1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 1996 - 2001 Brian Somers <brian@Awfulhak.org>
5 * based on work by Toshiharu OHNO <tony-o@iij.ad.jp>
6 * Internet Initiative Japan, Inc (IIJ)
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
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
105 static void DoLoop(struct bundle *);
106 static void TerminalStop(int);
107
108 static struct bundle *SignalBundle;
109 static struct prompt *SignalPrompt;
110 struct libalias *la;
111
112 void
Cleanup(void)113 Cleanup(void)
114 {
115 SignalBundle->CleaningUp = 1;
116 bundle_Close(SignalBundle, NULL, CLOSE_STAYDOWN);
117 }
118
119 void
AbortProgram(int excode)120 AbortProgram(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
133 static void
CloseConnection(int signo)134 CloseConnection(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
143 static void
CloseSession(int signo)144 CloseSession(int signo)
145 {
146 log_Printf(LogPHASE, "Signal %d, terminate.\n", signo);
147 Cleanup();
148 }
149
150 static pid_t BGPid = 0;
151
152 static void
KillChild(int signo)153 KillChild(int signo)
154 {
155 signal(signo, SIG_IGN);
156 log_Printf(LogPHASE, "Parent: Signal %d\n", signo);
157 kill(BGPid, SIGINT);
158 }
159
160 static void
TerminalCont(int signo __unused)161 TerminalCont(int signo __unused)
162 {
163 signal(SIGCONT, SIG_DFL);
164 prompt_Continue(SignalPrompt);
165 }
166
167 static void
TerminalStop(int signo __unused)168 TerminalStop(int signo __unused)
169 {
170 prompt_Suspend(SignalPrompt);
171 signal(SIGCONT, TerminalCont);
172 raise(SIGSTOP);
173 }
174
175 static void
BringDownServer(int signo __unused)176 BringDownServer(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
183 static void
RestartServer(int signo __unused)184 RestartServer(int signo __unused)
185 {
186 /* Drops all child prompts and re-opens the socket */
187 server_Reopen(SignalBundle);
188 }
189
190 static void
Usage(void)191 Usage(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
202 struct switches {
203 unsigned nat : 1;
204 unsigned fg : 1;
205 unsigned quiet : 1;
206 int mode;
207 int unit;
208 };
209
210 static int
ProcessArgs(int argc,char ** argv,struct switches * sw)211 ProcessArgs(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
285 static void
CheckLabel(const char * label,struct prompt * prompt,int mode)286 CheckLabel(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
301 int
main(int argc,char ** argv)302 main(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
539 static void
DoLoop(struct bundle * bundle)540 DoLoop(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