1/*-
2 * Copyright (c) 1996 - 2001 Brian Somers <brian@Awfulhak.org>
3 *          based on work by Toshiharu OHNO <tony-o@iij.ad.jp>
4 *                           Internet Initiative Japan, Inc (IIJ)
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 * $FreeBSD$
29 */
30
31#include <sys/param.h>
32#include <netinet/in.h>
33#include <netinet/in_systm.h>
34#include <netinet/ip.h>
35#include <sys/un.h>
36#include <sys/socket.h>
37#include <net/route.h>
38
39#include <errno.h>
40#include <fcntl.h>
41#include <paths.h>
42#include <signal.h>
43#include <stdarg.h>
44#include <stdio.h>
45#include <stdlib.h>
46#include <string.h>
47#include <sys/time.h>
48#include <termios.h>
49#include <unistd.h>
50#include <sys/stat.h>
51
52#ifndef NONAT
53#ifdef LOCALNAT
54#include "alias.h"
55#else
56#include <alias.h>
57#endif
58#endif
59
60#include "layer.h"
61#include "probe.h"
62#include "mbuf.h"
63#include "log.h"
64#include "defs.h"
65#include "id.h"
66#include "timer.h"
67#include "fsm.h"
68#include "lqr.h"
69#include "hdlc.h"
70#include "lcp.h"
71#include "ccp.h"
72#include "iplist.h"
73#include "throughput.h"
74#include "slcompress.h"
75#include "ncpaddr.h"
76#include "ipcp.h"
77#include "filter.h"
78#include "descriptor.h"
79#include "link.h"
80#include "mp.h"
81#ifndef NORADIUS
82#include "radius.h"
83#endif
84#include "ipv6cp.h"
85#include "ncp.h"
86#include "bundle.h"
87#include "auth.h"
88#include "systems.h"
89#include "sig.h"
90#include "main.h"
91#include "server.h"
92#include "prompt.h"
93#include "chat.h"
94#include "chap.h"
95#include "cbcp.h"
96#include "datalink.h"
97#include "iface.h"
98
99#ifndef O_NONBLOCK
100#ifdef O_NDELAY
101#define	O_NONBLOCK O_NDELAY
102#endif
103#endif
104
105static void DoLoop(struct bundle *);
106static void TerminalStop(int);
107
108static struct bundle *SignalBundle;
109static struct prompt *SignalPrompt;
110struct libalias *la;
111
112void
113Cleanup()
114{
115  SignalBundle->CleaningUp = 1;
116  bundle_Close(SignalBundle, NULL, CLOSE_STAYDOWN);
117}
118
119void
120AbortProgram(int excode)
121{
122  if (SignalBundle)
123    server_Close(SignalBundle);
124  log_Printf(LogPHASE, "PPP Terminated (%s).\n", ex_desc(excode));
125  if (SignalBundle) {
126    bundle_Close(SignalBundle, NULL, CLOSE_STAYDOWN);
127    bundle_Destroy(SignalBundle);
128  }
129  log_Close();
130  exit(excode);
131}
132
133static void
134CloseConnection(int signo)
135{
136  /* NOTE, these are manual, we've done a setsid() */
137  sig_signal(SIGINT, SIG_IGN);
138  log_Printf(LogPHASE, "Caught signal %d, abort connection(s)\n", signo);
139  bundle_Down(SignalBundle, CLOSE_STAYDOWN);
140  sig_signal(SIGINT, CloseConnection);
141}
142
143static void
144CloseSession(int signo)
145{
146  log_Printf(LogPHASE, "Signal %d, terminate.\n", signo);
147  Cleanup();
148}
149
150static pid_t BGPid = 0;
151
152static void
153KillChild(int signo)
154{
155  signal(signo, SIG_IGN);
156  log_Printf(LogPHASE, "Parent: Signal %d\n", signo);
157  kill(BGPid, SIGINT);
158}
159
160static void
161TerminalCont(int signo __unused)
162{
163  signal(SIGCONT, SIG_DFL);
164  prompt_Continue(SignalPrompt);
165}
166
167static void
168TerminalStop(int signo __unused)
169{
170  prompt_Suspend(SignalPrompt);
171  signal(SIGCONT, TerminalCont);
172  raise(SIGSTOP);
173}
174
175static void
176BringDownServer(int signo __unused)
177{
178  /* Drops all child prompts too ! */
179  if (server_Close(SignalBundle))
180    log_Printf(LogPHASE, "Closed server socket\n");
181}
182
183static void
184RestartServer(int signo __unused)
185{
186  /* Drops all child prompts and re-opens the socket */
187  server_Reopen(SignalBundle);
188}
189
190static void
191Usage(void)
192{
193  fprintf(stderr, "usage: ppp [-auto | -foreground | -background | -direct |"
194          " -dedicated | -ddial | -interactive]"
195#ifndef NONAT
196          " [-nat]"
197#endif
198          " [-quiet] [-unit N] [system ...]\n");
199  exit(EX_START);
200}
201
202struct switches {
203  unsigned nat : 1;
204  unsigned fg : 1;
205  unsigned quiet : 1;
206  int mode;
207  int unit;
208};
209
210static int
211ProcessArgs(int argc, char **argv, struct switches *sw)
212{
213  int optc, newmode, arg;
214  char *cp;
215
216  optc = 0;
217  memset(sw, '\0', sizeof *sw);
218  sw->mode = PHYS_INTERACTIVE;
219  sw->unit = -1;
220
221  for (arg = 1; arg < argc && *argv[arg] == '-'; arg++, optc++) {
222    cp = argv[arg] + 1;
223    newmode = Nam2mode(cp);
224    switch (newmode) {
225      case PHYS_NONE:
226        if (strcmp(cp, "nat") == 0) {
227#ifdef NONAT
228          log_Printf(LogWARN, "%s ignored: NAT is compiled out\n", argv[arg]);
229#else
230          sw->nat = 1;
231#endif
232          optc--;			/* this option isn't exclusive */
233        } else if (strcmp(cp, "alias") == 0) {
234#ifdef NONAT
235          log_Printf(LogWARN, "%s ignored: NAT is compiled out\n", argv[arg]);
236          fprintf(stderr, "%s ignored: NAT is compiled out\n", argv[arg]);
237#else
238          log_Printf(LogWARN, "%s is deprecated\n", argv[arg]);
239          fprintf(stderr, "%s is deprecated\n", argv[arg]);
240          sw->nat = 1;
241#endif
242          optc--;			/* this option isn't exclusive */
243        } else if (strncmp(cp, "unit", 4) == 0) {
244          optc--;			/* this option isn't exclusive */
245          if (cp[4] == '\0') {
246            optc--;			/* nor is the argument */
247            if (++arg == argc) {
248              fprintf(stderr, "-unit: Expected unit number\n");
249              Usage();
250            } else
251              sw->unit = atoi(argv[arg]);
252          } else
253            sw->unit = atoi(cp + 4);
254        } else if (strcmp(cp, "quiet") == 0) {
255          sw->quiet = 1;
256          optc--;			/* this option isn't exclusive */
257        } else
258          Usage();
259        break;
260
261      case PHYS_ALL:
262        Usage();
263        break;
264
265      default:
266        sw->mode = newmode;
267        if (newmode == PHYS_FOREGROUND)
268          sw->fg = 1;
269    }
270  }
271
272  if (optc > 1) {
273    fprintf(stderr, "You may specify only one mode.\n");
274    exit(EX_START);
275  }
276
277  if (sw->mode == PHYS_AUTO && arg == argc) {
278    fprintf(stderr, "A system must be specified in auto mode.\n");
279    exit(EX_START);
280  }
281
282  return arg;		/* Don't SetLabel yet ! */
283}
284
285static void
286CheckLabel(const char *label, struct prompt *prompt, int mode)
287{
288  const char *err;
289
290  if ((err = system_IsValid(label, prompt, mode)) != NULL) {
291    fprintf(stderr, "%s: %s\n", label, err);
292    if (mode == PHYS_DIRECT)
293      log_Printf(LogWARN, "Label %s rejected -direct connection: %s\n",
294                 label, err);
295    log_Close();
296    exit(1);
297  }
298}
299
300
301int
302main(int argc, char **argv)
303{
304  char *name;
305  const char *lastlabel;
306  int arg, holdfd[3], label;
307  unsigned f;
308  struct bundle *bundle;
309  struct prompt *prompt;
310  struct switches sw;
311
312  probe_Init();
313
314  /*
315   * We open 3 descriptors to ensure that STDIN_FILENO, STDOUT_FILENO and
316   * STDERR_FILENO are always open.  These are closed before DoLoop(),
317   * but *after* we've avoided the possibility of erroneously closing
318   * an important descriptor with close(STD{IN,OUT,ERR}_FILENO).
319   */
320  if ((holdfd[0] = open(_PATH_DEVNULL, O_RDWR)) == -1) {
321    fprintf(stderr, "Cannot open %s !\n", _PATH_DEVNULL);
322    return 2;
323  }
324  for (f = 1; f < sizeof holdfd / sizeof *holdfd; f++)
325    holdfd[f] = dup(holdfd[0]);
326
327  name = strrchr(argv[0], '/');
328  log_Open(name ? name + 1 : argv[0]);
329
330#ifndef NONAT
331  la = LibAliasInit(NULL);
332#endif
333  label = ProcessArgs(argc, argv, &sw);
334
335  /*
336   * A FreeBSD & OpenBSD hack to dodge a bug in the tty driver that drops
337   * output occasionally.... I must find the real reason some time.  To
338   * display the dodgy behaviour, comment out this bit, make yourself a large
339   * routing table and then run ppp in interactive mode.  The `show route'
340   * command will drop chunks of data !!!
341   */
342  if (sw.mode == PHYS_INTERACTIVE) {
343    close(STDIN_FILENO);
344    if (open(_PATH_TTY, O_RDONLY) != STDIN_FILENO) {
345      fprintf(stderr, "Cannot open %s for input !\n", _PATH_TTY);
346      return 2;
347    }
348  }
349
350  /* Allow output for the moment (except in direct mode) */
351  if (sw.mode == PHYS_DIRECT)
352    prompt = NULL;
353  else
354    SignalPrompt = prompt = prompt_Create(NULL, NULL, PROMPT_STD);
355
356  ID0init();
357  if (ID0realuid() != 0) {
358    char conf[200], *ptr;
359
360    snprintf(conf, sizeof conf, "%s/%s", PPP_CONFDIR, CONFFILE);
361    do {
362      struct stat sb;
363
364      if (stat(conf, &sb) == 0 && sb.st_mode & S_IWOTH) {
365        log_Printf(LogALERT, "ppp: Access violation: Please protect %s\n",
366                   conf);
367        return -1;
368      }
369      ptr = conf + strlen(conf)-2;
370      while (ptr > conf && *ptr != '/')
371        *ptr-- = '\0';
372    } while (ptr >= conf);
373  }
374
375  if (label < argc)
376    for (arg = label; arg < argc; arg++)
377      CheckLabel(argv[arg], prompt, sw.mode);
378  else
379    CheckLabel("default", prompt, sw.mode);
380
381  if (!sw.quiet)
382    prompt_Printf(prompt, "Working in %s mode\n", mode2Nam(sw.mode));
383
384  if ((bundle = bundle_Create(TUN_PREFIX, sw.mode, sw.unit)) == NULL)
385    return EX_START;
386
387  /* NOTE:  We may now have changed argv[1] via a ``set proctitle'' */
388
389  SignalBundle = bundle;
390  bundle->NatEnabled = sw.nat;
391  if (sw.nat)
392    opt_enable(bundle, OPT_IFACEALIAS);
393
394  if (system_Select(bundle, "default", CONFFILE, prompt, NULL) < 0)
395    prompt_Printf(prompt, "Warning: No default entry found in config file.\n");
396
397  sig_signal(SIGHUP, CloseSession);
398  sig_signal(SIGTERM, CloseSession);
399  sig_signal(SIGINT, CloseConnection);
400  sig_signal(SIGQUIT, CloseSession);
401  sig_signal(SIGALRM, SIG_IGN);
402  signal(SIGPIPE, SIG_IGN);
403
404  if (sw.mode == PHYS_INTERACTIVE)
405    sig_signal(SIGTSTP, TerminalStop);
406
407  sig_signal(SIGUSR1, RestartServer);
408  sig_signal(SIGUSR2, BringDownServer);
409
410  lastlabel = argv[argc - 1];
411  for (arg = label; arg < argc; arg++) {
412    /* In case we use LABEL or ``set enddisc label'' */
413    bundle_SetLabel(bundle, lastlabel);
414    system_Select(bundle, argv[arg], CONFFILE, prompt, NULL);
415  }
416
417  if (label < argc)
418    /* In case the last label did a ``load'' */
419    bundle_SetLabel(bundle, lastlabel);
420
421  if (sw.mode == PHYS_AUTO &&
422      ncprange_family(&bundle->ncp.ipcp.cfg.peer_range) == AF_UNSPEC) {
423    prompt_Printf(prompt, "You must ``set ifaddr'' with a peer address "
424                  "in auto mode.\n");
425    AbortProgram(EX_START);
426  }
427
428  if (prompt) {
429    prompt->bundle = bundle;	/* couldn't do it earlier */
430    if (!sw.quiet)
431      prompt_Printf(prompt, "Using interface: %s\n", bundle->iface->name);
432  }
433
434  if (sw.mode != PHYS_INTERACTIVE) {
435    if (sw.mode != PHYS_DIRECT) {
436      if (!sw.fg) {
437        int bgpipe[2];
438        pid_t bgpid;
439
440        if (sw.mode == PHYS_BACKGROUND && pipe(bgpipe)) {
441          log_Printf(LogERROR, "pipe: %s\n", strerror(errno));
442	  AbortProgram(EX_SOCK);
443        }
444
445        bgpid = fork();
446        if (bgpid == -1) {
447	  log_Printf(LogERROR, "fork: %s\n", strerror(errno));
448	  AbortProgram(EX_SOCK);
449        }
450
451        if (bgpid) {
452	  char c = EX_NORMAL;
453          int ret;
454
455	  if (sw.mode == PHYS_BACKGROUND) {
456	    close(bgpipe[1]);
457	    BGPid = bgpid;
458            /* If we get a signal, kill the child */
459            signal(SIGHUP, KillChild);
460            signal(SIGTERM, KillChild);
461            signal(SIGINT, KillChild);
462            signal(SIGQUIT, KillChild);
463
464	    /* Wait for our child to close its pipe before we exit */
465            while ((ret = read(bgpipe[0], &c, 1)) == 1) {
466              switch (c) {
467                case EX_NORMAL:
468                  if (!sw.quiet) {
469	            prompt_Printf(prompt, "PPP enabled\n");
470	            log_Printf(LogPHASE, "Parent: PPP enabled\n");
471                  }
472	          break;
473                case EX_REDIAL:
474                  if (!sw.quiet)
475	            prompt_Printf(prompt, "Attempting redial\n");
476                  continue;
477                case EX_RECONNECT:
478                  if (!sw.quiet)
479	            prompt_Printf(prompt, "Attempting reconnect\n");
480                  continue;
481	        default:
482	          prompt_Printf(prompt, "Child failed (%s)\n",
483                                ex_desc((int)c));
484	          log_Printf(LogPHASE, "Parent: Child failed (%s)\n",
485		             ex_desc((int) c));
486	      }
487	      break;
488            }
489            if (ret != 1) {
490	      prompt_Printf(prompt, "Child exit, no status.\n");
491	      log_Printf(LogPHASE, "Parent: Child exit, no status.\n");
492	    }
493	    close(bgpipe[0]);
494	  }
495	  return c;
496        } else if (sw.mode == PHYS_BACKGROUND) {
497	  close(bgpipe[0]);
498          bundle->notify.fd = bgpipe[1];
499        }
500
501        bundle_ChangedPID(bundle);
502        bundle_LockTun(bundle);	/* we have a new pid */
503      }
504
505      /* -auto, -dedicated, -ddial, -foreground & -background */
506      prompt_Destroy(prompt, 0);
507      close(STDOUT_FILENO);
508      close(STDERR_FILENO);
509      close(STDIN_FILENO);
510      if (!sw.fg)
511        setsid();
512    } else {
513      /*
514       * -direct - STDIN_FILENO gets used by physical_Open.  STDOUT_FILENO
515       * *may* get used in exec/pipe mode.
516       */
517      prompt_TtyInit(NULL);
518      close(STDERR_FILENO);
519    }
520  } else {
521    /* -interactive */
522    close(STDERR_FILENO);
523    prompt_TtyInit(prompt);
524    prompt_TtyCommandMode(prompt);
525    prompt_Required(prompt);
526  }
527
528  /* We can get rid of these now */
529  for (f = 0; f < sizeof holdfd / sizeof *holdfd; f++)
530    close(holdfd[f]);
531
532  log_Printf(LogPHASE, "PPP Started (%s mode).\n", mode2Nam(sw.mode));
533  DoLoop(bundle);
534  AbortProgram(EX_NORMAL);
535
536  return EX_NORMAL;
537}
538
539static void
540DoLoop(struct bundle *bundle)
541{
542  fd_set *rfds, *wfds, *efds;
543  int i, nfds, nothing_done;
544
545  if ((rfds = mkfdset()) == NULL) {
546    log_Printf(LogERROR, "DoLoop: Cannot create fd_set\n");
547    return;
548  }
549
550  if ((wfds = mkfdset()) == NULL) {
551    log_Printf(LogERROR, "DoLoop: Cannot create fd_set\n");
552    free(rfds);
553    return;
554  }
555
556  if ((efds = mkfdset()) == NULL) {
557    log_Printf(LogERROR, "DoLoop: Cannot create fd_set\n");
558    free(rfds);
559    free(wfds);
560    return;
561  }
562
563  for (; !bundle_IsDead(bundle); bundle_CleanDatalinks(bundle)) {
564    nfds = 0;
565    zerofdset(rfds);
566    zerofdset(wfds);
567    zerofdset(efds);
568
569    /* All our datalinks, the tun device and the MP socket */
570    descriptor_UpdateSet(&bundle->desc, rfds, wfds, efds, &nfds);
571
572    /* All our prompts and the diagnostic socket */
573    descriptor_UpdateSet(&server.desc, rfds, NULL, NULL, &nfds);
574
575    bundle_CleanDatalinks(bundle);
576    if (bundle_IsDead(bundle))
577      /* Don't select - we'll be here forever */
578      break;
579
580    /*
581     * It's possible that we've had a signal since we last checked.  If
582     * we don't check again before calling select(), we may end up stuck
583     * after having missed the event.... sig_Handle() tries to be as
584     * quick as possible if nothing is likely to have happened.
585     * This is only really likely if we block in open(... O_NONBLOCK)
586     * which will happen with a misconfigured device.
587     */
588    if (sig_Handle())
589      continue;
590
591    i = select(nfds, rfds, wfds, efds, NULL);
592
593    if (i < 0 && errno != EINTR) {
594      log_Printf(LogERROR, "DoLoop: select(): %s\n", strerror(errno));
595      if (log_IsKept(LogTIMER)) {
596        struct timeval t;
597
598        for (i = 0; i <= nfds; i++) {
599          if (FD_ISSET(i, rfds)) {
600            log_Printf(LogTIMER, "Read set contains %d\n", i);
601            FD_CLR(i, rfds);
602            t.tv_sec = t.tv_usec = 0;
603            if (select(nfds, rfds, wfds, efds, &t) != -1) {
604              log_Printf(LogTIMER, "The culprit !\n");
605              break;
606            }
607          }
608          if (FD_ISSET(i, wfds)) {
609            log_Printf(LogTIMER, "Write set contains %d\n", i);
610            FD_CLR(i, wfds);
611            t.tv_sec = t.tv_usec = 0;
612            if (select(nfds, rfds, wfds, efds, &t) != -1) {
613              log_Printf(LogTIMER, "The culprit !\n");
614              break;
615            }
616          }
617          if (FD_ISSET(i, efds)) {
618            log_Printf(LogTIMER, "Error set contains %d\n", i);
619            FD_CLR(i, efds);
620            t.tv_sec = t.tv_usec = 0;
621            if (select(nfds, rfds, wfds, efds, &t) != -1) {
622              log_Printf(LogTIMER, "The culprit !\n");
623              break;
624            }
625          }
626        }
627      }
628      break;
629    }
630
631    log_Printf(LogTIMER, "Select returns %d\n", i);
632
633    sig_Handle();
634
635    if (i <= 0)
636      continue;
637
638    for (i = 0; i <= nfds; i++)
639      if (FD_ISSET(i, efds)) {
640        log_Printf(LogPHASE, "Exception detected on descriptor %d\n", i);
641        /* We deal gracefully with link descriptor exceptions */
642        if (!bundle_Exception(bundle, i)) {
643          log_Printf(LogERROR, "Exception cannot be handled !\n");
644          break;
645        }
646      }
647
648    if (i <= nfds)
649      break;
650
651    nothing_done = 1;
652
653    if (descriptor_IsSet(&server.desc, rfds)) {
654      descriptor_Read(&server.desc, bundle, rfds);
655      nothing_done = 0;
656    }
657
658    if (descriptor_IsSet(&bundle->desc, rfds)) {
659      descriptor_Read(&bundle->desc, bundle, rfds);
660      nothing_done = 0;
661    }
662
663    if (descriptor_IsSet(&bundle->desc, wfds))
664      if (descriptor_Write(&bundle->desc, bundle, wfds) <= 0 && nothing_done) {
665        /*
666         * This is disastrous.  The OS has told us that something is
667         * writable, and all our write()s have failed.  Rather than
668         * going back immediately to do our UpdateSet()s and select(),
669         * we sleep for a bit to avoid gobbling up all cpu time.
670         */
671        struct timeval t;
672
673        t.tv_sec = 0;
674        t.tv_usec = 100000;
675        select(0, NULL, NULL, NULL, &t);
676      }
677  }
678
679  log_Printf(LogDEBUG, "DoLoop done.\n");
680}
681