source: rtems/cpukit/pppd/options.c @ dc7fb59b

/*
 * options.c - handles option processing for PPP.
 *
 * Copyright (c) 1989 Carnegie Mellon University.
 * 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.
 */

#define RCSID   "$Id$"

#include <ctype.h>
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <termios.h>
#include <string.h>
#include <netdb.h>
#include <pwd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#ifdef PLUGIN
#include <dlfcn.h>
#endif
#ifdef PPP_FILTER
#include <pcap.h>
#include <pcap-int.h>   /* XXX: To get struct pcap */
#endif

#include "pppd.h"
#include "pathnames.h"
#include "patchlevel.h"
#include "fsm.h"
#include "lcp.h"
#include "ipcp.h"
#include "upap.h"
#include "chap.h"
#include "ccp.h"

#include <net/ppp-comp.h>

#if defined(ultrix) || defined(NeXT)
char *strdup __P((char *));
#endif

static const char rcsid[] = RCSID;

/*
 * Option variables and default values.
 */
#ifdef PPP_FILTER
int     dflag = 0;              /* Tell libpcap we want debugging */
#endif
int     debug = 0;              /* Debug flag */
int     kdebugflag = 0;         /* Tell kernel to print debug messages */
int     default_device = 1;     /* Using /dev/tty or equivalent */
char    devnam[MAXPATHLEN];     /* Device name */
int     crtscts = 0;            /* Use hardware flow control */
bool    modem = 1;              /* Use modem control lines */
int     inspeed = 0;            /* Input/Output speed requested */
u_int32_t netmask = 0;          /* IP netmask to set on interface */
bool    lockflag = 0;           /* Create lock file to lock the serial dev */
bool    nodetach = 0;           /* Don't detach from controlling tty */
bool    updetach = 0;           /* Detach once link is up */
char    *initializer = NULL;    /* Script to initialize physical link */
char    *connect_script = NULL; /* Script to establish physical link */
char    *disconnect_script = NULL; /* Script to disestablish physical link */
char    *welcomer = NULL;       /* Script to run after phys link estab. */
char    *ptycommand = NULL;     /* Command to run on other side of pty */
int     maxconnect = 0;         /* Maximum connect time */
char    user[MAXNAMELEN];       /* Username for PAP */
char    passwd[MAXSECRETLEN];   /* Password for PAP */
bool    persist = 0;            /* Reopen link after it goes down */
char    our_name[MAXNAMELEN];   /* Our name for authentication purposes */
bool    demand = 0;             /* do dial-on-demand */
char    *ipparam = NULL;        /* Extra parameter for ip up/down scripts */
int     idle_time_limit = 0;    /* Disconnect if idle for this many seconds */
int     holdoff = 30;           /* # seconds to pause before reconnecting */
bool    holdoff_specified;      /* true if a holdoff value has been given */
bool    notty = 0;              /* Stdin/out is not a tty */
char    *record_file = NULL;    /* File to record chars sent/received */
int     using_pty = 0;
bool    sync_serial = 0;        /* Device is synchronous serial device */
int     log_to_fd = 1;          /* send log messages to this fd too */
int     maxfail = 10;           /* max # of unsuccessful connection attempts */
char    linkname[MAXPATHLEN];   /* logical name for link */
bool    tune_kernel;            /* may alter kernel settings */
int     connect_delay = 1000;   /* wait this many ms after connect script */

extern option_t auth_options[];
extern struct stat devstat;
extern int prepass;             /* Doing pre-pass to find device name */

struct option_info initializer_info;
struct option_info connect_script_info;
struct option_info disconnect_script_info;
struct option_info welcomer_info;
struct option_info devnam_info;
struct option_info ptycommand_info;

#ifdef PPP_FILTER
struct  bpf_program pass_filter;/* Filter program for packets to pass */
struct  bpf_program active_filter; /* Filter program for link-active pkts */
pcap_t  pc;                     /* Fake struct pcap so we can compile expr */
#endif

char *current_option;           /* the name of the option being parsed */
int  privileged_option;         /* set iff the current option came from root */
char *option_source;            /* string saying where the option came from */
bool log_to_file;               /* log_to_fd is a file opened by us */

/*
 * Prototypes
 */
static int setdevname __P((char *));
static int setipaddr __P((char *));
static int setspeed __P((char *));
static int noopt __P((char **));
static int setdomain __P((char **));
static int setnetmask __P((char **));
static int setxonxoff __P((char **));
static int readfile __P((char **));
static int callfile __P((char **));
static void usage __P((void));
static int setlogfile __P((char **));
#ifdef PLUGIN
static int loadplugin __P((char **));
#endif

#ifdef PPP_FILTER
static int setpassfilter __P((char **));
static int setactivefilter __P((char **));
#endif

static option_t *find_option __P((char *name));
static int process_option __P((option_t *, char **));
static int n_arguments __P((option_t *));
static int number_option __P((char *, u_int32_t *, int));

/*
 * Structure to store extra lists of options.
 */
struct option_list {
    option_t *options;
    struct option_list *next;
};

static struct option_list *extra_options = NULL;

/*
 * Valid arguments.
 */
option_t general_options[] = {
    { "debug", o_int, &debug,
      "Increase debugging level", OPT_INC|OPT_NOARG|1 },
    { "-d", o_int, &debug,
      "Increase debugging level", OPT_INC|OPT_NOARG|1 },
    { "kdebug", o_int, &kdebugflag,
      "Set kernel driver debug level" },
    { "nodetach", o_bool, &nodetach,
      "Don't detach from controlling tty", 1 },
    { "-detach", o_bool, &nodetach,
      "Don't detach from controlling tty", 1 },
    { "updetach", o_bool, &updetach,
      "Detach from controlling tty once link is up", 1 },
    { "holdoff", o_int, &holdoff,
      "Set time in seconds before retrying connection" },
    { "idle", o_int, &idle_time_limit,
      "Set time in seconds before disconnecting idle link" },
    { "lock", o_bool, &lockflag,
      "Lock serial device with UUCP-style lock file", 1 },
    { "-all", o_special_noarg, noopt,
      "Don't request/allow any LCP or IPCP options (useless)" },
    { "init", o_string, &initializer,
      "A program to initialize the device",
      OPT_A2INFO | OPT_PRIVFIX, &initializer_info },
    { "connect", o_string, &connect_script,
      "A program to set up a connection",
      OPT_A2INFO | OPT_PRIVFIX, &connect_script_info },
    { "disconnect", o_string, &disconnect_script,
      "Program to disconnect serial device",
      OPT_A2INFO | OPT_PRIVFIX, &disconnect_script_info },
    { "welcome", o_string, &welcomer,
      "Script to welcome client",
      OPT_A2INFO | OPT_PRIVFIX, &welcomer_info },
    { "pty", o_string, &ptycommand,
      "Script to run on pseudo-tty master side",
      OPT_A2INFO | OPT_PRIVFIX | OPT_DEVNAM, &ptycommand_info },
    { "notty", o_bool, &notty,
      "Input/output is not a tty", OPT_DEVNAM | 1 },
    { "record", o_string, &record_file,
      "Record characters sent/received to file" },
    { "maxconnect", o_int, &maxconnect,
      "Set connection time limit", OPT_LLIMIT|OPT_NOINCR|OPT_ZEROINF },
    { "crtscts", o_int, &crtscts,
      "Set hardware (RTS/CTS) flow control", OPT_NOARG|OPT_VAL(1) },
    { "nocrtscts", o_int, &crtscts,
      "Disable hardware flow control", OPT_NOARG|OPT_VAL(-1) },
    { "-crtscts", o_int, &crtscts,
      "Disable hardware flow control", OPT_NOARG|OPT_VAL(-1) },
    { "cdtrcts", o_int, &crtscts,
      "Set alternate hardware (DTR/CTS) flow control", OPT_NOARG|OPT_VAL(2) },
    { "nocdtrcts", o_int, &crtscts,
      "Disable hardware flow control", OPT_NOARG|OPT_VAL(-1) },
    { "xonxoff", o_special_noarg, setxonxoff,
      "Set software (XON/XOFF) flow control" },
    { "domain", o_special, setdomain,
      "Add given domain name to hostname" },
    { "mtu", o_int, &lcp_allowoptions[0].mru,
      "Set our MTU", OPT_LIMITS, NULL, MAXMRU, MINMRU },
    { "netmask", o_special, setnetmask,
      "set netmask" },
    { "modem", o_bool, &modem,
      "Use modem control lines", 1 },
    { "local", o_bool, &modem,
      "Don't use modem control lines" },
    { "file", o_special, readfile,
      "Take options from a file", OPT_PREPASS },
    { "call", o_special, callfile,
      "Take options from a privileged file", OPT_PREPASS },
    { "persist", o_bool, &persist,
      "Keep on reopening connection after close", 1 },
    { "nopersist", o_bool, &persist,
      "Turn off persist option" },
    { "demand", o_bool, &demand,
      "Dial on demand", OPT_INITONLY | 1, &persist },
    { "sync", o_bool, &sync_serial,
      "Use synchronous HDLC serial encoding", 1 },
    { "logfd", o_int, &log_to_fd,
      "Send log messages to this file descriptor" },
    { "logfile", o_special, setlogfile,
      "Append log messages to this file" },
    { "nolog", o_int, &log_to_fd,
      "Don't send log messages to any file",
      OPT_NOARG | OPT_VAL(-1) },
    { "nologfd", o_int, &log_to_fd,
      "Don't send log messages to any file descriptor",
      OPT_NOARG | OPT_VAL(-1) },
    { "linkname", o_string, linkname,
      "Set logical name for link",
      OPT_PRIV|OPT_STATIC, NULL, MAXPATHLEN },
    { "maxfail", o_int, &maxfail,
      "Maximum number of unsuccessful connection attempts to allow" },
    { "ktune", o_bool, &tune_kernel,
      "Alter kernel settings as necessary", 1 },
    { "noktune", o_bool, &tune_kernel,
      "Don't alter kernel settings", 0 },
    { "connect-delay", o_int, &connect_delay,
      "Maximum time (in ms) to wait after connect script finishes" },
#ifdef PLUGIN
    { "plugin", o_special, loadplugin,
      "Load a plug-in module into pppd", OPT_PRIV },
#endif

#ifdef PPP_FILTER
    { "pdebug", o_int, &dflag,
      "libpcap debugging" },
    { "pass-filter", 1, setpassfilter,
      "set filter for packets to pass" },
    { "active-filter", 1, setactivefilter,
      "set filter for active pkts" },
#endif

    { NULL }
};

#ifndef IMPLEMENTATION
#define IMPLEMENTATION ""
#endif

static char *usage_string = "\
pppd version %s.%d%s\n\
Usage: %s [ options ], where options are:\n\
        <device>        Communicate over the named device\n\
        <speed>         Set the baud rate to <speed>\n\
        <loc>:<rem>     Set the local and/or remote interface IP\n\
                        addresses.  Either one may be omitted.\n\
        asyncmap <n>    Set the desired async map to hex <n>\n\
        auth            Require authentication from peer\n\
        connect <p>     Invoke shell command <p> to set up the serial line\n\
        crtscts         Use hardware RTS/CTS flow control\n\
        defaultroute    Add default route through interface\n\
        file <f>        Take options from file <f>\n\
        modem           Use modem control lines\n\
        mru <n>         Set MRU value to <n> for negotiation\n\
See pppd(8) for more options.\n\
";

/*
 * parse_args - parse a string of arguments from the command line.
 * If prepass is true, we are scanning for the device name and only
 * processing a few options, so error messages are suppressed.
 */
int
parse_args(argc, argv)
    int argc;
    char **argv;
{
    char *arg;
    option_t *opt;
    int ret;

    privileged_option = privileged;
    option_source = "command line";
    while (argc > 0) {
        arg = *argv++;
        --argc;

        /*
         * First see if it's an option in the new option list.
         */
        opt = find_option(arg);
        if (opt != NULL) {
            int n = n_arguments(opt);
            if (argc < n) {
                option_error("too few parameters for option %s", arg);
                return 0;
            }
            current_option = arg;
            if (!process_option(opt, argv))
                return 0;
            argc -= n;
            argv += n;
            continue;
        }

        /*
         * Maybe a tty name, speed or IP address?
         */
        if ((ret = setdevname(arg)) == 0
            && (ret = setspeed(arg)) == 0
            && (ret = setipaddr(arg)) == 0
            && !prepass) {
            option_error("unrecognized option '%s'", arg);
            usage();
            return 0;
        }
        if (ret < 0)    /* error */
            return 0;
    }
    return 1;
}

#if 0
/*
 * scan_args - scan the command line arguments to get the tty name,
 * if specified.  Also checks whether the notty or pty option was given.
 */
void
scan_args(argc, argv)
    int argc;
    char **argv;
{
    char *arg;
    option_t *opt;

    privileged_option = privileged;
    while (argc > 0) {
        arg = *argv++;
        --argc;

        if (strcmp(arg, "notty") == 0 || strcmp(arg, "pty") == 0)
            using_pty = 1;

        /* Skip options and their arguments */
        opt = find_option(arg);
        if (opt != NULL) {
            int n = n_arguments(opt);
            argc -= n;
            argv += n;
            continue;
        }

        /* Check if it's a tty name and copy it if so */
        (void) setdevname(arg, 1);
    }
}
#endif

/*
 * options_from_file - Read a string of options from a file,
 * and interpret them.
 */
int
options_from_file(filename, must_exist, check_prot, priv)
    char *filename;
    int must_exist;
    int check_prot;
    int priv;
{
    FILE *f;
    int i, newline, ret, err;
    option_t *opt;
    int oldpriv;
    char *oldsource;
    char *argv[MAXARGS];
    char args[MAXARGS][MAXWORDLEN];
    char cmd[MAXWORDLEN];

    f = fopen(filename, "r");
    err = errno;
    if (f == NULL) {
        if (!must_exist && err == ENOENT)
            return 1;
        errno = err;
        option_error("Can't open options file %s: %m", filename);
        return 0;
    }

    oldpriv = privileged_option;
    privileged_option = priv;
    oldsource = option_source;
    option_source = strdup(filename);
    if (option_source == NULL)
        option_source = "file";
    ret = 0;
    while (getword(f, cmd, &newline, filename)) {
        /*
         * First see if it's a command.
         */
        opt = find_option(cmd);
        if (opt != NULL) {
            int n = n_arguments(opt);
            for (i = 0; i < n; ++i) {
                if (!getword(f, args[i], &newline, filename)) {
                    option_error(
                        "In file %s: too few parameters for option '%s'",
                        filename, cmd);
                    goto err;
                }
                argv[i] = args[i];
            }
            current_option = cmd;
            if ((opt->flags & OPT_DEVEQUIV) && devnam_fixed) {
                option_error("the %s option may not be used in the %s file",
                             cmd, filename);
                goto err;
            }
            if (!process_option(opt, argv))
                goto err;
            continue;
        }

        /*
         * Maybe a tty name, speed or IP address?
         */
        if ((i = setdevname(cmd)) == 0
            && (i = setspeed(cmd)) == 0
            && (i = setipaddr(cmd)) == 0) {
            option_error("In file %s: unrecognized option '%s'",
                         filename, cmd);
            goto err;
        }
        if (i < 0)              /* error */
            goto err;
    }
    ret = 1;

err:
    fclose(f);
    privileged_option = oldpriv;
    option_source = oldsource;
    return ret;
}

/*
 * options_from_user - See if the use has a ~/.ppprc file,
 * and if so, interpret options from it.
 */
int
options_from_user()
{
    return 0;
}

/*
 * options_for_tty - See if an options file exists for the serial
 * device, and if so, interpret options from it.
 */
int
options_for_tty()
{
    char *dev, *path, *p;
    int ret;
    size_t pl;

    dev = devnam;
    if (strncmp(dev, "/dev/", 5) == 0)
        dev += 5;
    if (dev[0] == 0 || strcmp(dev, "tty") == 0)
        return 1;               /* don't look for /etc/ppp/options.tty */
    pl = strlen(_PATH_TTYOPT) + strlen(dev) + 1;
    path = malloc(pl);
    if (path == NULL)
        novm("tty init file name");
    slprintf(path, pl, "%s%s", _PATH_TTYOPT, dev);
    /* Turn slashes into dots, for Solaris case (e.g. /dev/term/a) */
    for (p = path + strlen(_PATH_TTYOPT); *p != 0; ++p)
        if (*p == '/')
            *p = '.';
    ret = options_from_file(path, 0, 0, 1);
    free(path);
    return ret;
}

/*
 * options_from_list - process a string of options in a wordlist.
 */
int
options_from_list(w, priv)
    struct wordlist *w;
    int priv;
{
    char *argv[MAXARGS];
    option_t *opt;
    int i, ret = 0;

    privileged_option = priv;
    option_source = "secrets file";

    while (w != NULL) {
        /*
         * First see if it's a command.
         */
        opt = find_option(w->word);
        if (opt != NULL) {
            int n = n_arguments(opt);
            struct wordlist *w0 = w;
            for (i = 0; i < n; ++i) {
                w = w->next;
                if (w == NULL) {
                    option_error(
                        "In secrets file: too few parameters for option '%s'",
                        w0->word);
                    goto err;
                }
                argv[i] = w->word;
            }
            current_option = w0->word;
            if (!process_option(opt, argv))
                goto err;
            w = w->next;
            continue;
        }

        /*
         * Maybe a tty name, speed or IP address?
         */
        if ((i = setdevname(w->word)) == 0
            && (i = setspeed(w->word)) == 0
            && (i = setipaddr(w->word)) == 0) {
            option_error("In secrets file: unrecognized option '%s'",
                         w->word);
            goto err;
        }
        if (i < 0)              /* error */
            goto err;
        w = w->next;
    }
    ret = 1;

err:
    return ret;
}

/*
 * find_option - scan the option lists for the various protocols
 * looking for an entry with the given name.
 * This could be optimized by using a hash table.
 */
static option_t *
find_option(name)
    char *name;
{
    option_t *opt;
    struct option_list *list;
    int i;

    for (list = extra_options; list != NULL; list = list->next)
        for (opt = list->options; opt->name != NULL; ++opt)
            if (strcmp(name, opt->name) == 0)
                return opt;
    for (opt = general_options; opt->name != NULL; ++opt)
        if (strcmp(name, opt->name) == 0)
            return opt;
    for (opt = auth_options; opt->name != NULL; ++opt)
        if (strcmp(name, opt->name) == 0)
            return opt;
    for (i = 0; protocols[i] != NULL; ++i)
        if ((opt = protocols[i]->options) != NULL)
            for (; opt->name != NULL; ++opt)
                if (strcmp(name, opt->name) == 0)
                    return opt;
    return NULL;
}

/*
 * process_option - process one new-style option.
 */
static int
process_option(opt, argv)
    option_t *opt;
    char **argv;
{
    u_int32_t v;
    int iv, a;
    char *sv;
    int (*parser) __P((char **));

    if ((opt->flags & OPT_PREPASS) == 0 && prepass)
        return 1;
    if ((opt->flags & OPT_INITONLY) && phase != PHASE_INITIALIZE) {
        option_error("it's too late to use the %s option", opt->name);
        return 0;
    }
    if ((opt->flags & OPT_PRIV) && !privileged_option) {
        option_error("using the %s option requires root privilege", opt->name);
        return 0;
    }
    if ((opt->flags & OPT_ENABLE) && *(bool *)(opt->addr2) == 0) {
        option_error("%s option is disabled", opt->name);
        return 0;
    }
    if ((opt->flags & OPT_PRIVFIX) && !privileged_option) {
        struct option_info *ip = (struct option_info *) opt->addr2;
        if (ip && ip->priv) {
            option_error("%s option cannot be overridden", opt->name);
            return 0;
        }
    }

    switch (opt->type) {
    case o_bool:
        v = opt->flags & OPT_VALUE;
        *(bool *)(opt->addr) = v;
        if (opt->addr2 && (opt->flags & OPT_A2COPY))
            *(bool *)(opt->addr2) = v;
        break;

    case o_int:
        iv = 0;
        if ((opt->flags & OPT_NOARG) == 0) {
            if (!int_option(*argv, &iv))
                return 0;
            if ((((opt->flags & OPT_LLIMIT) && iv < opt->lower_limit)
                 || ((opt->flags & OPT_ULIMIT) && iv > opt->upper_limit))
                && !((opt->flags & OPT_ZEROOK && iv == 0))) {
                char *zok = (opt->flags & OPT_ZEROOK)? " zero or": "";
                switch (opt->flags & OPT_LIMITS) {
                case OPT_LLIMIT:
                    option_error("%s value must be%s >= %d",
                                 opt->name, zok, opt->lower_limit);
                    break;
                case OPT_ULIMIT:
                    option_error("%s value must be%s <= %d",
                                 opt->name, zok, opt->upper_limit);
                    break;
                case OPT_LIMITS:
                    option_error("%s value must be%s between %d and %d",
                                opt->name, opt->lower_limit, opt->upper_limit);
                    break;
                }
                return 0;
            }
        }
        a = opt->flags & OPT_VALUE;
        if (a >= 128)
            a -= 256;           /* sign extend */
        iv += a;
        if (opt->flags & OPT_INC)
            iv += *(int *)(opt->addr);
        if ((opt->flags & OPT_NOINCR) && !privileged_option) {
            int oldv = *(int *)(opt->addr);
            if ((opt->flags & OPT_ZEROINF) ?
                (oldv != 0 && (iv == 0 || iv > oldv)) : (iv > oldv)) {
                option_error("%s value cannot be increased", opt->name);
                return 0;
            }
        }
        *(int *)(opt->addr) = iv;
        if (opt->addr2 && (opt->flags & OPT_A2COPY))
            *(int *)(opt->addr2) = iv;
        break;

    case o_uint32:
        if (opt->flags & OPT_NOARG) {
            v = opt->flags & OPT_VALUE;
        } else if (!number_option(*argv, &v, 16))
            return 0;
        if (opt->flags & OPT_OR)
            v |= *(u_int32_t *)(opt->addr);
        *(u_int32_t *)(opt->addr) = v;
        if (opt->addr2 && (opt->flags & OPT_A2COPY))
            *(u_int32_t *)(opt->addr2) = v;
        break;

    case o_string:
        if (opt->flags & OPT_STATIC) {
            strlcpy((char *)(opt->addr), *argv, opt->upper_limit);
        } else {
            sv = strdup(*argv);
            if (sv == NULL)
                novm("option argument");
            if ( *(char **)(opt->addr) != NULL ) {
                free((void *)*(char **)(opt->addr));
                *(char **)(opt->addr) = NULL;
            }
            *(char **)(opt->addr) = sv;
        }
        break;

    case o_special_noarg:
    case o_special:
        parser = (int (*) __P((char **))) opt->addr;
        if (!(*parser)(argv))
            return 0;
        break;
    }

    if (opt->addr2) {
        if (opt->flags & OPT_A2INFO) {
            struct option_info *ip = (struct option_info *) opt->addr2;
            ip->priv = privileged_option;
            ip->source = option_source;
        } else if ((opt->flags & (OPT_A2COPY|OPT_ENABLE)) == 0)
            *(bool *)(opt->addr2) = 1;
    }

    return 1;
}

/*
 * n_arguments - tell how many arguments an option takes
 */
static int
n_arguments(opt)
    option_t *opt;
{
    return (opt->type == o_bool || opt->type == o_special_noarg
            || (opt->flags & OPT_NOARG))? 0: 1;
}

/*
 * add_options - add a list of options to the set we grok.
 */
void
add_options(opt)
    option_t *opt;
{
    struct option_list *list;

    list = malloc(sizeof(*list));
    if (list == 0)
        novm("option list entry");
    list->options = opt;
    list->next = extra_options;
    extra_options = list;
}

/*
 * usage - print out a message telling how to use the program.
 */
static void
usage()
{
    if (phase == PHASE_INITIALIZE)
        fprintf(stderr, usage_string, VERSION, PATCHLEVEL, IMPLEMENTATION,
                progname);
}

/*
 * option_error - print a message about an error in an option.
 * The message is logged, and also sent to
 * stderr if phase == PHASE_INITIALIZE.
 */
void
option_error __V((char *fmt, ...))
{
    va_list args;
    char buf[256];

#if defined(__STDC__)
    va_start(args, fmt);
#else
    char *fmt;
    va_start(args);
    fmt = va_arg(args, char *);
#endif
    if (prepass) {
        va_end(args);
        return;
    }
    vslprintf(buf, sizeof(buf), fmt, args);
    va_end(args);

    fprintf(stderr, "pppd: %s\n", buf);
}

/*
 * Read a word from a file.
 * Words are delimited by white-space or by quotes (" or ').
 * Quotes, white-space and \ may be escaped with \.
 * \<newline> is ignored.
 */
int
getword(f, word, newlinep, filename)
    FILE *f;
    char *word;
    int *newlinep;
    char *filename;
{
    int c, len, escape;
    int quoted, comment;
    int value, digit, got, n;

#define isoctal(c) ((c) >= '0' && (c) < '8')

    *newlinep = 0;
    len = 0;
    escape = 0;
    comment = 0;

    /*
     * First skip white-space and comments.
     */
    for (;;) {
        c = getc(f);
        if (c == EOF)
            break;

        /*
         * A newline means the end of a comment; backslash-newline
         * is ignored.  Note that we cannot have escape && comment.
         */
        if (c == '\n') {
            if (!escape) {
                *newlinep = 1;
                comment = 0;
            } else
                escape = 0;
            continue;
        }

        /*
         * Ignore characters other than newline in a comment.
         */
        if (comment)
            continue;

        /*
         * If this character is escaped, we have a word start.
         */
        if (escape)
            break;

        /*
         * If this is the escape character, look at the next character.
         */
        if (c == '\\') {
            escape = 1;
            continue;
        }

        /*
         * If this is the start of a comment, ignore the rest of the line.
         */
        if (c == '#') {
            comment = 1;
            continue;
        }

        /*
         * A non-whitespace character is the start of a word.
         */
        if (!isspace(c))
            break;
    }

    /*
     * Save the delimiter for quoted strings.
     */
    if (!escape && (c == '"' || c == '\'')) {
        quoted = c;
        c = getc(f);
    } else
        quoted = 0;

    /*
     * Process characters until the end of the word.
     */
    while (c != EOF) {
        if (escape) {
            /*
             * This character is escaped: backslash-newline is ignored,
             * various other characters indicate particular values
             * as for C backslash-escapes.
             */
            escape = 0;
            if (c == '\n') {
                c = getc(f);
                continue;
            }

            got = 0;
            switch (c) {
            case 'a':
                value = '\a';
                break;
            case 'b':
                value = '\b';
                break;
            case 'f':
                value = '\f';
                break;
            case 'n':
                value = '\n';
                break;
            case 'r':
                value = '\r';
                break;
            case 's':
                value = ' ';
                break;
            case 't':
                value = '\t';
                break;

            default:
                if (isoctal(c)) {
                    /*
                     * \ddd octal sequence
                     */
                    value = 0;
                    for (n = 0; n < 3 && isoctal(c); ++n) {
                        value = (value << 3) + (c & 07);
                        c = getc(f);
                    }
                    got = 1;
                    break;
                }

                if (c == 'x') {
                    /*
                     * \x<hex_string> sequence
                     */
                    value = 0;
                    c = getc(f);
                    for (n = 0; n < 2 && isxdigit(c); ++n) {
                        digit = toupper(c) - '0';
                        if (digit > 10)
                            digit += '0' + 10 - 'A';
                        value = (value << 4) + digit;
                        c = getc (f);
                    }
                    got = 1;
                    break;
                }

                /*
                 * Otherwise the character stands for itself.
                 */
                value = c;
                break;
            }

            /*
             * Store the resulting character for the escape sequence.
             */
            if (len < MAXWORDLEN-1)
                word[len] = value;
            ++len;

            if (!got)
                c = getc(f);
            continue;

        }

        /*
         * Not escaped: see if we've reached the end of the word.
         */
        if (quoted) {
            if (c == quoted)
                break;
        } else {
            if (isspace(c) || c == '#') {
                ungetc (c, f);
                break;
            }
        }

        /*
         * Backslash starts an escape sequence.
         */
        if (c == '\\') {
            escape = 1;
            c = getc(f);
            continue;
        }

        /*
         * An ordinary character: store it in the word and get another.
         */
        if (len < MAXWORDLEN-1)
            word[len] = c;
        ++len;

        c = getc(f);
    }

    /*
     * End of the word: check for errors.
     */
    if (c == EOF) {
        if (ferror(f)) {
            if (errno == 0)
                errno = EIO;
            option_error("Error reading %s: %m", filename);
            die(1);
        }
        /*
         * If len is zero, then we didn't find a word before the
         * end of the file.
         */
        if (len == 0)
            return 0;
    }

    /*
     * Warn if the word was too long, and append a terminating null.
     */
    if (len >= MAXWORDLEN) {
        option_error("warning: word in file %s too long (%.20s...)",
                     filename, word);
        len = MAXWORDLEN - 1;
    }
    word[len] = 0;

    return 1;

#undef isoctal

}

/*
 * number_option - parse an unsigned numeric parameter for an option.
 */
static int
number_option(str, valp, base)
    char *str;
    u_int32_t *valp;
    int base;
{
    char *ptr;

    *valp = strtoul(str, &ptr, base);
    if (ptr == str) {
        option_error("invalid numeric parameter '%s' for %s option",
                     str, current_option);
        return 0;
    }
    return 1;
}


/*
 * int_option - like number_option, but valp is int *,
 * the base is assumed to be 0, and *valp is not changed
 * if there is an error.
 */
int
int_option(str, valp)
    char *str;
    int *valp;
{
    u_int32_t v;

    if (!number_option(str, &v, 0))
        return 0;
    *valp = (int) v;
    return 1;
}


/*
 * The following procedures parse options.
 */

/*
 * readfile - take commands from a file.
 */
static int
readfile(argv)
    char **argv;
{
    return options_from_file(*argv, 1, 1, privileged_option);
}

/*
 * callfile - take commands from /etc/ppp/peers/<name>.
 * Name may not contain /../, start with / or ../, or end in /..
 */
static int
callfile(argv)
    char **argv;
{
    char *fname, *arg, *p;
    int l, ok;

    arg = *argv;
    ok = 1;
    if (arg[0] == '/' || arg[0] == 0)
        ok = 0;
    else {
        for (p = arg; *p != 0; ) {
            if (p[0] == '.' && p[1] == '.' && (p[2] == '/' || p[2] == 0)) {
                ok = 0;
                break;
            }
            while (*p != '/' && *p != 0)
                ++p;
            if (*p == '/')
                ++p;
        }
    }
    if (!ok) {
        option_error("call option value may not contain .. or start with /");
        return 0;
    }

    l = strlen(arg) + strlen(_PATH_PEERFILES) + 1;
    if ((fname = (char *) malloc(l)) == NULL)
        novm("call file name");
    slprintf(fname, l, "%s%s", _PATH_PEERFILES, arg);

    ok = options_from_file(fname, 1, 1, 1);

    free(fname);
    return ok;
}

#ifdef PPP_FILTER
/*
 * setpdebug - Set libpcap debugging level.
 */
static int
setpdebug(argv)
    char **argv;
{
    return int_option(*argv, &dflag);
}

/*
 * setpassfilter - Set the pass filter for packets
 */
static int
setpassfilter(argv)
    char **argv;
{
    pc.linktype = DLT_PPP;
    pc.snapshot = PPP_HDRLEN;
 
    if (pcap_compile(&pc, &pass_filter, *argv, 1, netmask) == 0)
        return 1;
    option_error("error in pass-filter expression: %s\n", pcap_geterr(&pc));
    return 0;
}

/*
 * setactivefilter - Set the active filter for packets
 */
static int
setactivefilter(argv)
    char **argv;
{
    pc.linktype = DLT_PPP;
    pc.snapshot = PPP_HDRLEN;
 
    if (pcap_compile(&pc, &active_filter, *argv, 1, netmask) == 0)
        return 1;
    option_error("error in active-filter expression: %s\n", pcap_geterr(&pc));
    return 0;
}
#endif

/*
 * noopt - Disable all options.
 */
static int
noopt(argv)
    char **argv;
{
    BZERO((char *) &lcp_wantoptions[0], sizeof (struct lcp_options));
    BZERO((char *) &lcp_allowoptions[0], sizeof (struct lcp_options));
    BZERO((char *) &ipcp_wantoptions[0], sizeof (struct ipcp_options));
    BZERO((char *) &ipcp_allowoptions[0], sizeof (struct ipcp_options));

    return (1);
}

/*
 * setdomain - Set domain name to append to hostname 
 */
static int
setdomain(argv)
    char **argv;
{
    if (!privileged_option) {
        option_error("using the domain option requires root privilege");
        return 0;
    }
    gethostname(hostname, MAXNAMELEN);
    if (**argv != 0) {
        if (**argv != '.')
            strncat(hostname, ".", MAXNAMELEN - strlen(hostname));
        strncat(hostname, *argv, MAXNAMELEN - strlen(hostname));
    }
    hostname[MAXNAMELEN-1] = 0;
    return (1);
}


/*
 * setspeed - Set the speed.
 */
static int
setspeed(arg)
    char *arg;
{
  int      spd;
  int      ret      = (int    )1;
  speed_t  spdValue = (speed_t)0;
  char    *ptr;

  if ( !prepass ) {
    spd = strtol(arg, &ptr, 0);
    if (ptr == arg || *ptr != 0 || spd == 0) {
      ret = (int)0;
    }
    else {
      switch ( spd ) {
        case 2400:
          spdValue = B2400;
          break;
        case 4800:
          spdValue = B4800;
          break;
        case 9600:
          spdValue = B9600;
          break;
        case 19200:
          spdValue = B19200;
          break;
        case 38400:
          spdValue = B38400;
          break;
        case 57600:
          spdValue = B57600;
          break;
        case 115200:
          spdValue = B115200;
          break;
        default:
          ret = (int)0;
          break;
      }

      if ( spdValue ) {
        inspeed = spdValue;
      }
    }
  }

  return ( ret );
}


/*
 * setdevname - Set the device name.
 */
static int
setdevname(cp)
    char *cp;
{
    struct stat statbuf;
    char dev[MAXPATHLEN];

    if (*cp == 0)
        return 0;

    if (strncmp("/dev/", cp, 5) != 0) {
        strlcpy(dev, "/dev/", sizeof(dev));
        strlcat(dev, cp, sizeof(dev));
        cp = dev;
    }

    /*
     * Check if there is a character device by this name.
     */
    if (stat(cp, &statbuf) < 0) {
        if (errno == ENOENT)
            return 0;
        option_error("Couldn't stat %s: %m", cp);
        return -1;
    }
    if (!S_ISCHR(statbuf.st_mode)) {
        option_error("%s is not a character device", cp);
        return -1;
    }

    if (phase != PHASE_INITIALIZE) {
        option_error("device name cannot be changed after initialization");
        return -1;
    } else if (devnam_fixed) {
        option_error("per-tty options file may not specify device name");
        return -1;
    }

    if (devnam_info.priv && !privileged_option) {
        option_error("device name cannot be overridden");
        return -1;
    }

    strlcpy(devnam, cp, sizeof(devnam));
    devstat = statbuf;
    default_device = 0;
    devnam_info.priv = privileged_option;
    devnam_info.source = option_source;
  
    return 1;
}


/*
 * setipaddr - Set the IP address
 */
static int
setipaddr(arg)
    char *arg;
{
    struct hostent *hp;
    char *colon;
    u_int32_t local, remote;
    ipcp_options *wo = &ipcp_wantoptions[0];
  
    /*
     * IP address pair separated by ":".
     */
    if ((colon = strchr(arg, ':')) == NULL)
        return 0;
    if (prepass)
        return 1;
  
    /*
     * If colon first character, then no local addr.
     */
    if (colon != arg) {
        *colon = '\0';
        if ((local = inet_addr(arg)) == (u_int32_t) -1) {
            if ((hp = gethostbyname(arg)) == NULL) {
                option_error("unknown host: %s", arg);
                return -1;
            } else {
                local = *(u_int32_t *)hp->h_addr;
            }
        }
        if (bad_ip_adrs(local)) {
            option_error("bad local IP address %s", ip_ntoa(local));
            return -1;
        }
        if (local != 0)
            wo->ouraddr = local;
        *colon = ':';
    }
  
    /*
     * If colon last character, then no remote addr.
     */
    if (*++colon != '\0') {
        if ((remote = inet_addr(colon)) == (u_int32_t) -1) {
            if ((hp = gethostbyname(colon)) == NULL) {
                option_error("unknown host: %s", colon);
                return -1;
            } else {
                remote = *(u_int32_t *)hp->h_addr;
                if (remote_name[0] == 0)
                    strlcpy(remote_name, colon, sizeof(remote_name));
            }
        }
        if (bad_ip_adrs(remote)) {
            option_error("bad remote IP address %s", ip_ntoa(remote));
            return -1;
        }
        if (remote != 0)
            wo->hisaddr = remote;
    }

    return 1;
}


/*
 * setnetmask - set the netmask to be used on the interface.
 */
static int
setnetmask(argv)
    char **argv;
{
    u_int32_t mask, b;
    int n, ok;
    char *p, *endp;

    /*
     * Unfortunately, if we use inet_addr, we can't tell whether
     * a result of all 1s is an error or a valid 255.255.255.255.
     */
    p = *argv;
    ok = 0;
    mask = 0;
    for (n = 3;; --n) {
        b = strtoul(p, &endp, 0);
        if (endp == p)
            break;
        if (b > 255) {
            if (n == 3) {
                /* accept e.g. 0xffffff00 */
                p = endp;
                mask = b;
            }
            break;
        }
        mask |= b << (n * 8);
        p = endp;
        if (*p != '.' || n == 0)
            break;
        ++p;
    }

    mask = htonl(mask);

    if (*p != 0 || (netmask & ~mask) != 0) {
        option_error("invalid netmask value '%s'", *argv);
        return 0;
    }

    netmask = mask;
    return (1);
}

static int
setxonxoff(argv)
    char **argv;
{
    lcp_wantoptions[0].asyncmap |= 0x000A0000;  /* escape ^S and ^Q */
    lcp_wantoptions[0].neg_asyncmap = 1;

    crtscts = -2;
    return (1);
}

static int
setlogfile(argv)
    char **argv;
{
    int fd, err;

    fd = open(*argv, O_WRONLY | O_APPEND | O_CREAT | O_EXCL, 0644);
    if (fd < 0 && errno == EEXIST)
        fd = open(*argv, O_WRONLY | O_APPEND);
    err = errno;
    if (fd < 0) {
        errno = err;
        option_error("Can't open log file %s: %m", *argv);
        return 0;
    }
    if (log_to_file && log_to_fd >= 0)
        close(log_to_fd);
    log_to_fd = fd;
    log_to_file = 1;
    return 1;
}

#ifdef PLUGIN
static int
loadplugin(argv)
    char **argv;
{
    char *arg = *argv;
    void *handle;
    const char *err;
    void (*init) __P((void));

    handle = dlopen(arg, RTLD_GLOBAL | RTLD_NOW);
    if (handle == 0) {
        err = dlerror();
        if (err != 0)
            option_error("%s", err);
        option_error("Couldn't load plugin %s", arg);
        return 0;
    }
    init = dlsym(handle, "plugin_init");
    if (init == 0) {
        option_error("%s has no initialization entry point", arg);
        dlclose(handle);
        return 0;
    }
    info("Plugin %s loaded.", arg);
    (*init)();
    return 1;
}
#endif /* PLUGIN */