source: rtems/cpukit/pppd/rtemsmain.c @ 24312f34

/*
 * main.c - Point-to-Point Protocol main module
 *
 * 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.
 */

#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#include <pwd.h>
#include <setjmp.h>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <netinet/in.h>

#include <rtems.h>
#include <rtems/rtems_bsdnet.h>

#include "pppd.h"
#include "magic.h"
#include "fsm.h"
#include "lcp.h"
#include "ipcp.h"
#ifdef INET6
#include "ipv6cp.h"
#endif
#include "upap.h"
#include "chap.h"
#include "ccp.h"
#include "pathnames.h"
#include "patchlevel.h"
#include <rtems/rtemsdialer.h>

#ifdef CBCP_SUPPORT
#include "cbcp.h"
#endif

#ifdef IPX_CHANGE
#include "ipxcp.h"
#endif /* IPX_CHANGE */
#ifdef AT_CHANGE
#include "atcp.h"
#endif

/* interface vars */
char ifname[32];                /* Interface name */
int pppifunit;                  /* Interface unit number */

char hostname[MAXNAMELEN];      /* Our hostname */
static char ppp_devnam[MAXPATHLEN]; /* name of PPP tty (maybe ttypx) */

int pppd_ttyfd;                 /* Serial port file descriptor */
int baud_rate;                  /* Actual bits/second for serial device */
int hungup;                     /* terminal has been hung up */
int privileged;                 /* we're running as real uid root */
int need_holdoff;               /* need holdoff period before restarting */
int detached;                   /* have detached from terminal */
struct stat devstat;            /* result of stat() on devnam */
int prepass = 0;                /* doing prepass to find device name */
int devnam_fixed;               /* set while in options.ttyxx file */
volatile int pppd_status;               /* exit status for pppd */
int unsuccess;                  /* # unsuccessful connection attempts */
int do_callback;                /* != 0 if we should do callback next */
int doing_callback;             /* != 0 if we are doing callback */
char *callback_script;          /* script for doing callback */
dialerfp pppd_dialer;

int (*holdoff_hook)(void) = NULL;
int (*new_phase_hook)(int) = NULL;

static int fd_ppp = -1;         /* fd for talking PPP */
static int pty_master;          /* fd for master side of pty */
static int pty_slave;           /* fd for slave side of pty */
static int real_ttyfd;          /* fd for actual serial port (not pty) */

int pppd_phase;                 /* where the link is at */
int pppd_kill_link;
int open_ccp_flag;

char **script_env;              /* Env. variable values for scripts */
int s_env_nalloc;               /* # words avail at script_env */

u_char outpacket_buf[PPP_MRU+PPP_HDRLEN]; /* buffer for outgoing packet */
u_char inpacket_buf[PPP_MRU+PPP_HDRLEN]; /* buffer for incoming packet */

char *no_ppp_msg = "Sorry - this system lacks PPP kernel support\n";

static struct timeval start_time;       /* Time when link was started. */

struct pppd_stats link_stats;
int link_connect_time;
int link_stats_valid;

/* Prototypes for procedures local to this file. */

static void cleanup(void);
static void close_tty(void);
static void get_input(void);
static void calltimeout(void);
static struct timeval *timeleft(struct timeval *);
static void holdoff_end(void *);
static int device_script(int, int, char *);

extern  char    *ttyname(int);
extern  char    *getlogin(void);
int pppdmain(int, char *[]);

/*
 * PPP Data Link Layer "protocol" table.
 * One entry per supported protocol.
 * The last entry must be NULL.
 */
struct protent *protocols[] = {
    &lcp_protent,
    &pap_protent,
    &chap_protent,
#ifdef CBCP_SUPPORT
    &cbcp_protent,
#endif
    &ipcp_protent,
#ifdef INET6
    &ipv6cp_protent,
#endif
    &ccp_protent,
#ifdef IPX_CHANGE
    &ipxcp_protent,
#endif
#ifdef AT_CHANGE
    &atcp_protent,
#endif
    NULL
};

int
pppdmain(
    int argc,
    char *argv[])
{
    int i, fdflags, t;
    char *connector;
    struct timeval timo;
    struct protent *protp;

    new_phase(PHASE_INITIALIZE);

    script_env = NULL;
    hostname[MAXNAMELEN-1] = 0;
    privileged = 1;
    privileged_option = 1;

    /*
     * Initialize magic number generator now so that protocols may
     * use magic numbers in initialization.
     */
    magic_init();

#ifdef XXX_XXX
    /* moved code the the rtems_pppd_reset_options function */

    /*
     * Initialize to the standard option set, then parse, in order,
     * the system options file, the user's options file,
     * the tty's options file, and the command line arguments.
     */
    for (i = 0; (protp = protocols[i]) != NULL; ++i)
        (*protp->init)(0);
#endif


    if (!ppp_available()) {
        option_error(no_ppp_msg);
        return(EXIT_NO_KERNEL_SUPPORT);
    }

    /*
     * Check that the options given are valid and consistent.
     */
    if (!sys_check_options()) {
        return(EXIT_OPTION_ERROR);
    }
    if (!auth_check_options()) {
        return(EXIT_OPTION_ERROR);
    }
    for (i = 0; (protp = protocols[i]) != NULL; ++i)
        if (protp->check_options != NULL)
            (*protp->check_options)();

    /* default holdoff to 0 if no connect script has been given */
    if (connect_script == 0 && !holdoff_specified)
        holdoff = 0;

    if (default_device)
        nodetach = 1;

    /*
     * Initialize system-dependent stuff.
     */
    sys_init();
    /* if (debug)
        setlogmask(LOG_UPTO(LOG_DEBUG));
    */

    do_callback = 0;
    for (;;) {

        need_holdoff = 1;
        pppd_ttyfd = -1;
        real_ttyfd = -1;
        pppd_status = EXIT_OK;
        ++unsuccess;
        doing_callback = do_callback;
        do_callback = 0;

        new_phase(PHASE_SERIALCONN);

        /*
         * Get a pty master/slave pair if the pty, notty, or record
         * options were specified.
         */
        strlcpy(ppp_devnam, devnam, sizeof(ppp_devnam));
        pty_master = -1;
        pty_slave = -1;

        /*
         * Open the serial device and set it up to be the ppp interface.
         * First we open it in non-blocking mode so we can set the
         * various termios flags appropriately.  If we aren't dialling
         * out and we want to use the modem lines, we reopen it later
         * in order to wait for the carrier detect signal from the modem.
         */
        hungup = 0;
        pppd_kill_link = 0;
        connector = doing_callback? callback_script: connect_script;
        if (devnam[0] != 0) {
            for (;;) {
                /* If the user specified the device name, become the
                   user before opening it. */
                int err;
                pppd_ttyfd = open(devnam, O_NONBLOCK | O_RDWR, 0);
                err = errno;
                if (pppd_ttyfd >= 0) {
                    break;
                }
                errno = err;
                if (err != EINTR) {
                    error("Failed to open %s: %m", devnam);
                    pppd_status = EXIT_OPEN_FAILED;
                }
                if (!persist || err != EINTR)
                    goto fail;
            }
            if ((fdflags = fcntl(pppd_ttyfd, F_GETFL)) == -1
                || fcntl(pppd_ttyfd, F_SETFL, fdflags & ~O_NONBLOCK) < 0)
                warn("Couldn't reset non-blocking mode on device: %m");

            /*
             * Set line speed, flow control, etc.
             * If we have a non-null connection or initializer script,
             * on most systems we set CLOCAL for now so that we can talk
             * to the modem before carrier comes up.  But this has the
             * side effect that we might miss it if CD drops before we
             * get to clear CLOCAL below.  On systems where we can talk
             * successfully to the modem with CLOCAL clear and CD down,
             * we could clear CLOCAL at this point.
             */
            set_up_tty(pppd_ttyfd, ((connector != NULL && connector[0] != 0)
                               || initializer != NULL));
            real_ttyfd = pppd_ttyfd;
        }

        /* run connection script */
        if ((connector && connector[0]) || initializer) {
            if (real_ttyfd != -1) {
                /* XXX do this if doing_callback == CALLBACK_DIALIN? */
                if (!default_device && modem) {
                    setdtr(real_ttyfd, 0);      /* in case modem is off hook */
                    sleep(1);
                    setdtr(real_ttyfd, 1);
                }
            }

            if (initializer && initializer[0]) {
                if (device_script(pppd_ttyfd, DIALER_INIT, initializer) < 0) {
                    error("Initializer script failed");
                    pppd_status = EXIT_INIT_FAILED;
                    goto fail;
                }
                if (pppd_kill_link)
                    goto disconnect;

                info("Serial port initialized.");
            }

            if (connector && connector[0]) {
                if (device_script(pppd_ttyfd, DIALER_CONNECT, connector) < 0) {
                    error("Connect script failed");
                    pppd_status = EXIT_CONNECT_FAILED;
                    goto fail;
                }
                if (pppd_kill_link)
                    goto disconnect;

                info("Serial connection established.");
            }

            /* set line speed, flow control, etc.;
               clear CLOCAL if modem option */
            if (real_ttyfd != -1)
                set_up_tty(real_ttyfd, 0);

            if (doing_callback == CALLBACK_DIALIN)
                connector = NULL;
        }

        /* reopen tty if necessary to wait for carrier */
        if (connector == NULL && modem && devnam[0] != 0) {
            for (;;) {
                if ((i = open(devnam, O_RDWR)) >= 0)
                    break;
                if (errno != EINTR) {
                    error("Failed to reopen %s: %m", devnam);
                    pppd_status = EXIT_OPEN_FAILED;
                }
                if (!persist || errno != EINTR || hungup || pppd_kill_link)
                    goto fail;
            }
            close(i);
        }

        info("Serial connection established.");
        sleep(1);

        /* run welcome script, if any */
        if (welcomer && welcomer[0]) {
            if (device_script(pppd_ttyfd, DIALER_WELCOME, welcomer) < 0)
                warn("Welcome script failed");
        }

        /* set up the serial device as a ppp interface */
        fd_ppp = establish_ppp(pppd_ttyfd);
        if (fd_ppp < 0) {
            pppd_status = EXIT_FATAL_ERROR;
            goto disconnect;
        }

        if (!demand) {
            info("Using interface ppp%d", pppifunit);
            slprintf(ifname, sizeof(ifname), "ppp%d", pppifunit);
        }

        /*
         * Start opening the connection and wait for
         * incoming events (reply, timeout, etc.).
         */
        notice("Connect: %s <--> %s", ifname, ppp_devnam);
        gettimeofday(&start_time, NULL);

        lcp_lowerup(0);
        lcp_open(0);            /* Start protocol */

        open_ccp_flag = 0;
        pppd_status = EXIT_NEGOTIATION_FAILED;
        new_phase(PHASE_ESTABLISH);
        while (pppd_phase != PHASE_DEAD) {
            wait_input(timeleft(&timo));
            calltimeout();
            get_input();

            if (pppd_kill_link) {
                lcp_close(0, "User request");
                pppd_kill_link = 0;
            }
            if (open_ccp_flag) {
                if (pppd_phase == PHASE_NETWORK || pppd_phase == PHASE_RUNNING) {
                    ccp_fsm[0].flags = OPT_RESTART; /* clears OPT_SILENT */
                    (*ccp_protent.open)(0);
                }
                open_ccp_flag = 0;
            }
        }

        /*
         * If we may want to bring the link up again, transfer
         * the ppp unit back to the loopback.  Set the
         * real serial device back to its normal mode of operation.
         */
        clean_check();
        if (demand)
            restore_loop();
        disestablish_ppp(pppd_ttyfd);
        fd_ppp = -1;
        if (!hungup)
            lcp_lowerdown(0);

        /*
         * Run disconnector script, if requested.
         * XXX we may not be able to do this if the line has hung up!
         */
    disconnect:
        if (disconnect_script && !hungup) {
            new_phase(PHASE_DISCONNECT);
            if (real_ttyfd >= 0)
                set_up_tty(real_ttyfd, 1);
            if (device_script(pppd_ttyfd, DIALER_DISCONNECT, disconnect_script) < 0) {
                warn("disconnect script failed");
            } else {
                info("Serial link disconnected.");
            }
        }

    fail:
        if (pty_master >= 0)
            close(pty_master);
        if (pty_slave >= 0)
            close(pty_slave);
        if (real_ttyfd >= 0)
            close_tty();

        if (!persist || (maxfail > 0 && unsuccess >= maxfail))
            break;

        pppd_kill_link = 0;
        if (demand)
            demand_discard();
        t = need_holdoff? holdoff: 0;
        if (holdoff_hook)
            t = (*holdoff_hook)();
        if (t > 0) {
            new_phase(PHASE_HOLDOFF);
            TIMEOUT(holdoff_end, NULL, t);
            do {
                wait_input(timeleft(&timo));

                calltimeout();
                if (pppd_kill_link) {
                    pppd_kill_link = 0;
                    new_phase(PHASE_DORMANT); /* allow signal to end holdoff */
                }
            } while (pppd_phase == PHASE_HOLDOFF);
            if (!persist)
                break;
        }
    }

    die(pppd_status);
    return pppd_status;
}

/*
 * holdoff_end - called via a timeout when the holdoff period ends.
 */
static void
holdoff_end(
    void *arg)
{
    new_phase(PHASE_DORMANT);
}

/* List of protocol names, to make our messages a little more informative. */
struct protocol_list {
    u_short     proto;
    const char  *name;
} protocol_list[] = {
    { 0x21,     "IP" },
    { 0x23,     "OSI Network Layer" },
    { 0x25,     "Xerox NS IDP" },
    { 0x27,     "DECnet Phase IV" },
    { 0x29,     "Appletalk" },
    { 0x2b,     "Novell IPX" },
    { 0x2d,     "VJ compressed TCP/IP" },
    { 0x2f,     "VJ uncompressed TCP/IP" },
    { 0x31,     "Bridging PDU" },
    { 0x33,     "Stream Protocol ST-II" },
    { 0x35,     "Banyan Vines" },
    { 0x39,     "AppleTalk EDDP" },
    { 0x3b,     "AppleTalk SmartBuffered" },
    { 0x3d,     "Multi-Link" },
    { 0x3f,     "NETBIOS Framing" },
    { 0x41,     "Cisco Systems" },
    { 0x43,     "Ascom Timeplex" },
    { 0x45,     "Fujitsu Link Backup and Load Balancing (LBLB)" },
    { 0x47,     "DCA Remote Lan" },
    { 0x49,     "Serial Data Transport Protocol (PPP-SDTP)" },
    { 0x4b,     "SNA over 802.2" },
    { 0x4d,     "SNA" },
    { 0x4f,     "IP6 Header Compression" },
    { 0x6f,     "Stampede Bridging" },
    { 0xfb,     "single-link compression" },
    { 0xfd,     "1st choice compression" },
    { 0x0201,   "802.1d Hello Packets" },
    { 0x0203,   "IBM Source Routing BPDU" },
    { 0x0205,   "DEC LANBridge100 Spanning Tree" },
    { 0x0231,   "Luxcom" },
    { 0x0233,   "Sigma Network Systems" },
    { 0x8021,   "Internet Protocol Control Protocol" },
    { 0x8023,   "OSI Network Layer Control Protocol" },
    { 0x8025,   "Xerox NS IDP Control Protocol" },
    { 0x8027,   "DECnet Phase IV Control Protocol" },
    { 0x8029,   "Appletalk Control Protocol" },
    { 0x802b,   "Novell IPX Control Protocol" },
    { 0x8031,   "Bridging NCP" },
    { 0x8033,   "Stream Protocol Control Protocol" },
    { 0x8035,   "Banyan Vines Control Protocol" },
    { 0x803d,   "Multi-Link Control Protocol" },
    { 0x803f,   "NETBIOS Framing Control Protocol" },
    { 0x8041,   "Cisco Systems Control Protocol" },
    { 0x8043,   "Ascom Timeplex" },
    { 0x8045,   "Fujitsu LBLB Control Protocol" },
    { 0x8047,   "DCA Remote Lan Network Control Protocol (RLNCP)" },
    { 0x8049,   "Serial Data Control Protocol (PPP-SDCP)" },
    { 0x804b,   "SNA over 802.2 Control Protocol" },
    { 0x804d,   "SNA Control Protocol" },
    { 0x804f,   "IP6 Header Compression Control Protocol" },
    { 0x006f,   "Stampede Bridging Control Protocol" },
    { 0x80fb,   "Single Link Compression Control Protocol" },
    { 0x80fd,   "Compression Control Protocol" },
    { 0xc021,   "Link Control Protocol" },
    { 0xc023,   "Password Authentication Protocol" },
    { 0xc025,   "Link Quality Report" },
    { 0xc027,   "Shiva Password Authentication Protocol" },
    { 0xc029,   "CallBack Control Protocol (CBCP)" },
    { 0xc081,   "Container Control Protocol" },
    { 0xc223,   "Challenge Handshake Authentication Protocol" },
    { 0xc281,   "Proprietary Authentication Protocol" },
    { 0,        NULL },
};

/*
 * protocol_name - find a name for a PPP protocol.
 */
static const char *
protocol_name(
    int proto)
{
    struct protocol_list *lp;

    for (lp = protocol_list; lp->proto != 0; ++lp)
        if (proto == lp->proto)
            return lp->name;
    return NULL;
}

/*
 * get_input - called when incoming data is available.
 */
static void
get_input(void)
{
    int len, i;
    u_char *p;
    u_short protocol;
    struct protent *protp;

    p = inpacket_buf;   /* point to beginning of packet buffer */

    len = read_packet(inpacket_buf);
    if (len < 0)
        return;

    if (len == 0) {
        notice("Modem hangup");
        hungup = 1;
        pppd_status = EXIT_HANGUP;
        lcp_lowerdown(0);       /* serial link is no longer available */
        link_terminated(0);
        return;
    }

    if (debug /*&& (debugflags & DBG_INPACKET)*/)
        dbglog("rcvd %P", p, len);

    if (len < PPP_HDRLEN) {
        MAINDEBUG(("io(): Received short packet."));
        return;
    }

    p += 2;                             /* Skip address and control */
    GETSHORT(protocol, p);
    len -= PPP_HDRLEN;

    /*
     * Toss all non-LCP packets unless LCP is OPEN.
     */
    if (protocol != PPP_LCP && lcp_fsm[0].state != OPENED) {
        MAINDEBUG(("get_input: Received non-LCP packet when LCP not open."));
        return;
    }

    /*
     * Until we get past the authentication phase, toss all packets
     * except LCP, LQR and authentication packets.
     */
    if (pppd_phase <= PHASE_AUTHENTICATE
        && !(protocol == PPP_LCP || protocol == PPP_LQR
             || protocol == PPP_PAP || protocol == PPP_CHAP)) {
        MAINDEBUG(("get_input: discarding proto 0x%x in phase %d",
                   protocol, pppd_phase));
        return;
    }

    /*
     * Upcall the proper protocol input routine.
     */
    for (i = 0; (protp = protocols[i]) != NULL; ++i) {
        if (protp->protocol == protocol && protp->enabled_flag) {
            (*protp->input)(0, p, len);
            return;
        }
        if (protocol == (protp->protocol & ~0x8000) && protp->enabled_flag
            && protp->datainput != NULL) {
            (*protp->datainput)(0, p, len);
            return;
        }
    }

    if (debug) {
        const char *pname = protocol_name(protocol);
        if (pname != NULL)
            warn("Unsupported protocol '%s' (0x%x) received", pname, protocol);
        else
            warn("Unsupported protocol 0x%x received", protocol);
    }
    lcp_sprotrej(0, p - PPP_HDRLEN, len + PPP_HDRLEN);

    return;
}

/*
 * new_phase - signal the start of a new phase of pppd's operation.
 */
void
new_phase(
    int p)
{
    pppd_phase = p;
    if (new_phase_hook)
        (*new_phase_hook)(p);
}

/*
 * die - clean up state and exit with the specified status.
 */
void
die(
    int status)
{
    cleanup();
}

/*
 * cleanup - restore anything which needs to be restored before we exit
 */
/* ARGSUSED */
static void
cleanup(void)
{
    sys_cleanup();

    if (fd_ppp >= 0)
        disestablish_ppp(pppd_ttyfd);
    if (real_ttyfd >= 0)
        close_tty();

    sys_close();
}

/*
 * close_tty - restore the terminal device and close it.
 */
static void
close_tty(void)
{
    /* drop dtr to hang up */
    if (!default_device && modem) {
        setdtr(real_ttyfd, 0);
        /*
         * This sleep is in case the serial port has CLOCAL set by default,
         * and consequently will reassert DTR when we close the device.
         */
        sleep(1);
    }

    restore_tty(real_ttyfd);

    close(real_ttyfd);
    real_ttyfd = -1;
}

/*
 * update_link_stats - get stats at link termination.
 */
void
update_link_stats(
    int u)
{
    struct timeval now;
    char numbuf[32];

    if (!get_ppp_stats(u, &link_stats)
        || gettimeofday(&now, NULL) < 0)
        return;
    link_connect_time = now.tv_sec - start_time.tv_sec;
    link_stats_valid = 1;

    slprintf(numbuf, sizeof(numbuf), "%d", link_connect_time);
    slprintf(numbuf, sizeof(numbuf), "%d", link_stats.bytes_out);
    slprintf(numbuf, sizeof(numbuf), "%d", link_stats.bytes_in);
}

struct  callout {
    struct timeval      c_time;         /* time at which to call routine */
    void                *c_arg;         /* argument to routine */
    void                (*c_func)(void *); /* routine */
    struct              callout *c_next;
};

static struct callout *callout = NULL;  /* Callout list */
static struct timeval timenow;          /* Current time */

/*
 * timeout - Schedule a timeout.
 *
 * Note that this timeout takes the number of seconds, NOT hz (as in
 * the kernel).
 */
void
ppptimeout(
    void (*func)(void *),
    void *arg,
    int time)
{
    struct callout *newp, *p, **pp;

    MAINDEBUG(("Timeout %p:%p in %d seconds.", func, arg, time));

    /*
     * Allocate timeout.
     */
    if ((newp = (struct callout *) malloc(sizeof(struct callout))) == NULL)
        fatal("Out of memory in timeout()!");
    newp->c_arg = arg;
    newp->c_func = func;
    gettimeofday(&timenow, NULL);
    newp->c_time.tv_sec = timenow.tv_sec + time;
    newp->c_time.tv_usec = timenow.tv_usec;

    /*
     * Find correct place and link it in.
     */
    for (pp = &callout; (p = *pp); pp = &p->c_next)
        if (newp->c_time.tv_sec < p->c_time.tv_sec
            || (newp->c_time.tv_sec == p->c_time.tv_sec
                && newp->c_time.tv_usec < p->c_time.tv_usec))
            break;
    newp->c_next = p;
    *pp = newp;
}


/*
 * untimeout - Unschedule a timeout.
 */
void
pppuntimeout(
    void (*func)(void *),
    void *arg)
{
    struct callout **copp, *freep;

    MAINDEBUG(("Untimeout %p:%p.", func, arg));

    /*
     * Find first matching timeout and remove it from the list.
     */
    for (copp = &callout; (freep = *copp); copp = &freep->c_next)
        if (freep->c_func == func && freep->c_arg == arg) {
            *copp = freep->c_next;
            free((char *) freep);
            break;
        }
}


/*
 * calltimeout - Call any timeout routines which are now due.
 */
static void
calltimeout(void)
{
    struct callout *p;

    while (callout != NULL) {
        p = callout;

        if (gettimeofday(&timenow, NULL) < 0)
            fatal("Failed to get time of day: %m");
        if (!(p->c_time.tv_sec < timenow.tv_sec
              || (p->c_time.tv_sec == timenow.tv_sec
                  && p->c_time.tv_usec <= timenow.tv_usec)))
            break;              /* no, it's not time yet */

        callout = p->c_next;
        (*p->c_func)(p->c_arg);

        free((char *) p);
    }
}


/*
 * timeleft - return the length of time until the next timeout is due.
 */
static struct timeval *
timeleft(
    struct timeval *tvp)
{
    if (callout == NULL)
        return NULL;

    gettimeofday(&timenow, NULL);
    tvp->tv_sec = callout->c_time.tv_sec - timenow.tv_sec;
    tvp->tv_usec = callout->c_time.tv_usec - timenow.tv_usec;
    if (tvp->tv_usec < 0) {
        tvp->tv_usec += 1000000;
        tvp->tv_sec -= 1;
    }
    if (tvp->tv_sec < 0)
        tvp->tv_sec = tvp->tv_usec = 0;

    return tvp;
}

/*
 * device_script - run a program to talk to the serial device
 * (e.g. to run the connector or disconnector script).
 */
static int device_script(int fd, int mode, char *program)
{
    int    iReturn = -1;
    char   pScript[128];

    /* copyt script into temporary location */
    strcpy(pScript, program);

    /* check to see if dialer was initialized */
    if ( !pppd_dialer ) {
      /* set default dialer to chatmain */
      pppd_dialer = chatmain;
    }

    /* check to see if dialer is set */
    if ( pppd_dialer ) {
      /* call the dialer */
      iReturn = (*pppd_dialer)(fd, mode, program);
    }

    return ( -iReturn );
}

/*
 * novm - log an error message saying we ran out of memory, and die.
 */
void
novm(
    char *msg)
{
    fatal("Virtual memory exhausted allocating %s\n", msg);
}