2 * main.c - Point-to-Point Protocol main module
4 * Copyright (c) 1989 Carnegie Mellon University.
7 * Redistribution and use in source and binary forms are permitted
8 * provided that the above copyright notice and this paragraph are
9 * duplicated in all such forms and that any documentation,
10 * advertising materials, and other materials related to such
11 * distribution and use acknowledge that the software was developed
12 * by Carnegie Mellon University. The name of the
13 * University may not be used to endorse or promote products derived
14 * from this software without specific prior written permission.
15 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
17 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
21 static char rcsid[] = "$Id: main.c,v 1.31 1996/01/18 03:21:53 paulus Exp $";
34 #include <sys/param.h>
35 #include <sys/types.h>
38 #include <sys/resource.h>
40 #include <sys/socket.h>
51 #include "pathnames.h"
52 #include "patchlevel.h"
56 #endif /* IPX_CHANGE */
59 * If REQ_SYSOPTIONS is defined to 1, pppd will not run unless
60 * /etc/ppp/options exists.
62 #ifndef REQ_SYSOPTIONS
63 #define REQ_SYSOPTIONS 1
67 char ifname[IFNAMSIZ]; /* Interface name */
68 int ifunit; /* Interface unit number */
70 char *progname; /* Name of this program */
71 char hostname[MAXNAMELEN]; /* Our hostname */
72 static char pidfilename[MAXPATHLEN]; /* name of pid file */
73 static char default_devnam[MAXPATHLEN]; /* name of default device */
74 static pid_t pid; /* Our pid */
75 static pid_t pgrpid; /* Process Group ID */
76 static uid_t uid; /* Our real user-id */
78 int ttyfd = -1; /* Serial port file descriptor */
80 int phase; /* where the link is at */
84 static int loop_fd = -1; /* fd for loopback device */
86 u_char outpacket_buf[PPP_MRU+PPP_HDRLEN]; /* buffer for outgoing packet */
87 u_char inpacket_buf[PPP_MRU+PPP_HDRLEN]; /* buffer for incoming packet */
89 int hungup; /* terminal has been hung up */
90 static int n_children; /* # child processes still running */
92 int baud_rate; /* Actual bits/second for serial device */
94 static int locked; /* lock() has succeeded */
96 char *no_ppp_msg = "Sorry - this system lacks PPP kernel support\n";
98 /* Prototypes for procedures local to this file. */
100 static void cleanup __P((void));
101 static void close_tty __P((void));
102 static void get_input __P((void));
103 static void connect_time_expired __P((caddr_t));
104 static void calltimeout __P((void));
105 static struct timeval *timeleft __P((struct timeval *));
106 static void hup __P((int));
107 static void term __P((int));
108 static void chld __P((int));
109 static void toggle_debug __P((int));
110 static void open_ccp __P((int));
111 static void bad_signal __P((int));
112 static void holdoff_end __P((void *));
113 static int device_script __P((char *, int, int));
114 static void reap_kids __P((void));
115 static void pr_log __P((void *, char *, ...));
117 extern char *ttyname __P((int));
118 extern char *getlogin __P((void));
122 #define O_NONBLOCK O_NDELAY
126 * PPP Data Link Layer "protocol" table.
127 * One entry per supported protocol.
128 * The last entry must be NULL.
130 struct protent *protocols[] = {
146 int i, nonblock, fdflags;
154 struct protent *protp;
159 strcpy(default_devnam, devnam);
161 if (gethostname(hostname, MAXNAMELEN) < 0 ) {
162 perror("couldn't get hostname");
165 hostname[MAXNAMELEN-1] = 0;
170 * Initialize to the standard option set, then parse, in order,
171 * the system options file, the user's options file, and the command
174 for (i = 0; (protp = protocols[i]) != NULL; ++i)
179 if (!options_from_file(_PATH_SYSOPTIONS, REQ_SYSOPTIONS, 0) ||
180 !options_for_tty() ||
181 !options_from_user() ||
182 !parse_args(argc-1, argv+1))
185 if (!ppp_available()) {
186 fprintf(stderr, no_ppp_msg);
191 auth_check_options();
192 for (i = 0; (protp = protocols[i]) != NULL; ++i)
193 if (protp->check_options != NULL)
194 (*protp->check_options)();
197 * If the user has specified the default device name explicitly,
198 * pretend they hadn't.
200 if (!default_device && strcmp(devnam, default_devnam) == 0)
204 * Initialize system-dependent stuff and magic number package.
210 * Detach ourselves from the terminal, if required,
211 * and identify who is running us.
213 if (!default_device && !nodetach && daemon(0, 0) < 0) {
214 perror("Couldn't detach from controlling terminal");
221 if (pw != NULL && pw->pw_name != NULL)
226 syslog(LOG_NOTICE, "pppd %s.%d started by %s, uid %d",
227 VERSION, PATCHLEVEL, p, uid);
230 * Compute mask of all interesting signals and install signal handlers
231 * for each. Only one signal handler may be active at a time. Therefore,
232 * all other signals should be masked when any handler is executing.
235 sigaddset(&mask, SIGHUP);
236 sigaddset(&mask, SIGINT);
237 sigaddset(&mask, SIGTERM);
238 sigaddset(&mask, SIGCHLD);
240 #define SIGNAL(s, handler) { \
241 sa.sa_handler = handler; \
242 if (sigaction(s, &sa, NULL) < 0) { \
243 syslog(LOG_ERR, "Couldn't establish signal handler (%d): %m", s); \
250 SIGNAL(SIGHUP, hup); /* Hangup */
251 SIGNAL(SIGINT, term); /* Interrupt */
252 SIGNAL(SIGTERM, term); /* Terminate */
253 SIGNAL(SIGCHLD, chld);
255 SIGNAL(SIGUSR1, toggle_debug); /* Toggle debug flag */
256 SIGNAL(SIGUSR2, open_ccp); /* Reopen CCP */
259 * Install a handler for other signals which would otherwise
260 * cause pppd to exit without cleaning up.
262 SIGNAL(SIGABRT, bad_signal);
263 SIGNAL(SIGALRM, bad_signal);
264 SIGNAL(SIGFPE, bad_signal);
265 SIGNAL(SIGILL, bad_signal);
266 SIGNAL(SIGPIPE, bad_signal);
267 SIGNAL(SIGQUIT, bad_signal);
268 SIGNAL(SIGSEGV, bad_signal);
270 SIGNAL(SIGBUS, bad_signal);
273 SIGNAL(SIGEMT, bad_signal);
276 SIGNAL(SIGPOLL, bad_signal);
279 SIGNAL(SIGPROF, bad_signal);
282 SIGNAL(SIGSYS, bad_signal);
285 SIGNAL(SIGTRAP, bad_signal);
288 SIGNAL(SIGVTALRM, bad_signal);
291 SIGNAL(SIGXCPU, bad_signal);
294 SIGNAL(SIGXFSZ, bad_signal);
298 * If we're doing dial-on-demand, set up the interface now.
302 * Open the loopback channel and set it up to be the ppp interface.
306 syslog(LOG_INFO, "Using interface ppp%d", ifunit);
307 (void) sprintf(ifname, "ppp%d", ifunit);
309 /* write pid to file */
310 (void) sprintf(pidfilename, "%s%s.pid", _PATH_VARRUN, ifname);
311 if ((pidfile = fopen(pidfilename, "w")) != NULL) {
312 fprintf(pidfile, "%d\n", pid);
313 (void) fclose(pidfile);
315 syslog(LOG_ERR, "Failed to create pid file %s: %m", pidfilename);
320 * Configure the interface and mark it up, etc.
329 * Don't do anything until we see some activity.
331 phase = PHASE_DORMANT;
335 wait_loop_output(timeleft(&timo));
342 if (get_loop_output())
348 * Now we want to bring up the link.
351 syslog(LOG_INFO, "Starting link");
355 * Lock the device if we've been asked to.
357 if (lockflag && !default_device) {
358 if (lock(devnam) < 0)
364 * Open the serial device and set it up to be the ppp interface.
365 * If we're dialling out, or we don't want to use the modem lines,
366 * we open it in non-blocking mode, but then we need to clear
367 * the non-blocking I/O bit.
369 nonblock = (connector || !modem)? O_NONBLOCK: 0;
370 if ((ttyfd = open(devnam, nonblock | O_RDWR, 0)) < 0) {
371 syslog(LOG_ERR, "Failed to open %s: %m", devnam);
375 if ((fdflags = fcntl(ttyfd, F_GETFL)) == -1
376 || fcntl(ttyfd, F_SETFL, fdflags & ~O_NONBLOCK) < 0)
378 "Couldn't reset non-blocking mode on device: %m");
383 /* run connection script */
384 if (connector && connector[0]) {
385 MAINDEBUG((LOG_INFO, "Connecting with <%s>", connector));
387 /* set line speed, flow control, etc.; set CLOCAL for now */
388 set_up_tty(ttyfd, 1);
390 /* drop dtr to hang up in case modem is off hook */
391 if (!default_device && modem) {
392 setdtr(ttyfd, FALSE);
397 if (device_script(connector, ttyfd, ttyfd) < 0) {
398 syslog(LOG_ERR, "Connect script failed");
399 setdtr(ttyfd, FALSE);
403 syslog(LOG_INFO, "Serial connection established.");
404 sleep(1); /* give it time to set up its terminal */
407 /* set line speed, flow control, etc.; clear CLOCAL if modem option */
408 set_up_tty(ttyfd, 0);
410 /* run welcome script, if any */
411 if (welcomer && welcomer[0]) {
412 if (device_script(welcomer, ttyfd, ttyfd) < 0)
413 syslog(LOG_WARNING, "Welcome script failed");
416 /* set up the serial device as a ppp interface */
417 establish_ppp(ttyfd);
421 syslog(LOG_INFO, "Using interface ppp%d", ifunit);
422 (void) sprintf(ifname, "ppp%d", ifunit);
424 /* write pid to file */
425 (void) sprintf(pidfilename, "%s%s.pid", _PATH_VARRUN, ifname);
426 if ((pidfile = fopen(pidfilename, "w")) != NULL) {
427 fprintf(pidfile, "%d\n", pid);
428 (void) fclose(pidfile);
430 syslog(LOG_ERR, "Failed to create pid file %s: %m",
437 * Set a timeout to close the connection once the maximum
438 * connect time has expired.
441 TIMEOUT(connect_time_expired, 0, maxconnect);
444 * Start opening the connection and wait for
445 * incoming events (reply, timeout, etc.).
447 syslog(LOG_NOTICE, "Connect: %s <--> %s", ifname, devnam);
449 lcp_open(0); /* Start protocol */
450 for (phase = PHASE_ESTABLISH; phase != PHASE_DEAD; ) {
451 wait_input(timeleft(&timo));
455 lcp_close(0, "User request");
456 phase = PHASE_TERMINATE;
460 if (phase == PHASE_NETWORK) {
461 ccp_fsm[0].flags = OPT_RESTART; /* clears OPT_SILENT */
466 reap_kids(); /* Don't leave dead kids lying around */
470 * If we may want to bring the link up again, transfer
471 * the ppp unit back to the loopback. Set the
472 * real serial device back to its normal mode of operation.
477 disestablish_ppp(ttyfd);
480 * Run disconnector script, if requested.
481 * XXX we may not be able to do this if the line has hung up!
483 if (disconnector && !hungup) {
484 set_up_tty(ttyfd, 1);
485 if (device_script(disconnector, ttyfd, ttyfd) < 0) {
486 syslog(LOG_WARNING, "disconnect script failed");
488 syslog(LOG_INFO, "Serial link disconnected.");
500 if (unlink(pidfilename) < 0 && errno != ENOENT)
501 syslog(LOG_WARNING, "unable to delete pid file: %m");
511 phase = PHASE_HOLDOFF;
512 TIMEOUT(holdoff_end, NULL, holdoff);
514 wait_time(timeleft(&timo));
520 phase = PHASE_DORMANT; /* allow signal to end holdoff */
523 } while (phase == PHASE_HOLDOFF);
531 * holdoff_end - called via a timeout when the holdoff period ends.
537 phase = PHASE_DORMANT;
541 * get_input - called when incoming data is available.
549 struct protent *protp;
551 p = inpacket_buf; /* point to beginning of packet buffer */
553 len = read_packet(inpacket_buf);
558 syslog(LOG_NOTICE, "Modem hangup");
560 lcp_lowerdown(0); /* serial link is no longer available */
565 if (debug /*&& (debugflags & DBG_INPACKET)*/)
566 log_packet(p, len, "rcvd ");
568 if (len < PPP_HDRLEN) {
569 MAINDEBUG((LOG_INFO, "io(): Received short packet."));
573 p += 2; /* Skip address and control */
574 GETSHORT(protocol, p);
578 * Toss all non-LCP packets unless LCP is OPEN.
580 if (protocol != PPP_LCP && lcp_fsm[0].state != OPENED) {
582 "io(): Received non-LCP packet when LCP not open."));
587 * Upcall the proper protocol input routine.
589 for (i = 0; (protp = protocols[i]) != NULL; ++i) {
590 if (protp->protocol == protocol && protp->enabled_flag) {
591 (*protp->input)(0, p, len);
594 if (protocol == (protp->protocol & ~0x8000) && protp->enabled_flag
595 && protp->datainput != NULL) {
596 (*protp->datainput)(0, p, len);
602 syslog(LOG_WARNING, "Unsupported protocol (0x%x) received", protocol);
603 lcp_sprotrej(0, p - PPP_HDRLEN, len + PPP_HDRLEN);
608 * quit - Clean up state and exit (with an error indication).
617 * die - like quit, except we can specify an exit status.
624 syslog(LOG_INFO, "Exit.");
629 * connect_time_expired - log a message and close the connection.
632 connect_time_expired(arg)
635 syslog(LOG_INFO, "Connect time expired");
637 phase = PHASE_TERMINATE;
638 lcp_close(0, "Connect time expired"); /* Close connection */
642 * cleanup - restore anything which needs to be restored before we exit
653 if (pidfilename[0] != 0 && unlink(pidfilename) < 0 && errno != ENOENT)
654 syslog(LOG_WARNING, "unable to delete pid file: %m");
662 * close_tty - restore the terminal device and close it.
667 disestablish_ppp(ttyfd);
669 /* drop dtr to hang up */
671 setdtr(ttyfd, FALSE);
681 struct timeval c_time; /* time at which to call routine */
682 caddr_t c_arg; /* argument to routine */
683 void (*c_func)(); /* routine */
684 struct callout *c_next;
687 static struct callout *callout = NULL; /* Callout list */
688 static struct timeval timenow; /* Current time */
691 * timeout - Schedule a timeout.
693 * Note that this timeout takes the number of seconds, NOT hz (as in
697 timeout(func, arg, time)
702 struct callout *newp, *p, **pp;
704 MAINDEBUG((LOG_DEBUG, "Timeout %lx:%lx in %d seconds.",
705 (long) func, (long) arg, time));
710 if ((newp = (struct callout *) malloc(sizeof(struct callout))) == NULL) {
711 syslog(LOG_ERR, "Out of memory in timeout()!");
716 gettimeofday(&timenow, NULL);
717 newp->c_time.tv_sec = timenow.tv_sec + time;
718 newp->c_time.tv_usec = timenow.tv_usec;
721 * Find correct place and link it in.
723 for (pp = &callout; (p = *pp); pp = &p->c_next)
724 if (newp->c_time.tv_sec < p->c_time.tv_sec
725 || (newp->c_time.tv_sec == p->c_time.tv_sec
726 && newp->c_time.tv_usec < p->c_time.tv_sec))
734 * untimeout - Unschedule a timeout.
741 struct itimerval itv;
742 struct callout **copp, *freep;
745 MAINDEBUG((LOG_DEBUG, "Untimeout %lx:%lx.", (long) func, (long) arg));
748 * Find first matching timeout and remove it from the list.
750 for (copp = &callout; (freep = *copp); copp = &freep->c_next)
751 if (freep->c_func == func && freep->c_arg == arg) {
752 *copp = freep->c_next;
753 (void) free((char *) freep);
760 * calltimeout - Call any timeout routines which are now due.
767 while (callout != NULL) {
770 if (gettimeofday(&timenow, NULL) < 0) {
771 syslog(LOG_ERR, "Failed to get time of day: %m");
774 if (!(p->c_time.tv_sec < timenow.tv_sec
775 || (p->c_time.tv_sec == timenow.tv_sec
776 && p->c_time.tv_usec <= timenow.tv_usec)))
777 break; /* no, it's not time yet */
780 (*p->c_func)(p->c_arg);
788 * timeleft - return the length of time until the next timeout is due.
790 static struct timeval *
797 gettimeofday(&timenow, NULL);
798 tvp->tv_sec = callout->c_time.tv_sec - timenow.tv_sec;
799 tvp->tv_usec = callout->c_time.tv_usec - timenow.tv_usec;
800 if (tvp->tv_usec < 0) {
801 tvp->tv_usec += 1000000;
805 tvp->tv_sec = tvp->tv_usec = 0;
812 * hup - Catch SIGHUP signal.
814 * Indicates that the physical layer has been disconnected.
815 * We don't rely on this indication; if the user has sent this
816 * signal, we just take the link down.
822 syslog(LOG_INFO, "Hangup (SIGHUP)");
828 * term - Catch SIGTERM signal and SIGINT signal (^C/del).
830 * Indicates that we should initiate a graceful disconnect and exit.
837 syslog(LOG_INFO, "Terminating on signal %d.", sig);
838 persist = 0; /* don't try to restart */
844 * chld - Catch SIGCHLD signal.
845 * Calls reap_kids to get status for any dead kids.
856 * toggle_debug - Catch SIGUSR1 signal.
871 * open_ccp - Catch SIGUSR2 signal.
873 * Try to (re)negotiate compression.
885 * bad_signal - We've caught a fatal signal. Clean up state and exit.
891 syslog(LOG_ERR, "Fatal signal %d", sig);
897 * device_script - run a program to connect or disconnect the
901 device_script(program, in, out)
912 syslog(LOG_ERR, "Failed to create child process: %m");
920 errfd = open(_PATH_CONNERRS, O_WRONLY | O_APPEND | O_CREAT, 0644);
925 execl("/bin/sh", "sh", "-c", program, (char *)0);
926 syslog(LOG_ERR, "could not exec /bin/sh: %m");
931 while (waitpid(pid, &status, 0) < 0) {
934 syslog(LOG_ERR, "error waiting for (dis)connection process: %m");
938 return (status == 0 ? 0 : -1);
943 * run-program - execute a program with given arguments,
944 * but don't wait for it.
945 * If the program can't be executed, logs an error unless
946 * must_exist is 0 and the program file doesn't exist.
949 run_program(prog, args, must_exist)
959 syslog(LOG_ERR, "Failed to create child process for %s: %m", prog);
965 /* Leave the current location */
966 (void) setsid(); /* No controlling tty. */
967 (void) umask (S_IRWXG|S_IRWXO);
968 (void) chdir ("/"); /* no current directory. */
972 /* Ensure that nothing of our device environment is inherited. */
977 close (ttyfd); /* tty interface to the ppp device */
979 /* Don't pass handles to the PPP device, even by accident. */
980 new_fd = open (_PATH_DEVNULL, O_RDWR);
983 dup2 (new_fd, 0); /* stdin <- /dev/null */
986 dup2 (0, 1); /* stdout -> /dev/null */
987 dup2 (0, 2); /* stderr -> /dev/null */
991 /* Force the priority back to zero if pppd is running higher. */
992 if (setpriority (PRIO_PROCESS, 0, 0) < 0)
993 syslog (LOG_WARNING, "can't reset priority to 0: %m");
996 /* SysV recommends a second fork at this point. */
998 /* run the program; give it a null environment */
1000 execve(prog, args, nullenv);
1001 if (must_exist || errno != ENOENT)
1002 syslog(LOG_WARNING, "Can't execute %s: %m", prog);
1005 MAINDEBUG((LOG_DEBUG, "Script %s started; pid = %d", prog, pid));
1012 * reap_kids - get status from any dead child processes,
1013 * and log a message for abnormal terminations.
1020 if (n_children == 0)
1022 if ((pid = waitpid(-1, &status, WNOHANG)) == -1) {
1023 if (errno != ECHILD)
1024 syslog(LOG_ERR, "Error waiting for child process: %m");
1029 if (WIFSIGNALED(status)) {
1030 syslog(LOG_WARNING, "Child process %d terminated with signal %d",
1031 pid, WTERMSIG(status));
1038 * log_packet - format a packet and log it.
1041 char line[256]; /* line to be logged accumulated here */
1045 log_packet(p, len, prefix)
1050 strcpy(line, prefix);
1051 linep = line + strlen(line);
1052 format_packet(p, len, pr_log, NULL);
1054 syslog(LOG_DEBUG, "%s", line);
1058 * format_packet - make a readable representation of a packet,
1059 * calling `printer(arg, format, ...)' to output it.
1062 format_packet(p, len, printer, arg)
1065 void (*printer) __P((void *, char *, ...));
1071 struct protent *protp;
1073 if (len >= PPP_HDRLEN && p[0] == PPP_ALLSTATIONS && p[1] == PPP_UI) {
1077 for (i = 0; (protp = protocols[i]) != NULL; ++i)
1078 if (proto == protp->protocol)
1080 if (protp != NULL) {
1081 printer(arg, "[%s", protp->name);
1082 n = (*protp->printpkt)(p, len, printer, arg);
1087 printer(arg, "[proto=0x%x]", proto);
1091 for (; len > 0; --len) {
1093 printer(arg, " %.2x", x);
1101 pr_log(void *arg, char *fmt, ...)
1107 va_start(pvar, fmt);
1108 vsprintf(buf, fmt, pvar);
1112 if (linep + n + 1 > line + sizeof(line)) {
1113 syslog(LOG_DEBUG, "%s", line);
1120 #else /* __STDC__ */
1121 #include <varargs.h>
1124 pr_log(arg, fmt, va_alist)
1134 vsprintf(buf, fmt, pvar);
1138 if (linep + n + 1 > line + sizeof(line)) {
1139 syslog(LOG_DEBUG, "%s", line);
1148 * print_string - print a readable representation of a string using
1152 print_string(p, len, printer, arg)
1155 void (*printer) __P((void *, char *, ...));
1161 for (; len > 0; --len) {
1163 if (' ' <= c && c <= '~')
1164 printer(arg, "%c", c);
1166 printer(arg, "\\%.3o", c);
1172 * novm - log an error message saying we ran out of memory, and die.
1178 syslog(LOG_ERR, "Virtual memory exhausted allocating %s\n", msg);