecvIdent,     0, 0, "Ident"        },
86   { FsmRecvTimeRemain,0, 0, "TimeRemain"   },
87   { FsmRecvResetReq,  0, 0, "ResetReqt"    },
88   { FsmRecvResetAck,  0, 1, "ResetAck"     }
89 };
90 
91 static const char *
92 Code2Nam(u_int code)
93 {
94   if (code == 0 || code > sizeof FsmCodes / sizeof FsmCodes[0])
95     return "Unknown";
96   return FsmCodes[code-1].name;
97 }
98 
99 const char *
100 State2Nam(u_int state)
101 {
102   static const char *StateNames[] = {
103     "Initial", "Starting", "Closed", "Stopped", "Closing", "Stopping",
104     "Req-Sent", "Ack-Rcvd", "Ack-Sent", "Opened",
105   };
106 
107   if (state >= sizeof StateNames / sizeof StateNames[0])
108     return "unknown";
109   return StateNames[state];
110 }
111 
112 static void
113 StoppedTimeout(void *v)
114 {
115   struct fsm *fp = (struct fsm *)v;
116 
117   log_Printf(fp->LogLevel, "%s: Stopped timer expired\n", fp->link->name);
118   if (fp->OpenTimer.state == TIMER_RUNNING) {
119     log_Printf(LogWARN, "%s: %s: aborting open delay due to stopped timer\n",
120               fp->link->name, fp->name);
121     timer_Stop(&fp->OpenTimer);
122   }
123   if (fp->state == ST_STOPPED)
124     fsm2initial(fp);
125 }
126 
127 void
128 fsm_Init(struct fsm *fp, const char *name, u_short proto, int mincode,
129          int maxcode, int maxcfg, int LogLevel, struct bundle *bundle,
130          struct link *l, const struct fsm_parent *parent,
131          struct fsm_callbacks *fn, const char *timer_names[3])
132 {
133   fp->name = name;
134   fp->proto = proto;
135   fp->min_code = mincode;
136   fp->max_code = maxcode;
137   fp->state = fp->min_code > CODE_TERMACK ? ST_OPENED : ST_INITIAL;
138   fp->reqid = 1;
139   fp->restart = 1;
140   fp->maxconfig = maxcfg;
141   memset(&fp->FsmTimer, '\0', sizeof fp->FsmTimer);
142   memset(&fp->OpenTimer, '\0', sizeof fp->OpenTimer);
143   memset(&fp->StoppedTimer, '\0', sizeof fp->StoppedTimer);
144   fp->LogLevel = LogLevel;
145   fp->link = l;
146   fp->bundle = bundle;
147   fp->parent = parent;
148   fp->fn = fn;
149   fp->FsmTimer.name = timer_names[0];
150   fp->OpenTimer.name = timer_names[1];
151   fp->StoppedTimer.name = timer_names[2];
152 }
153 
154 static void
155 NewState(struct fsm * fp, int new)
156 {
157   log_Printf(fp->LogLevel, "%s: State change %s --> %s\n",
158 	    fp->link->name, State2Nam(fp->state), State2Nam(new));
159   if (fp->state == ST_STOPPED && fp->StoppedTimer.state == TIMER_RUNNING)
160     timer_Stop(&fp->StoppedTimer);
161   fp->state = new;
162   if ((new >= ST_INITIAL && new <= ST_STOPPED) || (new == ST_OPENED)) {
163     timer_Stop(&fp->FsmTimer);
164     if (new == ST_STOPPED && fp->StoppedTimer.load) {
165       timer_Stop(&fp->StoppedTimer);
166       fp->StoppedTimer.func = StoppedTimeout;
167       fp->StoppedTimer.arg = (void *) fp;
168       timer_Start(&fp->StoppedTimer);
169     }
170   }
171 }
172 
173 void
174 fsm_Output(struct fsm *fp, u_int code, u_int id, u_char *ptr, int count)
175 {
176   int plen;
177   struct fsmheader lh;
178   struct mbuf *bp;
179 
180   if (log_IsKept(fp->LogLevel)) {
181     log_Printf(fp->LogLevel, "%s: Send%s(%d) state = %s\n",
182               fp->link->name, Code2Nam(code), id, State2Nam(fp->state));
183     switch (code) {
184       case CODE_CONFIGREQ:
185       case CODE_CONFIGACK:
186       case CODE_CONFIGREJ:
187       case CODE_CONFIGNAK:
188         (*fp->fn->DecodeConfig)(fp, ptr, count, MODE_NOP, NULL);
189         if (count < sizeof(struct fsmconfig))
190           log_Printf(fp->LogLevel, "  [EMPTY]\n");
191         break;
192     }
193   }
194 
195   plen = sizeof(struct fsmheader) + count;
196   lh.code = code;
197   lh.id = id;
198   lh.length = htons(plen);
199   bp = mbuf_Alloc(plen, MB_FSM);
200   memcpy(MBUF_CTOP(bp), &lh, sizeof(struct fsmheader));
201   if (count)
202     memcpy(MBUF_CTOP(bp) + sizeof(struct fsmheader), ptr, count);
203   log_DumpBp(LogDEBUG, "fsm_Output", bp);
204   hdlc_Output(fp->link, PRI_LINK, fp->proto, bp);
205 }
206 
207 static void
208 FsmOpenNow(void *v)
209 {
210   struct fsm *fp = (struct fsm *)v;
211 
212   timer_Stop(&fp->OpenTimer);
213   if (fp->state <= ST_STOPPED) {
214     if (fp->state != ST_STARTING) {
215       /*
216        * In practice, we're only here in ST_STOPPED (when delaying the
217        * first config request) or ST_CLOSED (when openmode == 0).
218        *
219        * The ST_STOPPED bit is breaking the RFC already :-(
220        *
221        * According to the RFC (1661) state transition table, a TLS isn't
222        * required for an Open event when state == Closed, but the RFC
223        * must be wrong as TLS hasn't yet been called (since the last TLF)
224        * ie, Initial gets an `Up' event, Closing gets a RTA etc.
225        */
226       (*fp->fn->LayerStart)(fp);
227       (*fp->parent->LayerStart)(fp->parent->object, fp);
228     }
229     FsmInitRestartCounter(fp);
230     FsmSendConfigReq(fp);
231     NewState(fp, ST_REQSENT);
232   }
233 }
234 
235 void
236 fsm_Open(struct fsm * fp)
237 {
238   switch (fp->state) {
239   case ST_INITIAL:
240     NewState(fp, ST_STARTING);
241     (*fp->fn->LayerStart)(fp);
242     (*fp->parent->LayerStart)(fp->parent->object, fp);
243     break;
244   case ST_CLOSED:
245     if (fp->open_mode == OPEN_PASSIVE) {
246       NewState(fp, ST_STOPPED);		/* XXX: This is a hack ! */
247     } else if (fp->open_mode > 0) {
248       if (fp->open_mode > 1)
249         log_Printf(LogPHASE, "%s: Entering STOPPED state for %d seconds\n",
250                   fp->link->name, fp->open_mode);
251       NewState(fp, ST_STOPPED);		/* XXX: This is a not-so-bad hack ! */
252       timer_Stop(&fp->OpenTimer);
253       fp->OpenTimer.load = fp->open_mode * SECTICKS;
254       fp->OpenTimer.func = FsmOpenNow;
255       fp->OpenTimer.arg = (void *)fp;
256       timer_Start(&fp->OpenTimer);
257     } else
258       FsmOpenNow(fp);
259     break;
260   case ST_STOPPED:		/* XXX: restart option */
261   case ST_REQSENT:
262   case ST_ACKRCVD:
263   case ST_ACKSENT:
264   case ST_OPENED:		/* XXX: restart option */
265     break;
266   case ST_CLOSING:		/* XXX: restart option */
267   case ST_STOPPING:		/* XXX: restart option */
268     NewState(fp, ST_STOPPING);
269     break;
270   }
271 }
272 
273 void
274 fsm_Up(struct fsm * fp)
275 {
276   switch (fp->state) {
277   case ST_INITIAL:
278     log_Printf(fp->LogLevel, "FSM: Using \"%s\" as a transport\n",
279               fp->link->name);
280     NewState(fp, ST_CLOSED);
281     break;
282   case ST_STARTING:
283     FsmInitRestartCounter(fp);
284     FsmSendConfigReq(fp);
285     NewState(fp, ST_REQSENT);
286     break;
287   default:
288     log_Printf(fp->LogLevel, "%s: Oops, Up at %s\n",
289               fp->link->name, State2Nam(fp->state));
290     break;
291   }
292 }
293 
294 void
295 fsm_Down(struct fsm *fp)
296 {
297   switch (fp->state) {
298   case ST_CLOSED:
299     NewState(fp, ST_INITIAL);
300     break;
301   case ST_CLOSING:
302     (*fp->fn->LayerFinish)(fp);
303     NewState(fp, ST_INITIAL);
304     (*fp->parent->LayerFinish)(fp->parent->object, fp);
305     break;
306   case ST_STOPPED:
307     NewState(fp, ST_STARTING);
308     (*fp->fn->LayerStart)(fp);
309     (*fp->parent->LayerStart)(fp->parent->object, fp);
310     break;
311   case ST_STOPPING:
312   case ST_REQSENT:
313   case ST_ACKRCVD:
314   case ST_ACKSENT:
315     NewState(fp, ST_STARTING);
316     break;
317   case ST_OPENED:
318     (*fp->fn->LayerDown)(fp);
319     NewState(fp, ST_STARTING);
320     (*fp->parent->LayerDown)(fp->parent->object, fp);
321     break;
322   }
323 }
324 
325 void
326 fsm_Close(struct fsm *fp)
327 {
328   switch (fp->state) {
329   case ST_STARTING:
330     (*fp->fn->LayerFinish)(fp);
331     NewState(fp, ST_INITIAL);
332     (*fp->parent->LayerFinish)(fp->parent->object, fp);
333     break;
334   case ST_STOPPED:
335     NewState(fp, ST_CLOSED);
336     break;
337   case ST_STOPPING:
338     NewState(fp, ST_CLOSING);
339     break;
340   case ST_OPENED:
341     (*fp->fn->LayerDown)(fp);
342     FsmInitRestartCounter(fp);
343     FsmSendTerminateReq(fp);
344     NewState(fp, ST_CLOSING);
345     (*fp->parent->LayerDown)(fp->parent->object, fp);
346     break;
347   case ST_REQSENT:
348   case ST_ACKRCVD:
349   case ST_ACKSENT:
350     FsmInitRestartCounter(fp);
351     FsmSendTerminateReq(fp);
352     NewState(fp, ST_CLOSING);
353     break;
354   }
355 }
356 
357 /*
358  *	Send functions
359  */
360 static void
361 FsmSendConfigReq(struct fsm * fp)
362 {
363   if (--fp->maxconfig > 0) {
364     (*fp->fn->SendConfigReq)(fp);
365     timer_Start(&fp->FsmTimer);	/* Start restart timer */
366     fp->restart--;		/* Decrement restart counter */
367   } else {
368     fsm_Close(fp);
369   }
370 }
371 
372 static void
373 FsmSendTerminateReq(struct fsm *fp)
374 {
375   fsm_Output(fp, CODE_TERMREQ, fp->reqid, NULL, 0);
376   (*fp->fn->SentTerminateReq)(fp);
377   timer_Start(&fp->FsmTimer);	/* Start restart timer */
378   fp->restart--;		/* Decrement restart counter */
379 }
380 
381 /*
382  *	Timeout actions
383  */
384 static void
385 FsmTimeout(void *v)
386 {
387   struct fsm *fp = (struct fsm *)v;
388 
389   if (fp->restart) {
390     switch (fp->state) {
391     case ST_CLOSING:
392     case ST_STOPPING:
393       FsmSendTerminateReq(fp);
394       break;
395     case ST_REQSENT:
396     case ST_ACKSENT:
397       FsmSendConfigReq(fp);
398       break;
399     case ST_ACKRCVD:
400       FsmSendConfigReq(fp);
401       NewState(fp, ST_REQSENT);
402       break;
403     }
404     timer_Start(&fp->FsmTimer);
405   } else {
406     switch (fp->state) {
407     case ST_CLOSING:
408       (*fp->fn->LayerFinish)(fp);
409       NewState(fp, ST_CLOSED);
410       (*fp->parent->LayerFinish)(fp->parent->object, fp);
411       break;
412     case ST_STOPPING:
413       (*fp->fn->LayerFinish)(fp);
414       NewState(fp, ST_STOPPED);
415       (*fp->parent->LayerFinish)(fp->parent->object, fp);
416       break;
417     case ST_REQSENT:		/* XXX: 3p */
418     case ST_ACKSENT:
419     case ST_ACKRCVD:
420       (*fp->fn->LayerFinish)(fp);
421       NewState(fp, ST_STOPPED);
422       (*fp->parent->LayerFinish)(fp->parent->object, fp);
423       break;
424     }
425   }
426 }
427 
428 static void
429 FsmInitRestartCounter(struct fsm * fp)
430 {
431   timer_Stop(&fp->FsmTimer);
432   fp->FsmTimer.func = FsmTimeout;
433   fp->FsmTimer.arg = (void *) fp;
434   (*fp->fn->InitRestartCounter)(fp);
435 }
436 
437 /*
438  *   Actions when receive packets
439  */
440 static void
441 FsmRecvConfigReq(struct fsm *fp, struct fsmheader *lhp, struct mbuf *bp)
442 /* RCR */
443 {
444   struct fsm_decode dec;
445   int plen, flen;
446   int ackaction = 0;
447 
448   plen = mbuf_Length(bp);
449   flen = ntohs(lhp->length) - sizeof *lhp;
450   if (plen < flen) {
451     log_Printf(LogWARN, "%s: FsmRecvConfigReq: plen (%d) < flen (%d)\n",
452 	      fp->link->name, plen, flen);
453     mbuf_Free(bp);
454     return;
455   }
456 
457   /*
458    * Check and process easy case
459    */
460   switch (fp->state) {
461   case ST_INITIAL:
462     if (fp->proto == PROTO_CCP && fp->link->lcp.fsm.state == ST_OPENED) {
463       /*
464        * ccp_SetOpenMode() leaves us in initial if we're disabling
465        * & denying everything.  This is a bit smelly, we know that
466        * ``bp'' really has ``fsmheader'' in front of it, and CCP_PROTO
467        * in front of that.  CCP_PROTO isn't compressed either 'cos it
468        * doesn't begin with 0x00....
469        */
470       bp->offset -= sizeof(struct fsmheader) + 2;
471       bp->cnt += sizeof(struct fsmheader) + 2;
472       lcp_SendProtoRej(&fp->link->lcp, MBUF_CTOP(bp), bp->cnt);
473       mbuf_Free(bp);
474       return;
475     }
476     /* Drop through */
477   case ST_STARTING:
478     log_Printf(fp->LogLevel, "%s: Oops, RCR in %s.\n",
479               fp->link->name, State2Nam(fp->state));
480     mbuf_Free(bp);
481     return;
482   case ST_CLOSED:
483     (*fp->fn->SendTerminateAck)(fp, lhp->id);
484     mbuf_Free(bp);
485     return;
486   case ST_CLOSING:
487     log_Printf(fp->LogLevel, "%s: Error: Got ConfigReq while state = %s\n",
488               fp->link->name, State2Nam(fp->state));
489   case ST_STOPPING:
490     mbuf_Free(bp);
491     return;
492   case ST_OPENED:
493     (*fp->fn->LayerDown)(fp);
494     (*fp->parent->LayerDown)(fp->parent->object, fp);
495     break;
496   }
497 
498   dec.ackend = dec.ack;
499   dec.nakend = dec.nak;
500   dec.rejend = dec.rej;
501   (*fp->fn->DecodeConfig)(fp, MBUF_CTOP(bp), flen, MODE_REQ, &dec);
502   if (flen < sizeof(struct fsmconfig))
503     log_Printf(fp->LogLevel, "  [EMPTY]\n");
504 
505   if (dec.nakend == dec.nak && dec.rejend == dec.rej)
506     ackaction = 1;
507 
508   switch (fp->state) {
509   case ST_STOPPED:
510     FsmInitRestartCounter(fp);
511     /* Fall through */
512 
513   case ST_OPENED:
514     FsmSendConfigReq(fp);
515     break;
516   }
517 
518   if (dec.rejend != dec.rej)
519     fsm_Output(fp, CODE_CONFIGREJ, lhp->id, dec.rej, dec.rejend - dec.rej);
520   if (dec.nakend != dec.nak)
521     fsm_Output(fp, CODE_CONFIGNAK, lhp->id, dec.nak, dec.nakend - dec.nak);
522   if (ackaction)
523     fsm_Output(fp, CODE_CONFIGACK, lhp->id, dec.ack, dec.ackend - dec.ack);
524 
525   switch (fp->state) {
526   case ST_OPENED:
527   case ST_STOPPED:
528     if (ackaction)
529       NewState(fp, ST_ACKSENT);
530     else
531       NewState(fp, ST_REQSENT);
532     break;
533   case ST_REQSENT:
534     if (ackaction)
535       NewState(fp, ST_ACKSENT);
536     break;
537   case ST_ACKRCVD:
538     if (ackaction) {
539       NewState(fp, ST_OPENED);
540       if ((*fp->fn->LayerUp)(fp))
541         (*fp->parent->LayerUp)(fp->parent->object, fp);
542       else {
543         (*fp->fn->LayerDown)(fp);
544         FsmInitRestartCounter(fp);
545         FsmSendTerminateReq(fp);
546         NewState(fp, ST_CLOSING);
547       }
548     }
549     break;
550   case ST_ACKSENT:
551     if (!ackaction)
552       NewState(fp, ST_REQSENT);
553     break;
554   }
555   mbuf_Free(bp);
556 }
557 
558 static void
559 FsmRecvConfigAck(struct fsm *fp, struct fsmheader *lhp, struct mbuf *bp)
560 /* RCA */
561 {
562   switch (fp->state) {
563     case ST_CLOSED:
564     case ST_STOPPED:
565     (*fp->fn->SendTerminateAck)(fp, lhp->id);
566     break;
567   case ST_CLOSING:
568   case ST_STOPPING:
569     break;
570   case ST_REQSENT:
571     FsmInitRestartCounter(fp);
572     NewState(fp, ST_ACKRCVD);
573     break;
574   case ST_ACKRCVD:
575     FsmSendConfigReq(fp);
576     NewState(fp, ST_REQSENT);
577     break;
578   case ST_ACKSENT:
579     FsmInitRestartCounter(fp);
580     NewState(fp, ST_OPENED);
581     if ((*fp->fn->LayerUp)(fp))
582       (*fp->parent->LayerUp)(fp->parent->object, fp);
583     else {
584       (*fp->fn->LayerDown)(fp);
585       FsmInitRestartCounter(fp);
586       FsmSendTerminateReq(fp);
587       NewState(fp, ST_CLOSING);
588     }
589     break;
590   case ST_OPENED:
591     (*fp->fn->LayerDown)(fp);
592     FsmSendConfigReq(fp);
593     NewState(fp, ST_REQSENT);
594     (*fp->parent->LayerDown)(fp->parent->object, fp);
595     break;
596   }
597   mbuf_Free(bp);
598 }
599 
600 static void
601 FsmRecvConfigNak(struct fsm *fp, struct fsmheader *lhp, struct mbuf *bp)
602 /* RCN */
603 {
604   struct fsm_decode dec;
605   int plen, flen;
606 
607   plen = mbuf_Length(bp);
608   flen = ntohs(lhp->length) - sizeof *lhp;
609   if (plen < flen) {
610     mbuf_Free(bp);
611     return;
612   }
613 
614   /*
615    * Check and process easy case
616    */
617   switch (fp->state) {
618   case ST_INITIAL:
619   case ST_STARTING:
620     log_Printf(fp->LogLevel, "%s: Oops, RCN in %s.\n",
621               fp->link->name, State2Nam(fp->state));
622     mbuf_Free(bp);
623     return;
624   case ST_CLOSED:
625   case ST_STOPPED:
626     (*fp->fn->SendTerminateAck)(fp, lhp->id);
627     mbuf_Free(bp);
628     return;
629   case ST_CLOSING:
630   case ST_STOPPING:
631     mbuf_Free(bp);
632     return;
633   }
634 
635   dec.ackend = dec.ack;
636   dec.nakend = dec.nak;
637   dec.rejend = dec.rej;
638   (*fp->fn->DecodeConfig)(fp, MBUF_CTOP(bp), flen, MODE_NAK, &dec);
639   if (flen < sizeof(struct fsmconfig))
640     log_Printf(fp->LogLevel, "  [EMPTY]\n");
641 
642   switch (fp->state) {
643   case ST_REQSENT:
644   case ST_ACKSENT:
645     FsmInitRestartCounter(fp);
646     FsmSendConfigReq(fp);
647     break;
648   case ST_OPENED:
649     (*fp->fn->LayerDown)(fp);
650     FsmSendConfigReq(fp);
651     NewState(fp, ST_REQSENT);
652     (*fp->parent->LayerDown)(fp->parent->object, fp);
653     break;
654   case ST_ACKRCVD:
655     FsmSendConfigReq(fp);
656     NewState(fp, ST_REQSENT);
657     break;
658   }
659 
660   mbuf_Free(bp);
661 }
662 
663 static void
664 FsmRecvTermReq(struct fsm *fp, struct fsmheader *lhp, struct mbuf *bp)
665 /* RTR */
666 {
667   switch (fp->state) {
668   case ST_INITIAL:
669   case ST_STARTING:
670     log_Printf(fp->LogLevel, "%s: Oops, RTR in %s\n",
671               fp->link->name, State2Nam(fp->state));
672     break;
673   case ST_CLOSED:
674   case ST_STOPPED:
675   case ST_CLOSING:
676   case ST_STOPPING:
677   case ST_REQSENT:
678     (*fp->fn->SendTerminateAck)(fp, lhp->id);
679     break;
680   case ST_ACKRCVD:
681   case ST_ACKSENT:
682     (*fp->fn->SendTerminateAck)(fp, lhp->id);
683     NewState(fp, ST_REQSENT);
684     break;
685   case ST_OPENED:
686     (*fp->fn->LayerDown)(fp);
687     (*fp->fn->SendTerminateAck)(fp, lhp->id);
688     FsmInitRestartCounter(fp);
689     timer_Start(&fp->FsmTimer);	/* Start restart timer */
690     fp->restart = 0;
691     NewState(fp, ST_STOPPING);
692     (*fp->parent->LayerDown)(fp->parent->object, fp);
693     break;
694   }
695   mbuf_Free(bp);
696 }
697 
698 static void
699 FsmRecvTermAck(struct fsm * fp, struct fsmheader * lhp, struct mbuf * bp)
700 /* RTA */
701 {
702   switch (fp->state) {
703   case ST_CLOSING:
704     (*fp->fn->LayerFinish)(fp);
705     NewState(fp, ST_CLOSED);
706     (*fp->parent->LayerFinish)(fp->parent->object, fp);
707     break;
708   case ST_STOPPING:
709     (*fp->fn->LayerFinish)(fp);
710     NewState(fp, ST_STOPPED);
711     (*fp->parent->LayerFinish)(fp->parent->object, fp);
712     break;
713   case ST_ACKRCVD:
714     NewState(fp, ST_REQSENT);
715     break;
716   case ST_OPENED:
717     (*fp->fn->LayerDown)(fp);
718     FsmSendConfigReq(fp);
719     NewState(fp, ST_REQSENT);
720     (*fp->parent->LayerDown)(fp->parent->object, fp);
721     break;
722   }
723   mbuf_Free(bp);
724 }
725 
726 static void
727 FsmRecvConfigRej(struct fsm *fp, struct fsmheader *lhp, struct mbuf *bp)
728 /* RCJ */
729 {
730   struct fsm_decode dec;
731   int plen, flen;
732 
733   plen = mbuf_Length(bp);
734   flen = ntohs(lhp->length) - sizeof *lhp;
735   if (plen < flen) {
736     mbuf_Free(bp);
737     return;
738   }
739 
740   /*
741    * Check and process easy case
742    */
743   switch (fp->state) {
744   case ST_INITIAL:
745   case ST_STARTING:
746     log_Printf(fp->LogLevel, "%s: Oops, RCJ in %s.\n",
747               fp->link->name, State2Nam(fp->state));
748     mbuf_Free(bp);
749     return;
750   case ST_CLOSED:
751   case ST_STOPPED:
752     (*fp->fn->SendTerminateAck)(fp, lhp->id);
753     mbuf_Free(bp);
754     return;
755   case ST_CLOSING:
756   case ST_STOPPING:
757     mbuf_Free(bp);
758     return;
759   }
760 
761   dec.ackend = dec.ack;
762   dec.nakend = dec.nak;
763   dec.rejend = dec.rej;
764   (*fp->fn->DecodeConfig)(fp, MBUF_CTOP(bp), flen, MODE_REJ, &dec);
765   if (flen < sizeof(struct fsmconfig))
766     log_Printf(fp->LogLevel, "  [EMPTY]\n");
767 
768   switch (fp->state) {
769   case ST_REQSENT:
770   case ST_ACKSENT:
771     FsmInitRestartCounter(fp);
772     FsmSendConfigReq(fp);
773     break;
774   case ST_OPENED:
775     (*fp->fn->LayerDown)(fp);
776     FsmSendConfigReq(fp);
777     NewState(fp, ST_REQSENT);
778     (*fp->parent->LayerDown)(fp->parent->object, fp);
779     break;
780   case ST_ACKRCVD:
781     FsmSendConfigReq(fp);
782     NewState(fp, ST_REQSENT);
783     break;
784   }
785   mbuf_Free(bp);
786 }
787 
788 static void
789 FsmRecvCodeRej(struct fsm *fp, struct fsmheader *lhp, struct mbuf *bp)
790 {
791   mbuf_Free(bp);
792 }
793 
794 static void
795 FsmRecvProtoRej(struct fsm *fp, struct fsmheader *lhp, struct mbuf *bp)
796 {
797   struct physical *p = link2physical(fp->link);
798   u_short *sp, proto;
799 
800   sp = (u_short *)MBUF_CTOP(bp);
801   proto = ntohs(*sp);
802   log_Printf(fp->LogLevel, "%s: -- Protocol 0x%04x (%s) was rejected!\n",
803             fp->link->name, proto, hdlc_Protocol2Nam(proto));
804 
805   switch (proto) {
806   case PROTO_LQR:
807     if (p)
808       lqr_Stop(p, LQM_LQR);
809     else
810       log_Printf(LogERROR, "%s: FsmRecvProtoRej: Not a physical link !\n",
811                 fp->link->name);
812     break;
813   case PROTO_CCP:
814     if (fp->proto == PROTO_LCP) {
815       fp = &fp->link->ccp.fsm;
816       (*fp->fn->LayerFinish)(fp);
817       switch (fp->state) {
818       case ST_CLOSED:
819       case ST_CLOSING:
820         NewState(fp, ST_CLOSED);
821       default:
822         NewState(fp, ST_STOPPED);
823         break;
824       }
825       (*fp->parent->LayerFinish)(fp->parent->object, fp);
826     }
827     break;
828   case PROTO_MP:
829     if (fp->proto == PROTO_LCP) {
830       struct lcp *lcp = fsm2lcp(fp);
831 
832       if (lcp->want_mrru && lcp->his_mrru) {
833         log_Printf(LogPHASE, "%s: MP protocol reject is fatal !\n",
834                   fp->link->name);
835         fsm_Close(fp);
836       }
837     }
838     break;
839   }
840   mbuf_Free(bp);
841 }
842 
843 static void
844 FsmRecvEchoReq(struct fsm *fp, struct fsmheader *lhp, struct mbuf *bp)
845 {
846   struct lcp *lcp = fsm2lcp(fp);
847   u_char *cp;
848   u_int32_t magic;
849 
850   if (lcp) {
851     cp = MBUF_CTOP(bp);
852     ua_ntohl(cp, &magic);
853     if (magic != lcp->his_magic) {
854       log_Printf(fp->LogLevel, "%s: RecvEchoReq: Error: His magic is bad!!\n",
855                 fp->link->name);
856       /* XXX: We should send terminate request */
857     }
858     if (fp->state == ST_OPENED) {
859       ua_htonl(&lcp->want_magic, cp);		/* local magic */
860       fsm_Output(fp, CODE_ECHOREP, lhp->id, cp, mbuf_Length(bp));
861     }
862   }
863   mbuf_Free(bp);
864 }
865 
866 static void
867 FsmRecvEchoRep(struct fsm *fp, struct fsmheader *lhp, struct mbuf *bp)
868 {
869   struct lcp *lcp = fsm2lcp(fp);
870   u_int32_t magic;
871 
872   if (lcp) {
873     ua_ntohl(MBUF_CTOP(bp), &magic);
874     /* Tolerate echo replies with either magic number */
875     if (magic != 0 && magic != lcp->his_magic && magic != lcp->want_magic) {
876       log_Printf(LogWARN,
877                 "%s: RecvEchoRep: Bad magic: expected 0x%08x, got: 0x%08x\n",
878 	        fp->link->name, lcp->his_magic, magic);
879       /*
880        * XXX: We should send terminate request. But poor implementations may
881        * die as a result.
882        */
883     }
884     lqr_RecvEcho(fp, bp);
885   }
886   mbuf_Free(bp);
887 }
888 
889 static void
890 FsmRecvDiscReq(struct fsm * fp, struct fsmheader * lhp, struct mbuf * bp)
891 {
892   mbuf_Free(bp);
893 }
894 
895 static void
896 FsmRecvIdent(struct fsm * fp, struct fsmheader * lhp, struct mbuf * bp)
897 {
898   mbuf_Free(bp);
899 }
900 
901 static void
902 FsmRecvTimeRemain(struct fsm * fp, struct fsmheader * lhp, struct mbuf * bp)
903 {
904   mbuf_Free(bp);
905 }
906 
907 static void
908 FsmRecvResetReq(struct fsm *fp, struct fsmheader *lhp, struct mbuf *bp)
909 {
910   (*fp->fn->RecvResetReq)(fp);
911   /*
912    * All sendable compressed packets are queued in the PRI_NORMAL modem
913    * output queue.... dump 'em to the priority queue so that they arrive
914    * at the peer before our ResetAck.
915    */
916   link_SequenceQueue(fp->link);
917   fsm_Output(fp, CODE_RESETACK, lhp->id, NULL, 0);
918   mbuf_Free(bp);
919 }
920 
921 static void
922 FsmRecvResetAck(struct fsm *fp, struct fsmheader *lhp, struct mbuf *bp)
923 {
924   (*fp->fn->RecvResetAck)(fp, lhp->id);
925   mbuf_Free(bp);
926 }
927 
928 void
929 fsm_Input(struct fsm *fp, struct mbuf *bp)
930 {
931   int len;
932   struct fsmheader *lhp;
933   const struct fsmcodedesc *codep;
934 
935   len = mbuf_Length(bp);
936   if (len < sizeof(struct fsmheader)) {
937     mbuf_Free(bp);
938     return;
939   }
940   lhp = (struct fsmheader *) MBUF_CTOP(bp);
941   if (lhp->code < fp->min_code || lhp->code > fp->max_code ||
942       lhp->code > sizeof FsmCodes / sizeof *FsmCodes) {
943     /*
944      * Use a private id.  This is really a response-type packet, but we
945      * MUST send a unique id for each REQ....
946      */
947     static u_char id;
948 
949     fsm_Output(fp, CODE_CODEREJ, id++, MBUF_CTOP(bp), bp->cnt);
950     mbuf_Free(bp);
951     return;
952   }
953   bp->offset += sizeof(struct fsmheader);
954   bp->cnt -= sizeof(struct fsmheader);
955 
956   codep = FsmCodes + lhp->code - 1;
957   if (lhp->id != fp->reqid && codep->check_reqid &&
958       Enabled(fp->bundle, OPT_IDCHECK)) {
959     log_Printf(fp->LogLevel, "%s: Recv%s(%d), dropped (expected %d)\n",
960 	      fp->link->name, codep->name, lhp->id, fp->reqid);
961     return;
962   }
963 
964   log_Printf(fp->LogLevel, "%s: Recv%s(%d) state = %s\n",
965 	    fp->link->name, codep->name, lhp->id, State2Nam(fp->state));
966 
967   if (log_IsKept(LogDEBUG))
968     mbuf_Log();
969 
970   if (codep->inc_reqid && (lhp->id == fp->reqid ||
971       (!Enabled(fp->bundle, OPT_IDCHECK) && codep->check_reqid)))
972     fp->reqid++;	/* That's the end of that ``exchange''.... */
973 
974   (*codep->recv)(fp, lhp, bp);
975 
976   if (log_IsKept(LogDEBUG))
977     mbuf_Log();
978 }
979 
980 void
981 fsm_NullRecvResetReq(struct fsm *fp)
982 {
983   log_Printf(fp->LogLevel, "%s: Oops - received unexpected reset req\n",
984             fp->link->name);
985 }
986 
987 void
988 fsm_NullRecvResetAck(struct fsm *fp, u_char id)
989 {
990   log_Printf(fp->LogLevel, "%s: Oops - received unexpected reset ack\n",
991             fp->link->name);
992 }
993 
994 void
995 fsm_Reopen(struct fsm *fp)
996 {
997   if (fp->state == ST_OPENED) {
998     (*fp->fn->LayerDown)(fp);
999     FsmInitRestartCounter(fp);
1000     FsmSendConfigReq(fp);
1001     NewState(fp, ST_REQSENT);
1002     (*fp->parent->LayerDown)(fp->parent->object, fp);
1003   }
1004 }
1005 
1006 void
1007 fsm2initial(struct fsm *fp)
1008 {
1009   if (fp->state == ST_STOPPED)
1010     fsm_Close(fp);
1011   if (fp->state > ST_INITIAL)
1012     fsm_Down(fp);
1013   if (fp->state > ST_INITIAL)
1014     fsm_Close(fp);
1015 }
1016