xref: /illumos-gate/usr/src/cmd/cmd-inet/usr.bin/pppd/lcp.c (revision 4f62a657)

/*
 * lcp.c - PPP Link Control Protocol.
 *
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 1989 Carnegie Mellon University.
 * All rights reserved.
 *
 * Copyright (c) 2016 by Delphix. All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by Carnegie Mellon University.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#if defined(CHAPMS) || defined(CHAPMSV2)
#ifdef HAVE_CRYPT_H
#include <crypt.h>
#endif
#ifndef USE_CRYPT
#include <des.h>
#endif
#ifdef SOL2
#include <errno.h>
#endif
#endif

#include "pppd.h"
#include "fsm.h"
#include "lcp.h"
#include "chap.h"
#include "magic.h"
#include "patchlevel.h"

/*
 * Special failure codes for logging link failure reasons.
 */
bool peer_nak_auth;		/* Peer sent nak for our auth request */
u_short nak_auth_orig;		/* Auth proto peer naked */
u_short nak_auth_proto;		/* Auth proto peer suggested instead */
bool unsolicited_nak_auth;	/* Peer asked us to authenticate */
u_short unsolicit_auth_proto;	/* Auth proto peer wants */
bool peer_reject_auth;		/* Peer sent reject for auth */
u_short reject_auth_proto;	/* Protocol that peer rejected */
bool rejected_peers_auth;	/* We sent a reject to the peer */
u_short rejected_auth_proto;	/* Protocol that peer wanted to use */
bool naked_peers_auth;		/* We sent a nak to the peer */
u_short naked_auth_orig;	/* Protocol that we wanted to use */
u_short naked_auth_proto;	/* Protocol that peer wants us to use */

/*
 * LCP-related command-line options.
 */
int	lcp_echo_interval = 0; 	/* Interval between LCP echo-requests */
int	lcp_echo_fails = 0;	/* Tolerance to unanswered echo-requests */
bool	lax_recv = 0;		/* accept control chars in asyncmap */
static int use_accm_test = 2;	/* use big echo-requests to check ACCM */
#define	ACCM_TEST_FAILS	5

#define _tostr2(x)	#x
#define _tostr(x)	_tostr2(x)
static char identstr[256] =	/* Identification string */
	"ppp-" VERSION "." _tostr(PATCHLEVEL) IMPLEMENTATION;
static int noident = 0;		/* 1 to disable; 2 to reject */
static int sentident = 0;	/* counts the # of ident codes sent */

/* set if we're allowed to send an unsolicited Configure-Nak for MRU. */
static bool unsolicit_mru;

static int setescape __P((char **, option_t *));

static bool do_msft_workaround = 1;
static int setasyncmap __P((char **, option_t *));

bool	noendpoint = 0;		/* don't send/accept endpoint discriminator */
static int setendpoint __P((char **, option_t *));

static char *callback_strings[] = {
	"auth", "dialstring", "location", "E.164", "X.500", "", "CBCP", NULL
};

/* This is used in packet printing even if NEGOTIATE_FCS isn't enabled */
static char *fcsalt_strings[] = {
	"null", "crc16", "crc32", NULL
};

#ifdef NEGOTIATE_FCS
static int setfcsallow __P((char **, option_t *));
static int setfcswant __P((char **, option_t *));
#endif

/* Backward compatibility for Linux */
#ifndef PPP_MAXMRU
#define	PPP_MTU		1500	/* Default MTU (size of Info field) */
#define	PPP_MAXMTU	65535 - (PPP_HDRLEN + PPP_FCSLEN)
#define	PPP_MINMTU	64
#define	PPP_MAXMRU	65000	/* Largest MRU we allow */
#define	PPP_MINMRU	128
#endif

static option_t lcp_option_list[] = {
    /* LCP options */
    { "noaccomp", o_bool, &lcp_wantoptions[0].neg_accompression,
      "Disable address/control compression",
      OPT_A2COPY, &lcp_allowoptions[0].neg_accompression },
    { "-ac", o_bool, &lcp_wantoptions[0].neg_accompression,
      "Disable address/control compression",
      OPT_A2COPY, &lcp_allowoptions[0].neg_accompression },
    { "default-asyncmap", o_bool, &lcp_wantoptions[0].neg_asyncmap,
      "Disable asyncmap negotiation",
      OPT_A2COPY, &lcp_allowoptions[0].neg_asyncmap },
    { "-am", o_bool, &lcp_wantoptions[0].neg_asyncmap,
      "Disable asyncmap negotiation",
      OPT_A2COPY, &lcp_allowoptions[0].neg_asyncmap },
    { "asyncmap", o_special, (void *)setasyncmap,
      "Set asyncmap (for received packets)" },
    { "-as", o_special, (void *)setasyncmap,
      "Set asyncmap (for received packets)" },
    { "nomagic", o_bool, &lcp_wantoptions[0].neg_magicnumber,
      "Disable magic number option (looped-back line detect)",
      OPT_A2COPY, &lcp_allowoptions[0].neg_magicnumber },
    { "-mn", o_bool, &lcp_wantoptions[0].neg_magicnumber,
      "Disable magic number option (looped-back line detect)",
      OPT_A2COPY, &lcp_allowoptions[0].neg_magicnumber },
    { "default-mru", o_bool, &lcp_wantoptions[0].neg_mru,
      "Disable MRU negotiation (use default 1500)",
      OPT_A2COPY, &lcp_allowoptions[0].neg_mru },
    { "-mru", o_bool, &lcp_wantoptions[0].neg_mru,
      "Disable MRU negotiation (use default 1500)",
      OPT_A2COPY, &lcp_allowoptions[0].neg_mru },
    { "mru", o_int, &lcp_wantoptions[0].mru,
      "Set MRU (maximum received packet size) for negotiation",
      OPT_LIMITS, &lcp_wantoptions[0].neg_mru, PPP_MAXMRU, PPP_MINMRU },
    { "mtu", o_int, &lcp_allowoptions[0].mru,
      "Set our MTU", OPT_LIMITS|OPT_A2COPY, &lcp_allowoptions[0].mrru,
      PPP_MAXMTU, PPP_MINMTU },
    { "nopcomp", o_bool, &lcp_wantoptions[0].neg_pcompression,
      "Disable protocol field compression",
      OPT_A2COPY, &lcp_allowoptions[0].neg_pcompression },
    { "-pc", o_bool, &lcp_wantoptions[0].neg_pcompression,
      "Disable protocol field compression",
      OPT_A2COPY, &lcp_allowoptions[0].neg_pcompression },
    { "-p", o_bool, &lcp_wantoptions[0].passive,
      "Set passive mode", 1 },
    { "passive", o_bool, &lcp_wantoptions[0].passive,
      "Set passive mode", 1 },
    { "silent", o_bool, &lcp_wantoptions[0].silent,
      "Set silent mode", 1 },
    { "escape", o_special, (void *)setescape,
      "List of character codes to escape on transmission" },
    { "lcp-echo-failure", o_int, &lcp_echo_fails,
      "Number of consecutive echo failures for link failure" },
    { "lcp-echo-interval", o_int, &lcp_echo_interval,
      "Set time in seconds between LCP echo requests" },
    { "no-accm-test", o_int, &use_accm_test,
      "Disable use of LCP Echo-Request asyncmap checking",
      OPT_NOARG|OPT_VAL(0) },
    { "small-accm-test", o_int, &use_accm_test,
      "Use only small Echo-Requests for asyncmap checking",
      OPT_NOARG|OPT_VAL(1) },
    { "lcp-restart", o_int, &lcp_fsm[0].timeouttime,
      "Set time in seconds between LCP retransmissions" },
    { "lcp-max-terminate", o_int, &lcp_fsm[0].maxtermtransmits,
      "Maximum number of LCP terminate-request transmissions" },
    { "lcp-max-configure", o_int, &lcp_fsm[0].maxconfreqtransmits,
      "Maximum number of LCP configure-request transmissions" },
    { "lcp-max-failure", o_int, &lcp_fsm[0].maxnakloops,
      "Set limit on number of LCP configure-naks" },
    { "receive-all", o_bool, &lax_recv,
      "Accept all received control characters", 1 },
#ifdef HAVE_MULTILINK
    { "mrru", o_int, &lcp_wantoptions[0].mrru,
      "Maximum received packet size for multilink bundle",
      OPT_LIMITS, &lcp_wantoptions[0].neg_mrru, PPP_MAXMRU, PPP_MINMRU },
    { "mpshortseq", o_bool, &lcp_wantoptions[0].neg_ssnhf,
      "Use short sequence numbers in multilink headers",
      OPT_A2COPY | 1, &lcp_allowoptions[0].neg_ssnhf },
    { "nompshortseq", o_bool, &lcp_wantoptions[0].neg_ssnhf,
      "Don't use short sequence numbers in multilink headers",
      OPT_A2COPY, &lcp_allowoptions[0].neg_ssnhf },
#endif /* HAVE_MULTILINK */
    { "endpoint", o_special, (void *)setendpoint,
      "Endpoint discriminator for multilink", },
    { "noendpoint", o_bool, &noendpoint,
      "Don't send or accept multilink endpoint discriminator", 1 },
    { "ident", o_string, identstr,
      "LCP Identification string", OPT_STATIC, NULL, sizeof(identstr) },
    { "noident", o_int, &noident,
      "Disable use of LCP Identification", OPT_INC|OPT_NOARG|1 },
#ifdef NEGOTIATE_FCS
    { "default-fcs", o_bool, &lcp_wantoptions[0].neg_fcs,
      "Disable FCS Alternatives option (use default CRC-16)",
      OPT_A2COPY, &lcp_allowoptions[0].neg_fcs },
    { "allow-fcs", o_special, (void *)setfcsallow,
      "Set allowable FCS types; crc16, crc32, null, or number" },
    { "fcs", o_special, (void *)setfcswant,
      "Set FCS type(s) desired; crc16, crc32, null, or number" },
#endif
#ifdef MUX_FRAME
    /*
     * if pppmux option is turned on, then the parameter to this
     * is time value in microseconds
     */
    { "pppmux", o_int, &lcp_wantoptions[0].pppmux,
      "Set PPP Multiplexing option timer", OPT_LLIMIT | OPT_A2COPY,
	&lcp_allowoptions[0].pppmux, 0, 0 },
#endif
    {NULL}
};

/* global vars */
fsm lcp_fsm[NUM_PPP];			/* LCP fsm structure (global)*/
lcp_options lcp_wantoptions[NUM_PPP];	/* Options that we want to request */
lcp_options lcp_gotoptions[NUM_PPP];	/* Options that peer ack'd */
lcp_options lcp_allowoptions[NUM_PPP];	/* Options we allow peer to request */
lcp_options lcp_hisoptions[NUM_PPP];	/* Options that we ack'd */
u_int32_t xmit_accm[NUM_PPP][8];	/* extended transmit ACCM */

/*
 * These variables allow a plugin to assert limits on the maximum
 * MRU/MTU values that can be negotiated.
 */
int absmax_mru = PPP_MAXMRU;
int absmax_mtu = PPP_MAXMTU;

static int lcp_echos_pending = 0;	/* Number of outstanding echo msgs */
static int lcp_echo_number   = 0;	/* ID number of next echo frame */
static int lcp_echo_timer_running = 0;  /* set if a timer is running */
static bool lcp_echo_accm_test = 0;	/* flag if still testing ACCM */
static int lcp_echo_badreplies = 0;	/* number of bad replies from peer */
/*
 * The maximum number of bad replies we tolerate before bringing the
 * link down.
 */
#define LCP_ECHO_MAX_BADREPLIES	10

/*
 * Callbacks for fsm code.  (CI = Configuration Information)
 */
static void lcp_resetci __P((fsm *));	/* Reset our CI */
static int  lcp_cilen __P((fsm *));		/* Return length of our CI */
static void lcp_addci __P((fsm *, u_char *, int *)); /* Add our CI to pkt */
static int  lcp_ackci __P((fsm *, u_char *, int)); /* Peer ack'd our CI */
static int  lcp_nakci __P((fsm *, u_char *, int)); /* Peer nak'd our CI */
static int  lcp_rejci __P((fsm *, u_char *, int)); /* Peer rej'd our CI */
static int  lcp_reqci __P((fsm *, u_char *, int *, int)); /* Rcv peer CI */
static void lcp_up __P((fsm *));		/* We're UP */
static void lcp_down __P((fsm *));		/* We're DOWN */
static void lcp_starting __P((fsm *));	/* We need lower layer up */
static void lcp_finished __P((fsm *));	/* We need lower layer down */
static int  lcp_extcode __P((fsm *, int, int, u_char *, int));
static void lcp_rprotrej __P((fsm *, u_char *, int));
static int lcp_coderej __P((fsm *f, int code, int id, u_char *inp, int len));

/*
 * routines to send LCP echos to peer
 */

static void lcp_echo_lowerup __P((int));
static void lcp_echo_lowerdown __P((int));
static void LcpEchoTimeout __P((void *));
static int lcp_received_echo_reply __P((fsm *, int, u_char *, int));
static void LcpSendEchoRequest __P((fsm *));
static void LcpLinkFailure __P((fsm *));
static void LcpEchoCheck __P((fsm *));

/*
 * routines to send and receive additional LCP packets described in
 * section 1 of rfc1570.
 */
static void LcpSendIdentification __P((fsm *));
static void lcp_received_identification __P((fsm *, int, u_char *, int));
static void LcpSendTimeRemaining __P((fsm *, u_int32_t));
static void lcp_timeremaining __P((void *));
static void lcp_received_timeremain __P((fsm *, int, u_char *, int));


static fsm_callbacks lcp_callbacks = {	/* LCP callback routines */
    lcp_resetci,		/* Reset our Configuration Information */
    lcp_cilen,			/* Length of our Configuration Information */
    lcp_addci,			/* Add our Configuration Information */
    lcp_ackci,			/* ACK our Configuration Information */
    lcp_nakci,			/* NAK our Configuration Information */
    lcp_rejci,			/* Reject our Configuration Information */
    lcp_reqci,			/* Request peer's Configuration Information */
    lcp_up,			/* Called when fsm reaches OPENED state */
    lcp_down,			/* Called when fsm leaves OPENED state */
    lcp_starting,		/* Called when we want the lower layer up */
    lcp_finished,		/* Called when we want the lower layer down */
    NULL,			/* Retransmission is necessary */
    lcp_extcode,		/* Called to handle LCP-specific codes */
    "LCP",			/* String name of protocol */
    lcp_coderej,		/* Peer rejected a code number */
};

/*
 * Protocol entry points.
 * Some of these are called directly.
 */

static void lcp_init __P((int));
static void lcp_input __P((int, u_char *, int));
static void lcp_protrej __P((int));
static int  lcp_printpkt __P((u_char *, int,
    void (*) __P((void *, const char *, ...)), void *));


struct protent lcp_protent = {
    PPP_LCP,		/* Protocol Number for LCP */
    lcp_init,		/* Initializes LCP */
    lcp_input,		/* Processes a received LCP packet */
    lcp_protrej,	/* Process a received Protocol-reject */
    lcp_lowerup,	/* Called after the serial device has been set up */
    lcp_lowerdown,	/* Called when the link is brought down */
    lcp_open,		/* Called after lcp_lowerup when bringing up the link */
    lcp_close,		/* Called when the link goes down */
    lcp_printpkt,	/* Print a packet in human readable form */
    NULL,		/* Process a received data packet */
    1,			/* LCP is enabled by default */
    "LCP",		/* Name of the protocol */
    NULL,		/* Name of the corresponding data protocol */
    lcp_option_list,	/* List of LCP command-line options */
    NULL,		/* Assigns default values for options */
    NULL,		/* Configures demand-dial */
    NULL		/* Bring up the link for this packet? */
};

int lcp_loopbackfail = DEFLOOPBACKFAIL;

/*
 * Length of each type of configuration option (in octets)
 */
#define CILEN_VOID	2
#define CILEN_CHAR	3
#define CILEN_SHORT	4	/* CILEN_VOID + 2 */
#define CILEN_CHAP	5	/* CILEN_VOID + 2 + 1 */
#define CILEN_LONG	6	/* CILEN_VOID + 4 */
#define CILEN_LQR	8	/* CILEN_VOID + 2 + 4 */
#define CILEN_CBCP	3


/*
 * setescape - add chars to the set we escape on transmission.
 */
/*ARGSUSED*/
static int
setescape(argv, opt)
    char **argv;
    option_t *opt;
{
    int n, ret;
    char *p, *endp;

    p = *argv;
    ret = 1;
    while (*p != '\0') {
	n = strtol(p, &endp, 16);
	if (p == endp) {
	    option_error("escape parameter contains invalid hex number '%s'",
			 p);
	    return 0;
	}
	p = endp;
	if (n < 0 || n == 0x5E || n > 0xFF) {
	    option_error("can't escape character 0x%x", n);
	    ret = 0;
	} else
	    xmit_accm[0][n >> 5] |= 1 << (n & 0x1F);
	while (*p == ',' || *p == ' ')
	    ++p;
    }
    return ret;
}

/*
 * setasyncmap - set async map negotiated
 */
/*ARGSUSED*/
static int
setasyncmap(argv, opt)
    char **argv;
    option_t *opt;
{
    u_int32_t val;
    char *endp;

    val = strtoul(*argv, &endp, 16);
    if (*argv == endp) {
	option_error("invalid numeric parameter '%s' for 'asyncmap' option",
	    *argv);
	return 0;
    }
    lcp_wantoptions[0].asyncmap |= val;
    lcp_wantoptions[0].neg_asyncmap = (~lcp_wantoptions[0].asyncmap != 0);
    do_msft_workaround = 0;
    return 1;
}

/*ARGSUSED*/
static int
setendpoint(argv, opt)
    char **argv;
    option_t *opt;
{
    if (str_to_epdisc(&lcp_wantoptions[0].endpoint, *argv)) {
	lcp_wantoptions[0].neg_endpoint = 1;
	return 1;
    }
    option_error("Can't parse '%s' as an endpoint discriminator", *argv);
    return 0;
}

#ifdef NEGOTIATE_FCS
static int
str_to_fcstype(opt,arg)
    lcp_options *opt;
    char *arg;
{
    char **cpp, *cp;
    int val, len;

    if (*arg != '\0') {
	val = 0;
	while (*arg != '\0') {
	    len = 0;
	    if (isdigit(*arg)) {
		len = strtol(arg, &cp, 0);
		if (len < 0 || len > 255 || arg == cp ||
		    (*cp != '\0' && *cp != ','))
		    break;
		val |= len;
		len = cp - arg;
	    } else {
		for (cpp = fcsalt_strings; *cpp != NULL; cpp++) {
		    len = strlen(*cpp);
		    if (strncasecmp(arg, *cpp, len) == 0 &&
		        (arg[len] == '\0' || arg[len] == ','))
			break;
		}
		if (*cpp == NULL)
		    break;
		val |= 1<<(cpp-fcsalt_strings);
	    }
	    if (arg[len] == '\0') {
		opt->neg_fcs = 1;
		opt->fcs_type = val;
		return (1);
	    }
	    arg += len+1;
	}
    }
    option_error("Can't parse '%s' as an FCS type", arg);
    return (0);
}

/*ARGSUSED*/
static int
setfcsallow(argv, opt)
    char **argv;
    option_t *opt;
{
    return str_to_fcstype(&lcp_allowoptions[0], *argv);
}

/*ARGSUSED*/
static int
setfcswant(argv, opt)
    char **argv;
    option_t *opt;
{
    return str_to_fcstype(&lcp_wantoptions[0], *argv);
}
#endif

/*
 * lcp_init - Initialize LCP.
 */
static void
lcp_init(unit)
    int unit;
{
    fsm *f = &lcp_fsm[unit];
    lcp_options *wo = &lcp_wantoptions[unit];
    lcp_options *ao = &lcp_allowoptions[unit];

    f->unit = unit;
    f->protocol = PPP_LCP;
    f->callbacks = &lcp_callbacks;

    fsm_init(f);

    BZERO(wo, sizeof(*wo));
    wo->neg_mru = 1;
    wo->mru = PPP_MRU;
    wo->neg_asyncmap = 1;
    wo->chap_mdtype = CHAP_DIGEST_MD5;
    wo->neg_magicnumber = 1;
    wo->neg_pcompression = 1;
    wo->neg_accompression = 1;

    /*
     * Leave allowed MRU (MTU) at zero; configuration option sets it
     * non-zero if we should nak for something else.
     */
    BZERO(ao, sizeof(*ao));
    ao->neg_mru = 1;
    ao->neg_asyncmap = 1;
    ao->neg_chap = 1;
#if defined(CHAPMS) || defined(CHAPMSV2)
#ifdef SOL2
    /* Check if DES wasn't exported */
    errno = 0;
    setkey("\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"
	"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0");
    if (errno == 0)
#endif
    {
#ifdef CHAPMS
    ao->neg_mschap = 1;
#endif
#ifdef CHAPMSV2
    ao->neg_mschapv2 = 1;
#endif
    }
#endif
    ao->chap_mdtype = CHAP_DIGEST_MD5;
    ao->neg_upap = 1;
    ao->neg_magicnumber = 1;
    ao->neg_pcompression = 1;
    ao->neg_accompression = 1;
#ifdef CBCP_SUPPORT
    ao->neg_cbcp = 1;
#endif
    ao->neg_endpoint = 1;
#ifdef NEGOTIATE_FCS
    ao->neg_fcs = 1;
    ao->fcs_type = FCSALT_NULL|FCSALT_16|FCSALT_32;
#endif

    BZERO(xmit_accm[unit], sizeof(xmit_accm[0]));
    xmit_accm[unit][3] = 0x60000000;
}


/*
 * lcp_open - LCP is allowed to come up.
 */
void
lcp_open(unit)
    int unit;
{
    fsm *f = &lcp_fsm[unit];
    lcp_options *wo = &lcp_wantoptions[unit];

    f->flags = 0;
    if (wo->passive)
	f->flags |= OPT_PASSIVE;
    if (wo->silent)
	f->flags |= OPT_SILENT;
    fsm_open(f);
}


/*
 * lcp_close - Take LCP down.
 */
void
lcp_close(unit, reason)
    int unit;
    char *reason;
{
    fsm *f = &lcp_fsm[unit];

    if (phase != PHASE_DEAD)
	new_phase(PHASE_TERMINATE);
    if (f->state == STOPPED && (f->flags & (OPT_PASSIVE|OPT_SILENT))) {
	/*
	 * This action is not strictly according to the FSM in RFC1548,
	 * but it does mean that the program terminates if you do a
	 * lcp_close() in passive/silent mode when a connection hasn't
	 * been established.
	 */
	f->state = CLOSED;
	lcp_finished(f);

    } else
	fsm_close(&lcp_fsm[unit], reason);
}


/*
 * lcp_lowerup - The lower layer is up.
 */
void
lcp_lowerup(unit)
    int unit;
{
    lcp_options *wo = &lcp_wantoptions[unit];
    int mru, mtu;

    mru = PPP_MRU > absmax_mru ? absmax_mru : PPP_MRU;
    mtu = PPP_MTU > absmax_mtu ? absmax_mtu : PPP_MTU;

    /*
     * Don't use A/C or protocol compression on transmission,
     * but accept A/C and protocol compressed packets
     * if we are going to ask for A/C and protocol compression.
     */
    ppp_set_xaccm(unit, xmit_accm[unit]);
    ppp_send_config(unit, mtu, 0xffffffff, 0, 0);
    ppp_recv_config(unit, mru, (lax_recv? 0: 0xffffffff),
		    wo->neg_pcompression, wo->neg_accompression);
#ifdef NEGOTIATE_FCS
    ppp_send_fcs(unit, FCSALT_16);
    ppp_recv_fcs(unit, FCSALT_16);
#endif

    fsm_setpeermru(unit, mtu);
    lcp_allowoptions[unit].asyncmap = xmit_accm[unit][0];

    fsm_lowerup(&lcp_fsm[unit]);
}


/*
 * lcp_lowerdown - The lower layer is down.
 */
void
lcp_lowerdown(unit)
    int unit;
{
    fsm_lowerdown(&lcp_fsm[unit]);
}


/*
 * lcp_input - Input LCP packet.
 */
static void
lcp_input(unit, p, len)
    int unit;
    u_char *p;
    int len;
{
    fsm *f = &lcp_fsm[unit];

    fsm_input(f, p, len);
}


/*
 * lcp_extcode - Handle a LCP-specific code.
 */
static int
lcp_extcode(f, code, id, inp, len)
    fsm *f;
    int code, id;
    u_char *inp;
    int len;
{
    u_char *magp;

    switch( code ){
    case CODE_PROTREJ:
	lcp_rprotrej(f, inp, len);
	break;

    case CODE_ECHOREQ:
	if (f->state != OPENED)
	    break;
	magp = inp;
	PUTLONG(lcp_gotoptions[f->unit].magicnumber, magp);
	fsm_sdata(f, CODE_ECHOREP, id, inp, len);
	break;

    case CODE_ECHOREP:
	if (!lcp_received_echo_reply(f, id, inp, len)) {
	    lcp_echo_badreplies++;
	    if (lcp_echo_badreplies > LCP_ECHO_MAX_BADREPLIES) {
		LcpLinkFailure(f);
		lcp_echos_pending = 0;
		lcp_echo_badreplies = 0;
	    }
	}
	break;

    case CODE_DISCREQ:
	break;

    case CODE_IDENT:
	/* More than one 'noident' tells us to reject the code number. */
	if (noident > 1)
	    return 0;
	lcp_received_identification(f, id, inp, len);
	break;

    case CODE_TIMEREMAIN:
	lcp_received_timeremain(f, id, inp, len);
	break;

    default:
	return 0;
    }
    return 1;
}

/*
 * lcp_rprotrej - Receive an Protocol-Reject.
 *
 * Figure out which protocol is rejected and inform it.
 */
static void
lcp_rprotrej(f, inp, len)
    fsm *f;
    u_char *inp;
    int len;
{
    int i;
    struct protent *protp;
    u_short prot;

    if (len < 2) {
	dbglog("lcp_rprotrej: Rcvd short Protocol-Reject packet!");
	return;
    }

    GETSHORT(prot, inp);

    /*
     * Protocol-Reject packets received in any state other than the LCP
     * OPENED state SHOULD be silently discarded.
     */
    if( f->state != OPENED ){
	dbglog("Protocol-Reject discarded: LCP in state %s",
	    fsm_state(f->state));
	return;
    }

    /*
     * Upcall the proper Protocol-Reject routine.
     */
    for (i = 0; (protp = protocols[i]) != NULL; ++i)
	if (protp->protocol == prot && protp->enabled_flag) {
	    (*protp->protrej)(f->unit);
	    return;
	}

    warn("Protocol-Reject for unsupported protocol 0x%x", prot);
}


/*
 * lcp_protrej - A Protocol-Reject was received.
 */
/*ARGSUSED*/
static void
lcp_protrej(unit)
    int unit;
{
    /*
     * Can't reject LCP!
     */
    error("Received Protocol-Reject for LCP!");
}

/*
 * lcp_coderej - A Code-Reject was received.
 */
/*ARGSUSED*/
static int
lcp_coderej(f, code, id, inp, len)
	fsm *f;
	int code;
	int id;
	u_char *inp;
	int len;
{
	/* The peer cannot reject these code numbers. */
	if (code >= CODE_CONFREQ && code <= CODE_PROTREJ)
		return 1;
	switch (code) {
	case CODE_ECHOREQ:
	    /*
	     * If the peer rejects an Echo-Request, then stop doing that.
	     */
	    if (lcp_echo_timer_running != 0) {
		UNTIMEOUT (LcpEchoTimeout, f);
		lcp_echo_timer_running = 0;
		lcp_echo_interval = 0;
	    }
	    break;
	}
	return 0;
}

/*
 * lcp_sprotrej - Send a Protocol-Reject for some protocol.
 */
void
lcp_sprotrej(unit, p, len)
    int unit;
    u_char *p;
    int len;
{
    /*
     * Send back the protocol and the information field of the
     * rejected packet.  We only get here if LCP is in the OPENED state.
     */
    p += 2;
    len -= 2;

    fsm_sdata(&lcp_fsm[unit], CODE_PROTREJ, ++lcp_fsm[unit].id,
	      p, len);
}


/*
 * lcp_resetci - Reset our CI.
 */
static void
lcp_resetci(f)
    fsm *f;
{
    lcp_options *wo = &lcp_wantoptions[f->unit];
    lcp_options *go = &lcp_gotoptions[f->unit];
    lcp_options *ao = &lcp_allowoptions[f->unit];

    wo->magicnumber = magic();
    wo->numloops = 0;
    sentident = 0;
    *go = *wo;
    if (!multilink) {
	go->neg_mrru = 0;
	go->neg_ssnhf = 0;
    }
    if (noendpoint)
	ao->neg_endpoint = 0;
    if (go->mru > absmax_mru)
	go->mru = absmax_mru;
    if (ao->mru > absmax_mtu)
	ao->mru = absmax_mtu;
    unsolicit_mru = 1;
    fsm_setpeermru(f->unit, PPP_MTU > absmax_mtu ? absmax_mtu : PPP_MTU);
    auth_reset(f->unit);
}


/*
 * lcp_cilen - Return length of our CI.
 */
static int
lcp_cilen(f)
    fsm *f;
{
    lcp_options *go = &lcp_gotoptions[f->unit];

#define LENCIVOID(neg)	((neg) ? CILEN_VOID : 0)
#define LENCICHAP(neg)	((neg) ? CILEN_CHAP : 0)
#define LENCICHAR(neg)	((neg) ? CILEN_CHAR : 0)
#define LENCISHORT(neg)	((neg) ? CILEN_SHORT : 0)
#define LENCILONG(neg)	((neg) ? CILEN_LONG : 0)
#define LENCILQR(neg)	((neg) ? CILEN_LQR: 0)
#define LENCICBCP(neg)	((neg) ? CILEN_CBCP: 0)
    /*
     * NB: we only ask for one of CHAP and UPAP, even if we will
     * accept either.
     */
    return (LENCISHORT(go->neg_mru && go->mru != PPP_MRU) +
	    LENCILONG(go->neg_asyncmap && go->asyncmap != 0xFFFFFFFF) +
	    LENCICHAP(go->neg_chap || go->neg_mschap || go->neg_mschapv2) +
	    LENCISHORT(!go->neg_chap && go->neg_upap && !go->neg_mschap &&
		!go->neg_mschapv2) +
	    LENCILQR(go->neg_lqr) +
	    LENCICBCP(go->neg_cbcp) +
	    LENCILONG(go->neg_magicnumber) +
	    LENCIVOID(go->neg_pcompression) +
	    LENCIVOID(go->neg_accompression) +
	    LENCICHAR(go->neg_fcs) +
	    LENCISHORT(go->neg_mrru) +
	    LENCIVOID(go->neg_ssnhf) +
#ifdef MUX_FRAME
            LENCIVOID(go->pppmux) +
#endif
	    (go->neg_endpoint? CILEN_CHAR + go->endpoint.length: 0));
}


/*
 * lcp_addci - Add our desired CIs to a packet.
 */
static void
lcp_addci(f, ucp, lenp)
    fsm *f;
    u_char *ucp;
    int *lenp;
{
    lcp_options *go = &lcp_gotoptions[f->unit];
    lcp_options *ho = &lcp_hisoptions[f->unit];
    u_char *start_ucp = ucp;

#define ADDCIVOID(opt, neg) \
    if (neg) { \
	PUTCHAR(opt, ucp); \
	PUTCHAR(CILEN_VOID, ucp); \
    }
#define ADDCISHORT(opt, neg, val) \
    if (neg) { \
	PUTCHAR(opt, ucp); \
	PUTCHAR(CILEN_SHORT, ucp); \
	PUTSHORT(val, ucp); \
    }
#define ADDCICHAP(opt, neg, val, digest) \
    if (neg) { \
	PUTCHAR(opt, ucp); \
	PUTCHAR(CILEN_CHAP, ucp); \
	PUTSHORT(val, ucp); \
	PUTCHAR(digest, ucp); \
    }
#define ADDCILONG(opt, neg, val) \
    if (neg) { \
	PUTCHAR(opt, ucp); \
	PUTCHAR(CILEN_LONG, ucp); \
	PUTLONG(val, ucp); \
    }
#define ADDCILQR(opt, neg, val) \
    if (neg) { \
	PUTCHAR(opt, ucp); \
	PUTCHAR(CILEN_LQR, ucp); \
	PUTSHORT(PPP_LQR, ucp); \
	PUTLONG(val, ucp); \
    }
#define ADDCICHAR(opt, neg, val) \
    if (neg) { \
	PUTCHAR(opt, ucp); \
	PUTCHAR(CILEN_CHAR, ucp); \
	PUTCHAR(val, ucp); \
    }
#define ADDCIENDP(opt, neg, class, val, len) \
    if (neg) { \
	int i; \
	PUTCHAR(opt, ucp); \
	PUTCHAR(CILEN_CHAR + len, ucp); \
	PUTCHAR(class, ucp); \
	for (i = 0; i < len; ++i) \
	    PUTCHAR(val[i], ucp); \
    }

    ADDCISHORT(CI_MRU, go->neg_mru && go->mru != PPP_MRU, go->mru);
    ADDCILONG(CI_ASYNCMAP, go->neg_asyncmap && go->asyncmap != 0xFFFFFFFF,
	      go->asyncmap);
    /* go->chap_mdtype always points to a useful value */
    ADDCICHAP(CI_AUTHTYPE, go->neg_chap || go->neg_mschap || go->neg_mschapv2,
	PPP_CHAP, go->chap_mdtype);
    ADDCISHORT(CI_AUTHTYPE, !(go->neg_chap || go->neg_mschap ||
	go->neg_mschapv2) && go->neg_upap, PPP_PAP);
    /* We can't both say zero for LQR period. */
    if (f->state == ACKSENT && go->neg_lqr && go->lqr_period == 0 &&
	ho->neg_lqr && ho->lqr_period == 0)
	go->lqr_period = 500;
    ADDCILQR(CI_QUALITY, go->neg_lqr, go->lqr_period);
    ADDCICHAR(CI_CALLBACK, go->neg_cbcp, CBOP_CBCP);
    ADDCILONG(CI_MAGICNUMBER, go->neg_magicnumber, go->magicnumber);
    ADDCIVOID(CI_PCOMPRESSION, go->neg_pcompression);
    ADDCIVOID(CI_ACCOMPRESSION, go->neg_accompression);
    ADDCICHAR(CI_FCSALTERN, (go->neg_fcs && go->fcs_type != 0), go->fcs_type);
    ADDCIENDP(CI_EPDISC, go->neg_endpoint, go->endpoint.class,
	      go->endpoint.value, go->endpoint.length);
#ifdef MUX_FRAME
    ADDCIVOID(CI_MUXING, go->pppmux);
#endif
    ADDCISHORT(CI_MRRU, go->neg_mrru, go->mrru);
    ADDCIVOID(CI_SSNHF, go->neg_ssnhf);

    if (ucp - start_ucp != *lenp) {
	/* this should never happen, because peer_mtu should be 1500 */
	error("Bug in lcp_addci: wrong length");
    }
}


/*
 * lcp_ackci - Ack our CIs.
 * This should not modify any state if the Ack is bad.
 *
 * Returns:
 *	0 - Ack was bad.
 *	1 - Ack was good.
 */
static int
lcp_ackci(f, p, len)
    fsm *f;
    u_char *p;
    int len;
{
    lcp_options *go = &lcp_gotoptions[f->unit];
#ifdef MUX_FRAME
    lcp_options *ao = &lcp_allowoptions[f->unit];
#endif
    u_char cilen, citype, cichar;
    u_short cishort;
    u_int32_t cilong;

    /*
     * CIs must be in exactly the same order that we sent.
     * Check packet length and CI length at each step.
     * If we find any deviations, then this packet is bad.
     */
#define ACKCIVOID(opt, neg) \
    if (neg) { \
	if ((len -= CILEN_VOID) < 0) \
	    goto bad; \
	GETCHAR(citype, p); \
	GETCHAR(cilen, p); \
	if (cilen != CILEN_VOID || \
	    citype != opt) \
	    goto bad; \
    }
#define ACKCISHORT(opt, neg, val) \
    if (neg) { \
	if ((len -= CILEN_SHORT) < 0) \
	    goto bad; \
	GETCHAR(citype, p); \
	GETCHAR(cilen, p); \
	if (cilen != CILEN_SHORT || \
	    citype != opt) \
	    goto bad; \
	GETSHORT(cishort, p); \
	if (cishort != val) \
	    goto bad; \
    }
#define ACKCIAUTH(opt, neg, val) \
    if (neg) { \
	if ((len -= CILEN_SHORT) < 0) \
	    goto bad; \
	GETCHAR(citype, p); \
	GETCHAR(cilen, p); \
	if (cilen != CILEN_SHORT || \
	    citype != opt) \
	    goto bad; \
	GETSHORT(cishort, p); \
	if (cishort != val) \
	    goto bad; \
	peer_nak_auth = 0; \
	peer_reject_auth = 0; \
    }
#define ACKCICHAR(opt, neg, val) \
    if (neg) { \
	if ((len -= CILEN_CHAR) < 0) \
	    goto bad; \
	GETCHAR(citype, p); \
	GETCHAR(cilen, p); \
	if (cilen != CILEN_CHAR || \
	    citype != opt) \
	    goto bad; \
	GETCHAR(cichar, p); \
	if (cichar != val) \
	    goto bad; \
    }
#define ACKCICHAP(opt, neg, val, digest) \
    if (neg) { \
	if ((len -= CILEN_CHAP) < 0) \
	    goto bad; \
	GETCHAR(citype, p); \
	GETCHAR(cilen, p); \
	if (cilen != CILEN_CHAP || \
	    citype != opt) \
	    goto bad; \
	GETSHORT(cishort, p); \
	if (cishort != val) \
	    goto bad; \
	GETCHAR(cichar, p); \
	if (cichar != digest) \
	  goto bad; \
	peer_nak_auth = 0; \
	peer_reject_auth = 0; \
    }
#define ACKCILONG(opt, neg, val) \
    if (neg) { \
	if ((len -= CILEN_LONG) < 0) \
	    goto bad; \
	GETCHAR(citype, p); \
	GETCHAR(cilen, p); \
	if (cilen != CILEN_LONG || \
	    citype != opt) \
	    goto bad; \
	GETLONG(cilong, p); \
	if (cilong != val) \
	    goto bad; \
    }
#define ACKCILQR(opt, neg, val) \
    if (neg) { \
	if ((len -= CILEN_LQR) < 0) \
	    goto bad; \
	GETCHAR(citype, p); \
	GETCHAR(cilen, p); \
	if (cilen != CILEN_LQR || \
	    citype != opt) \
	    goto bad; \
	GETSHORT(cishort, p); \
	if (cishort != PPP_LQR) \
	    goto bad; \
	GETLONG(cilong, p); \
	if (cilong != val) \
	  goto bad; \
    }
#define ACKCIENDP(opt, neg, class, val, vlen) \
    if (neg) { \
	int i; \
	if ((len -= CILEN_CHAR + vlen) < 0) \
	    goto bad; \
	GETCHAR(citype, p); \
	GETCHAR(cilen, p); \
	if (cilen != CILEN_CHAR + vlen || \
	    citype != opt) \
	    goto bad; \
	GETCHAR(cichar, p); \
	if (cichar != class) \
	    goto bad; \
	for (i = 0; i < vlen; ++i) { \
	    GETCHAR(cichar, p); \
	    if (cichar != val[i]) \
		goto bad; \
	} \
    }

    ACKCISHORT(CI_MRU, go->neg_mru && go->mru != PPP_MRU, go->mru);
    ACKCILONG(CI_ASYNCMAP, go->neg_asyncmap && go->asyncmap != 0xFFFFFFFF,
	      go->asyncmap);
    /* go->chap_mdtype always points to a useful value */