initial import of NetBSD tree

1 files changed, 1087 insertions, 0 deletions

diff --git a/usr.sbin/pppd/main.c b/usr.sbin/pppd/main.c
new file mode 100644
index 00000000000..77a643b7173
--- /dev/null
+++ b/usr.sbin/pppd/main.c
@@ -0,0 +1,1087 @@
+/*
+ * 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.
+ */
+
+#ifndef lint
+static char rcsid[] = "$Id: main.c,v 1.1 1995/10/18 08:47:59 deraadt Exp $";
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <signal.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <syslog.h>
+#include <netdb.h>
+#include <utmp.h>
+#include <pwd.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 <net/if.h>
+
+#include "pppd.h"
+#include "magic.h"
+#include "fsm.h"
+#include "lcp.h"
+#include "ipcp.h"
+#include "upap.h"
+#include "chap.h"
+#include "ccp.h"
+#include "pathnames.h"
+#include "patchlevel.h"
+
+/*
+ * If REQ_SYSOPTIONS is defined to 1, pppd will not run unless
+ * /etc/ppp/options exists.
+ */
+#ifndef	REQ_SYSOPTIONS
+#define REQ_SYSOPTIONS	1
+#endif
+
+/* interface vars */
+char ifname[IFNAMSIZ];		/* Interface name */
+int ifunit;			/* Interface unit number */
+
+char *progname;			/* Name of this program */
+char hostname[MAXNAMELEN];	/* Our hostname */
+static char pidfilename[MAXPATHLEN];	/* name of pid file */
+static char default_devnam[MAXPATHLEN];	/* name of default device */
+static pid_t	pid;		/* Our pid */
+static pid_t	pgrpid;		/* Process Group ID */
+static uid_t uid;		/* Our real user-id */
+
+int fd = -1;			/* Device file descriptor */
+
+int phase;			/* where the link is at */
+int kill_link;
+int open_ccp_flag;
+
+static int initfdflags = -1;	/* Initial file descriptor flags */
+
+u_char outpacket_buf[PPP_MRU+PPP_HDRLEN]; /* buffer for outgoing packet */
+static u_char inpacket_buf[PPP_MRU+PPP_HDRLEN]; /* buffer for incoming packet */
+
+int hungup;			/* terminal has been hung up */
+static int n_children;		/* # child processes still running */
+
+int baud_rate;
+
+char *no_ppp_msg = "Sorry - this system lacks PPP kernel support\n";
+
+/* prototypes */
+static void hup __P((int));
+static void term __P((int));
+static void chld __P((int));
+static void toggle_debug __P((int));
+static void open_ccp __P((int));
+static void bad_signal __P((int));
+
+static void get_input __P((void));
+void establish_ppp __P((void));
+void calltimeout __P((void));
+struct timeval *timeleft __P((struct timeval *));
+void reap_kids __P((void));
+void cleanup __P((int, caddr_t));
+void close_fd __P((void));
+void die __P((int));
+void novm __P((char *));
+
+void log_packet __P((u_char *, int, char *));
+void format_packet __P((u_char *, int,
+			   void (*) (void *, char *, ...), void *));
+void pr_log __P((void *, char *, ...));
+
+extern	char	*ttyname __P((int));
+extern	char	*getlogin __P((void));
+
+#ifdef ultrix
+#undef	O_NONBLOCK
+#define	O_NONBLOCK	O_NDELAY
+#endif
+
+/*
+ * PPP Data Link Layer "protocol" table.
+ * One entry per supported protocol.
+ */
+static struct protent {
+    u_short protocol;
+    void (*init)();
+    void (*input)();
+    void (*protrej)();
+    int  (*printpkt)();
+    void (*datainput)();
+    char *name;
+} prottbl[] = {
+    { PPP_LCP, lcp_init, lcp_input, lcp_protrej,
+	  lcp_printpkt, NULL, "LCP" },
+    { PPP_IPCP, ipcp_init, ipcp_input, ipcp_protrej,
+	  ipcp_printpkt, NULL, "IPCP" },
+    { PPP_PAP, upap_init, upap_input, upap_protrej,
+	  upap_printpkt, NULL, "PAP" },
+    { PPP_CHAP, ChapInit, ChapInput, ChapProtocolReject,
+	  ChapPrintPkt, NULL, "CHAP" },
+    { PPP_CCP, ccp_init, ccp_input, ccp_protrej,
+	  ccp_printpkt, ccp_datainput, "CCP" },
+};
+
+#define N_PROTO		(sizeof(prottbl) / sizeof(prottbl[0]))
+
+main(argc, argv)
+    int argc;
+    char *argv[];
+{
+    int i, nonblock;
+    struct sigaction sa;
+    struct cmd *cmdp;
+    FILE *pidfile;
+    char *p;
+    struct passwd *pw;
+    struct timeval timo;
+    sigset_t mask;
+
+    p = ttyname(0);
+    if (p)
+	strcpy(devnam, p);
+    strcpy(default_devnam, devnam);
+
+    if (gethostname(hostname, MAXNAMELEN) < 0 ) {
+	perror("couldn't get hostname");
+	die(1);
+    }
+    hostname[MAXNAMELEN-1] = 0;
+
+    uid = getuid();
+
+    if (!ppp_available()) {
+	fprintf(stderr, no_ppp_msg);
+	exit(1);
+    }
+
+    /*
+     * Initialize to the standard option set, then parse, in order,
+     * the system options file, the user's options file, and the command
+     * line arguments.
+     */
+    for (i = 0; i < N_PROTO; i++)
+	(*prottbl[i].init)(0);
+  
+    progname = *argv;
+
+    if (!options_from_file(_PATH_SYSOPTIONS, REQ_SYSOPTIONS, 0) ||
+	!options_from_user() ||
+	!parse_args(argc-1, argv+1) ||
+	!options_for_tty())
+	die(1);
+    check_auth_options();
+    setipdefault();
+
+    /*
+     * If the user has specified the default device name explicitly,
+     * pretend they hadn't.
+     */
+    if (!default_device && strcmp(devnam, default_devnam) == 0)
+	default_device = 1;
+
+    /*
+     * Initialize system-dependent stuff and magic number package.
+     */
+    sys_init();
+    magic_init();
+
+    /*
+     * Detach ourselves from the terminal, if required,
+     * and identify who is running us.
+     */
+    if (!default_device && !nodetach && daemon(0, 0) < 0) {
+	perror("Couldn't detach from controlling terminal");
+	exit(1);
+    }
+    pid = getpid();
+    p = getlogin();
+    if (p == NULL) {
+	pw = getpwuid(uid);
+	if (pw != NULL && pw->pw_name != NULL)
+	    p = pw->pw_name;
+	else
+	    p = "(unknown)";
+    }
+    syslog(LOG_NOTICE, "pppd %s.%d started by %s, uid %d",
+	   VERSION, PATCHLEVEL, p, uid);
+  
+    /*
+     * Compute mask of all interesting signals and install signal handlers
+     * for each.  Only one signal handler may be active at a time.  Therefore,
+     * all other signals should be masked when any handler is executing.
+     */
+    sigemptyset(&mask);
+    sigaddset(&mask, SIGHUP);
+    sigaddset(&mask, SIGINT);
+    sigaddset(&mask, SIGTERM);
+    sigaddset(&mask, SIGCHLD);
+
+#define SIGNAL(s, handler)	{ \
+	sa.sa_handler = handler; \
+	if (sigaction(s, &sa, NULL) < 0) { \
+	    syslog(LOG_ERR, "Couldn't establish signal handler (%d): %m", s); \
+	    die(1); \
+	} \
+    }
+
+    sa.sa_mask = mask;
+    sa.sa_flags = 0;
+    SIGNAL(SIGHUP, hup);		/* Hangup */
+    SIGNAL(SIGINT, term);		/* Interrupt */
+    SIGNAL(SIGTERM, term);		/* Terminate */
+    SIGNAL(SIGCHLD, chld);
+
+    SIGNAL(SIGUSR1, toggle_debug);	/* Toggle debug flag */
+    SIGNAL(SIGUSR2, open_ccp);		/* Reopen CCP */
+
+    /*
+     * Install a handler for other signals which would otherwise
+     * cause pppd to exit without cleaning up.
+     */
+    SIGNAL(SIGABRT, bad_signal);
+    SIGNAL(SIGALRM, bad_signal);
+    SIGNAL(SIGFPE, bad_signal);
+    SIGNAL(SIGILL, bad_signal);
+    SIGNAL(SIGPIPE, bad_signal);
+    SIGNAL(SIGQUIT, bad_signal);
+    SIGNAL(SIGSEGV, bad_signal);
+#ifdef SIGBUS
+    SIGNAL(SIGBUS, bad_signal);
+#endif
+#ifdef SIGEMT
+    SIGNAL(SIGEMT, bad_signal);
+#endif
+#ifdef SIGPOLL
+    SIGNAL(SIGPOLL, bad_signal);
+#endif
+#ifdef SIGPROF
+    SIGNAL(SIGPROF, bad_signal);
+#endif
+#ifdef SIGSYS
+    SIGNAL(SIGSYS, bad_signal);
+#endif
+#ifdef SIGTRAP
+    SIGNAL(SIGTRAP, bad_signal);
+#endif
+#ifdef SIGVTALRM
+    SIGNAL(SIGVTALRM, bad_signal);
+#endif
+#ifdef SIGXCPU
+    SIGNAL(SIGXCPU, bad_signal);
+#endif
+#ifdef SIGXFSZ
+    SIGNAL(SIGXFSZ, bad_signal);
+#endif
+
+    /*
+     * Lock the device if we've been asked to.
+     */
+    if (lockflag && !default_device)
+	if (lock(devnam) < 0)
+	    die(1);
+
+    do {
+
+	/*
+	 * Open the serial device and set it up to be the ppp interface.
+	 * If we're dialling out, or we don't want to use the modem lines,
+	 * we open it in non-blocking mode, but then we need to clear
+	 * the non-blocking I/O bit.
+	 */
+	nonblock = (connector || !modem)? O_NONBLOCK: 0;
+	if ((fd = open(devnam, nonblock | O_RDWR, 0)) < 0) {
+	    syslog(LOG_ERR, "Failed to open %s: %m", devnam);
+	    die(1);
+	}
+	if ((initfdflags = fcntl(fd, F_GETFL)) == -1) {
+	    syslog(LOG_ERR, "Couldn't get device fd flags: %m");
+	    die(1);
+	}
+	if (nonblock) {
+	    initfdflags &= ~O_NONBLOCK;
+	    fcntl(fd, F_SETFL, initfdflags);
+	}
+	hungup = 0;
+	kill_link = 0;
+
+	/* run connection script */
+	if (connector && connector[0]) {
+	    MAINDEBUG((LOG_INFO, "Connecting with <%s>", connector));
+
+	    /* set line speed, flow control, etc.; set CLOCAL for now */
+	    set_up_tty(fd, 1);
+
+	    /* drop dtr to hang up in case modem is off hook */
+	    if (!default_device && modem) {
+		setdtr(fd, FALSE);
+		sleep(1);
+		setdtr(fd, TRUE);
+	    }
+
+	    if (device_script(connector, fd, fd) < 0) {
+		syslog(LOG_ERR, "Connect script failed");
+		setdtr(fd, FALSE);
+		die(1);
+	    }
+
+	    syslog(LOG_INFO, "Serial connection established.");
+	    sleep(1);		/* give it time to set up its terminal */
+	}
+
+	/* set line speed, flow control, etc.; clear CLOCAL if modem option */
+	set_up_tty(fd, 0);
+
+	/* set up the serial device as a ppp interface */
+	establish_ppp();
+
+	syslog(LOG_INFO, "Using interface ppp%d", ifunit);
+	(void) sprintf(ifname, "ppp%d", ifunit);
+
+	/* write pid to file */
+	(void) sprintf(pidfilename, "%s%s.pid", _PATH_VARRUN, ifname);
+	if ((pidfile = fopen(pidfilename, "w")) != NULL) {
+	    fprintf(pidfile, "%d\n", pid);
+	    (void) fclose(pidfile);
+	} else {
+	    syslog(LOG_ERR, "Failed to create pid file %s: %m", pidfilename);
+	    pidfilename[0] = 0;
+	}
+
+	/*
+	 * Set device for non-blocking reads.
+	 */
+	if (fcntl(fd, F_SETFL, initfdflags | O_NONBLOCK) == -1) {
+	    syslog(LOG_ERR, "Couldn't set device to non-blocking mode: %m");
+	    die(1);
+	}
+  
+	/*
+	 * Block all signals, start opening the connection, and wait for
+	 * incoming events (reply, timeout, etc.).
+	 */
+	syslog(LOG_NOTICE, "Connect: %s <--> %s", ifname, devnam);
+	lcp_lowerup(0);
+	lcp_open(0);		/* Start protocol */
+	for (phase = PHASE_ESTABLISH; phase != PHASE_DEAD; ) {
+	    wait_input(timeleft(&timo));
+	    calltimeout();
+	    get_input();
+	    if (kill_link) {
+		lcp_close(0);
+		kill_link = 0;
+	    }
+	    if (open_ccp_flag) {
+		if (phase == PHASE_NETWORK) {
+		    ccp_fsm[0].flags = OPT_RESTART; /* clears OPT_SILENT */
+		    ccp_open(0);
+		}
+		open_ccp_flag = 0;
+	    }
+	    reap_kids();	/* Don't leave dead kids lying around */
+	}
+
+	/*
+	 * Run disconnector script, if requested.
+	 * First we need to reset non-blocking mode.
+	 * XXX we may not be able to do this if the line has hung up!
+	 */
+	if (initfdflags != -1 && fcntl(fd, F_SETFL, initfdflags) >= 0)
+	    initfdflags = -1;
+	disestablish_ppp();
+	if (disconnector) {
+	    set_up_tty(fd, 1);
+	    if (device_script(disconnector, fd, fd) < 0) {
+		syslog(LOG_WARNING, "disconnect script failed");
+	    } else {
+		syslog(LOG_INFO, "Serial link disconnected.");
+	    }
+	}
+
+	close_fd();
+	if (unlink(pidfilename) < 0 && errno != ENOENT) 
+	    syslog(LOG_WARNING, "unable to delete pid file: %m");
+	pidfilename[0] = 0;
+
+    } while (persist);
+
+    die(0);
+}
+
+
+/*
+ * get_input - called when incoming data is available.
+ */
+static void
+get_input()
+{
+    int len, i;
+    u_char *p;
+    u_short protocol;
+
+    p = inpacket_buf;	/* point to beginning of packet buffer */
+
+    len = read_packet(inpacket_buf);
+    if (len < 0)
+	return;
+
+    if (len == 0) {
+	syslog(LOG_NOTICE, "Modem hangup");
+	hungup = 1;
+	lcp_lowerdown(0);	/* serial link is no longer available */
+	phase = PHASE_DEAD;
+	return;
+    }
+
+    if (debug /*&& (debugflags & DBG_INPACKET)*/)
+	log_packet(p, len, "rcvd ");
+
+    if (len < PPP_HDRLEN) {
+	MAINDEBUG((LOG_INFO, "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((LOG_INFO,
+		   "io(): Received non-LCP packet when LCP not open."));
+	return;
+    }
+
+    /*
+     * Upcall the proper protocol input routine.
+     */
+    for (i = 0; i < sizeof (prottbl) / sizeof (struct protent); i++) {
+	if (prottbl[i].protocol == protocol) {
+	    (*prottbl[i].input)(0, p, len);
+	    return;
+	}
+        if (protocol == (prottbl[i].protocol & ~0x8000)
+	    && prottbl[i].datainput != NULL) {
+	    (*prottbl[i].datainput)(0, p, len);
+	    return;
+	}
+    }
+
+    if (debug)
+    	syslog(LOG_WARNING, "Unknown protocol (0x%x) received", protocol);
+    lcp_sprotrej(0, p - PPP_HDRLEN, len + PPP_HDRLEN);
+}
+
+
+/*
+ * demuxprotrej - Demultiplex a Protocol-Reject.
+ */
+void
+demuxprotrej(unit, protocol)
+    int unit;
+    u_short protocol;
+{
+    int i;
+
+    /*
+     * Upcall the proper Protocol-Reject routine.
+     */
+    for (i = 0; i < sizeof (prottbl) / sizeof (struct protent); i++)
+	if (prottbl[i].protocol == protocol) {
+	    (*prottbl[i].protrej)(unit);
+	    return;
+	}
+
+    syslog(LOG_WARNING,
+	   "demuxprotrej: Unrecognized Protocol-Reject for protocol 0x%x",
+	   protocol);
+}
+
+
+/*
+ * bad_signal - We've caught a fatal signal.  Clean up state and exit.
+ */
+static void
+bad_signal(sig)
+    int sig;
+{
+    syslog(LOG_ERR, "Fatal signal %d", sig);
+    die(1);
+}
+
+/*
+ * quit - Clean up state and exit (with an error indication).
+ */
+void 
+quit()
+{
+    die(1);
+}
+
+/*
+ * die - like quit, except we can specify an exit status.
+ */
+void
+die(status)
+    int status;
+{
+    cleanup(0, NULL);
+    syslog(LOG_INFO, "Exit.");
+    exit(status);
+}
+
+/*
+ * cleanup - restore anything which needs to be restored before we exit
+ */
+/* ARGSUSED */
+void
+cleanup(status, arg)
+    int status;
+    caddr_t arg;
+{
+    if (fd >= 0)
+	close_fd();
+
+    if (pidfilename[0] != 0 && unlink(pidfilename) < 0 && errno != ENOENT) 
+	syslog(LOG_WARNING, "unable to delete pid file: %m");
+    pidfilename[0] = 0;
+
+    if (lockflag && !default_device)
+	unlock();
+}
+
+/*
+ * close_fd - restore the terminal device and close it.
+ */
+void
+close_fd()
+{
+    disestablish_ppp();
+
+    /* drop dtr to hang up */
+    if (modem)
+	setdtr(fd, FALSE);
+
+    if (initfdflags != -1 && fcntl(fd, F_SETFL, initfdflags) < 0)
+	syslog(LOG_WARNING, "Couldn't restore device fd flags: %m");
+    initfdflags = -1;
+
+    restore_tty();
+
+    close(fd);
+    fd = -1;
+}
+
+
+struct	callout {
+    struct timeval	c_time;		/* time at which to call routine */
+    caddr_t		c_arg;		/* argument to routine */
+    void		(*c_func)();	/* 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
+timeout(func, arg, time)
+    void (*func)();
+    caddr_t arg;
+    int time;
+{
+    struct callout *newp, *p, **pp;
+  
+    MAINDEBUG((LOG_DEBUG, "Timeout %lx:%lx in %d seconds.",
+	       (long) func, (long) arg, time));
+  
+    /*
+     * Allocate timeout.
+     */
+    if ((newp = (struct callout *) malloc(sizeof(struct callout))) == NULL) {
+	syslog(LOG_ERR, "Out of memory in timeout()!");
+	die(1);
+    }
+    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_sec))
+	    break;
+    newp->c_next = p;
+    *pp = newp;
+}
+
+
+/*
+ * untimeout - Unschedule a timeout.
+ */
+void
+untimeout(func, arg)
+    void (*func)();
+    caddr_t arg;
+{
+    struct itimerval itv;
+    struct callout **copp, *freep;
+    int reschedule = 0;
+  
+    MAINDEBUG((LOG_DEBUG, "Untimeout %lx:%lx.", (long) func, (long) 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;
+	    (void) free((char *) freep);
+	    break;
+	}
+}
+
+
+/*
+ * calltimeout - Call any timeout routines which are now due.
+ */
+void
+calltimeout()
+{
+    struct callout *p;
+
+    while (callout != NULL) {
+	p = callout;
+
+	if (gettimeofday(&timenow, NULL) < 0) {
+	    syslog(LOG_ERR, "Failed to get time of day: %m");
+	    die(1);
+	}
+	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.
+ */
+struct timeval *
+timeleft(tvp)
+    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;
+}
+    
+
+/*
+ * hup - Catch SIGHUP signal.
+ *
+ * Indicates that the physical layer has been disconnected.
+ * We don't rely on this indication; if the user has sent this
+ * signal, we just take the link down.
+ */
+static void
+hup(sig)
+    int sig;
+{
+    syslog(LOG_INFO, "Hangup (SIGHUP)");
+    kill_link = 1;
+}
+
+
+/*
+ * term - Catch SIGTERM signal and SIGINT signal (^C/del).
+ *
+ * Indicates that we should initiate a graceful disconnect and exit.
+ */
+/*ARGSUSED*/
+static void
+term(sig)
+    int sig;
+{
+    syslog(LOG_INFO, "Terminating on signal %d.", sig);
+    persist = 0;		/* don't try to restart */
+    kill_link = 1;
+}
+
+
+/*
+ * chld - Catch SIGCHLD signal.
+ * Calls reap_kids to get status for any dead kids.
+ */
+static void
+chld(sig)
+    int sig;
+{
+    reap_kids();
+}
+
+
+/*
+ * toggle_debug - Catch SIGUSR1 signal.
+ *
+ * Toggle debug flag.
+ */
+/*ARGSUSED*/
+static void
+toggle_debug(sig)
+    int sig;
+{
+    debug = !debug;
+    note_debug_level();
+}
+
+
+/*
+ * open_ccp - Catch SIGUSR2 signal.
+ *
+ * Try to (re)negotiate compression.
+ */
+/*ARGSUSED*/
+static void
+open_ccp(sig)
+    int sig;
+{
+    open_ccp_flag = 1;
+}
+
+
+/*
+ * device_script - run a program to connect or disconnect the
+ * serial device.
+ */
+int
+device_script(program, in, out)
+    char *program;
+    int in, out;
+{
+    int pid;
+    int status;
+    int errfd;
+
+    pid = fork();
+
+    if (pid < 0) {
+	syslog(LOG_ERR, "Failed to create child process: %m");
+	die(1);
+    }
+
+    if (pid == 0) {
+	dup2(in, 0);
+	dup2(out, 1);
+	errfd = open(_PATH_CONNERRS, O_WRONLY | O_APPEND | O_CREAT, 0644);
+	if (errfd >= 0)
+	    dup2(errfd, 2);
+	setuid(getuid());
+	setgid(getgid());
+	execl("/bin/sh", "sh", "-c", program, (char *)0);
+	syslog(LOG_ERR, "could not exec /bin/sh: %m");
+	_exit(99);
+	/* NOTREACHED */
+    }
+
+    while (waitpid(pid, &status, 0) < 0) {
+	if (errno == EINTR)
+	    continue;
+	syslog(LOG_ERR, "error waiting for (dis)connection process: %m");
+	die(1);
+    }
+
+    return (status == 0 ? 0 : -1);
+}
+
+
+/*
+ * run-program - execute a program with given arguments,
+ * but don't wait for it.
+ * If the program can't be executed, logs an error unless
+ * must_exist is 0 and the program file doesn't exist.
+ */
+int
+run_program(prog, args, must_exist)
+    char *prog;
+    char **args;
+    int must_exist;
+{
+    int pid;
+    char *nullenv[1];
+
+    pid = fork();
+    if (pid == -1) {
+	syslog(LOG_ERR, "Failed to create child process for %s: %m", prog);
+	return -1;
+    }
+    if (pid == 0) {
+	int new_fd;
+
+	/* Leave the current location */
+	(void) setsid();    /* No controlling tty. */
+	(void) umask (S_IRWXG|S_IRWXO);
+	(void) chdir ("/"); /* no current directory. */
+	setuid(geteuid());
+	setgid(getegid());
+
+	/* Ensure that nothing of our device environment is inherited. */
+	close (0);
+	close (1);
+	close (2);
+	close (fd);  /* tty interface to the ppp device */
+	/* XXX should call sysdep cleanup procedure here */
+
+        /* Don't pass handles to the PPP device, even by accident. */
+	new_fd = open (_PATH_DEVNULL, O_RDWR);
+	if (new_fd >= 0) {
+	    if (new_fd != 0) {
+	        dup2  (new_fd, 0); /* stdin <- /dev/null */
+		close (new_fd);
+	    }
+	    dup2 (0, 1); /* stdout -> /dev/null */
+	    dup2 (0, 2); /* stderr -> /dev/null */
+	}
+
+#ifdef BSD
+	/* Force the priority back to zero if pppd is running higher. */
+	if (setpriority (PRIO_PROCESS, 0, 0) < 0)
+	    syslog (LOG_WARNING, "can't reset priority to 0: %m"); 
+#endif
+
+	/* SysV recommends a second fork at this point. */
+
+	/* run the program; give it a null environment */
+	nullenv[0] = NULL;
+	execve(prog, args, nullenv);
+	if (must_exist || errno != ENOENT)
+	    syslog(LOG_WARNING, "Can't execute %s: %m", prog);
+	_exit(-1);
+    }
+    MAINDEBUG((LOG_DEBUG, "Script %s started; pid = %d", prog, pid));
+    ++n_children;
+    return 0;
+}
+
+
+/*
+ * reap_kids - get status from any dead child processes,
+ * and log a message for abnormal terminations.
+ */
+void
+reap_kids()
+{
+    int pid, status;
+
+    if (n_children == 0)
+	return;
+    if ((pid = waitpid(-1, &status, WNOHANG)) == -1) {
+	if (errno != ECHILD)
+	    syslog(LOG_ERR, "Error waiting for child process: %m");
+	return;
+    }
+    if (pid > 0) {
+	--n_children;
+	if (WIFSIGNALED(status)) {
+	    syslog(LOG_WARNING, "Child process %d terminated with signal %d",
+		   pid, WTERMSIG(status));
+	}
+    }
+}
+
+
+/*
+ * log_packet - format a packet and log it.
+ */
+
+char line[256];			/* line to be logged accumulated here */
+char *linep;
+
+void
+log_packet(p, len, prefix)
+    u_char *p;
+    int len;
+    char *prefix;
+{
+    strcpy(line, prefix);
+    linep = line + strlen(line);
+    format_packet(p, len, pr_log, NULL);
+    if (linep != line)
+	syslog(LOG_DEBUG, "%s", line);
+}
+
+/*
+ * format_packet - make a readable representation of a packet,
+ * calling `printer(arg, format, ...)' to output it.
+ */
+void
+format_packet(p, len, printer, arg)
+    u_char *p;
+    int len;
+    void (*printer) __P((void *, char *, ...));
+    void *arg;
+{
+    int i, n;
+    u_short proto;
+    u_char x;
+
+    if (len >= PPP_HDRLEN && p[0] == PPP_ALLSTATIONS && p[1] == PPP_UI) {
+	p += 2;
+	GETSHORT(proto, p);
+	len -= PPP_HDRLEN;
+	for (i = 0; i < N_PROTO; ++i)
+	    if (proto == prottbl[i].protocol)
+		break;
+	if (i < N_PROTO) {
+	    printer(arg, "[%s", prottbl[i].name);
+	    n = (*prottbl[i].printpkt)(p, len, printer, arg);
+	    printer(arg, "]");
+	    p += n;
+	    len -= n;
+	} else {
+	    printer(arg, "[proto=0x%x]", proto);
+	}
+    }
+
+    for (; len > 0; --len) {
+	GETCHAR(x, p);
+	printer(arg, " %.2x", x);
+    }
+}
+
+#ifdef __STDC__
+#include <stdarg.h>
+
+void
+pr_log(void *arg, char *fmt, ...)
+{
+    int n;
+    va_list pvar;
+    char buf[256];
+
+    va_start(pvar, fmt);
+    vsprintf(buf, fmt, pvar);
+    va_end(pvar);
+
+    n = strlen(buf);
+    if (linep + n + 1 > line + sizeof(line)) {
+	syslog(LOG_DEBUG, "%s", line);
+	linep = line;
+    }
+    strcpy(linep, buf);
+    linep += n;
+}
+
+#else /* __STDC__ */
+#include <varargs.h>
+
+void
+pr_log(arg, fmt, va_alist)
+void *arg;
+char *fmt;
+va_dcl
+{
+    int n;
+    va_list pvar;
+    char buf[256];
+
+    va_start(pvar);
+    vsprintf(buf, fmt, pvar);
+    va_end(pvar);
+
+    n = strlen(buf);
+    if (linep + n + 1 > line + sizeof(line)) {
+	syslog(LOG_DEBUG, "%s", line);
+	linep = line;
+    }
+    strcpy(linep, buf);
+    linep += n;
+}
+#endif
+
+/*
+ * print_string - print a readable representation of a string using
+ * printer.
+ */
+void
+print_string(p, len, printer, arg)
+    char *p;
+    int len;
+    void (*printer) __P((void *, char *, ...));
+    void *arg;
+{
+    int c;
+
+    printer(arg, "\"");
+    for (; len > 0; --len) {
+	c = *p++;
+	if (' ' <= c && c <= '~')
+	    printer(arg, "%c", c);
+	else
+	    printer(arg, "\\%.3o", c);
+    }
+    printer(arg, "\"");
+}
+
+/*
+ * novm - log an error message saying we ran out of memory, and die.
+ */
+void
+novm(msg)
+    char *msg;
+{
+    syslog(LOG_ERR, "Virtual memory exhausted allocating %s\n", msg);
+    die(1);
+}