old DLPI doesn't have dl_sap_length
[ppp.git] / pppd / chap.c
1 /*
2  * chap.c - Crytographic Handshake Authentication Protocol.
3  *
4  * Copyright (c) 1991 Gregory M. Christy.
5  * All rights reserved.
6  *
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 Gregory M. Christy.  The name of the author may not be used to
13  * endorse or promote products derived from this software without
14  * specific prior written permission.
15  *
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
21 #ifndef lint
22 static char rcsid[] = "$Id: chap.c,v 1.8 1995/07/04 12:32:26 paulus Exp $";
23 #endif
24
25 /*
26  * TODO:
27  */
28
29 #include <stdio.h>
30 #include <string.h>
31 #include <sys/types.h>
32 #include <sys/time.h>
33 #include <syslog.h>
34
35 #include "pppd.h"
36 #include "chap.h"
37 #include "md5.h"
38
39 chap_state chap[NUM_PPP];               /* CHAP state; one for each unit */
40
41 static void ChapChallengeTimeout __P((caddr_t));
42 static void ChapResponseTimeout __P((caddr_t));
43 static void ChapReceiveChallenge __P((chap_state *, u_char *, int, int));
44 static void ChapReceiveResponse __P((chap_state *, u_char *, int, int));
45 static void ChapReceiveSuccess __P((chap_state *, u_char *, int, int));
46 static void ChapReceiveFailure __P((chap_state *, u_char *, int, int));
47 static void ChapSendStatus __P((chap_state *, int));
48 static void ChapSendChallenge __P((chap_state *));
49 static void ChapSendResponse __P((chap_state *));
50 static void ChapGenChallenge __P((chap_state *));
51
52 extern double drand48 __P((void));
53 extern void srand48 __P((long));
54
55 /*
56  * ChapInit - Initialize a CHAP unit.
57  */
58 void
59 ChapInit(unit)
60     int unit;
61 {
62     chap_state *cstate = &chap[unit];
63
64     BZERO(cstate, sizeof(*cstate));
65     cstate->unit = unit;
66     cstate->clientstate = CHAPCS_INITIAL;
67     cstate->serverstate = CHAPSS_INITIAL;
68     cstate->timeouttime = CHAP_DEFTIMEOUT;
69     cstate->max_transmits = CHAP_DEFTRANSMITS;
70     /* random number generator is initialized in magic_init */
71 }
72
73
74 /*
75  * ChapAuthWithPeer - Authenticate us with our peer (start client).
76  *
77  */
78 void
79 ChapAuthWithPeer(unit, our_name, digest)
80     int unit;
81     char *our_name;
82     int digest;
83 {
84     chap_state *cstate = &chap[unit];
85
86     cstate->resp_name = our_name;
87     cstate->resp_type = digest;
88
89     if (cstate->clientstate == CHAPCS_INITIAL ||
90         cstate->clientstate == CHAPCS_PENDING) {
91         /* lower layer isn't up - wait until later */
92         cstate->clientstate = CHAPCS_PENDING;
93         return;
94     }
95
96     /*
97      * We get here as a result of LCP coming up.
98      * So even if CHAP was open before, we will 
99      * have to re-authenticate ourselves.
100      */
101     cstate->clientstate = CHAPCS_LISTEN;
102 }
103
104
105 /*
106  * ChapAuthPeer - Authenticate our peer (start server).
107  */
108 void
109 ChapAuthPeer(unit, our_name, digest)
110     int unit;
111     char *our_name;
112     int digest;
113 {
114     chap_state *cstate = &chap[unit];
115   
116     cstate->chal_name = our_name;
117     cstate->chal_type = digest;
118
119     if (cstate->serverstate == CHAPSS_INITIAL ||
120         cstate->serverstate == CHAPSS_PENDING) {
121         /* lower layer isn't up - wait until later */
122         cstate->serverstate = CHAPSS_PENDING;
123         return;
124     }
125
126     ChapGenChallenge(cstate);
127     ChapSendChallenge(cstate);          /* crank it up dude! */
128     cstate->serverstate = CHAPSS_INITIAL_CHAL;
129 }
130
131
132 /*
133  * ChapChallengeTimeout - Timeout expired on sending challenge.
134  */
135 static void
136 ChapChallengeTimeout(arg)
137     caddr_t arg;
138 {
139     chap_state *cstate = (chap_state *) arg;
140   
141     /* if we aren't sending challenges, don't worry.  then again we */
142     /* probably shouldn't be here either */
143     if (cstate->serverstate != CHAPSS_INITIAL_CHAL &&
144         cstate->serverstate != CHAPSS_RECHALLENGE)
145         return;
146
147     if (cstate->chal_transmits >= cstate->max_transmits) {
148         /* give up on peer */
149         syslog(LOG_ERR, "Peer failed to respond to CHAP challenge");
150         cstate->serverstate = CHAPSS_BADAUTH;
151         auth_peer_fail(cstate->unit, PPP_CHAP);
152         return;
153     }
154
155     ChapSendChallenge(cstate);          /* Re-send challenge */
156 }
157
158
159 /*
160  * ChapResponseTimeout - Timeout expired on sending response.
161  */
162 static void
163 ChapResponseTimeout(arg)
164     caddr_t arg;
165 {
166     chap_state *cstate = (chap_state *) arg;
167
168     /* if we aren't sending a response, don't worry. */
169     if (cstate->clientstate != CHAPCS_RESPONSE)
170         return;
171
172     ChapSendResponse(cstate);           /* re-send response */
173 }
174
175
176 /*
177  * ChapRechallenge - Time to challenge the peer again.
178  */
179 static void
180 ChapRechallenge(arg)
181     caddr_t arg;
182 {
183     chap_state *cstate = (chap_state *) arg;
184
185     /* if we aren't sending a response, don't worry. */
186     if (cstate->serverstate != CHAPSS_OPEN)
187         return;
188
189     ChapGenChallenge(cstate);
190     ChapSendChallenge(cstate);
191     cstate->serverstate = CHAPSS_RECHALLENGE;
192 }
193
194
195 /*
196  * ChapLowerUp - The lower layer is up.
197  *
198  * Start up if we have pending requests.
199  */
200 void
201 ChapLowerUp(unit)
202     int unit;
203 {
204     chap_state *cstate = &chap[unit];
205   
206     if (cstate->clientstate == CHAPCS_INITIAL)
207         cstate->clientstate = CHAPCS_CLOSED;
208     else if (cstate->clientstate == CHAPCS_PENDING)
209         cstate->clientstate = CHAPCS_LISTEN;
210
211     if (cstate->serverstate == CHAPSS_INITIAL)
212         cstate->serverstate = CHAPSS_CLOSED;
213     else if (cstate->serverstate == CHAPSS_PENDING) {
214         ChapGenChallenge(cstate);
215         ChapSendChallenge(cstate);
216         cstate->serverstate = CHAPSS_INITIAL_CHAL;
217     }
218 }
219
220
221 /*
222  * ChapLowerDown - The lower layer is down.
223  *
224  * Cancel all timeouts.
225  */
226 void
227 ChapLowerDown(unit)
228     int unit;
229 {
230     chap_state *cstate = &chap[unit];
231   
232     /* Timeout(s) pending?  Cancel if so. */
233     if (cstate->serverstate == CHAPSS_INITIAL_CHAL ||
234         cstate->serverstate == CHAPSS_RECHALLENGE)
235         UNTIMEOUT(ChapChallengeTimeout, (caddr_t) cstate);
236     else if (cstate->serverstate == CHAPSS_OPEN
237              && cstate->chal_interval != 0)
238         UNTIMEOUT(ChapRechallenge, (caddr_t) cstate);
239     if (cstate->clientstate == CHAPCS_RESPONSE)
240         UNTIMEOUT(ChapResponseTimeout, (caddr_t) cstate);
241
242     cstate->clientstate = CHAPCS_INITIAL;
243     cstate->serverstate = CHAPSS_INITIAL;
244 }
245
246
247 /*
248  * ChapProtocolReject - Peer doesn't grok CHAP.
249  */
250 void
251 ChapProtocolReject(unit)
252     int unit;
253 {
254     chap_state *cstate = &chap[unit];
255
256     if (cstate->serverstate != CHAPSS_INITIAL &&
257         cstate->serverstate != CHAPSS_CLOSED)
258         auth_peer_fail(unit, PPP_CHAP);
259     if (cstate->clientstate != CHAPCS_INITIAL &&
260         cstate->clientstate != CHAPCS_CLOSED)
261         auth_withpeer_fail(unit, PPP_CHAP);
262     ChapLowerDown(unit);                /* shutdown chap */
263 }
264
265
266 /*
267  * ChapInput - Input CHAP packet.
268  */
269 void
270 ChapInput(unit, inpacket, packet_len)
271     int unit;
272     u_char *inpacket;
273     int packet_len;
274 {
275     chap_state *cstate = &chap[unit];
276     u_char *inp;
277     u_char code, id;
278     int len;
279   
280     /*
281      * Parse header (code, id and length).
282      * If packet too short, drop it.
283      */
284     inp = inpacket;
285     if (packet_len < CHAP_HEADERLEN) {
286         CHAPDEBUG((LOG_INFO, "ChapInput: rcvd short header."));
287         return;
288     }
289     GETCHAR(code, inp);
290     GETCHAR(id, inp);
291     GETSHORT(len, inp);
292     if (len < CHAP_HEADERLEN) {
293         CHAPDEBUG((LOG_INFO, "ChapInput: rcvd illegal length."));
294         return;
295     }
296     if (len > packet_len) {
297         CHAPDEBUG((LOG_INFO, "ChapInput: rcvd short packet."));
298         return;
299     }
300     len -= CHAP_HEADERLEN;
301   
302     /*
303      * Action depends on code (as in fact it usually does :-).
304      */
305     switch (code) {
306     case CHAP_CHALLENGE:
307         ChapReceiveChallenge(cstate, inp, id, len);
308         break;
309     
310     case CHAP_RESPONSE:
311         ChapReceiveResponse(cstate, inp, id, len);
312         break;
313     
314     case CHAP_FAILURE:
315         ChapReceiveFailure(cstate, inp, id, len);
316         break;
317
318     case CHAP_SUCCESS:
319         ChapReceiveSuccess(cstate, inp, id, len);
320         break;
321
322     default:                            /* Need code reject? */
323         syslog(LOG_WARNING, "Unknown CHAP code (%d) received.", code);
324         break;
325     }
326 }
327
328
329 /*
330  * ChapReceiveChallenge - Receive Challenge and send Response.
331  */
332 static void
333 ChapReceiveChallenge(cstate, inp, id, len)
334     chap_state *cstate;
335     u_char *inp;
336     int id;
337     int len;
338 {
339     int rchallenge_len;
340     u_char *rchallenge;
341     int secret_len;
342     char secret[MAXSECRETLEN];
343     char rhostname[256];
344     MD5_CTX mdContext;
345  
346     CHAPDEBUG((LOG_INFO, "ChapReceiveChallenge: Rcvd id %d.", id));
347     if (cstate->clientstate == CHAPCS_CLOSED ||
348         cstate->clientstate == CHAPCS_PENDING) {
349         CHAPDEBUG((LOG_INFO, "ChapReceiveChallenge: in state %d",
350                    cstate->clientstate));
351         return;
352     }
353
354     if (len < 2) {
355         CHAPDEBUG((LOG_INFO, "ChapReceiveChallenge: rcvd short packet."));
356         return;
357     }
358
359     GETCHAR(rchallenge_len, inp);
360     len -= sizeof (u_char) + rchallenge_len;    /* now name field length */
361     if (len < 0) {
362         CHAPDEBUG((LOG_INFO, "ChapReceiveChallenge: rcvd short packet."));
363         return;
364     }
365     rchallenge = inp;
366     INCPTR(rchallenge_len, inp);
367
368     if (len >= sizeof(rhostname))
369         len = sizeof(rhostname) - 1;
370     BCOPY(inp, rhostname, len);
371     rhostname[len] = '\000';
372
373     CHAPDEBUG((LOG_INFO, "ChapReceiveChallenge: received name field: %s",
374                rhostname));
375
376     /* get secret for authenticating ourselves with the specified host */
377     if (!get_secret(cstate->unit, cstate->resp_name, rhostname,
378                     secret, &secret_len, 0)) {
379         secret_len = 0;         /* assume null secret if can't find one */
380         syslog(LOG_WARNING, "No CHAP secret found for authenticating us to %s",
381                rhostname);
382     }
383
384     /* cancel response send timeout if necessary */
385     if (cstate->clientstate == CHAPCS_RESPONSE)
386         UNTIMEOUT(ChapResponseTimeout, (caddr_t) cstate);
387
388     cstate->resp_id = id;
389     cstate->resp_transmits = 0;
390
391     /*  generate MD based on negotiated type */
392     switch (cstate->resp_type) { 
393
394     case CHAP_DIGEST_MD5:               /* only MD5 is defined for now */
395         MD5Init(&mdContext);
396         MD5Update(&mdContext, &cstate->resp_id, 1);
397         MD5Update(&mdContext, secret, secret_len);
398         MD5Update(&mdContext, rchallenge, rchallenge_len);
399         MD5Final(&mdContext);
400         BCOPY(mdContext.digest, cstate->response, MD5_SIGNATURE_SIZE);
401         cstate->resp_length = MD5_SIGNATURE_SIZE;
402         break;
403
404     default:
405         CHAPDEBUG((LOG_INFO, "unknown digest type %d", cstate->resp_type));
406         return;
407     }
408
409     ChapSendResponse(cstate);
410 }
411
412
413 /*
414  * ChapReceiveResponse - Receive and process response.
415  */
416 static void
417 ChapReceiveResponse(cstate, inp, id, len)
418     chap_state *cstate;
419     u_char *inp;
420     int id;
421     int len;
422 {
423     u_char *remmd, remmd_len;
424     int secret_len, old_state;
425     int code;
426     char rhostname[256];
427     u_char buf[256];
428     MD5_CTX mdContext;
429     u_char msg[256];
430     char secret[MAXSECRETLEN];
431
432     CHAPDEBUG((LOG_INFO, "ChapReceiveResponse: Rcvd id %d.", id));
433
434     if (cstate->serverstate == CHAPSS_CLOSED ||
435         cstate->serverstate == CHAPSS_PENDING) {
436         CHAPDEBUG((LOG_INFO, "ChapReceiveResponse: in state %d",
437                    cstate->serverstate));
438         return;
439     }
440
441     if (id != cstate->chal_id)
442         return;                 /* doesn't match ID of last challenge */
443
444     /*
445      * If we have received a duplicate or bogus Response,
446      * we have to send the same answer (Success/Failure)
447      * as we did for the first Response we saw.
448      */
449     if (cstate->serverstate == CHAPSS_OPEN) {
450         ChapSendStatus(cstate, CHAP_SUCCESS);
451         return;
452     }
453     if (cstate->serverstate == CHAPSS_BADAUTH) {
454         ChapSendStatus(cstate, CHAP_FAILURE);
455         return;
456     }
457
458     if (len < 2) {
459         CHAPDEBUG((LOG_INFO, "ChapReceiveResponse: rcvd short packet."));
460         return;
461     }
462     GETCHAR(remmd_len, inp);            /* get length of MD */
463     remmd = inp;                        /* get pointer to MD */
464     INCPTR(remmd_len, inp);
465
466     len -= sizeof (u_char) + remmd_len;
467     if (len < 0) {
468         CHAPDEBUG((LOG_INFO, "ChapReceiveResponse: rcvd short packet."));
469         return;
470     }
471
472     UNTIMEOUT(ChapChallengeTimeout, (caddr_t) cstate);
473
474     if (len >= sizeof(rhostname))
475         len = sizeof(rhostname) - 1;
476     BCOPY(inp, rhostname, len);
477     rhostname[len] = '\000';
478
479     CHAPDEBUG((LOG_INFO, "ChapReceiveResponse: received name field: %s",
480                rhostname));
481
482     /*
483      * Get secret for authenticating them with us,
484      * do the hash ourselves, and compare the result.
485      */
486     code = CHAP_FAILURE;
487     if (!get_secret(cstate->unit, rhostname, cstate->chal_name,
488                    secret, &secret_len, 1)) {
489         syslog(LOG_WARNING, "No CHAP secret found for authenticating %s",
490                rhostname);
491     } else {
492
493         /*  generate MD based on negotiated type */
494         switch (cstate->chal_type) { 
495
496         case CHAP_DIGEST_MD5:           /* only MD5 is defined for now */
497             if (remmd_len != MD5_SIGNATURE_SIZE)
498                 break;                  /* it's not even the right length */
499             MD5Init(&mdContext);
500             MD5Update(&mdContext, &cstate->chal_id, 1);
501             MD5Update(&mdContext, secret, secret_len);
502             MD5Update(&mdContext, cstate->challenge, cstate->chal_len);
503             MD5Final(&mdContext); 
504
505             /* compare local and remote MDs and send the appropriate status */
506             if (memcmp (mdContext.digest, remmd, MD5_SIGNATURE_SIZE) == 0)
507                 code = CHAP_SUCCESS;    /* they are the same! */
508             break;
509
510         default:
511             CHAPDEBUG((LOG_INFO, "unknown digest type %d", cstate->chal_type));
512         }
513     }
514
515     ChapSendStatus(cstate, code);
516
517     if (code == CHAP_SUCCESS) {
518         old_state = cstate->serverstate;
519         cstate->serverstate = CHAPSS_OPEN;
520         if (old_state == CHAPSS_INITIAL_CHAL) {
521             auth_peer_success(cstate->unit, PPP_CHAP);
522         }
523         if (cstate->chal_interval != 0)
524             TIMEOUT(ChapRechallenge, (caddr_t) cstate, cstate->chal_interval);
525
526     } else {
527         syslog(LOG_ERR, "CHAP peer authentication failed");
528         cstate->serverstate = CHAPSS_BADAUTH;
529         auth_peer_fail(cstate->unit, PPP_CHAP);
530     }
531 }
532
533 /*
534  * ChapReceiveSuccess - Receive Success
535  */
536 static void
537 ChapReceiveSuccess(cstate, inp, id, len)
538     chap_state *cstate;
539     u_char *inp;
540     u_char id;
541     int len;
542 {
543
544     CHAPDEBUG((LOG_INFO, "ChapReceiveSuccess: Rcvd id %d.", id));
545
546     if (cstate->clientstate == CHAPCS_OPEN)
547         /* presumably an answer to a duplicate response */
548         return;
549
550     if (cstate->clientstate != CHAPCS_RESPONSE) {
551         /* don't know what this is */
552         CHAPDEBUG((LOG_INFO, "ChapReceiveSuccess: in state %d\n",
553                    cstate->clientstate));
554         return;
555     }
556
557     UNTIMEOUT(ChapResponseTimeout, (caddr_t) cstate);
558
559     /*
560      * Print message.
561      */
562     if (len > 0)
563         PRINTMSG(inp, len);
564
565     cstate->clientstate = CHAPCS_OPEN;
566
567     auth_withpeer_success(cstate->unit, PPP_CHAP);
568 }
569
570
571 /*
572  * ChapReceiveFailure - Receive failure.
573  */
574 static void
575 ChapReceiveFailure(cstate, inp, id, len)
576     chap_state *cstate;
577     u_char *inp;
578     u_char id;
579     int len;
580 {
581     u_char msglen;
582     u_char *msg;
583   
584     CHAPDEBUG((LOG_INFO, "ChapReceiveFailure: Rcvd id %d.", id));
585
586     if (cstate->clientstate != CHAPCS_RESPONSE) {
587         /* don't know what this is */
588         CHAPDEBUG((LOG_INFO, "ChapReceiveFailure: in state %d\n",
589                    cstate->clientstate));
590         return;
591     }
592
593     UNTIMEOUT(ChapResponseTimeout, (caddr_t) cstate);
594
595     /*
596      * Print message.
597      */
598     if (len > 0)
599         PRINTMSG(inp, len);
600
601     syslog(LOG_ERR, "CHAP authentication failed");
602     auth_withpeer_fail(cstate->unit, PPP_CHAP);
603 }
604
605
606 /*
607  * ChapSendChallenge - Send an Authenticate challenge.
608  */
609 static void
610 ChapSendChallenge(cstate)
611     chap_state *cstate;
612 {
613     u_char *outp;
614     int chal_len, name_len;
615     int outlen;
616
617     chal_len = cstate->chal_len;
618     name_len = strlen(cstate->chal_name);
619     outlen = CHAP_HEADERLEN + sizeof (u_char) + chal_len + name_len;
620     outp = outpacket_buf;
621
622     MAKEHEADER(outp, PPP_CHAP);         /* paste in a CHAP header */
623
624     PUTCHAR(CHAP_CHALLENGE, outp);
625     PUTCHAR(cstate->chal_id, outp);
626     PUTSHORT(outlen, outp);
627
628     PUTCHAR(chal_len, outp);            /* put length of challenge */
629     BCOPY(cstate->challenge, outp, chal_len);
630     INCPTR(chal_len, outp);
631
632     BCOPY(cstate->chal_name, outp, name_len);   /* append hostname */
633
634     output(cstate->unit, outpacket_buf, outlen + PPP_HDRLEN);
635   
636     CHAPDEBUG((LOG_INFO, "ChapSendChallenge: Sent id %d.", cstate->chal_id));
637
638     TIMEOUT(ChapChallengeTimeout, (caddr_t) cstate, cstate->timeouttime);
639     ++cstate->chal_transmits;
640 }
641
642
643 /*
644  * ChapSendStatus - Send a status response (ack or nak).
645  */
646 static void
647 ChapSendStatus(cstate, code)
648     chap_state *cstate;
649     int code;
650 {
651     u_char *outp;
652     int outlen, msglen;
653     char msg[256];
654
655     if (code == CHAP_SUCCESS)
656         sprintf(msg, "Welcome to %s.", hostname);
657     else
658         sprintf(msg, "I don't like you.  Go 'way.");
659     msglen = strlen(msg);
660
661     outlen = CHAP_HEADERLEN + msglen;
662     outp = outpacket_buf;
663
664     MAKEHEADER(outp, PPP_CHAP); /* paste in a header */
665   
666     PUTCHAR(code, outp);
667     PUTCHAR(cstate->chal_id, outp);
668     PUTSHORT(outlen, outp);
669     BCOPY(msg, outp, msglen);
670     output(cstate->unit, outpacket_buf, outlen + PPP_HDRLEN);
671   
672     CHAPDEBUG((LOG_INFO, "ChapSendStatus: Sent code %d, id %d.", code,
673                cstate->chal_id));
674 }
675
676 /*
677  * ChapGenChallenge is used to generate a pseudo-random challenge string of
678  * a pseudo-random length between min_len and max_len.  The challenge
679  * string and its length are stored in *cstate, and various other fields of
680  * *cstate are initialized.
681  */
682
683 static void
684 ChapGenChallenge(cstate)
685     chap_state *cstate;
686 {
687     int chal_len;
688     u_char *ptr = cstate->challenge;
689     unsigned int i;
690
691     /* pick a random challenge length between MIN_CHALLENGE_LENGTH and 
692        MAX_CHALLENGE_LENGTH */  
693     chal_len =  (unsigned) ((drand48() *
694                              (MAX_CHALLENGE_LENGTH - MIN_CHALLENGE_LENGTH)) +
695                             MIN_CHALLENGE_LENGTH);
696     cstate->chal_len = chal_len;
697     cstate->chal_id = ++cstate->id;
698     cstate->chal_transmits = 0;
699
700     /* generate a random string */
701     for (i = 0; i < chal_len; i++ )
702         *ptr++ = (char) (drand48() * 0xff);
703 }
704
705 /*
706  * ChapSendResponse - send a response packet with values as specified
707  * in *cstate.
708  */
709 /* ARGSUSED */
710 static void
711 ChapSendResponse(cstate)
712     chap_state *cstate;
713 {
714     u_char *outp;
715     int outlen, md_len, name_len;
716
717     md_len = cstate->resp_length;
718     name_len = strlen(cstate->resp_name);
719     outlen = CHAP_HEADERLEN + sizeof (u_char) + md_len + name_len;
720     outp = outpacket_buf;
721
722     MAKEHEADER(outp, PPP_CHAP);
723
724     PUTCHAR(CHAP_RESPONSE, outp);       /* we are a response */
725     PUTCHAR(cstate->resp_id, outp);     /* copy id from challenge packet */
726     PUTSHORT(outlen, outp);             /* packet length */
727
728     PUTCHAR(md_len, outp);              /* length of MD */
729     BCOPY(cstate->response, outp, md_len);      /* copy MD to buffer */
730     INCPTR(md_len, outp);
731
732     BCOPY(cstate->resp_name, outp, name_len); /* append our name */
733
734     /* send the packet */
735     output(cstate->unit, outpacket_buf, outlen + PPP_HDRLEN);
736
737     cstate->clientstate = CHAPCS_RESPONSE;
738     TIMEOUT(ChapResponseTimeout, (caddr_t) cstate, cstate->timeouttime);
739     ++cstate->resp_transmits;
740 }
741
742 /*
743  * ChapPrintPkt - print the contents of a CHAP packet.
744  */
745 char *ChapCodenames[] = {
746     "Challenge", "Response", "Success", "Failure"
747 };
748
749 int
750 ChapPrintPkt(p, plen, printer, arg)
751     u_char *p;
752     int plen;
753     void (*printer) __P((void *, char *, ...));
754     void *arg;
755 {
756     int code, id, len;
757     int clen, nlen;
758     u_char x;
759
760     if (plen < CHAP_HEADERLEN)
761         return 0;
762     GETCHAR(code, p);
763     GETCHAR(id, p);
764     GETSHORT(len, p);
765     if (len < CHAP_HEADERLEN || len > plen)
766         return 0;
767
768     if (code >= 1 && code <= sizeof(ChapCodenames) / sizeof(char *))
769         printer(arg, " %s", ChapCodenames[code-1]);
770     else
771         printer(arg, " code=0x%x", code);
772     printer(arg, " id=0x%x", id);
773     len -= CHAP_HEADERLEN;
774     switch (code) {
775     case CHAP_CHALLENGE:
776     case CHAP_RESPONSE:
777         if (len < 1)
778             break;
779         clen = p[0];
780         if (len < clen + 1)
781             break;
782         ++p;
783         nlen = len - clen - 1;
784         printer(arg, " <");
785         for (; clen > 0; --clen) {
786             GETCHAR(x, p);
787             printer(arg, "%.2x", x);
788         }
789         printer(arg, ">, name = ");
790         print_string((char *)p, nlen, printer, arg);
791         break;
792     case CHAP_FAILURE:
793     case CHAP_SUCCESS:
794         printer(arg, " ");
795         print_string((char *)p, len, printer, arg);
796         break;
797     default:
798         for (clen = len; clen > 0; --clen) {
799             GETCHAR(x, p);
800             printer(arg, " %.2x", x);
801         }
802     }
803
804     return len + CHAP_HEADERLEN;
805 }