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      1 /*
      2  * lcp.c - PPP Link Control Protocol.
      3  *
      4  * Copyright (c) 1984-2000 Carnegie Mellon University. All rights reserved.
      5  *
      6  * Redistribution and use in source and binary forms, with or without
      7  * modification, are permitted provided that the following conditions
      8  * are met:
      9  *
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  *
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in
     15  *    the documentation and/or other materials provided with the
     16  *    distribution.
     17  *
     18  * 3. The name "Carnegie Mellon University" must not be used to
     19  *    endorse or promote products derived from this software without
     20  *    prior written permission. For permission or any legal
     21  *    details, please contact
     22  *      Office of Technology Transfer
     23  *      Carnegie Mellon University
     24  *      5000 Forbes Avenue
     25  *      Pittsburgh, PA  15213-3890
     26  *      (412) 268-4387, fax: (412) 268-7395
     27  *      tech-transfer (at) andrew.cmu.edu
     28  *
     29  * 4. Redistributions of any form whatsoever must retain the following
     30  *    acknowledgment:
     31  *    "This product includes software developed by Computing Services
     32  *     at Carnegie Mellon University (http://www.cmu.edu/computing/)."
     33  *
     34  * CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
     35  * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
     36  * AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
     37  * FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
     38  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
     39  * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
     40  * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
     41  */
     42 
     43 #define RCSID	"$Id: lcp.c,v 1.74 2004/11/13 02:28:15 paulus Exp $"
     44 
     45 /*
     46  * TODO:
     47  */
     48 
     49 #include <stdio.h>
     50 #include <string.h>
     51 #include <stdlib.h>
     52 
     53 #include "pppd.h"
     54 #include "fsm.h"
     55 #include "lcp.h"
     56 #include "chap-new.h"
     57 #include "magic.h"
     58 
     59 static const char rcsid[] = RCSID;
     60 
     61 /*
     62  * When the link comes up we want to be able to wait for a short while,
     63  * or until seeing some input from the peer, before starting to send
     64  * configure-requests.  We do this by delaying the fsm_lowerup call.
     65  */
     66 /* steal a bit in fsm flags word */
     67 #define DELAYED_UP	0x100
     68 
     69 static void lcp_delayed_up __P((void *));
     70 
     71 /*
     72  * LCP-related command-line options.
     73  */
     74 int	lcp_echo_interval = 0; 	/* Interval between LCP echo-requests */
     75 int	lcp_echo_fails = 0;	/* Tolerance to unanswered echo-requests */
     76 bool	lax_recv = 0;		/* accept control chars in asyncmap */
     77 bool	noendpoint = 0;		/* don't send/accept endpoint discriminator */
     78 
     79 static int noopt __P((char **));
     80 
     81 #ifdef HAVE_MULTILINK
     82 static int setendpoint __P((char **));
     83 static void printendpoint __P((option_t *, void (*)(void *, char *, ...),
     84 			       void *));
     85 #endif /* HAVE_MULTILINK */
     86 
     87 static option_t lcp_option_list[] = {
     88     /* LCP options */
     89     { "-all", o_special_noarg, (void *)noopt,
     90       "Don't request/allow any LCP options" },
     91 
     92     { "noaccomp", o_bool, &lcp_wantoptions[0].neg_accompression,
     93       "Disable address/control compression",
     94       OPT_A2CLR, &lcp_allowoptions[0].neg_accompression },
     95     { "-ac", o_bool, &lcp_wantoptions[0].neg_accompression,
     96       "Disable address/control compression",
     97       OPT_ALIAS | OPT_A2CLR, &lcp_allowoptions[0].neg_accompression },
     98 
     99     { "asyncmap", o_uint32, &lcp_wantoptions[0].asyncmap,
    100       "Set asyncmap (for received packets)",
    101       OPT_OR, &lcp_wantoptions[0].neg_asyncmap },
    102     { "-as", o_uint32, &lcp_wantoptions[0].asyncmap,
    103       "Set asyncmap (for received packets)",
    104       OPT_ALIAS | OPT_OR, &lcp_wantoptions[0].neg_asyncmap },
    105     { "default-asyncmap", o_uint32, &lcp_wantoptions[0].asyncmap,
    106       "Disable asyncmap negotiation",
    107       OPT_OR | OPT_NOARG | OPT_VAL(~0U) | OPT_A2CLR,
    108       &lcp_allowoptions[0].neg_asyncmap },
    109     { "-am", o_uint32, &lcp_wantoptions[0].asyncmap,
    110       "Disable asyncmap negotiation",
    111       OPT_ALIAS | OPT_OR | OPT_NOARG | OPT_VAL(~0U) | OPT_A2CLR,
    112       &lcp_allowoptions[0].neg_asyncmap },
    113 
    114     { "nomagic", o_bool, &lcp_wantoptions[0].neg_magicnumber,
    115       "Disable magic number negotiation (looped-back line detection)",
    116       OPT_A2CLR, &lcp_allowoptions[0].neg_magicnumber },
    117     { "-mn", o_bool, &lcp_wantoptions[0].neg_magicnumber,
    118       "Disable magic number negotiation (looped-back line detection)",
    119       OPT_ALIAS | OPT_A2CLR, &lcp_allowoptions[0].neg_magicnumber },
    120 
    121     { "mru", o_int, &lcp_wantoptions[0].mru,
    122       "Set MRU (maximum received packet size) for negotiation",
    123       OPT_PRIO, &lcp_wantoptions[0].neg_mru },
    124     { "default-mru", o_bool, &lcp_wantoptions[0].neg_mru,
    125       "Disable MRU negotiation (use default 1500)",
    126       OPT_PRIOSUB | OPT_A2CLR, &lcp_allowoptions[0].neg_mru },
    127     { "-mru", o_bool, &lcp_wantoptions[0].neg_mru,
    128       "Disable MRU negotiation (use default 1500)",
    129       OPT_ALIAS | OPT_PRIOSUB | OPT_A2CLR, &lcp_allowoptions[0].neg_mru },
    130 
    131     { "mtu", o_int, &lcp_allowoptions[0].mru,
    132       "Set our MTU", OPT_LIMITS, NULL, MAXMRU, MINMRU },
    133 
    134     { "nopcomp", o_bool, &lcp_wantoptions[0].neg_pcompression,
    135       "Disable protocol field compression",
    136       OPT_A2CLR, &lcp_allowoptions[0].neg_pcompression },
    137     { "-pc", o_bool, &lcp_wantoptions[0].neg_pcompression,
    138       "Disable protocol field compression",
    139       OPT_ALIAS | OPT_A2CLR, &lcp_allowoptions[0].neg_pcompression },
    140 
    141     { "passive", o_bool, &lcp_wantoptions[0].passive,
    142       "Set passive mode", 1 },
    143     { "-p", o_bool, &lcp_wantoptions[0].passive,
    144       "Set passive mode", OPT_ALIAS | 1 },
    145 
    146     { "silent", o_bool, &lcp_wantoptions[0].silent,
    147       "Set silent mode", 1 },
    148 
    149     { "lcp-echo-failure", o_int, &lcp_echo_fails,
    150       "Set number of consecutive echo failures to indicate link failure",
    151       OPT_PRIO },
    152     { "lcp-echo-interval", o_int, &lcp_echo_interval,
    153       "Set time in seconds between LCP echo requests", OPT_PRIO },
    154     { "lcp-restart", o_int, &lcp_fsm[0].timeouttime,
    155       "Set time in seconds between LCP retransmissions", OPT_PRIO },
    156     { "lcp-max-terminate", o_int, &lcp_fsm[0].maxtermtransmits,
    157       "Set maximum number of LCP terminate-request transmissions", OPT_PRIO },
    158     { "lcp-max-configure", o_int, &lcp_fsm[0].maxconfreqtransmits,
    159       "Set maximum number of LCP configure-request transmissions", OPT_PRIO },
    160     { "lcp-max-failure", o_int, &lcp_fsm[0].maxnakloops,
    161       "Set limit on number of LCP configure-naks", OPT_PRIO },
    162 
    163     { "receive-all", o_bool, &lax_recv,
    164       "Accept all received control characters", 1 },
    165 
    166 #ifdef HAVE_MULTILINK
    167     { "mrru", o_int, &lcp_wantoptions[0].mrru,
    168       "Maximum received packet size for multilink bundle",
    169       OPT_PRIO, &lcp_wantoptions[0].neg_mrru },
    170 
    171     { "mpshortseq", o_bool, &lcp_wantoptions[0].neg_ssnhf,
    172       "Use short sequence numbers in multilink headers",
    173       OPT_PRIO | 1, &lcp_allowoptions[0].neg_ssnhf },
    174     { "nompshortseq", o_bool, &lcp_wantoptions[0].neg_ssnhf,
    175       "Don't use short sequence numbers in multilink headers",
    176       OPT_PRIOSUB | OPT_A2CLR, &lcp_allowoptions[0].neg_ssnhf },
    177 
    178     { "endpoint", o_special, (void *) setendpoint,
    179       "Endpoint discriminator for multilink",
    180       OPT_PRIO | OPT_A2PRINTER, (void *) printendpoint },
    181 #endif /* HAVE_MULTILINK */
    182 
    183     { "noendpoint", o_bool, &noendpoint,
    184       "Don't send or accept multilink endpoint discriminator", 1 },
    185 
    186     {NULL}
    187 };
    188 
    189 /* global vars */
    190 fsm lcp_fsm[NUM_PPP];			/* LCP fsm structure (global)*/
    191 lcp_options lcp_wantoptions[NUM_PPP];	/* Options that we want to request */
    192 lcp_options lcp_gotoptions[NUM_PPP];	/* Options that peer ack'd */
    193 lcp_options lcp_allowoptions[NUM_PPP];	/* Options we allow peer to request */
    194 lcp_options lcp_hisoptions[NUM_PPP];	/* Options that we ack'd */
    195 
    196 static int lcp_echos_pending = 0;	/* Number of outstanding echo msgs */
    197 static int lcp_echo_number   = 0;	/* ID number of next echo frame */
    198 static int lcp_echo_timer_running = 0;  /* set if a timer is running */
    199 
    200 static u_char nak_buffer[PPP_MRU];	/* where we construct a nak packet */
    201 
    202 /*
    203  * Callbacks for fsm code.  (CI = Configuration Information)
    204  */
    205 static void lcp_resetci __P((fsm *));	/* Reset our CI */
    206 static int  lcp_cilen __P((fsm *));		/* Return length of our CI */
    207 static void lcp_addci __P((fsm *, u_char *, int *)); /* Add our CI to pkt */
    208 static int  lcp_ackci __P((fsm *, u_char *, int)); /* Peer ack'd our CI */
    209 static int  lcp_nakci __P((fsm *, u_char *, int, int)); /* Peer nak'd our CI */
    210 static int  lcp_rejci __P((fsm *, u_char *, int)); /* Peer rej'd our CI */
    211 static int  lcp_reqci __P((fsm *, u_char *, int *, int)); /* Rcv peer CI */
    212 static void lcp_up __P((fsm *));		/* We're UP */
    213 static void lcp_down __P((fsm *));		/* We're DOWN */
    214 static void lcp_starting __P((fsm *));	/* We need lower layer up */
    215 static void lcp_finished __P((fsm *));	/* We need lower layer down */
    216 static int  lcp_extcode __P((fsm *, int, int, u_char *, int));
    217 static void lcp_rprotrej __P((fsm *, u_char *, int));
    218 
    219 /*
    220  * routines to send LCP echos to peer
    221  */
    222 
    223 static void lcp_echo_lowerup __P((int));
    224 static void lcp_echo_lowerdown __P((int));
    225 static void LcpEchoTimeout __P((void *));
    226 static void lcp_received_echo_reply __P((fsm *, int, u_char *, int));
    227 static void LcpSendEchoRequest __P((fsm *));
    228 static void LcpLinkFailure __P((fsm *));
    229 static void LcpEchoCheck __P((fsm *));
    230 
    231 static fsm_callbacks lcp_callbacks = {	/* LCP callback routines */
    232     lcp_resetci,		/* Reset our Configuration Information */
    233     lcp_cilen,			/* Length of our Configuration Information */
    234     lcp_addci,			/* Add our Configuration Information */
    235     lcp_ackci,			/* ACK our Configuration Information */
    236     lcp_nakci,			/* NAK our Configuration Information */
    237     lcp_rejci,			/* Reject our Configuration Information */
    238     lcp_reqci,			/* Request peer's Configuration Information */
    239     lcp_up,			/* Called when fsm reaches OPENED state */
    240     lcp_down,			/* Called when fsm leaves OPENED state */
    241     lcp_starting,		/* Called when we want the lower layer up */
    242     lcp_finished,		/* Called when we want the lower layer down */
    243     NULL,			/* Called when Protocol-Reject received */
    244     NULL,			/* Retransmission is necessary */
    245     lcp_extcode,		/* Called to handle LCP-specific codes */
    246     "LCP"			/* String name of protocol */
    247 };
    248 
    249 /*
    250  * Protocol entry points.
    251  * Some of these are called directly.
    252  */
    253 
    254 static void lcp_init __P((int));
    255 static void lcp_input __P((int, u_char *, int));
    256 static void lcp_protrej __P((int));
    257 static int  lcp_printpkt __P((u_char *, int,
    258 			      void (*) __P((void *, char *, ...)), void *));
    259 
    260 struct protent lcp_protent = {
    261     PPP_LCP,
    262     lcp_init,
    263     lcp_input,
    264     lcp_protrej,
    265     lcp_lowerup,
    266     lcp_lowerdown,
    267     lcp_open,
    268     lcp_close,
    269     lcp_printpkt,
    270     NULL,
    271     1,
    272     "LCP",
    273     NULL,
    274     lcp_option_list,
    275     NULL,
    276     NULL,
    277     NULL
    278 };
    279 
    280 int lcp_loopbackfail = DEFLOOPBACKFAIL;
    281 
    282 /*
    283  * Length of each type of configuration option (in octets)
    284  */
    285 #define CILEN_VOID	2
    286 #define CILEN_CHAR	3
    287 #define CILEN_SHORT	4	/* CILEN_VOID + 2 */
    288 #define CILEN_CHAP	5	/* CILEN_VOID + 2 + 1 */
    289 #define CILEN_LONG	6	/* CILEN_VOID + 4 */
    290 #define CILEN_LQR	8	/* CILEN_VOID + 2 + 4 */
    291 #define CILEN_CBCP	3
    292 
    293 #define CODENAME(x)	((x) == CONFACK ? "ACK" : \
    294 			 (x) == CONFNAK ? "NAK" : "REJ")
    295 
    296 /*
    297  * noopt - Disable all options (why?).
    298  */
    299 static int
    300 noopt(argv)
    301     char **argv;
    302 {
    303     BZERO((char *) &lcp_wantoptions[0], sizeof (struct lcp_options));
    304     BZERO((char *) &lcp_allowoptions[0], sizeof (struct lcp_options));
    305 
    306     return (1);
    307 }
    308 
    309 #ifdef HAVE_MULTILINK
    310 static int
    311 setendpoint(argv)
    312     char **argv;
    313 {
    314     if (str_to_epdisc(&lcp_wantoptions[0].endpoint, *argv)) {
    315 	lcp_wantoptions[0].neg_endpoint = 1;
    316 	return 1;
    317     }
    318     option_error("Can't parse '%s' as an endpoint discriminator", *argv);
    319     return 0;
    320 }
    321 
    322 static void
    323 printendpoint(opt, printer, arg)
    324     option_t *opt;
    325     void (*printer) __P((void *, char *, ...));
    326     void *arg;
    327 {
    328 	printer(arg, "%s", epdisc_to_str(&lcp_wantoptions[0].endpoint));
    329 }
    330 #endif /* HAVE_MULTILINK */
    331 
    332 /*
    333  * lcp_init - Initialize LCP.
    334  */
    335 static void
    336 lcp_init(unit)
    337     int unit;
    338 {
    339     fsm *f = &lcp_fsm[unit];
    340     lcp_options *wo = &lcp_wantoptions[unit];
    341     lcp_options *ao = &lcp_allowoptions[unit];
    342 
    343     f->unit = unit;
    344     f->protocol = PPP_LCP;
    345     f->callbacks = &lcp_callbacks;
    346 
    347     fsm_init(f);
    348 
    349     BZERO(wo, sizeof(*wo));
    350     wo->neg_mru = 1;
    351     wo->mru = DEFMRU;
    352     wo->neg_asyncmap = 1;
    353     wo->neg_magicnumber = 1;
    354     wo->neg_pcompression = 1;
    355     wo->neg_accompression = 1;
    356 
    357     BZERO(ao, sizeof(*ao));
    358     ao->neg_mru = 1;
    359     ao->mru = MAXMRU;
    360     ao->neg_asyncmap = 1;
    361     ao->neg_chap = 1;
    362     ao->chap_mdtype = chap_mdtype_all;
    363     ao->neg_upap = 1;
    364     ao->neg_eap = 1;
    365     ao->neg_magicnumber = 1;
    366     ao->neg_pcompression = 1;
    367     ao->neg_accompression = 1;
    368     ao->neg_endpoint = 1;
    369 }
    370 
    371 
    372 /*
    373  * lcp_open - LCP is allowed to come up.
    374  */
    375 void
    376 lcp_open(unit)
    377     int unit;
    378 {
    379     fsm *f = &lcp_fsm[unit];
    380     lcp_options *wo = &lcp_wantoptions[unit];
    381 
    382     f->flags &= ~(OPT_PASSIVE | OPT_SILENT);
    383     if (wo->passive)
    384 	f->flags |= OPT_PASSIVE;
    385     if (wo->silent)
    386 	f->flags |= OPT_SILENT;
    387     fsm_open(f);
    388 }
    389 
    390 
    391 /*
    392  * lcp_close - Take LCP down.
    393  */
    394 void
    395 lcp_close(unit, reason)
    396     int unit;
    397     char *reason;
    398 {
    399     fsm *f = &lcp_fsm[unit];
    400 
    401     if (phase != PHASE_DEAD && phase != PHASE_MASTER)
    402 	new_phase(PHASE_TERMINATE);
    403     if (f->state == STOPPED && f->flags & (OPT_PASSIVE|OPT_SILENT)) {
    404 	/*
    405 	 * This action is not strictly according to the FSM in RFC1548,
    406 	 * but it does mean that the program terminates if you do a
    407 	 * lcp_close() in passive/silent mode when a connection hasn't
    408 	 * been established.
    409 	 */
    410 	f->state = CLOSED;
    411 	lcp_finished(f);
    412 
    413     } else
    414 	fsm_close(f, reason);
    415 }
    416 
    417 
    418 /*
    419  * lcp_lowerup - The lower layer is up.
    420  */
    421 void
    422 lcp_lowerup(unit)
    423     int unit;
    424 {
    425     lcp_options *wo = &lcp_wantoptions[unit];
    426     fsm *f = &lcp_fsm[unit];
    427 
    428     /*
    429      * Don't use A/C or protocol compression on transmission,
    430      * but accept A/C and protocol compressed packets
    431      * if we are going to ask for A/C and protocol compression.
    432      */
    433     if (ppp_send_config(unit, PPP_MRU, 0xffffffff, 0, 0) < 0
    434 	|| ppp_recv_config(unit, PPP_MRU, (lax_recv? 0: 0xffffffff),
    435 			   wo->neg_pcompression, wo->neg_accompression) < 0)
    436 	    return;
    437     peer_mru[unit] = PPP_MRU;
    438 
    439     if (listen_time != 0) {
    440 	f->flags |= DELAYED_UP;
    441 	timeout(lcp_delayed_up, f, 0, listen_time * 1000);
    442     } else
    443 	fsm_lowerup(f);
    444 }
    445 
    446 
    447 /*
    448  * lcp_lowerdown - The lower layer is down.
    449  */
    450 void
    451 lcp_lowerdown(unit)
    452     int unit;
    453 {
    454     fsm *f = &lcp_fsm[unit];
    455 
    456     if (f->flags & DELAYED_UP)
    457 	f->flags &= ~DELAYED_UP;
    458     else
    459 	fsm_lowerdown(&lcp_fsm[unit]);
    460 }
    461 
    462 
    463 /*
    464  * lcp_delayed_up - Bring the lower layer up now.
    465  */
    466 static void
    467 lcp_delayed_up(arg)
    468     void *arg;
    469 {
    470     fsm *f = arg;
    471 
    472     if (f->flags & DELAYED_UP) {
    473 	f->flags &= ~DELAYED_UP;
    474 	fsm_lowerup(f);
    475     }
    476 }
    477 
    478 
    479 /*
    480  * lcp_input - Input LCP packet.
    481  */
    482 static void
    483 lcp_input(unit, p, len)
    484     int unit;
    485     u_char *p;
    486     int len;
    487 {
    488     fsm *f = &lcp_fsm[unit];
    489 
    490     if (f->flags & DELAYED_UP) {
    491 	f->flags &= ~DELAYED_UP;
    492 	fsm_lowerup(f);
    493     }
    494     fsm_input(f, p, len);
    495 }
    496 
    497 
    498 /*
    499  * lcp_extcode - Handle a LCP-specific code.
    500  */
    501 static int
    502 lcp_extcode(f, code, id, inp, len)
    503     fsm *f;
    504     int code, id;
    505     u_char *inp;
    506     int len;
    507 {
    508     u_char *magp;
    509 
    510     switch( code ){
    511     case PROTREJ:
    512 	lcp_rprotrej(f, inp, len);
    513 	break;
    514 
    515     case ECHOREQ:
    516 	if (f->state != OPENED)
    517 	    break;
    518 	magp = inp;
    519 	PUTLONG(lcp_gotoptions[f->unit].magicnumber, magp);
    520 	fsm_sdata(f, ECHOREP, id, inp, len);
    521 	break;
    522 
    523     case ECHOREP:
    524 	lcp_received_echo_reply(f, id, inp, len);
    525 	break;
    526 
    527     case DISCREQ:
    528 	break;
    529 
    530     default:
    531 	return 0;
    532     }
    533     return 1;
    534 }
    535 
    536 
    537 /*
    538  * lcp_rprotrej - Receive an Protocol-Reject.
    539  *
    540  * Figure out which protocol is rejected and inform it.
    541  */
    542 static void
    543 lcp_rprotrej(f, inp, len)
    544     fsm *f;
    545     u_char *inp;
    546     int len;
    547 {
    548     int i;
    549     struct protent *protp;
    550     u_short prot;
    551 
    552     if (len < 2) {
    553 	LCPDEBUG(("lcp_rprotrej: Rcvd short Protocol-Reject packet!"));
    554 	return;
    555     }
    556 
    557     GETSHORT(prot, inp);
    558 
    559     /*
    560      * Protocol-Reject packets received in any state other than the LCP
    561      * OPENED state SHOULD be silently discarded.
    562      */
    563     if( f->state != OPENED ){
    564 	LCPDEBUG(("Protocol-Reject discarded: LCP in state %d", f->state));
    565 	return;
    566     }
    567 
    568     /*
    569      * Upcall the proper Protocol-Reject routine.
    570      */
    571     for (i = 0; (protp = protocols[i]) != NULL; ++i)
    572 	if (protp->protocol == prot && protp->enabled_flag) {
    573 	    (*protp->protrej)(f->unit);
    574 	    return;
    575 	}
    576 
    577     warn("Protocol-Reject for unsupported protocol 0x%x", prot);
    578 }
    579 
    580 
    581 /*
    582  * lcp_protrej - A Protocol-Reject was received.
    583  */
    584 /*ARGSUSED*/
    585 static void
    586 lcp_protrej(unit)
    587     int unit;
    588 {
    589     /*
    590      * Can't reject LCP!
    591      */
    592     error("Received Protocol-Reject for LCP!");
    593     fsm_protreject(&lcp_fsm[unit]);
    594 }
    595 
    596 
    597 /*
    598  * lcp_sprotrej - Send a Protocol-Reject for some protocol.
    599  */
    600 void
    601 lcp_sprotrej(unit, p, len)
    602     int unit;
    603     u_char *p;
    604     int len;
    605 {
    606     /*
    607      * Send back the protocol and the information field of the
    608      * rejected packet.  We only get here if LCP is in the OPENED state.
    609      */
    610     p += 2;
    611     len -= 2;
    612 
    613     fsm_sdata(&lcp_fsm[unit], PROTREJ, ++lcp_fsm[unit].id,
    614 	      p, len);
    615 }
    616 
    617 
    618 /*
    619  * lcp_resetci - Reset our CI.
    620  */
    621 static void
    622 lcp_resetci(f)
    623     fsm *f;
    624 {
    625     lcp_options *wo = &lcp_wantoptions[f->unit];
    626     lcp_options *go = &lcp_gotoptions[f->unit];
    627     lcp_options *ao = &lcp_allowoptions[f->unit];
    628 
    629     wo->magicnumber = magic();
    630     wo->numloops = 0;
    631     *go = *wo;
    632     if (!multilink) {
    633 	go->neg_mrru = 0;
    634 	go->neg_ssnhf = 0;
    635 	go->neg_endpoint = 0;
    636     }
    637     if (noendpoint)
    638 	ao->neg_endpoint = 0;
    639     peer_mru[f->unit] = PPP_MRU;
    640     auth_reset(f->unit);
    641 }
    642 
    643 
    644 /*
    645  * lcp_cilen - Return length of our CI.
    646  */
    647 static int
    648 lcp_cilen(f)
    649     fsm *f;
    650 {
    651     lcp_options *go = &lcp_gotoptions[f->unit];
    652 
    653 #define LENCIVOID(neg)	((neg) ? CILEN_VOID : 0)
    654 #define LENCICHAP(neg)	((neg) ? CILEN_CHAP : 0)
    655 #define LENCISHORT(neg)	((neg) ? CILEN_SHORT : 0)
    656 #define LENCILONG(neg)	((neg) ? CILEN_LONG : 0)
    657 #define LENCILQR(neg)	((neg) ? CILEN_LQR: 0)
    658 #define LENCICBCP(neg)	((neg) ? CILEN_CBCP: 0)
    659     /*
    660      * NB: we only ask for one of CHAP, UPAP, or EAP, even if we will
    661      * accept more than one.  We prefer EAP first, then CHAP, then
    662      * PAP.
    663      */
    664     return (LENCISHORT(go->neg_mru && go->mru != DEFMRU) +
    665 	    LENCILONG(go->neg_asyncmap && go->asyncmap != 0xFFFFFFFF) +
    666 	    LENCISHORT(go->neg_eap) +
    667 	    LENCICHAP(!go->neg_eap && go->neg_chap) +
    668 	    LENCISHORT(!go->neg_eap && !go->neg_chap && go->neg_upap) +
    669 	    LENCILQR(go->neg_lqr) +
    670 	    LENCICBCP(go->neg_cbcp) +
    671 	    LENCILONG(go->neg_magicnumber) +
    672 	    LENCIVOID(go->neg_pcompression) +
    673 	    LENCIVOID(go->neg_accompression) +
    674 	    LENCISHORT(go->neg_mrru) +
    675 	    LENCIVOID(go->neg_ssnhf) +
    676 	    (go->neg_endpoint? CILEN_CHAR + go->endpoint.length: 0));
    677 }
    678 
    679 
    680 /*
    681  * lcp_addci - Add our desired CIs to a packet.
    682  */
    683 static void
    684 lcp_addci(f, ucp, lenp)
    685     fsm *f;
    686     u_char *ucp;
    687     int *lenp;
    688 {
    689     lcp_options *go = &lcp_gotoptions[f->unit];
    690     u_char *start_ucp = ucp;
    691 
    692 #define ADDCIVOID(opt, neg) \
    693     if (neg) { \
    694 	PUTCHAR(opt, ucp); \
    695 	PUTCHAR(CILEN_VOID, ucp); \
    696     }
    697 #define ADDCISHORT(opt, neg, val) \
    698     if (neg) { \
    699 	PUTCHAR(opt, ucp); \
    700 	PUTCHAR(CILEN_SHORT, ucp); \
    701 	PUTSHORT(val, ucp); \
    702     }
    703 #define ADDCICHAP(opt, neg, val) \
    704     if (neg) { \
    705 	PUTCHAR((opt), ucp); \
    706 	PUTCHAR(CILEN_CHAP, ucp); \
    707 	PUTSHORT(PPP_CHAP, ucp); \
    708 	PUTCHAR((CHAP_DIGEST(val)), ucp); \
    709     }
    710 #define ADDCILONG(opt, neg, val) \
    711     if (neg) { \
    712 	PUTCHAR(opt, ucp); \
    713 	PUTCHAR(CILEN_LONG, ucp); \
    714 	PUTLONG(val, ucp); \
    715     }
    716 #define ADDCILQR(opt, neg, val) \
    717     if (neg) { \
    718 	PUTCHAR(opt, ucp); \
    719 	PUTCHAR(CILEN_LQR, ucp); \
    720 	PUTSHORT(PPP_LQR, ucp); \
    721 	PUTLONG(val, ucp); \
    722     }
    723 #define ADDCICHAR(opt, neg, val) \
    724     if (neg) { \
    725 	PUTCHAR(opt, ucp); \
    726 	PUTCHAR(CILEN_CHAR, ucp); \
    727 	PUTCHAR(val, ucp); \
    728     }
    729 #define ADDCIENDP(opt, neg, class, val, len) \
    730     if (neg) { \
    731 	int i; \
    732 	PUTCHAR(opt, ucp); \
    733 	PUTCHAR(CILEN_CHAR + len, ucp); \
    734 	PUTCHAR(class, ucp); \
    735 	for (i = 0; i < len; ++i) \
    736 	    PUTCHAR(val[i], ucp); \
    737     }
    738 
    739     ADDCISHORT(CI_MRU, go->neg_mru && go->mru != DEFMRU, go->mru);
    740     ADDCILONG(CI_ASYNCMAP, go->neg_asyncmap && go->asyncmap != 0xFFFFFFFF,
    741 	      go->asyncmap);
    742     ADDCISHORT(CI_AUTHTYPE, go->neg_eap, PPP_EAP);
    743     ADDCICHAP(CI_AUTHTYPE, !go->neg_eap && go->neg_chap, go->chap_mdtype);
    744     ADDCISHORT(CI_AUTHTYPE, !go->neg_eap && !go->neg_chap && go->neg_upap,
    745 	       PPP_PAP);
    746     ADDCILQR(CI_QUALITY, go->neg_lqr, go->lqr_period);
    747     ADDCICHAR(CI_CALLBACK, go->neg_cbcp, CBCP_OPT);
    748     ADDCILONG(CI_MAGICNUMBER, go->neg_magicnumber, go->magicnumber);
    749     ADDCIVOID(CI_PCOMPRESSION, go->neg_pcompression);
    750     ADDCIVOID(CI_ACCOMPRESSION, go->neg_accompression);
    751     ADDCISHORT(CI_MRRU, go->neg_mrru, go->mrru);
    752     ADDCIVOID(CI_SSNHF, go->neg_ssnhf);
    753     ADDCIENDP(CI_EPDISC, go->neg_endpoint, go->endpoint.class,
    754 	      go->endpoint.value, go->endpoint.length);
    755 
    756     if (ucp - start_ucp != *lenp) {
    757 	/* this should never happen, because peer_mtu should be 1500 */
    758 	error("Bug in lcp_addci: wrong length");
    759     }
    760 }
    761 
    762 
    763 /*
    764  * lcp_ackci - Ack our CIs.
    765  * This should not modify any state if the Ack is bad.
    766  *
    767  * Returns:
    768  *	0 - Ack was bad.
    769  *	1 - Ack was good.
    770  */
    771 static int
    772 lcp_ackci(f, p, len)
    773     fsm *f;
    774     u_char *p;
    775     int len;
    776 {
    777     lcp_options *go = &lcp_gotoptions[f->unit];
    778     u_char cilen, citype, cichar;
    779     u_short cishort;
    780     u_int32_t cilong;
    781 
    782     /*
    783      * CIs must be in exactly the same order that we sent.
    784      * Check packet length and CI length at each step.
    785      * If we find any deviations, then this packet is bad.
    786      */
    787 #define ACKCIVOID(opt, neg) \
    788     if (neg) { \
    789 	if ((len -= CILEN_VOID) < 0) \
    790 	    goto bad; \
    791 	GETCHAR(citype, p); \
    792 	GETCHAR(cilen, p); \
    793 	if (cilen != CILEN_VOID || \
    794 	    citype != opt) \
    795 	    goto bad; \
    796     }
    797 #define ACKCISHORT(opt, neg, val) \
    798     if (neg) { \
    799 	if ((len -= CILEN_SHORT) < 0) \
    800 	    goto bad; \
    801 	GETCHAR(citype, p); \
    802 	GETCHAR(cilen, p); \
    803 	if (cilen != CILEN_SHORT || \
    804 	    citype != opt) \
    805 	    goto bad; \
    806 	GETSHORT(cishort, p); \
    807 	if (cishort != val) \
    808 	    goto bad; \
    809     }
    810 #define ACKCICHAR(opt, neg, val) \
    811     if (neg) { \
    812 	if ((len -= CILEN_CHAR) < 0) \
    813 	    goto bad; \
    814 	GETCHAR(citype, p); \
    815 	GETCHAR(cilen, p); \
    816 	if (cilen != CILEN_CHAR || \
    817 	    citype != opt) \
    818 	    goto bad; \
    819 	GETCHAR(cichar, p); \
    820 	if (cichar != val) \
    821 	    goto bad; \
    822     }
    823 #define ACKCICHAP(opt, neg, val) \
    824     if (neg) { \
    825 	if ((len -= CILEN_CHAP) < 0) \
    826 	    goto bad; \
    827 	GETCHAR(citype, p); \
    828 	GETCHAR(cilen, p); \
    829 	if (cilen != CILEN_CHAP || \
    830 	    citype != (opt)) \
    831 	    goto bad; \
    832 	GETSHORT(cishort, p); \
    833 	if (cishort != PPP_CHAP) \
    834 	    goto bad; \
    835 	GETCHAR(cichar, p); \
    836 	if (cichar != (CHAP_DIGEST(val))) \
    837 	  goto bad; \
    838     }
    839 #define ACKCILONG(opt, neg, val) \
    840     if (neg) { \
    841 	if ((len -= CILEN_LONG) < 0) \
    842 	    goto bad; \
    843 	GETCHAR(citype, p); \
    844 	GETCHAR(cilen, p); \
    845 	if (cilen != CILEN_LONG || \
    846 	    citype != opt) \
    847 	    goto bad; \
    848 	GETLONG(cilong, p); \
    849 	if (cilong != val) \
    850 	    goto bad; \
    851     }
    852 #define ACKCILQR(opt, neg, val) \
    853     if (neg) { \
    854 	if ((len -= CILEN_LQR) < 0) \
    855 	    goto bad; \
    856 	GETCHAR(citype, p); \
    857 	GETCHAR(cilen, p); \
    858 	if (cilen != CILEN_LQR || \
    859 	    citype != opt) \
    860 	    goto bad; \
    861 	GETSHORT(cishort, p); \
    862 	if (cishort != PPP_LQR) \
    863 	    goto bad; \
    864 	GETLONG(cilong, p); \
    865 	if (cilong != val) \
    866 	  goto bad; \
    867     }
    868 #define ACKCIENDP(opt, neg, class, val, vlen) \
    869     if (neg) { \
    870 	int i; \
    871 	if ((len -= CILEN_CHAR + vlen) < 0) \
    872 	    goto bad; \
    873 	GETCHAR(citype, p); \
    874 	GETCHAR(cilen, p); \
    875 	if (cilen != CILEN_CHAR + vlen || \
    876 	    citype != opt) \
    877 	    goto bad; \
    878 	GETCHAR(cichar, p); \
    879 	if (cichar != class) \
    880 	    goto bad; \
    881 	for (i = 0; i < vlen; ++i) { \
    882 	    GETCHAR(cichar, p); \
    883 	    if (cichar != val[i]) \
    884 		goto bad; \
    885 	} \
    886     }
    887 
    888     ACKCISHORT(CI_MRU, go->neg_mru && go->mru != DEFMRU, go->mru);
    889     ACKCILONG(CI_ASYNCMAP, go->neg_asyncmap && go->asyncmap != 0xFFFFFFFF,
    890 	      go->asyncmap);
    891     ACKCISHORT(CI_AUTHTYPE, go->neg_eap, PPP_EAP);
    892     ACKCICHAP(CI_AUTHTYPE, !go->neg_eap && go->neg_chap, go->chap_mdtype);
    893     ACKCISHORT(CI_AUTHTYPE, !go->neg_eap && !go->neg_chap && go->neg_upap,
    894 	       PPP_PAP);
    895     ACKCILQR(CI_QUALITY, go->neg_lqr, go->lqr_period);
    896     ACKCICHAR(CI_CALLBACK, go->neg_cbcp, CBCP_OPT);
    897     ACKCILONG(CI_MAGICNUMBER, go->neg_magicnumber, go->magicnumber);
    898     ACKCIVOID(CI_PCOMPRESSION, go->neg_pcompression);
    899     ACKCIVOID(CI_ACCOMPRESSION, go->neg_accompression);
    900     ACKCISHORT(CI_MRRU, go->neg_mrru, go->mrru);
    901     ACKCIVOID(CI_SSNHF, go->neg_ssnhf);
    902     ACKCIENDP(CI_EPDISC, go->neg_endpoint, go->endpoint.class,
    903 	      go->endpoint.value, go->endpoint.length);
    904 
    905     /*
    906      * If there are any remaining CIs, then this packet is bad.
    907      */
    908     if (len != 0)
    909 	goto bad;
    910     return (1);
    911 bad:
    912     LCPDEBUG(("lcp_acki: received bad Ack!"));
    913     return (0);
    914 }
    915 
    916 
    917 /*
    918  * lcp_nakci - Peer has sent a NAK for some of our CIs.
    919  * This should not modify any state if the Nak is bad
    920  * or if LCP is in the OPENED state.
    921  *
    922  * Returns:
    923  *	0 - Nak was bad.
    924  *	1 - Nak was good.
    925  */
    926 static int
    927 lcp_nakci(f, p, len, treat_as_reject)
    928     fsm *f;
    929     u_char *p;
    930     int len;
    931     int treat_as_reject;
    932 {
    933     lcp_options *go = &lcp_gotoptions[f->unit];
    934     lcp_options *wo = &lcp_wantoptions[f->unit];
    935     u_char citype, cichar, *next;
    936     u_short cishort;
    937     u_int32_t cilong;
    938     lcp_options no;		/* options we've seen Naks for */
    939     lcp_options try;		/* options to request next time */
    940     int looped_back = 0;
    941     int cilen;
    942 
    943     BZERO(&no, sizeof(no));
    944     try = *go;
    945 
    946     /*
    947      * Any Nak'd CIs must be in exactly the same order that we sent.
    948      * Check packet length and CI length at each step.
    949      * If we find any deviations, then this packet is bad.
    950      */
    951 #define NAKCIVOID(opt, neg) \
    952     if (go->neg && \
    953 	len >= CILEN_VOID && \
    954 	p[1] == CILEN_VOID && \
    955 	p[0] == opt) { \
    956 	len -= CILEN_VOID; \
    957 	INCPTR(CILEN_VOID, p); \
    958 	no.neg = 1; \
    959 	try.neg = 0; \
    960     }
    961 #define NAKCICHAP(opt, neg, code) \
    962     if (go->neg && \
    963 	len >= CILEN_CHAP && \
    964 	p[1] == CILEN_CHAP && \
    965 	p[0] == opt) { \
    966 	len -= CILEN_CHAP; \
    967 	INCPTR(2, p); \
    968 	GETSHORT(cishort, p); \
    969 	GETCHAR(cichar, p); \
    970 	no.neg = 1; \
    971 	code \
    972     }
    973 #define NAKCICHAR(opt, neg, code) \
    974     if (go->neg && \
    975 	len >= CILEN_CHAR && \
    976 	p[1] == CILEN_CHAR && \
    977 	p[0] == opt) { \
    978 	len -= CILEN_CHAR; \
    979 	INCPTR(2, p); \
    980 	GETCHAR(cichar, p); \
    981 	no.neg = 1; \
    982 	code \
    983     }
    984 #define NAKCISHORT(opt, neg, code) \
    985     if (go->neg && \
    986 	len >= CILEN_SHORT && \
    987 	p[1] == CILEN_SHORT && \
    988 	p[0] == opt) { \
    989 	len -= CILEN_SHORT; \
    990 	INCPTR(2, p); \
    991 	GETSHORT(cishort, p); \
    992 	no.neg = 1; \
    993 	code \
    994     }
    995 #define NAKCILONG(opt, neg, code) \
    996     if (go->neg && \
    997 	len >= CILEN_LONG && \
    998 	p[1] == CILEN_LONG && \
    999 	p[0] == opt) { \
   1000 	len -= CILEN_LONG; \
   1001 	INCPTR(2, p); \
   1002 	GETLONG(cilong, p); \
   1003 	no.neg = 1; \
   1004 	code \
   1005     }
   1006 #define NAKCILQR(opt, neg, code) \
   1007     if (go->neg && \
   1008 	len >= CILEN_LQR && \
   1009 	p[1] == CILEN_LQR && \
   1010 	p[0] == opt) { \
   1011 	len -= CILEN_LQR; \
   1012 	INCPTR(2, p); \
   1013 	GETSHORT(cishort, p); \
   1014 	GETLONG(cilong, p); \
   1015 	no.neg = 1; \
   1016 	code \
   1017     }
   1018 #define NAKCIENDP(opt, neg) \
   1019     if (go->neg && \
   1020 	len >= CILEN_CHAR && \
   1021 	p[0] == opt && \
   1022 	p[1] >= CILEN_CHAR && \
   1023 	p[1] <= len) { \
   1024 	len -= p[1]; \
   1025 	INCPTR(p[1], p); \
   1026 	no.neg = 1; \
   1027 	try.neg = 0; \
   1028     }
   1029 
   1030     /*
   1031      * NOTE!  There must be no assignments to individual fields of *go in
   1032      * the code below.  Any such assignment is a BUG!
   1033      */
   1034     /*
   1035      * We don't care if they want to send us smaller packets than
   1036      * we want.  Therefore, accept any MRU less than what we asked for,
   1037      * but then ignore the new value when setting the MRU in the kernel.
   1038      * If they send us a bigger MRU than what we asked, accept it, up to
   1039      * the limit of the default MRU we'd get if we didn't negotiate.
   1040      */
   1041     if (go->neg_mru && go->mru != DEFMRU) {
   1042 	NAKCISHORT(CI_MRU, neg_mru,
   1043 		   if (cishort <= wo->mru || cishort <= DEFMRU)
   1044 		       try.mru = cishort;
   1045 		   );
   1046     }
   1047 
   1048     /*
   1049      * Add any characters they want to our (receive-side) asyncmap.
   1050      */
   1051     if (go->neg_asyncmap && go->asyncmap != 0xFFFFFFFF) {
   1052 	NAKCILONG(CI_ASYNCMAP, neg_asyncmap,
   1053 		  try.asyncmap = go->asyncmap | cilong;
   1054 		  );
   1055     }
   1056 
   1057     /*
   1058      * If they've nak'd our authentication-protocol, check whether
   1059      * they are proposing a different protocol, or a different
   1060      * hash algorithm for CHAP.
   1061      */
   1062     if ((go->neg_chap || go->neg_upap || go->neg_eap)
   1063 	&& len >= CILEN_SHORT
   1064 	&& p[0] == CI_AUTHTYPE && p[1] >= CILEN_SHORT && p[1] <= len) {
   1065 	cilen = p[1];
   1066 	len -= cilen;
   1067 	no.neg_chap = go->neg_chap;
   1068 	no.neg_upap = go->neg_upap;
   1069 	no.neg_eap = go->neg_eap;
   1070 	INCPTR(2, p);
   1071 	GETSHORT(cishort, p);
   1072 	if (cishort == PPP_PAP && cilen == CILEN_SHORT) {
   1073 	    /* If we were asking for EAP, then we need to stop that. */
   1074 	    if (go->neg_eap)
   1075 		try.neg_eap = 0;
   1076 
   1077 	    /* If we were asking for CHAP, then we need to stop that. */
   1078 	    else if (go->neg_chap)
   1079 		try.neg_chap = 0;
   1080 	    /*
   1081 	     * If we weren't asking for CHAP or EAP, then we were asking for
   1082 	     * PAP, in which case this Nak is bad.
   1083 	     */
   1084 	    else
   1085 		goto bad;
   1086 
   1087 	} else if (cishort == PPP_CHAP && cilen == CILEN_CHAP) {
   1088 	    GETCHAR(cichar, p);
   1089 	    /* Stop asking for EAP, if we were. */
   1090 	    if (go->neg_eap) {
   1091 		try.neg_eap = 0;
   1092 		/* Try to set up to use their suggestion, if possible */
   1093 		if (CHAP_CANDIGEST(go->chap_mdtype, cichar))
   1094 		    try.chap_mdtype = CHAP_MDTYPE_D(cichar);
   1095 	    } else if (go->neg_chap) {
   1096 		/*
   1097 		 * We were asking for our preferred algorithm, they must
   1098 		 * want something different.
   1099 		 */
   1100 		if (cichar != CHAP_DIGEST(go->chap_mdtype)) {
   1101 		    if (CHAP_CANDIGEST(go->chap_mdtype, cichar)) {
   1102 			/* Use their suggestion if we support it ... */
   1103 			try.chap_mdtype = CHAP_MDTYPE_D(cichar);
   1104 		    } else {
   1105 			/* ... otherwise, try our next-preferred algorithm. */
   1106 			try.chap_mdtype &= ~(CHAP_MDTYPE(try.chap_mdtype));
   1107 			if (try.chap_mdtype == MDTYPE_NONE) /* out of algos */
   1108 			    try.neg_chap = 0;
   1109 		    }
   1110 		} else {
   1111 		    /*
   1112 		     * Whoops, they Nak'd our algorithm of choice
   1113 		     * but then suggested it back to us.
   1114 		     */
   1115 		    goto bad;
   1116 		}
   1117 	    } else {
   1118 		/*
   1119 		 * Stop asking for PAP if we were asking for it.
   1120 		 */
   1121 		try.neg_upap = 0;
   1122 	    }
   1123 
   1124 	} else {
   1125 
   1126 	    /*
   1127 	     * If we were asking for EAP, and they're Conf-Naking EAP,
   1128 	     * well, that's just strange.  Nobody should do that.
   1129 	     */
   1130 	    if (cishort == PPP_EAP && cilen == CILEN_SHORT && go->neg_eap)
   1131 		dbglog("Unexpected Conf-Nak for EAP");
   1132 
   1133 	    /*
   1134 	     * We don't recognize what they're suggesting.
   1135 	     * Stop asking for what we were asking for.
   1136 	     */
   1137 	    if (go->neg_eap)
   1138 		try.neg_eap = 0;
   1139 	    else if (go->neg_chap)
   1140 		try.neg_chap = 0;
   1141 	    else
   1142 		try.neg_upap = 0;
   1143 	    p += cilen - CILEN_SHORT;
   1144 	}
   1145     }
   1146 
   1147     /*
   1148      * If they can't cope with our link quality protocol, we'll have
   1149      * to stop asking for LQR.  We haven't got any other protocol.
   1150      * If they Nak the reporting period, take their value XXX ?
   1151      */
   1152     NAKCILQR(CI_QUALITY, neg_lqr,
   1153 	     if (cishort != PPP_LQR)
   1154 		 try.neg_lqr = 0;
   1155 	     else
   1156 		 try.lqr_period = cilong;
   1157 	     );
   1158 
   1159     /*
   1160      * Only implementing CBCP...not the rest of the callback options
   1161      */
   1162     NAKCICHAR(CI_CALLBACK, neg_cbcp,
   1163               try.neg_cbcp = 0;
   1164               );
   1165 
   1166     /*
   1167      * Check for a looped-back line.
   1168      */
   1169     NAKCILONG(CI_MAGICNUMBER, neg_magicnumber,
   1170 	      try.magicnumber = magic();
   1171 	      looped_back = 1;
   1172 	      );
   1173 
   1174     /*
   1175      * Peer shouldn't send Nak for protocol compression or
   1176      * address/control compression requests; they should send
   1177      * a Reject instead.  If they send a Nak, treat it as a Reject.
   1178      */
   1179     NAKCIVOID(CI_PCOMPRESSION, neg_pcompression);
   1180     NAKCIVOID(CI_ACCOMPRESSION, neg_accompression);
   1181 
   1182     /*
   1183      * Nak for MRRU option - accept their value if it is smaller
   1184      * than the one we want.
   1185      */
   1186     if (go->neg_mrru) {
   1187 	NAKCISHORT(CI_MRRU, neg_mrru,
   1188 		   if (treat_as_reject)
   1189 		       try.neg_mrru = 0;
   1190 		   else if (cishort <= wo->mrru)
   1191 		       try.mrru = cishort;
   1192 		   );
   1193     }
   1194 
   1195     /*
   1196      * Nak for short sequence numbers shouldn't be sent, treat it
   1197      * like a reject.
   1198      */
   1199     NAKCIVOID(CI_SSNHF, neg_ssnhf);
   1200 
   1201     /*
   1202      * Nak of the endpoint discriminator option is not permitted,
   1203      * treat it like a reject.
   1204      */
   1205     NAKCIENDP(CI_EPDISC, neg_endpoint);
   1206 
   1207     /*
   1208      * There may be remaining CIs, if the peer is requesting negotiation
   1209      * on an option that we didn't include in our request packet.
   1210      * If we see an option that we requested, or one we've already seen
   1211      * in this packet, then this packet is bad.
   1212      * If we wanted to respond by starting to negotiate on the requested
   1213      * option(s), we could, but we don't, because except for the
   1214      * authentication type and quality protocol, if we are not negotiating
   1215      * an option, it is because we were told not to.
   1216      * For the authentication type, the Nak from the peer means
   1217      * `let me authenticate myself with you' which is a bit pointless.
   1218      * For the quality protocol, the Nak means `ask me to send you quality
   1219      * reports', but if we didn't ask for them, we don't want them.
   1220      * An option we don't recognize represents the peer asking to
   1221      * negotiate some option we don't support, so ignore it.
   1222      */
   1223     while (len >= CILEN_VOID) {
   1224 	GETCHAR(citype, p);
   1225 	GETCHAR(cilen, p);
   1226 	if (cilen < CILEN_VOID || (len -= cilen) < 0)
   1227 	    goto bad;
   1228 	next = p + cilen - 2;
   1229 
   1230 	switch (citype) {
   1231 	case CI_MRU:
   1232 	    if ((go->neg_mru && go->mru != DEFMRU)
   1233 		|| no.neg_mru || cilen != CILEN_SHORT)
   1234 		goto bad;
   1235 	    GETSHORT(cishort, p);
   1236 	    if (cishort < DEFMRU) {
   1237 		try.neg_mru = 1;
   1238 		try.mru = cishort;
   1239 	    }
   1240 	    break;
   1241 	case CI_ASYNCMAP:
   1242 	    if ((go->neg_asyncmap && go->asyncmap != 0xFFFFFFFF)
   1243 		|| no.neg_asyncmap || cilen != CILEN_LONG)
   1244 		goto bad;
   1245 	    break;
   1246 	case CI_AUTHTYPE:
   1247 	    if (go->neg_chap || no.neg_chap || go->neg_upap || no.neg_upap ||
   1248 		go->neg_eap || no.neg_eap)
   1249 		goto bad;
   1250 	    break;
   1251 	case CI_MAGICNUMBER:
   1252 	    if (go->neg_magicnumber || no.neg_magicnumber ||
   1253 		cilen != CILEN_LONG)
   1254 		goto bad;
   1255 	    break;
   1256 	case CI_PCOMPRESSION:
   1257 	    if (go->neg_pcompression || no.neg_pcompression
   1258 		|| cilen != CILEN_VOID)
   1259 		goto bad;
   1260 	    break;
   1261 	case CI_ACCOMPRESSION:
   1262 	    if (go->neg_accompression || no.neg_accompression
   1263 		|| cilen != CILEN_VOID)
   1264 		goto bad;
   1265 	    break;
   1266 	case CI_QUALITY:
   1267 	    if (go->neg_lqr || no.neg_lqr || cilen != CILEN_LQR)
   1268 		goto bad;
   1269 	    break;
   1270 	case CI_MRRU:
   1271 	    if (go->neg_mrru || no.neg_mrru || cilen != CILEN_SHORT)
   1272 		goto bad;
   1273 	    break;
   1274 	case CI_SSNHF:
   1275 	    if (go->neg_ssnhf || no.neg_ssnhf || cilen != CILEN_VOID)
   1276 		goto bad;
   1277 	    try.neg_ssnhf = 1;
   1278 	    break;
   1279 	case CI_EPDISC:
   1280 	    if (go->neg_endpoint || no.neg_endpoint || cilen < CILEN_CHAR)
   1281 		goto bad;
   1282 	    break;
   1283 	}
   1284 	p = next;
   1285     }
   1286 
   1287     /*
   1288      * OK, the Nak is good.  Now we can update state.
   1289      * If there are any options left we ignore them.
   1290      */
   1291     if (f->state != OPENED) {
   1292 	if (looped_back) {
   1293 	    if (++try.numloops >= lcp_loopbackfail) {
   1294 		notice("Serial line is looped back.");
   1295 		lcp_close(f->unit, "Loopback detected");
   1296 		status = EXIT_LOOPBACK;
   1297 	    }
   1298 	} else
   1299 	    try.numloops = 0;
   1300 	*go = try;
   1301     }
   1302 
   1303     return 1;
   1304 
   1305 bad:
   1306     LCPDEBUG(("lcp_nakci: received bad Nak!"));
   1307     return 0;
   1308 }
   1309 
   1310 
   1311 /*
   1312  * lcp_rejci - Peer has Rejected some of our CIs.
   1313  * This should not modify any state if the Reject is bad
   1314  * or if LCP is in the OPENED state.
   1315  *
   1316  * Returns:
   1317  *	0 - Reject was bad.
   1318  *	1 - Reject was good.
   1319  */
   1320 static int
   1321 lcp_rejci(f, p, len)
   1322     fsm *f;
   1323     u_char *p;
   1324     int len;
   1325 {
   1326     lcp_options *go = &lcp_gotoptions[f->unit];
   1327     u_char cichar;
   1328     u_short cishort;
   1329     u_int32_t cilong;
   1330     lcp_options try;		/* options to request next time */
   1331 
   1332     try = *go;
   1333 
   1334     /*
   1335      * Any Rejected CIs must be in exactly the same order that we sent.
   1336      * Check packet length and CI length at each step.
   1337      * If we find any deviations, then this packet is bad.
   1338      */
   1339 #define REJCIVOID(opt, neg) \
   1340     if (go->neg && \
   1341 	len >= CILEN_VOID && \
   1342 	p[1] == CILEN_VOID && \
   1343 	p[0] == opt) { \
   1344 	len -= CILEN_VOID; \
   1345 	INCPTR(CILEN_VOID, p); \
   1346 	try.neg = 0; \
   1347     }
   1348 #define REJCISHORT(opt, neg, val) \
   1349     if (go->neg && \
   1350 	len >= CILEN_SHORT && \
   1351 	p[1] == CILEN_SHORT && \
   1352 	p[0] == opt) { \
   1353 	len -= CILEN_SHORT; \
   1354 	INCPTR(2, p); \
   1355 	GETSHORT(cishort, p); \
   1356 	/* Check rejected value. */ \
   1357 	if (cishort != val) \
   1358 	    goto bad; \
   1359 	try.neg = 0; \
   1360     }
   1361 #define REJCICHAP(opt, neg, val) \
   1362     if (go->neg && \
   1363 	len >= CILEN_CHAP && \
   1364 	p[1] == CILEN_CHAP && \
   1365 	p[0] == opt) { \
   1366 	len -= CILEN_CHAP; \
   1367 	INCPTR(2, p); \
   1368 	GETSHORT(cishort, p); \
   1369 	GETCHAR(cichar, p); \
   1370 	/* Check rejected value. */ \
   1371 	if ((cishort != PPP_CHAP) || (cichar != (CHAP_DIGEST(val)))) \
   1372 	    goto bad; \
   1373 	try.neg = 0; \
   1374 	try.neg_eap = try.neg_upap = 0; \
   1375     }
   1376 #define REJCILONG(opt, neg, val) \
   1377     if (go->neg && \
   1378 	len >= CILEN_LONG && \
   1379 	p[1] == CILEN_LONG && \
   1380 	p[0] == opt) { \
   1381 	len -= CILEN_LONG; \
   1382 	INCPTR(2, p); \
   1383 	GETLONG(cilong, p); \
   1384 	/* Check rejected value. */ \
   1385 	if (cilong != val) \
   1386 	    goto bad; \
   1387 	try.neg = 0; \
   1388     }
   1389 #define REJCILQR(opt, neg, val) \
   1390     if (go->neg && \
   1391 	len >= CILEN_LQR && \
   1392 	p[1] == CILEN_LQR && \
   1393 	p[0] == opt) { \
   1394 	len -= CILEN_LQR; \
   1395 	INCPTR(2, p); \
   1396 	GETSHORT(cishort, p); \
   1397 	GETLONG(cilong, p); \
   1398 	/* Check rejected value. */ \
   1399 	if (cishort != PPP_LQR || cilong != val) \
   1400 	    goto bad; \
   1401 	try.neg = 0; \
   1402     }
   1403 #define REJCICBCP(opt, neg, val) \
   1404     if (go->neg && \
   1405 	len >= CILEN_CBCP && \
   1406 	p[1] == CILEN_CBCP && \
   1407 	p[0] == opt) { \
   1408 	len -= CILEN_CBCP; \
   1409 	INCPTR(2, p); \
   1410 	GETCHAR(cichar, p); \
   1411 	/* Check rejected value. */ \
   1412 	if (cichar != val) \
   1413 	    goto bad; \
   1414 	try.neg = 0; \
   1415     }
   1416 #define REJCIENDP(opt, neg, class, val, vlen) \
   1417     if (go->neg && \
   1418 	len >= CILEN_CHAR + vlen && \
   1419 	p[0] == opt && \
   1420 	p[1] == CILEN_CHAR + vlen) { \
   1421 	int i; \
   1422 	len -= CILEN_CHAR + vlen; \
   1423 	INCPTR(2, p); \
   1424 	GETCHAR(cichar, p); \
   1425 	if (cichar != class) \
   1426 	    goto bad; \
   1427 	for (i = 0; i < vlen; ++i) { \
   1428 	    GETCHAR(cichar, p); \
   1429 	    if (cichar != val[i]) \
   1430 		goto bad; \
   1431 	} \
   1432 	try.neg = 0; \
   1433     }
   1434 
   1435     REJCISHORT(CI_MRU, neg_mru, go->mru);
   1436     REJCILONG(CI_ASYNCMAP, neg_asyncmap, go->asyncmap);
   1437     REJCISHORT(CI_AUTHTYPE, neg_eap, PPP_EAP);
   1438     if (!go->neg_eap) {
   1439 	REJCICHAP(CI_AUTHTYPE, neg_chap, go->chap_mdtype);
   1440 	if (!go->neg_chap) {
   1441 	    REJCISHORT(CI_AUTHTYPE, neg_upap, PPP_PAP);
   1442 	}
   1443     }
   1444     REJCILQR(CI_QUALITY, neg_lqr, go->lqr_period);
   1445     REJCICBCP(CI_CALLBACK, neg_cbcp, CBCP_OPT);
   1446     REJCILONG(CI_MAGICNUMBER, neg_magicnumber, go->magicnumber);
   1447     REJCIVOID(CI_PCOMPRESSION, neg_pcompression);
   1448     REJCIVOID(CI_ACCOMPRESSION, neg_accompression);
   1449     REJCISHORT(CI_MRRU, neg_mrru, go->mrru);
   1450     REJCIVOID(CI_SSNHF, neg_ssnhf);
   1451     REJCIENDP(CI_EPDISC, neg_endpoint, go->endpoint.class,
   1452 	      go->endpoint.value, go->endpoint.length);
   1453 
   1454     /*
   1455      * If there are any remaining CIs, then this packet is bad.
   1456      */
   1457     if (len != 0)
   1458 	goto bad;
   1459     /*
   1460      * Now we can update state.
   1461      */
   1462     if (f->state != OPENED)
   1463 	*go = try;
   1464     return 1;
   1465 
   1466 bad:
   1467     LCPDEBUG(("lcp_rejci: received bad Reject!"));
   1468     return 0;
   1469 }
   1470 
   1471 
   1472 /*
   1473  * lcp_reqci - Check the peer's requested CIs and send appropriate response.
   1474  *
   1475  * Returns: CONFACK, CONFNAK or CONFREJ and input packet modified
   1476  * appropriately.  If reject_if_disagree is non-zero, doesn't return
   1477  * CONFNAK; returns CONFREJ if it can't return CONFACK.
   1478  */
   1479 static int
   1480 lcp_reqci(f, inp, lenp, reject_if_disagree)
   1481     fsm *f;
   1482     u_char *inp;		/* Requested CIs */
   1483     int *lenp;			/* Length of requested CIs */
   1484     int reject_if_disagree;
   1485 {
   1486     lcp_options *go = &lcp_gotoptions[f->unit];
   1487     lcp_options *ho = &lcp_hisoptions[f->unit];
   1488     lcp_options *ao = &lcp_allowoptions[f->unit];
   1489     u_char *cip, *next;		/* Pointer to current and next CIs */
   1490     int cilen, citype, cichar;	/* Parsed len, type, char value */
   1491     u_short cishort;		/* Parsed short value */
   1492     u_int32_t cilong;		/* Parse long value */
   1493     int rc = CONFACK;		/* Final packet return code */
   1494     int orc;			/* Individual option return code */
   1495     u_char *p;			/* Pointer to next char to parse */
   1496     u_char *rejp;		/* Pointer to next char in reject frame */
   1497     u_char *nakp;		/* Pointer to next char in Nak frame */
   1498     int l = *lenp;		/* Length left */
   1499 
   1500     /*
   1501      * Reset all his options.
   1502      */
   1503     BZERO(ho, sizeof(*ho));
   1504 
   1505     /*
   1506      * Process all his options.
   1507      */
   1508     next = inp;
   1509     nakp = nak_buffer;
   1510     rejp = inp;
   1511     while (l) {
   1512 	orc = CONFACK;			/* Assume success */
   1513 	cip = p = next;			/* Remember begining of CI */
   1514 	if (l < 2 ||			/* Not enough data for CI header or */
   1515 	    p[1] < 2 ||			/*  CI length too small or */
   1516 	    p[1] > l) {			/*  CI length too big? */
   1517 	    LCPDEBUG(("lcp_reqci: bad CI length!"));
   1518 	    orc = CONFREJ;		/* Reject bad CI */
   1519 	    cilen = l;			/* Reject till end of packet */
   1520 	    l = 0;			/* Don't loop again */
   1521 	    citype = 0;
   1522 	    goto endswitch;
   1523 	}
   1524 	GETCHAR(citype, p);		/* Parse CI type */
   1525 	GETCHAR(cilen, p);		/* Parse CI length */
   1526 	l -= cilen;			/* Adjust remaining length */
   1527 	next += cilen;			/* Step to next CI */
   1528 
   1529 	switch (citype) {		/* Check CI type */
   1530 	case CI_MRU:
   1531 	    if (!ao->neg_mru ||		/* Allow option? */
   1532 		cilen != CILEN_SHORT) {	/* Check CI length */
   1533 		orc = CONFREJ;		/* Reject CI */
   1534 		break;
   1535 	    }
   1536 	    GETSHORT(cishort, p);	/* Parse MRU */
   1537 
   1538 	    /*
   1539 	     * He must be able to receive at least our minimum.
   1540 	     * No need to check a maximum.  If he sends a large number,
   1541 	     * we'll just ignore it.
   1542 	     */
   1543 	    if (cishort < MINMRU) {
   1544 		orc = CONFNAK;		/* Nak CI */
   1545 		PUTCHAR(CI_MRU, nakp);
   1546 		PUTCHAR(CILEN_SHORT, nakp);
   1547 		PUTSHORT(MINMRU, nakp);	/* Give him a hint */
   1548 		break;
   1549 	    }
   1550 	    ho->neg_mru = 1;		/* Remember he sent MRU */
   1551 	    ho->mru = cishort;		/* And remember value */
   1552 	    break;
   1553 
   1554 	case CI_ASYNCMAP:
   1555 	    if (!ao->neg_asyncmap ||
   1556 		cilen != CILEN_LONG) {
   1557 		orc = CONFREJ;
   1558 		break;
   1559 	    }
   1560 	    GETLONG(cilong, p);
   1561 
   1562 	    /*
   1563 	     * Asyncmap must have set at least the bits
   1564 	     * which are set in lcp_allowoptions[unit].asyncmap.
   1565 	     */
   1566 	    if ((ao->asyncmap & ~cilong) != 0) {
   1567 		orc = CONFNAK;
   1568 		PUTCHAR(CI_ASYNCMAP, nakp);
   1569 		PUTCHAR(CILEN_LONG, nakp);
   1570 		PUTLONG(ao->asyncmap | cilong, nakp);
   1571 		break;
   1572 	    }
   1573 	    ho->neg_asyncmap = 1;
   1574 	    ho->asyncmap = cilong;
   1575 	    break;
   1576 
   1577 	case CI_AUTHTYPE:
   1578 	    if (cilen < CILEN_SHORT ||
   1579 		!(ao->neg_upap || ao->neg_chap || ao->neg_eap)) {
   1580 		/*
   1581 		 * Reject the option if we're not willing to authenticate.
   1582 		 */
   1583 		dbglog("No auth is possible");
   1584 		orc = CONFREJ;
   1585 		break;
   1586 	    }
   1587 	    GETSHORT(cishort, p);
   1588 
   1589 	    /*
   1590 	     * Authtype must be PAP, CHAP, or EAP.
   1591 	     *
   1592 	     * Note: if more than one of ao->neg_upap, ao->neg_chap, and
   1593 	     * ao->neg_eap are set, and the peer sends a Configure-Request
   1594 	     * with two or more authenticate-protocol requests, then we will
   1595 	     * reject the second request.
   1596 	     * Whether we end up doing CHAP, UPAP, or EAP depends then on
   1597 	     * the ordering of the CIs in the peer's Configure-Request.
   1598              */
   1599 
   1600 	    if (cishort == PPP_PAP) {
   1601 		/* we've already accepted CHAP or EAP */
   1602 		if (ho->neg_chap || ho->neg_eap ||
   1603 		    cilen != CILEN_SHORT) {
   1604 		    LCPDEBUG(("lcp_reqci: rcvd AUTHTYPE PAP, rejecting..."));
   1605 		    orc = CONFREJ;
   1606 		    break;
   1607 		}
   1608 		if (!ao->neg_upap) {	/* we don't want to do PAP */
   1609 		    orc = CONFNAK;	/* NAK it and suggest CHAP or EAP */
   1610 		    PUTCHAR(CI_AUTHTYPE, nakp);
   1611 		    if (ao->neg_eap) {
   1612 			PUTCHAR(CILEN_SHORT, nakp);
   1613 			PUTSHORT(PPP_EAP, nakp);
   1614 		    } else {
   1615 			PUTCHAR(CILEN_CHAP, nakp);
   1616 			PUTSHORT(PPP_CHAP, nakp);
   1617 			PUTCHAR(CHAP_DIGEST(ao->chap_mdtype), nakp);
   1618 		    }
   1619 		    break;
   1620 		}
   1621 		ho->neg_upap = 1;
   1622 		break;
   1623 	    }
   1624 	    if (cishort == PPP_CHAP) {
   1625 		/* we've already accepted PAP or EAP */
   1626 		if (ho->neg_upap || ho->neg_eap ||
   1627 		    cilen != CILEN_CHAP) {
   1628 		    LCPDEBUG(("lcp_reqci: rcvd AUTHTYPE CHAP, rejecting..."));
   1629 		    orc = CONFREJ;
   1630 		    break;
   1631 		}
   1632 		if (!ao->neg_chap) {	/* we don't want to do CHAP */
   1633 		    orc = CONFNAK;	/* NAK it and suggest EAP or PAP */
   1634 		    PUTCHAR(CI_AUTHTYPE, nakp);
   1635 		    PUTCHAR(CILEN_SHORT, nakp);
   1636 		    if (ao->neg_eap) {
   1637 			PUTSHORT(PPP_EAP, nakp);
   1638 		    } else {
   1639 			PUTSHORT(PPP_PAP, nakp);
   1640 		    }
   1641 		    break;
   1642 		}
   1643 		GETCHAR(cichar, p);	/* get digest type */
   1644 		if (!(CHAP_CANDIGEST(ao->chap_mdtype, cichar))) {
   1645 		    /*
   1646 		     * We can't/won't do the requested type,
   1647 		     * suggest something else.
   1648 		     */
   1649 		    orc = CONFNAK;
   1650 		    PUTCHAR(CI_AUTHTYPE, nakp);
   1651 		    PUTCHAR(CILEN_CHAP, nakp);
   1652 		    PUTSHORT(PPP_CHAP, nakp);
   1653 		    PUTCHAR(CHAP_DIGEST(ao->chap_mdtype), nakp);
   1654 		    break;
   1655 		}
   1656 		ho->chap_mdtype = CHAP_MDTYPE_D(cichar); /* save md type */
   1657 		ho->neg_chap = 1;
   1658 		break;
   1659 	    }
   1660 	    if (cishort == PPP_EAP) {
   1661 		/* we've already accepted CHAP or PAP */
   1662 		if (ho->neg_chap || ho->neg_upap || cilen != CILEN_SHORT) {
   1663 		    LCPDEBUG(("lcp_reqci: rcvd AUTHTYPE EAP, rejecting..."));
   1664 		    orc = CONFREJ;
   1665 		    break;
   1666 		}
   1667 		if (!ao->neg_eap) {	/* we don't want to do EAP */
   1668 		    orc = CONFNAK;	/* NAK it and suggest CHAP or PAP */
   1669 		    PUTCHAR(CI_AUTHTYPE, nakp);
   1670 		    if (ao->neg_chap) {
   1671 			PUTCHAR(CILEN_CHAP, nakp);
   1672 			PUTSHORT(PPP_CHAP, nakp);
   1673 			PUTCHAR(CHAP_DIGEST(ao->chap_mdtype), nakp);
   1674 		    } else {
   1675 			PUTCHAR(CILEN_SHORT, nakp);
   1676 			PUTSHORT(PPP_PAP, nakp);
   1677 		    }
   1678 		    break;
   1679 		}
   1680 		ho->neg_eap = 1;
   1681 		break;
   1682 	    }
   1683 
   1684 	    /*
   1685 	     * We don't recognize the protocol they're asking for.
   1686 	     * Nak it with something we're willing to do.
   1687 	     * (At this point we know ao->neg_upap || ao->neg_chap ||
   1688 	     * ao->neg_eap.)
   1689 	     */
   1690 	    orc = CONFNAK;
   1691 	    PUTCHAR(CI_AUTHTYPE, nakp);
   1692 	    if (ao->neg_eap) {
   1693 		PUTCHAR(CILEN_SHORT, nakp);
   1694 		PUTSHORT(PPP_EAP, nakp);
   1695 	    } else if (ao->neg_chap) {
   1696 		PUTCHAR(CILEN_CHAP, nakp);
   1697 		PUTSHORT(PPP_CHAP, nakp);
   1698 		PUTCHAR(CHAP_DIGEST(ao->chap_mdtype), nakp);
   1699 	    } else {
   1700 		PUTCHAR(CILEN_SHORT, nakp);
   1701 		PUTSHORT(PPP_PAP, nakp);
   1702 	    }
   1703 	    break;
   1704 
   1705 	case CI_QUALITY:
   1706 	    if (!ao->neg_lqr ||
   1707 		cilen != CILEN_LQR) {
   1708 		orc = CONFREJ;
   1709 		break;
   1710 	    }
   1711 
   1712 	    GETSHORT(cishort, p);
   1713 	    GETLONG(cilong, p);
   1714 
   1715 	    /*
   1716 	     * Check the protocol and the reporting period.
   1717 	     * XXX When should we Nak this, and what with?
   1718 	     */
   1719 	    if (cishort != PPP_LQR) {
   1720 		orc = CONFNAK;
   1721 		PUTCHAR(CI_QUALITY, nakp);
   1722 		PUTCHAR(CILEN_LQR, nakp);
   1723 		PUTSHORT(PPP_LQR, nakp);
   1724 		PUTLONG(ao->lqr_period, nakp);
   1725 		break;
   1726 	    }
   1727 	    break;
   1728 
   1729 	case CI_MAGICNUMBER:
   1730 	    if (!(ao->neg_magicnumber || go->neg_magicnumber) ||
   1731 		cilen != CILEN_LONG) {
   1732 		orc = CONFREJ;
   1733 		break;
   1734 	    }
   1735 	    GETLONG(cilong, p);
   1736 
   1737 	    /*
   1738 	     * He must have a different magic number.
   1739 	     */
   1740 	    if (go->neg_magicnumber &&
   1741 		cilong == go->magicnumber) {
   1742 		cilong = magic();	/* Don't put magic() inside macro! */
   1743 		orc = CONFNAK;
   1744 		PUTCHAR(CI_MAGICNUMBER, nakp);
   1745 		PUTCHAR(CILEN_LONG, nakp);
   1746 		PUTLONG(cilong, nakp);
   1747 		break;
   1748 	    }
   1749 	    ho->neg_magicnumber = 1;
   1750 	    ho->magicnumber = cilong;
   1751 	    break;
   1752 
   1753 
   1754 	case CI_PCOMPRESSION:
   1755 	    if (!ao->neg_pcompression ||
   1756 		cilen != CILEN_VOID) {
   1757 		orc = CONFREJ;
   1758 		break;
   1759 	    }
   1760 	    ho->neg_pcompression = 1;
   1761 	    break;
   1762 
   1763 	case CI_ACCOMPRESSION:
   1764 	    if (!ao->neg_accompression ||
   1765 		cilen != CILEN_VOID) {
   1766 		orc = CONFREJ;
   1767 		break;
   1768 	    }
   1769 	    ho->neg_accompression = 1;
   1770 	    break;
   1771 
   1772 	case CI_MRRU:
   1773 	    if (!ao->neg_mrru || !multilink ||
   1774 		cilen != CILEN_SHORT) {
   1775 		orc = CONFREJ;
   1776 		break;
   1777 	    }
   1778 
   1779 	    GETSHORT(cishort, p);
   1780 	    /* possibly should insist on a minimum/maximum MRRU here */
   1781 	    ho->neg_mrru = 1;
   1782 	    ho->mrru = cishort;
   1783 	    break;
   1784 
   1785 	case CI_SSNHF:
   1786 	    if (!ao->neg_ssnhf || !multilink ||
   1787 		cilen != CILEN_VOID) {
   1788 		orc = CONFREJ;
   1789 		break;
   1790 	    }
   1791 	    ho->neg_ssnhf = 1;
   1792 	    break;
   1793 
   1794 	case CI_EPDISC:
   1795 	    if (!ao->neg_endpoint ||
   1796 		cilen < CILEN_CHAR ||
   1797 		cilen > CILEN_CHAR + MAX_ENDP_LEN) {
   1798 		orc = CONFREJ;
   1799 		break;
   1800 	    }
   1801 	    GETCHAR(cichar, p);
   1802 	    cilen -= CILEN_CHAR;
   1803 	    ho->neg_endpoint = 1;
   1804 	    ho->endpoint.class = cichar;
   1805 	    ho->endpoint.length = cilen;
   1806 	    BCOPY(p, ho->endpoint.value, cilen);
   1807 	    INCPTR(cilen, p);
   1808 	    break;
   1809 
   1810 	default:
   1811 	    LCPDEBUG(("lcp_reqci: rcvd unknown option %d", citype));
   1812 	    orc = CONFREJ;
   1813 	    break;
   1814 	}
   1815 
   1816 endswitch:
   1817 	if (orc == CONFACK &&		/* Good CI */
   1818 	    rc != CONFACK)		/*  but prior CI wasnt? */
   1819 	    continue;			/* Don't send this one */
   1820 
   1821 	if (orc == CONFNAK) {		/* Nak this CI? */
   1822 	    if (reject_if_disagree	/* Getting fed up with sending NAKs? */
   1823 		&& citype != CI_MAGICNUMBER) {
   1824 		orc = CONFREJ;		/* Get tough if so */
   1825 	    } else {
   1826 		if (rc == CONFREJ)	/* Rejecting prior CI? */
   1827 		    continue;		/* Don't send this one */
   1828 		rc = CONFNAK;
   1829 	    }
   1830 	}
   1831 	if (orc == CONFREJ) {		/* Reject this CI */
   1832 	    rc = CONFREJ;
   1833 	    if (cip != rejp)		/* Need to move rejected CI? */
   1834 		BCOPY(cip, rejp, cilen); /* Move it */
   1835 	    INCPTR(cilen, rejp);	/* Update output pointer */
   1836 	}
   1837     }
   1838 
   1839     /*
   1840      * If we wanted to send additional NAKs (for unsent CIs), the
   1841      * code would go here.  The extra NAKs would go at *nakp.
   1842      * At present there are no cases where we want to ask the
   1843      * peer to negotiate an option.
   1844      */
   1845 
   1846     switch (rc) {
   1847     case CONFACK:
   1848 	*lenp = next - inp;
   1849 	break;
   1850     case CONFNAK:
   1851 	/*
   1852 	 * Copy the Nak'd options from the nak_buffer to the caller's buffer.
   1853 	 */
   1854 	*lenp = nakp - nak_buffer;
   1855 	BCOPY(nak_buffer, inp, *lenp);
   1856 	break;
   1857     case CONFREJ:
   1858 	*lenp = rejp - inp;
   1859 	break;
   1860     }
   1861 
   1862     LCPDEBUG(("lcp_reqci: returning CONF%s.", CODENAME(rc)));
   1863     return (rc);			/* Return final code */
   1864 }
   1865 
   1866 
   1867 /*
   1868  * lcp_up - LCP has come UP.
   1869  */
   1870 static void
   1871 lcp_up(f)
   1872     fsm *f;
   1873 {
   1874     lcp_options *wo = &lcp_wantoptions[f->unit];
   1875     lcp_options *ho = &lcp_hisoptions[f->unit];
   1876     lcp_options *go = &lcp_gotoptions[f->unit];
   1877     lcp_options *ao = &lcp_allowoptions[f->unit];
   1878     int mtu, mru;
   1879 
   1880     if (!go->neg_magicnumber)
   1881 	go->magicnumber = 0;
   1882     if (!ho->neg_magicnumber)
   1883 	ho->magicnumber = 0;
   1884 
   1885     /*
   1886      * Set our MTU to the smaller of the MTU we wanted and
   1887      * the MRU our peer wanted.  If we negotiated an MRU,
   1888      * set our MRU to the larger of value we wanted and
   1889      * the value we got in the negotiation.
   1890      * Note on the MTU: the link MTU can be the MRU the peer wanted,
   1891      * the interface MTU is set to the lowest of that, the
   1892      * MTU we want to use, and our link MRU.
   1893      */
   1894     mtu = ho->neg_mru? ho->mru: PPP_MRU;
   1895     mru = go->neg_mru? MAX(wo->mru, go->mru): PPP_MRU;
   1896 #ifdef HAVE_MULTILINK
   1897     if (!(multilink && go->neg_mrru && ho->neg_mrru))
   1898 #endif /* HAVE_MULTILINK */
   1899 	netif_set_mtu(f->unit, MIN(MIN(mtu, mru), ao->mru));
   1900     ppp_send_config(f->unit, mtu,
   1901 		    (ho->neg_asyncmap? ho->asyncmap: 0xffffffff),
   1902 		    ho->neg_pcompression, ho->neg_accompression);
   1903     ppp_recv_config(f->unit, mru,
   1904 		    (lax_recv? 0: go->neg_asyncmap? go->asyncmap: 0xffffffff),
   1905 		    go->neg_pcompression, go->neg_accompression);
   1906 
   1907     if (ho->neg_mru)
   1908 	peer_mru[f->unit] = ho->mru;
   1909 
   1910     lcp_echo_lowerup(f->unit);  /* Enable echo messages */
   1911 
   1912     link_established(f->unit);
   1913 }
   1914 
   1915 
   1916 /*
   1917  * lcp_down - LCP has gone DOWN.
   1918  *
   1919  * Alert other protocols.
   1920  */
   1921 static void
   1922 lcp_down(f)
   1923     fsm *f;
   1924 {
   1925     lcp_options *go = &lcp_gotoptions[f->unit];
   1926 
   1927     lcp_echo_lowerdown(f->unit);
   1928 
   1929     link_down(f->unit);
   1930 
   1931     ppp_send_config(f->unit, PPP_MRU, 0xffffffff, 0, 0);
   1932     ppp_recv_config(f->unit, PPP_MRU,
   1933 		    (go->neg_asyncmap? go->asyncmap: 0xffffffff),
   1934 		    go->neg_pcompression, go->neg_accompression);
   1935     peer_mru[f->unit] = PPP_MRU;
   1936 }
   1937 
   1938 
   1939 /*
   1940  * lcp_starting - LCP needs the lower layer up.
   1941  */
   1942 static void
   1943 lcp_starting(f)
   1944     fsm *f;
   1945 {
   1946     link_required(f->unit);
   1947 }
   1948 
   1949 
   1950 /*
   1951  * lcp_finished - LCP has finished with the lower layer.
   1952  */
   1953 static void
   1954 lcp_finished(f)
   1955     fsm *f;
   1956 {
   1957     link_terminated(f->unit);
   1958 }
   1959 
   1960 
   1961 /*
   1962  * lcp_printpkt - print the contents of an LCP packet.
   1963  */
   1964 static char *lcp_codenames[] = {
   1965     "ConfReq", "ConfAck", "ConfNak", "ConfRej",
   1966     "TermReq", "TermAck", "CodeRej", "ProtRej",
   1967     "EchoReq", "EchoRep", "DiscReq"
   1968 };
   1969 
   1970 static int
   1971 lcp_printpkt(p, plen, printer, arg)
   1972     u_char *p;
   1973     int plen;
   1974     void (*printer) __P((void *, char *, ...));
   1975     void *arg;
   1976 {
   1977     int code, id, len, olen, i;
   1978     u_char *pstart, *optend;
   1979     u_short cishort;
   1980     u_int32_t cilong;
   1981 
   1982     if (plen < HEADERLEN)
   1983 	return 0;
   1984     pstart = p;
   1985     GETCHAR(code, p);
   1986     GETCHAR(id, p);
   1987     GETSHORT(len, p);
   1988     if (len < HEADERLEN || len > plen)
   1989 	return 0;
   1990 
   1991     if (code >= 1 && code <= sizeof(lcp_codenames) / sizeof(char *))
   1992 	printer(arg, " %s", lcp_codenames[code-1]);
   1993     else
   1994 	printer(arg, " code=0x%x", code);
   1995     printer(arg, " id=0x%x", id);
   1996     len -= HEADERLEN;
   1997     switch (code) {
   1998     case CONFREQ:
   1999     case CONFACK:
   2000     case CONFNAK:
   2001     case CONFREJ:
   2002 	/* print option list */
   2003 	while (len >= 2) {
   2004 	    GETCHAR(code, p);
   2005 	    GETCHAR(olen, p);
   2006 	    p -= 2;
   2007 	    if (olen < 2 || olen > len) {
   2008 		break;
   2009 	    }
   2010 	    printer(arg, " <");
   2011 	    len -= olen;
   2012 	    optend = p + olen;
   2013 	    switch (code) {
   2014 	    case CI_MRU:
   2015 		if (olen == CILEN_SHORT) {
   2016 		    p += 2;
   2017 		    GETSHORT(cishort, p);
   2018 		    printer(arg, "mru %d", cishort);
   2019 		}
   2020 		break;
   2021 	    case CI_ASYNCMAP:
   2022 		if (olen == CILEN_LONG) {
   2023 		    p += 2;
   2024 		    GETLONG(cilong, p);
   2025 		    printer(arg, "asyncmap 0x%x", cilong);
   2026 		}
   2027 		break;
   2028 	    case CI_AUTHTYPE:
   2029 		if (olen >= CILEN_SHORT) {
   2030 		    p += 2;
   2031 		    printer(arg, "auth ");
   2032 		    GETSHORT(cishort, p);
   2033 		    switch (cishort) {
   2034 		    case PPP_PAP:
   2035 			printer(arg, "pap");
   2036 			break;
   2037 		    case PPP_CHAP:
   2038 			printer(arg, "chap");
   2039 			if (p < optend) {
   2040 			    switch (*p) {
   2041 			    case CHAP_MD5:
   2042 				printer(arg, " MD5");
   2043 				++p;
   2044 				break;
   2045 #ifdef CHAPMS
   2046 			    case CHAP_MICROSOFT:
   2047 				printer(arg, " MS");
   2048 				++p;
   2049 				break;
   2050 
   2051 			    case CHAP_MICROSOFT_V2:
   2052 				printer(arg, " MS-v2");
   2053 				++p;
   2054 				break;
   2055 #endif
   2056 			    }
   2057 			}
   2058 			break;
   2059 		    case PPP_EAP:
   2060 			printer(arg, "eap");
   2061 			break;
   2062 		    default:
   2063 			printer(arg, "0x%x", cishort);
   2064 		    }
   2065 		}
   2066 		break;
   2067 	    case CI_QUALITY:
   2068 		if (olen >= CILEN_SHORT) {
   2069 		    p += 2;
   2070 		    printer(arg, "quality ");
   2071 		    GETSHORT(cishort, p);
   2072 		    switch (cishort) {
   2073 		    case PPP_LQR:
   2074 			printer(arg, "lqr");
   2075 			break;
   2076 		    default:
   2077 			printer(arg, "0x%x", cishort);
   2078 		    }
   2079 		}
   2080 		break;
   2081 	    case CI_CALLBACK:
   2082 		if (olen >= CILEN_CHAR) {
   2083 		    p += 2;
   2084 		    printer(arg, "callback ");
   2085 		    GETCHAR(cishort, p);
   2086 		    switch (cishort) {
   2087 		    case CBCP_OPT:
   2088 			printer(arg, "CBCP");
   2089 			break;
   2090 		    default:
   2091 			printer(arg, "0x%x", cishort);
   2092 		    }
   2093 		}
   2094 		break;
   2095 	    case CI_MAGICNUMBER:
   2096 		if (olen == CILEN_LONG) {
   2097 		    p += 2;
   2098 		    GETLONG(cilong, p);
   2099 		    printer(arg, "magic 0x%x", cilong);
   2100 		}
   2101 		break;
   2102 	    case CI_PCOMPRESSION:
   2103 		if (olen == CILEN_VOID) {
   2104 		    p += 2;
   2105 		    printer(arg, "pcomp");
   2106 		}
   2107 		break;
   2108 	    case CI_ACCOMPRESSION:
   2109 		if (olen == CILEN_VOID) {
   2110 		    p += 2;
   2111 		    printer(arg, "accomp");
   2112 		}
   2113 		break;
   2114 	    case CI_MRRU:
   2115 		if (olen == CILEN_SHORT) {
   2116 		    p += 2;
   2117 		    GETSHORT(cishort, p);
   2118 		    printer(arg, "mrru %d", cishort);
   2119 		}
   2120 		break;
   2121 	    case CI_SSNHF:
   2122 		if (olen == CILEN_VOID) {
   2123 		    p += 2;
   2124 		    printer(arg, "ssnhf");
   2125 		}
   2126 		break;
   2127 	    case CI_EPDISC:
   2128 #ifdef HAVE_MULTILINK
   2129 		if (olen >= CILEN_CHAR) {
   2130 		    struct epdisc epd;
   2131 		    p += 2;
   2132 		    GETCHAR(epd.class, p);
   2133 		    epd.length = olen - CILEN_CHAR;
   2134 		    if (epd.length > MAX_ENDP_LEN)
   2135 			epd.length = MAX_ENDP_LEN;
   2136 		    if (epd.length > 0) {
   2137 			BCOPY(p, epd.value, epd.length);
   2138 			p += epd.length;
   2139 		    }
   2140 		    printer(arg, "endpoint [%s]", epdisc_to_str(&epd));
   2141 		}
   2142 #else
   2143 		printer(arg, "endpoint");
   2144 #endif
   2145 		break;
   2146 	    }
   2147 	    while (p < optend) {
   2148 		GETCHAR(code, p);
   2149 		printer(arg, " %.2x", code);
   2150 	    }
   2151 	    printer(arg, ">");
   2152 	}
   2153 	break;
   2154 
   2155     case TERMACK:
   2156     case TERMREQ:
   2157 	if (len > 0 && *p >= ' ' && *p < 0x7f) {
   2158 	    printer(arg, " ");
   2159 	    print_string((char *)p, len, printer, arg);
   2160 	    p += len;
   2161 	    len = 0;
   2162 	}
   2163 	break;
   2164 
   2165     case ECHOREQ:
   2166     case ECHOREP:
   2167     case DISCREQ:
   2168 	if (len >= 4) {
   2169 	    GETLONG(cilong, p);
   2170 	    printer(arg, " magic=0x%x", cilong);
   2171 	    p += 4;
   2172 	    len -= 4;
   2173 	}
   2174 	break;
   2175     }
   2176 
   2177     /* print the rest of the bytes in the packet */
   2178     for (i = 0; i < len && i < 32; ++i) {
   2179 	GETCHAR(code, p);
   2180 	printer(arg, " %.2x", code);
   2181     }
   2182     if (i < len) {
   2183 	printer(arg, " ...");
   2184 	p += len - i;
   2185     }
   2186 
   2187     return p - pstart;
   2188 }
   2189 
   2190 /*
   2191  * Time to shut down the link because there is nothing out there.
   2192  */
   2193 
   2194 static
   2195 void LcpLinkFailure (f)
   2196     fsm *f;
   2197 {
   2198     if (f->state == OPENED) {
   2199 	info("No response to %d echo-requests", lcp_echos_pending);
   2200         notice("Serial link appears to be disconnected.");
   2201         lcp_close(f->unit, "Peer not responding");
   2202 	status = EXIT_PEER_DEAD;
   2203     }
   2204 }
   2205 
   2206 /*
   2207  * Timer expired for the LCP echo requests from this process.
   2208  */
   2209 
   2210 static void
   2211 LcpEchoCheck (f)
   2212     fsm *f;
   2213 {
   2214     LcpSendEchoRequest (f);
   2215     if (f->state != OPENED)
   2216 	return;
   2217 
   2218     /*
   2219      * Start the timer for the next interval.
   2220      */
   2221     if (lcp_echo_timer_running)
   2222 	warn("assertion lcp_echo_timer_running==0 failed");
   2223     TIMEOUT (LcpEchoTimeout, f, lcp_echo_interval);
   2224     lcp_echo_timer_running = 1;
   2225 }
   2226 
   2227 /*
   2228  * LcpEchoTimeout - Timer expired on the LCP echo
   2229  */
   2230 
   2231 static void
   2232 LcpEchoTimeout (arg)
   2233     void *arg;
   2234 {
   2235     if (lcp_echo_timer_running != 0) {
   2236         lcp_echo_timer_running = 0;
   2237         LcpEchoCheck ((fsm *) arg);
   2238     }
   2239 }
   2240 
   2241 /*
   2242  * LcpEchoReply - LCP has received a reply to the echo
   2243  */
   2244 
   2245 static void
   2246 lcp_received_echo_reply (f, id, inp, len)
   2247     fsm *f;
   2248     int id;
   2249     u_char *inp;
   2250     int len;
   2251 {
   2252     u_int32_t magic;
   2253 
   2254     /* Check the magic number - don't count replies from ourselves. */
   2255     if (len < 4) {
   2256 	dbglog("lcp: received short Echo-Reply, length %d", len);
   2257 	return;
   2258     }
   2259     GETLONG(magic, inp);
   2260     if (lcp_gotoptions[f->unit].neg_magicnumber
   2261 	&& magic == lcp_gotoptions[f->unit].magicnumber) {
   2262 	warn("appear to have received our own echo-reply!");
   2263 	return;
   2264     }
   2265 
   2266     /* Reset the number of outstanding echo frames */
   2267     lcp_echos_pending = 0;
   2268 }
   2269 
   2270 /*
   2271  * LcpSendEchoRequest - Send an echo request frame to the peer
   2272  */
   2273 
   2274 static void
   2275 LcpSendEchoRequest (f)
   2276     fsm *f;
   2277 {
   2278     u_int32_t lcp_magic;
   2279     u_char pkt[4], *pktp;
   2280 
   2281     /*
   2282      * Detect the failure of the peer at this point.
   2283      */
   2284     if (lcp_echo_fails != 0) {
   2285         if (lcp_echos_pending >= lcp_echo_fails) {
   2286             LcpLinkFailure(f);
   2287 	    lcp_echos_pending = 0;
   2288 	}
   2289     }
   2290 
   2291     /*
   2292      * Make and send the echo request frame.
   2293      */
   2294     if (f->state == OPENED) {
   2295         lcp_magic = lcp_gotoptions[f->unit].magicnumber;
   2296 	pktp = pkt;
   2297 	PUTLONG(lcp_magic, pktp);
   2298         fsm_sdata(f, ECHOREQ, lcp_echo_number++ & 0xFF, pkt, pktp - pkt);
   2299 	++lcp_echos_pending;
   2300     }
   2301 }
   2302 
   2303 /*
   2304  * lcp_echo_lowerup - Start the timer for the LCP frame
   2305  */
   2306 
   2307 static void
   2308 lcp_echo_lowerup (unit)
   2309     int unit;
   2310 {
   2311     fsm *f = &lcp_fsm[unit];
   2312 
   2313     /* Clear the parameters for generating echo frames */
   2314     lcp_echos_pending      = 0;
   2315     lcp_echo_number        = 0;
   2316     lcp_echo_timer_running = 0;
   2317 
   2318     /* If a timeout interval is specified then start the timer */
   2319     if (lcp_echo_interval != 0)
   2320         LcpEchoCheck (f);
   2321 }
   2322 
   2323 /*
   2324  * lcp_echo_lowerdown - Stop the timer for the LCP frame
   2325  */
   2326 
   2327 static void
   2328 lcp_echo_lowerdown (unit)
   2329     int unit;
   2330 {
   2331     fsm *f = &lcp_fsm[unit];
   2332 
   2333     if (lcp_echo_timer_running != 0) {
   2334         UNTIMEOUT (LcpEchoTimeout, f);
   2335         lcp_echo_timer_running = 0;
   2336     }
   2337 }
   2338