File: ntp.c

package info (click to toggle)
openntpd 3.9p1-3
  • links: PTS
  • area: main
  • in suites: etch, etch-m68k
  • size: 952 kB
  • ctags: 725
  • sloc: ansic: 4,379; sh: 2,730; yacc: 354; awk: 323; makefile: 218
file content (548 lines) | stat: -rw-r--r-- 12,767 bytes parent folder | download | duplicates (2)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
/*	$OpenBSD: ntp.c,v 1.67 2005/08/10 13:48:36 dtucker Exp $ */

/*
 * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
 * Copyright (c) 2004 Alexander Guy <alexander.guy@andern.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
 * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include "includes.h"

#include <sys/param.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <errno.h>
#include <fcntl.h>
#ifdef HAVE_PATHS_H
# include <paths.h>
#endif
#ifdef HAVE_POLL_H
# include <poll.h>
#endif
#include <pwd.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

#include "ntpd.h"
#include "ntp.h"

#define	PFD_PIPE_MAIN	0
#define	PFD_MAX		1

volatile sig_atomic_t	 ntp_quit = 0;
struct imsgbuf		*ibuf_main;
struct ntpd_conf	*conf;
u_int			 peer_cnt;

void	ntp_sighdlr(int);
int	ntp_dispatch_imsg(void);
void	peer_add(struct ntp_peer *);
void	peer_remove(struct ntp_peer *);
int	offset_compare(const void *, const void *);

void
ntp_sighdlr(int sig)
{
	switch (sig) {
	case SIGINT:
	case SIGTERM:
		ntp_quit = 1;
		break;
	}
}

pid_t
ntp_main(int pipe_prnt[2], struct ntpd_conf *nconf)
{
	int			 a, b, nfds, i, j, idx_peers, timeout, nullfd;
	u_int			 pfd_elms = 0, idx2peer_elms = 0;
	u_int			 listener_cnt, new_cnt, sent_cnt, trial_cnt;
	pid_t			 pid;
	struct pollfd		*pfd = NULL;
	struct passwd		*pw;
	struct servent		*se;
	struct listen_addr	*la;
	struct ntp_peer		*p;
	struct ntp_peer		**idx2peer = NULL;
	struct timespec		 tp;
	struct stat		 stb;
	time_t			 nextaction;
	void			*newp;
	char			*chrootdir;

	switch (pid = fork()) {
	case -1:
		fatal("cannot fork");
		break;
	case 0:
		break;
	default:
		return (pid);
	}

	if ((se = getservbyname("ntp", "udp")) == NULL)
		fatal("getservbyname");

	if ((pw = getpwnam(NTPD_USER)) == NULL)
		fatal("getpwnam");

	if ((nullfd = open(_PATH_DEVNULL, O_RDWR, 0)) == -1)
		fatal(NULL);

#ifdef NTPD_CHROOT_DIR
	chrootdir = NTPD_CHROOT_DIR;
#else
	chrootdir = pw->pw_dir;
#endif

	if (stat(chrootdir, &stb) == -1)
		fatal("stat");
	if (stb.st_uid != 0 || (stb.st_mode & (S_IWGRP|S_IWOTH)) != 0)
		fatal("bad privsep dir permissions");
	if (chroot(chrootdir) == -1)
		fatal("chroot");
	if (chdir("/") == -1)
		fatal("chdir(\"/\")");

	if (!nconf->debug) {
		dup2(nullfd, STDIN_FILENO);
		dup2(nullfd, STDOUT_FILENO);
		dup2(nullfd, STDERR_FILENO);
	}
	close(nullfd);

	setproctitle("ntp engine");

	conf = nconf;
	setup_listeners(se, conf, &listener_cnt);

	if (setgroups(1, &pw->pw_gid) ||
	    setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) ||
	    setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid))
		fatal("can't drop privileges");

	endservent();

	signal(SIGTERM, ntp_sighdlr);
	signal(SIGINT, ntp_sighdlr);
	signal(SIGPIPE, SIG_IGN);
	signal(SIGHUP, SIG_IGN);

	close(pipe_prnt[0]);
	if ((ibuf_main = malloc(sizeof(struct imsgbuf))) == NULL)
		fatal(NULL);
	imsg_init(ibuf_main, pipe_prnt[1]);

	TAILQ_FOREACH(p, &conf->ntp_peers, entry)
		client_peer_init(p);

	bzero(&conf->status, sizeof(conf->status));
	conf->status.synced = 0;
	clock_getres(CLOCK_REALTIME, &tp);
	b = 1000000000 / tp.tv_nsec;	/* convert to Hz */
	for (a = 0; b > 1; a--, b >>= 1)
		;
	conf->status.precision = a;
	conf->scale = 1;

	log_info("ntp engine ready");

	peer_cnt = 0;
	TAILQ_FOREACH(p, &conf->ntp_peers, entry)
		peer_cnt++;

	while (ntp_quit == 0) {
		if (peer_cnt > idx2peer_elms) {
			if ((newp = realloc(idx2peer, sizeof(void *) *
			    peer_cnt)) == NULL) {
				/* panic for now */
				log_warn("could not resize idx2peer from %u -> "
				    "%u entries", idx2peer_elms, peer_cnt);
				fatalx("exiting");
			}
			idx2peer = newp;
			idx2peer_elms = peer_cnt;
		}

		new_cnt = PFD_MAX + peer_cnt + listener_cnt;
		if (new_cnt > pfd_elms) {
			if ((newp = realloc(pfd, sizeof(struct pollfd) *
			    new_cnt)) == NULL) {
				/* panic for now */
				log_warn("could not resize pfd from %u -> "
				    "%u entries", pfd_elms, new_cnt);
				fatalx("exiting");
			}
			pfd = newp;
			pfd_elms = new_cnt;
		}

		bzero(pfd, sizeof(struct pollfd) * pfd_elms);
		bzero(idx2peer, sizeof(void *) * idx2peer_elms);
		nextaction = time(NULL) + 3600;
		pfd[PFD_PIPE_MAIN].fd = ibuf_main->fd;
		pfd[PFD_PIPE_MAIN].events = POLLIN;

		i = 1;
		TAILQ_FOREACH(la, &conf->listen_addrs, entry) {
			pfd[i].fd = la->fd;
			pfd[i].events = POLLIN;
			i++;
		}

		idx_peers = i;
		sent_cnt = trial_cnt = 0;
		TAILQ_FOREACH(p, &conf->ntp_peers, entry) {
			if (p->next > 0 && p->next <= time(NULL)) {
				if (p->state > STATE_DNS_INPROGRESS)
					trial_cnt++;
				if (client_query(p) == 0)
					sent_cnt++;
			}
			if (p->next > 0 && p->next < nextaction)
				nextaction = p->next;

			if (p->deadline > 0 && p->deadline < nextaction)
				nextaction = p->deadline;
			if (p->deadline > 0 && p->deadline <= time(NULL)) {
				timeout = error_interval();
				log_debug("no reply from %s received in time, "
				    "next query %ds", log_sockaddr(
				    (struct sockaddr *)&p->addr->ss), timeout);
				if (p->trustlevel >= TRUSTLEVEL_BADPEER &&
				    (p->trustlevel /= 2) < TRUSTLEVEL_BADPEER)
					log_info("peer %s now invalid",
					    log_sockaddr(
					    (struct sockaddr *)&p->addr->ss));
				client_nextaddr(p);
				set_next(p, timeout);
			}

			if (p->state == STATE_QUERY_SENT) {
				pfd[i].fd = p->query->fd;
				pfd[i].events = POLLIN;
				idx2peer[i - idx_peers] = p;
				i++;
			}
		}

		if (conf->settime &&
		    ((trial_cnt > 0 && sent_cnt == 0) || peer_cnt == 0))
			priv_settime(0);	/* no good peers, don't wait */

		if (ibuf_main->w.queued > 0)
			pfd[PFD_PIPE_MAIN].events |= POLLOUT;

		timeout = nextaction - time(NULL);
		if (timeout < 0)
			timeout = 0;

		if ((nfds = poll(pfd, i, timeout * 1000)) == -1)
			if (errno != EINTR) {
				log_warn("poll error");
				ntp_quit = 1;
			}

		if (nfds > 0 && (pfd[PFD_PIPE_MAIN].revents & POLLOUT))
			if (msgbuf_write(&ibuf_main->w) < 0) {
				log_warn("pipe write error (to parent)");
				ntp_quit = 1;
			}

		if (nfds > 0 && pfd[PFD_PIPE_MAIN].revents & (POLLIN|POLLERR)) {
			nfds--;
			if (ntp_dispatch_imsg() == -1)
				ntp_quit = 1;
		}

		for (j = 1; nfds > 0 && j < idx_peers; j++)
			if (pfd[j].revents & (POLLIN|POLLERR)) {
				nfds--;
				if (server_dispatch(pfd[j].fd, conf) == -1)
					ntp_quit = 1;
			}

		for (; nfds > 0 && j < i; j++)
			if (pfd[j].revents & (POLLIN|POLLERR)) {
				nfds--;
				if (client_dispatch(idx2peer[j - idx_peers],
				    conf->settime) == -1)
					ntp_quit = 1;
			}
	}

	msgbuf_write(&ibuf_main->w);
	msgbuf_clear(&ibuf_main->w);
	free(ibuf_main);

	log_info("ntp engine exiting");
	_exit(0);
}

int
ntp_dispatch_imsg(void)
{
	struct imsg		 imsg;
	int			 n;
	struct ntp_peer		*peer, *npeer;
	u_int16_t		 dlen;
	u_char			*p;
	struct ntp_addr		*h;

	if ((n = imsg_read(ibuf_main)) == -1)
		return (-1);

	if (n == 0) {	/* connection closed */
		log_warnx("ntp_dispatch_imsg in ntp engine: pipe closed");
		return (-1);
	}

	for (;;) {
		if ((n = imsg_get(ibuf_main, &imsg)) == -1)
			return (-1);

		if (n == 0)
			break;

		switch (imsg.hdr.type) {
		case IMSG_ADJTIME:
			memcpy(&n, imsg.data, sizeof(n));
			if (n == 1 && !conf->status.synced) {
				log_info("clock is now synced");
				conf->status.synced = 1;
			} else if (n == 0 && conf->status.synced) {
				log_info("clock is now unsynced");
				conf->status.synced = 0;
			}
			break;
		case IMSG_HOST_DNS:
			TAILQ_FOREACH(peer, &conf->ntp_peers, entry)
				if (peer->id == imsg.hdr.peerid)
					break;
			if (peer == NULL) {
				log_warnx("IMSG_HOST_DNS with invalid peerID");
				break;
			}
			if (peer->addr != NULL) {
				log_warnx("IMSG_HOST_DNS but addr != NULL!");
				break;
			}

			dlen = imsg.hdr.len - IMSG_HEADER_SIZE;
			if (dlen == 0) {	/* no data -> temp error */
				peer->state = STATE_DNS_TEMPFAIL;
				break;
			}

			p = (u_char *)imsg.data;
			while (dlen >= sizeof(struct sockaddr_storage)) {
				if ((h = calloc(1, sizeof(struct ntp_addr))) ==
				    NULL)
					fatal(NULL);
				memcpy(&h->ss, p, sizeof(h->ss));
				p += sizeof(h->ss);
				dlen -= sizeof(h->ss);
				if (peer->addr_head.pool) {
					npeer = new_peer();
					h->next = NULL;
					npeer->addr = h;
					npeer->addr_head.a = h;
					client_peer_init(npeer);
					npeer->state = STATE_DNS_DONE;
					peer_add(npeer);
				} else {
					h->next = peer->addr;
					peer->addr = h;
					peer->addr_head.a = peer->addr;
					peer->state = STATE_DNS_DONE;
				}
			}
			if (dlen != 0)
				fatalx("IMSG_HOST_DNS: dlen != 0");
			if (peer->addr_head.pool)
				peer_remove(peer);
			else
				client_addr_init(peer);
			break;
		default:
			break;
		}
		imsg_free(&imsg);
	}
	return (0);
}

void
peer_add(struct ntp_peer *p)
{
	TAILQ_INSERT_TAIL(&conf->ntp_peers, p, entry);
	peer_cnt++;
}

void
peer_remove(struct ntp_peer *p)
{
	TAILQ_REMOVE(&conf->ntp_peers, p, entry);
	free(p);
	peer_cnt--;
}

void
priv_adjtime(void)
{
	struct ntp_peer	 *p;
	int		  offset_cnt = 0, i = 0;
	struct ntp_peer	**peers;
	double		  offset_median;

	TAILQ_FOREACH(p, &conf->ntp_peers, entry) {
		if (p->trustlevel < TRUSTLEVEL_BADPEER)
			continue;
		if (!p->update.good)
			return;
		offset_cnt++;
	}

	if ((peers = calloc(offset_cnt, sizeof(struct ntp_peer *))) == NULL)
		fatal("calloc priv_adjtime");

	TAILQ_FOREACH(p, &conf->ntp_peers, entry) {
		if (p->trustlevel < TRUSTLEVEL_BADPEER)
			continue;
		peers[i++] = p;
	}

	qsort(peers, offset_cnt, sizeof(struct ntp_peer *), offset_compare);

	if (offset_cnt > 0) {
		if (offset_cnt > 1 && offset_cnt % 2 == 0) {
			offset_median =
			    (peers[offset_cnt / 2 - 1]->update.offset +
			    peers[offset_cnt / 2]->update.offset) / 2;
			conf->status.rootdelay =
			    (peers[offset_cnt / 2 - 1]->update.delay +
			    peers[offset_cnt / 2]->update.delay) / 2;
			conf->status.stratum = MAX(
			    peers[offset_cnt / 2 - 1]->update.status.stratum,
			    peers[offset_cnt / 2]->update.status.stratum);
		} else {
			offset_median = peers[offset_cnt / 2]->update.offset;
			conf->status.rootdelay =
			    peers[offset_cnt / 2]->update.delay;
			conf->status.stratum =
			    peers[offset_cnt / 2]->update.status.stratum;
		}
		conf->status.leap = peers[offset_cnt / 2]->update.status.leap;

		imsg_compose(ibuf_main, IMSG_ADJTIME, 0, 0,
		    &offset_median, sizeof(offset_median));

		conf->status.reftime = gettime();
		conf->status.stratum++;	/* one more than selected peer */
		update_scale(offset_median);

		conf->status.refid4 =
		    peers[offset_cnt / 2]->update.status.refid4;
		if (peers[offset_cnt / 2]->addr->ss.ss_family == AF_INET)
			conf->status.refid = ((struct sockaddr_in *)
			    &peers[offset_cnt / 2]->addr->ss)->sin_addr.s_addr;
		else
			conf->status.refid = conf->status.refid4;
	}

	free(peers);

	TAILQ_FOREACH(p, &conf->ntp_peers, entry)
		p->update.good = 0;
}

int
offset_compare(const void *aa, const void *bb)
{
	const struct ntp_peer * const *a;
	const struct ntp_peer * const *b;

	a = aa;
	b = bb;

	if ((*a)->update.offset < (*b)->update.offset)
		return (-1);
	else if ((*a)->update.offset > (*b)->update.offset)
		return (1);
	else
		return (0);
}

void
priv_settime(double offset)
{
	struct ntp_peer *p;

	imsg_compose(ibuf_main, IMSG_SETTIME, 0, 0, &offset, sizeof(offset));
	conf->settime = 0;

	TAILQ_FOREACH(p, &conf->ntp_peers, entry) {
		if (p->next)
			p->next -= offset;
		if (p->deadline)
			p->deadline -= offset;
	}
}

void
priv_host_dns(char *name, u_int32_t peerid)
{
	u_int16_t	dlen;

	dlen = strlen(name) + 1;
	imsg_compose(ibuf_main, IMSG_HOST_DNS, peerid, 0, name, dlen);
}

void
update_scale(double offset)
{
	if (offset < 0)
		offset = -offset;

	if (offset > QSCALE_OFF_MAX)
		conf->scale = 1;
	else if (offset < QSCALE_OFF_MIN)
		conf->scale = QSCALE_OFF_MAX / QSCALE_OFF_MIN;
	else
		conf->scale = QSCALE_OFF_MAX / offset;
}

time_t
scale_interval(time_t requested)
{
	time_t interval, r;

	interval = requested * conf->scale;
	r = arc4random() % MAX(5, interval / 10);
	return (interval + r);
}

time_t
error_interval(void)
{
	time_t interval, r;

	interval = INTERVAL_QUERY_PATHETIC * QSCALE_OFF_MAX / QSCALE_OFF_MIN;
	r = arc4random() % (interval / 10);
	return (interval + r);
}