1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
2
3 #include <errno.h>
4 #include <math.h>
5 #include <netinet/in.h>
6 #include <netinet/ip.h>
7 #include <resolv.h>
8 #include <stdlib.h>
9 #include <sys/timerfd.h>
10 #include <sys/timex.h>
11 #include <sys/types.h>
12
13 #include "sd-daemon.h"
14 #include "sd-messages.h"
15
16 #include "alloc-util.h"
17 #include "bus-polkit.h"
18 #include "dns-domain.h"
19 #include "event-util.h"
20 #include "fd-util.h"
21 #include "format-util.h"
22 #include "fs-util.h"
23 #include "list.h"
24 #include "log.h"
25 #include "network-util.h"
26 #include "ratelimit.h"
27 #include "resolve-private.h"
28 #include "socket-util.h"
29 #include "string-util.h"
30 #include "strv.h"
31 #include "time-util.h"
32 #include "timesyncd-conf.h"
33 #include "timesyncd-manager.h"
34 #include "user-util.h"
35 #include "util.h"
36
37 #ifndef ADJ_SETOFFSET
38 #define ADJ_SETOFFSET 0x0100 /* add 'time' to current time */
39 #endif
40
41 /* Expected accuracy of time synchronization; used to adjust the poll interval */
42 #define NTP_ACCURACY_SEC 0.2
43
44 /*
45 * Maximum delta in seconds which the system clock is gradually adjusted
46 * (slewed) to approach the network time. Deltas larger that this are set by
47 * letting the system time jump. The kernel's limit for adjtime is 0.5s.
48 */
49 #define NTP_MAX_ADJUST 0.4
50
51 /* Default of maximum acceptable root distance in microseconds. */
52 #define NTP_ROOT_DISTANCE_MAX_USEC (5 * USEC_PER_SEC)
53
54 /* Maximum number of missed replies before selecting another source. */
55 #define NTP_MAX_MISSED_REPLIES 2
56
57 #define RATELIMIT_INTERVAL_USEC (10*USEC_PER_SEC)
58 #define RATELIMIT_BURST 10
59
60 #define TIMEOUT_USEC (10*USEC_PER_SEC)
61
62 static int manager_arm_timer(Manager *m, usec_t next);
63 static int manager_clock_watch_setup(Manager *m);
64 static int manager_listen_setup(Manager *m);
65 static void manager_listen_stop(Manager *m);
66 static int manager_save_time_and_rearm(Manager *m, usec_t t);
67
ntp_ts_short_to_d(const struct ntp_ts_short * ts)68 static double ntp_ts_short_to_d(const struct ntp_ts_short *ts) {
69 return be16toh(ts->sec) + (be16toh(ts->frac) / 65536.0);
70 }
71
ntp_ts_to_d(const struct ntp_ts * ts)72 static double ntp_ts_to_d(const struct ntp_ts *ts) {
73 return be32toh(ts->sec) + ((double)be32toh(ts->frac) / UINT_MAX);
74 }
75
ts_to_d(const struct timespec * ts)76 static double ts_to_d(const struct timespec *ts) {
77 return ts->tv_sec + (1.0e-9 * ts->tv_nsec);
78 }
79
graceful_add_offset_1900_1970(time_t t)80 static uint32_t graceful_add_offset_1900_1970(time_t t) {
81 /* Adds OFFSET_1900_1970 to t and returns it as 32bit value. This is handles overflows
82 * gracefully in a deterministic and well-defined way by cutting off the top bits. */
83 uint64_t a = (uint64_t) t + OFFSET_1900_1970;
84 return (uint32_t) (a & UINT64_C(0xFFFFFFFF));
85 }
86
manager_timeout(sd_event_source * source,usec_t usec,void * userdata)87 static int manager_timeout(sd_event_source *source, usec_t usec, void *userdata) {
88 _cleanup_free_ char *pretty = NULL;
89 Manager *m = userdata;
90
91 assert(m);
92 assert(m->current_server_name);
93 assert(m->current_server_address);
94
95 server_address_pretty(m->current_server_address, &pretty);
96 log_info("Timed out waiting for reply from %s (%s).", strna(pretty), m->current_server_name->string);
97
98 return manager_connect(m);
99 }
100
manager_send_request(Manager * m)101 static int manager_send_request(Manager *m) {
102 _cleanup_free_ char *pretty = NULL;
103 struct ntp_msg ntpmsg = {
104 /*
105 * "The client initializes the NTP message header, sends the request
106 * to the server, and strips the time of day from the Transmit
107 * Timestamp field of the reply. For this purpose, all the NTP
108 * header fields are set to 0, except the Mode, VN, and optional
109 * Transmit Timestamp fields."
110 */
111 .field = NTP_FIELD(0, 4, NTP_MODE_CLIENT),
112 };
113 ssize_t len;
114 int r;
115
116 assert(m);
117 assert(m->current_server_name);
118 assert(m->current_server_address);
119
120 m->event_timeout = sd_event_source_unref(m->event_timeout);
121
122 r = manager_listen_setup(m);
123 if (r < 0)
124 return log_warning_errno(r, "Failed to set up connection socket: %m");
125
126 /*
127 * Set transmit timestamp, remember it; the server will send that back
128 * as the origin timestamp and we have an indication that this is the
129 * matching answer to our request.
130 *
131 * The actual value does not matter, We do not care about the correct
132 * NTP UINT_MAX fraction; we just pass the plain nanosecond value.
133 */
134 assert_se(clock_gettime(CLOCK_BOOTTIME, &m->trans_time_mon) >= 0);
135 assert_se(clock_gettime(CLOCK_REALTIME, &m->trans_time) >= 0);
136 ntpmsg.trans_time.sec = htobe32(graceful_add_offset_1900_1970(m->trans_time.tv_sec));
137 ntpmsg.trans_time.frac = htobe32(m->trans_time.tv_nsec);
138
139 server_address_pretty(m->current_server_address, &pretty);
140
141 len = sendto(m->server_socket, &ntpmsg, sizeof(ntpmsg), MSG_DONTWAIT, &m->current_server_address->sockaddr.sa, m->current_server_address->socklen);
142 if (len == sizeof(ntpmsg)) {
143 m->pending = true;
144 log_debug("Sent NTP request to %s (%s).", strna(pretty), m->current_server_name->string);
145 } else {
146 log_debug_errno(errno, "Sending NTP request to %s (%s) failed: %m", strna(pretty), m->current_server_name->string);
147 return manager_connect(m);
148 }
149
150 /* re-arm timer with increasing timeout, in case the packets never arrive back */
151 if (m->retry_interval == 0)
152 m->retry_interval = NTP_RETRY_INTERVAL_MIN_USEC;
153 else
154 m->retry_interval = MIN(m->retry_interval * 4/3, NTP_RETRY_INTERVAL_MAX_USEC);
155
156 r = manager_arm_timer(m, m->retry_interval);
157 if (r < 0)
158 return log_error_errno(r, "Failed to rearm timer: %m");
159
160 m->missed_replies++;
161 if (m->missed_replies > NTP_MAX_MISSED_REPLIES) {
162 r = sd_event_add_time(
163 m->event,
164 &m->event_timeout,
165 CLOCK_BOOTTIME,
166 now(CLOCK_BOOTTIME) + TIMEOUT_USEC, 0,
167 manager_timeout, m);
168 if (r < 0)
169 return log_error_errno(r, "Failed to arm timeout timer: %m");
170 }
171
172 return 0;
173 }
174
manager_timer(sd_event_source * source,usec_t usec,void * userdata)175 static int manager_timer(sd_event_source *source, usec_t usec, void *userdata) {
176 Manager *m = userdata;
177
178 assert(m);
179
180 return manager_send_request(m);
181 }
182
manager_arm_timer(Manager * m,usec_t next)183 static int manager_arm_timer(Manager *m, usec_t next) {
184 int r;
185
186 assert(m);
187
188 if (next == 0) {
189 m->event_timer = sd_event_source_unref(m->event_timer);
190 return 0;
191 }
192
193 if (m->event_timer) {
194 r = sd_event_source_set_time_relative(m->event_timer, next);
195 if (r < 0)
196 return r;
197
198 return sd_event_source_set_enabled(m->event_timer, SD_EVENT_ONESHOT);
199 }
200
201 return sd_event_add_time_relative(
202 m->event,
203 &m->event_timer,
204 CLOCK_BOOTTIME,
205 next, 0,
206 manager_timer, m);
207 }
208
manager_clock_watch(sd_event_source * source,int fd,uint32_t revents,void * userdata)209 static int manager_clock_watch(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
210 Manager *m = userdata;
211
212 assert(m);
213
214 /* rearm timer */
215 manager_clock_watch_setup(m);
216
217 /* skip our own jumps */
218 if (m->jumped) {
219 m->jumped = false;
220 return 0;
221 }
222
223 /* resync */
224 log_debug("System time changed. Resyncing.");
225 m->poll_resync = true;
226
227 return manager_send_request(m);
228 }
229
230 /* wake up when the system time changes underneath us */
manager_clock_watch_setup(Manager * m)231 static int manager_clock_watch_setup(Manager *m) {
232 int r;
233
234 assert(m);
235
236 m->event_clock_watch = sd_event_source_disable_unref(m->event_clock_watch);
237
238 r = event_add_time_change(m->event, &m->event_clock_watch, manager_clock_watch, m);
239 if (r < 0)
240 return log_error_errno(r, "Failed to create clock watch event source: %m");
241
242 return 0;
243 }
244
manager_adjust_clock(Manager * m,double offset,int leap_sec)245 static int manager_adjust_clock(Manager *m, double offset, int leap_sec) {
246 struct timex tmx;
247
248 assert(m);
249
250 /* For small deltas, tell the kernel to gradually adjust the system clock to the NTP time, larger
251 * deltas are just directly set. */
252 if (fabs(offset) < NTP_MAX_ADJUST) {
253 tmx = (struct timex) {
254 .modes = ADJ_STATUS | ADJ_NANO | ADJ_OFFSET | ADJ_TIMECONST | ADJ_MAXERROR | ADJ_ESTERROR,
255 .status = STA_PLL,
256 .offset = offset * NSEC_PER_SEC,
257 .constant = log2i(m->poll_interval_usec / USEC_PER_SEC) - 4,
258 };
259
260 log_debug(" adjust (slew): %+.3f sec", offset);
261 } else {
262 tmx = (struct timex) {
263 .modes = ADJ_STATUS | ADJ_NANO | ADJ_SETOFFSET | ADJ_MAXERROR | ADJ_ESTERROR,
264
265 /* ADJ_NANO uses nanoseconds in the microseconds field */
266 .time.tv_sec = (long)offset,
267 .time.tv_usec = (offset - (double) (long) offset) * NSEC_PER_SEC,
268 };
269
270 /* the kernel expects -0.3s as {-1, 7000.000.000} */
271 if (tmx.time.tv_usec < 0) {
272 tmx.time.tv_sec -= 1;
273 tmx.time.tv_usec += NSEC_PER_SEC;
274 }
275
276 m->jumped = true;
277 log_debug(" adjust (jump): %+.3f sec", offset);
278 }
279
280 /* An unset STA_UNSYNC will enable the kernel's 11-minute mode, which syncs the system time
281 * periodically to the RTC.
282 *
283 * In case the RTC runs in local time, never touch the RTC, we have no way to properly handle
284 * daylight saving changes and mobile devices moving between time zones. */
285 if (m->rtc_local_time)
286 tmx.status |= STA_UNSYNC;
287
288 switch (leap_sec) {
289 case 1:
290 tmx.status |= STA_INS;
291 break;
292 case -1:
293 tmx.status |= STA_DEL;
294 break;
295 }
296
297 if (clock_adjtime(CLOCK_REALTIME, &tmx) < 0)
298 return -errno;
299
300 m->drift_freq = tmx.freq;
301
302 log_debug(" status : %04i %s\n"
303 " time now : %"PRI_TIME".%03"PRI_USEC"\n"
304 " constant : %"PRI_TIMEX"\n"
305 " offset : %+.3f sec\n"
306 " freq offset : %+"PRI_TIMEX" (%+"PRI_TIMEX" ppm)\n",
307 tmx.status, tmx.status & STA_UNSYNC ? "unsync" : "sync",
308 tmx.time.tv_sec, tmx.time.tv_usec / NSEC_PER_MSEC,
309 tmx.constant,
310 (double)tmx.offset / NSEC_PER_SEC,
311 tmx.freq, tmx.freq / 65536);
312
313 return 0;
314 }
315
manager_sample_spike_detection(Manager * m,double offset,double delay)316 static bool manager_sample_spike_detection(Manager *m, double offset, double delay) {
317 unsigned i, idx_cur, idx_new, idx_min;
318 double jitter;
319 double j;
320
321 assert(m);
322
323 m->packet_count++;
324
325 /* ignore initial sample */
326 if (m->packet_count == 1)
327 return false;
328
329 /* store the current data in our samples array */
330 idx_cur = m->samples_idx;
331 idx_new = (idx_cur + 1) % ELEMENTSOF(m->samples);
332 m->samples_idx = idx_new;
333 m->samples[idx_new].offset = offset;
334 m->samples[idx_new].delay = delay;
335
336 /* calculate new jitter value from the RMS differences relative to the lowest delay sample */
337 jitter = m->samples_jitter;
338 for (idx_min = idx_cur, i = 0; i < ELEMENTSOF(m->samples); i++)
339 if (m->samples[i].delay > 0 && m->samples[i].delay < m->samples[idx_min].delay)
340 idx_min = i;
341
342 j = 0;
343 for (i = 0; i < ELEMENTSOF(m->samples); i++)
344 j += pow(m->samples[i].offset - m->samples[idx_min].offset, 2);
345 m->samples_jitter = sqrt(j / (ELEMENTSOF(m->samples) - 1));
346
347 /* ignore samples when resyncing */
348 if (m->poll_resync)
349 return false;
350
351 /* always accept offset if we are farther off than the round-trip delay */
352 if (fabs(offset) > delay)
353 return false;
354
355 /* we need a few samples before looking at them */
356 if (m->packet_count < 4)
357 return false;
358
359 /* do not accept anything worse than the maximum possible error of the best sample */
360 if (fabs(offset) > m->samples[idx_min].delay)
361 return true;
362
363 /* compare the difference between the current offset to the previous offset and jitter */
364 return fabs(offset - m->samples[idx_cur].offset) > 3 * jitter;
365 }
366
manager_adjust_poll(Manager * m,double offset,bool spike)367 static void manager_adjust_poll(Manager *m, double offset, bool spike) {
368 assert(m);
369
370 if (m->poll_resync) {
371 m->poll_interval_usec = m->poll_interval_min_usec;
372 m->poll_resync = false;
373 return;
374 }
375
376 /* set to minimal poll interval */
377 if (!spike && fabs(offset) > NTP_ACCURACY_SEC) {
378 m->poll_interval_usec = m->poll_interval_min_usec;
379 return;
380 }
381
382 /* increase polling interval */
383 if (fabs(offset) < NTP_ACCURACY_SEC * 0.25) {
384 if (m->poll_interval_usec < m->poll_interval_max_usec)
385 m->poll_interval_usec *= 2;
386 return;
387 }
388
389 /* decrease polling interval */
390 if (spike || fabs(offset) > NTP_ACCURACY_SEC * 0.75) {
391 if (m->poll_interval_usec > m->poll_interval_min_usec)
392 m->poll_interval_usec /= 2;
393 return;
394 }
395 }
396
manager_receive_response(sd_event_source * source,int fd,uint32_t revents,void * userdata)397 static int manager_receive_response(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
398 Manager *m = userdata;
399 struct ntp_msg ntpmsg;
400
401 struct iovec iov = {
402 .iov_base = &ntpmsg,
403 .iov_len = sizeof(ntpmsg),
404 };
405 /* This needs to be initialized with zero. See #20741. */
406 CMSG_BUFFER_TYPE(CMSG_SPACE_TIMESPEC) control = {};
407 union sockaddr_union server_addr;
408 struct msghdr msghdr = {
409 .msg_iov = &iov,
410 .msg_iovlen = 1,
411 .msg_control = &control,
412 .msg_controllen = sizeof(control),
413 .msg_name = &server_addr,
414 .msg_namelen = sizeof(server_addr),
415 };
416 struct timespec *recv_time = NULL;
417 triple_timestamp dts;
418 ssize_t len;
419 double origin, receive, trans, dest, delay, offset, root_distance;
420 bool spike;
421 int leap_sec, r;
422
423 assert(source);
424 assert(m);
425
426 if (revents & (EPOLLHUP|EPOLLERR)) {
427 log_warning("Server connection returned error.");
428 return manager_connect(m);
429 }
430
431 len = recvmsg_safe(fd, &msghdr, MSG_DONTWAIT);
432 if (len == -EAGAIN)
433 return 0;
434 if (len < 0) {
435 log_warning_errno(len, "Error receiving message, disconnecting: %m");
436 return manager_connect(m);
437 }
438
439 /* Too short or too long packet? */
440 if (iov.iov_len < sizeof(struct ntp_msg) || (msghdr.msg_flags & MSG_TRUNC)) {
441 log_warning("Invalid response from server. Disconnecting.");
442 return manager_connect(m);
443 }
444
445 if (!m->current_server_name ||
446 !m->current_server_address ||
447 !sockaddr_equal(&server_addr, &m->current_server_address->sockaddr)) {
448 log_debug("Response from unknown server.");
449 return 0;
450 }
451
452 recv_time = CMSG_FIND_DATA(&msghdr, SOL_SOCKET, SCM_TIMESTAMPNS, struct timespec);
453 if (!recv_time)
454 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Packet timestamp missing.");
455
456 if (!m->pending) {
457 log_debug("Unexpected reply. Ignoring.");
458 return 0;
459 }
460
461 m->missed_replies = 0;
462
463 /* check our "time cookie" (we just stored nanoseconds in the fraction field) */
464 if (be32toh(ntpmsg.origin_time.sec) != graceful_add_offset_1900_1970(m->trans_time.tv_sec) ||
465 be32toh(ntpmsg.origin_time.frac) != (unsigned long) m->trans_time.tv_nsec) {
466 log_debug("Invalid reply; not our transmit time. Ignoring.");
467 return 0;
468 }
469
470 m->event_timeout = sd_event_source_unref(m->event_timeout);
471
472 if (be32toh(ntpmsg.recv_time.sec) < TIME_EPOCH + OFFSET_1900_1970 ||
473 be32toh(ntpmsg.trans_time.sec) < TIME_EPOCH + OFFSET_1900_1970) {
474 log_debug("Invalid reply, returned times before epoch. Ignoring.");
475 return manager_connect(m);
476 }
477
478 if (NTP_FIELD_LEAP(ntpmsg.field) == NTP_LEAP_NOTINSYNC ||
479 ntpmsg.stratum == 0 || ntpmsg.stratum >= 16) {
480 log_debug("Server is not synchronized. Disconnecting.");
481 return manager_connect(m);
482 }
483
484 if (!IN_SET(NTP_FIELD_VERSION(ntpmsg.field), 3, 4)) {
485 log_debug("Response NTPv%d. Disconnecting.", NTP_FIELD_VERSION(ntpmsg.field));
486 return manager_connect(m);
487 }
488
489 if (NTP_FIELD_MODE(ntpmsg.field) != NTP_MODE_SERVER) {
490 log_debug("Unsupported mode %d. Disconnecting.", NTP_FIELD_MODE(ntpmsg.field));
491 return manager_connect(m);
492 }
493
494 root_distance = ntp_ts_short_to_d(&ntpmsg.root_delay) / 2 + ntp_ts_short_to_d(&ntpmsg.root_dispersion);
495 if (root_distance > (double) m->root_distance_max_usec / (double) USEC_PER_SEC) {
496 log_info("Server has too large root distance. Disconnecting.");
497 return manager_connect(m);
498 }
499
500 /* valid packet */
501 m->pending = false;
502 m->retry_interval = 0;
503
504 /* Stop listening */
505 manager_listen_stop(m);
506
507 /* announce leap seconds */
508 if (NTP_FIELD_LEAP(ntpmsg.field) & NTP_LEAP_PLUSSEC)
509 leap_sec = 1;
510 else if (NTP_FIELD_LEAP(ntpmsg.field) & NTP_LEAP_MINUSSEC)
511 leap_sec = -1;
512 else
513 leap_sec = 0;
514
515 /*
516 * "Timestamp Name ID When Generated
517 * ------------------------------------------------------------
518 * Originate Timestamp T1 time request sent by client
519 * Receive Timestamp T2 time request received by server
520 * Transmit Timestamp T3 time reply sent by server
521 * Destination Timestamp T4 time reply received by client
522 *
523 * The round-trip delay, d, and system clock offset, t, are defined as:
524 * d = (T4 - T1) - (T3 - T2) t = ((T2 - T1) + (T3 - T4)) / 2"
525 */
526 origin = ts_to_d(&m->trans_time) + OFFSET_1900_1970;
527 receive = ntp_ts_to_d(&ntpmsg.recv_time);
528 trans = ntp_ts_to_d(&ntpmsg.trans_time);
529 dest = ts_to_d(recv_time) + OFFSET_1900_1970;
530
531 offset = ((receive - origin) + (trans - dest)) / 2;
532 delay = (dest - origin) - (trans - receive);
533
534 spike = manager_sample_spike_detection(m, offset, delay);
535
536 manager_adjust_poll(m, offset, spike);
537
538 log_debug("NTP response:\n"
539 " leap : %u\n"
540 " version : %u\n"
541 " mode : %u\n"
542 " stratum : %u\n"
543 " precision : %.6f sec (%d)\n"
544 " root distance: %.6f sec\n"
545 " reference : %.4s\n"
546 " origin : %.3f\n"
547 " receive : %.3f\n"
548 " transmit : %.3f\n"
549 " dest : %.3f\n"
550 " offset : %+.3f sec\n"
551 " delay : %+.3f sec\n"
552 " packet count : %"PRIu64"\n"
553 " jitter : %.3f%s\n"
554 " poll interval: " USEC_FMT "\n",
555 NTP_FIELD_LEAP(ntpmsg.field),
556 NTP_FIELD_VERSION(ntpmsg.field),
557 NTP_FIELD_MODE(ntpmsg.field),
558 ntpmsg.stratum,
559 exp2(ntpmsg.precision), ntpmsg.precision,
560 root_distance,
561 ntpmsg.stratum == 1 ? ntpmsg.refid : "n/a",
562 origin - OFFSET_1900_1970,
563 receive - OFFSET_1900_1970,
564 trans - OFFSET_1900_1970,
565 dest - OFFSET_1900_1970,
566 offset, delay,
567 m->packet_count,
568 m->samples_jitter, spike ? " spike" : "",
569 m->poll_interval_usec / USEC_PER_SEC);
570
571 /* Get current monotonic/realtime clocks immediately before adjusting the latter */
572 triple_timestamp_get(&dts);
573
574 if (!spike) {
575 /* Fix up our idea of the time. */
576 dts.realtime = (usec_t) (dts.realtime + offset * USEC_PER_SEC);
577
578 r = manager_adjust_clock(m, offset, leap_sec);
579 if (r < 0)
580 log_error_errno(r, "Failed to call clock_adjtime(): %m");
581
582 (void) manager_save_time_and_rearm(m, dts.realtime);
583
584 /* If touch fails, there isn't much we can do. Maybe it'll work next time. */
585 r = touch("/run/systemd/timesync/synchronized");
586 if (r < 0)
587 log_debug_errno(r, "Failed to touch /run/systemd/timesync/synchronized, ignoring: %m");
588 }
589
590 /* Save NTP response */
591 m->ntpmsg = ntpmsg;
592 m->origin_time = m->trans_time;
593 m->dest_time = *recv_time;
594 m->spike = spike;
595
596 log_debug("interval/delta/delay/jitter/drift " USEC_FMT "s/%+.3fs/%.3fs/%.3fs/%+"PRIi64"ppm%s",
597 m->poll_interval_usec / USEC_PER_SEC, offset, delay, m->samples_jitter, m->drift_freq / 65536,
598 spike ? " (ignored)" : "");
599
600 if (sd_bus_is_ready(m->bus) > 0)
601 (void) sd_bus_emit_properties_changed(
602 m->bus,
603 "/org/freedesktop/timesync1",
604 "org.freedesktop.timesync1.Manager",
605 "NTPMessage",
606 NULL);
607
608 if (!m->talking) {
609 _cleanup_free_ char *pretty = NULL;
610
611 m->talking = true;
612
613 (void) server_address_pretty(m->current_server_address, &pretty);
614
615 log_info("Contacted time server %s (%s).", strna(pretty), m->current_server_name->string);
616 (void) sd_notifyf(false, "STATUS=Contacted time server %s (%s).", strna(pretty), m->current_server_name->string);
617 }
618
619 if (!spike && !m->synchronized) {
620 m->synchronized = true;
621
622 log_struct(LOG_INFO,
623 LOG_MESSAGE("Initial clock synchronization to %s.",
624 FORMAT_TIMESTAMP_STYLE(dts.realtime, TIMESTAMP_US)),
625 "MESSAGE_ID=" SD_MESSAGE_TIME_SYNC_STR,
626 "MONOTONIC_USEC=" USEC_FMT, dts.monotonic,
627 "REALTIME_USEC=" USEC_FMT, dts.realtime,
628 "BOOTIME_USEC=" USEC_FMT, dts.boottime);
629 }
630
631 r = manager_arm_timer(m, m->poll_interval_usec);
632 if (r < 0)
633 return log_error_errno(r, "Failed to rearm timer: %m");
634
635 return 0;
636 }
637
manager_listen_setup(Manager * m)638 static int manager_listen_setup(Manager *m) {
639 union sockaddr_union addr = {};
640 int r;
641
642 assert(m);
643
644 if (m->server_socket >= 0)
645 return 0;
646
647 assert(!m->event_receive);
648 assert(m->current_server_address);
649
650 addr.sa.sa_family = m->current_server_address->sockaddr.sa.sa_family;
651
652 m->server_socket = socket(addr.sa.sa_family, SOCK_DGRAM | SOCK_CLOEXEC, 0);
653 if (m->server_socket < 0)
654 return -errno;
655
656 r = bind(m->server_socket, &addr.sa, m->current_server_address->socklen);
657 if (r < 0)
658 return -errno;
659
660 r = setsockopt_int(m->server_socket, SOL_SOCKET, SO_TIMESTAMPNS, true);
661 if (r < 0)
662 return r;
663
664 if (addr.sa.sa_family == AF_INET)
665 (void) setsockopt_int(m->server_socket, IPPROTO_IP, IP_TOS, IPTOS_LOWDELAY);
666
667 return sd_event_add_io(m->event, &m->event_receive, m->server_socket, EPOLLIN, manager_receive_response, m);
668 }
669
manager_listen_stop(Manager * m)670 static void manager_listen_stop(Manager *m) {
671 assert(m);
672
673 m->event_receive = sd_event_source_unref(m->event_receive);
674 m->server_socket = safe_close(m->server_socket);
675 }
676
manager_begin(Manager * m)677 static int manager_begin(Manager *m) {
678 _cleanup_free_ char *pretty = NULL;
679 int r;
680
681 assert(m);
682 assert_return(m->current_server_name, -EHOSTUNREACH);
683 assert_return(m->current_server_address, -EHOSTUNREACH);
684
685 m->talking = false;
686 m->missed_replies = NTP_MAX_MISSED_REPLIES;
687 if (m->poll_interval_usec == 0)
688 m->poll_interval_usec = m->poll_interval_min_usec;
689
690 server_address_pretty(m->current_server_address, &pretty);
691 log_debug("Connecting to time server %s (%s).", strna(pretty), m->current_server_name->string);
692 (void) sd_notifyf(false, "STATUS=Connecting to time server %s (%s).", strna(pretty), m->current_server_name->string);
693
694 r = manager_clock_watch_setup(m);
695 if (r < 0)
696 return r;
697
698 return manager_send_request(m);
699 }
700
manager_set_server_name(Manager * m,ServerName * n)701 void manager_set_server_name(Manager *m, ServerName *n) {
702 assert(m);
703
704 if (m->current_server_name == n)
705 return;
706
707 m->current_server_name = n;
708 m->current_server_address = NULL;
709
710 manager_disconnect(m);
711
712 if (n)
713 log_debug("Selected server %s.", n->string);
714 }
715
manager_set_server_address(Manager * m,ServerAddress * a)716 void manager_set_server_address(Manager *m, ServerAddress *a) {
717 assert(m);
718
719 if (m->current_server_address == a)
720 return;
721
722 m->current_server_address = a;
723 /* If a is NULL, we are just clearing the address, without
724 * changing the name. Keep the existing name in that case. */
725 if (a)
726 m->current_server_name = a->name;
727
728 manager_disconnect(m);
729
730 if (a) {
731 _cleanup_free_ char *pretty = NULL;
732 server_address_pretty(a, &pretty);
733 log_debug("Selected address %s of server %s.", strna(pretty), a->name->string);
734 }
735 }
736
manager_resolve_handler(sd_resolve_query * q,int ret,const struct addrinfo * ai,Manager * m)737 static int manager_resolve_handler(sd_resolve_query *q, int ret, const struct addrinfo *ai, Manager *m) {
738 int r;
739
740 assert(q);
741 assert(m);
742 assert(m->current_server_name);
743
744 m->resolve_query = sd_resolve_query_unref(m->resolve_query);
745
746 if (ret != 0) {
747 log_debug("Failed to resolve %s: %s", m->current_server_name->string, gai_strerror(ret));
748
749 /* Try next host */
750 return manager_connect(m);
751 }
752
753 for (; ai; ai = ai->ai_next) {
754 _cleanup_free_ char *pretty = NULL;
755 ServerAddress *a;
756
757 assert(ai->ai_addr);
758 assert(ai->ai_addrlen >= offsetof(struct sockaddr, sa_data));
759
760 if (!IN_SET(ai->ai_addr->sa_family, AF_INET, AF_INET6)) {
761 log_warning("Unsuitable address protocol for %s", m->current_server_name->string);
762 continue;
763 }
764
765 r = server_address_new(m->current_server_name, &a, (const union sockaddr_union*) ai->ai_addr, ai->ai_addrlen);
766 if (r < 0)
767 return log_error_errno(r, "Failed to add server address: %m");
768
769 server_address_pretty(a, &pretty);
770 log_debug("Resolved address %s for %s.", pretty, m->current_server_name->string);
771 }
772
773 if (!m->current_server_name->addresses) {
774 log_error("Failed to find suitable address for host %s.", m->current_server_name->string);
775
776 /* Try next host */
777 return manager_connect(m);
778 }
779
780 manager_set_server_address(m, m->current_server_name->addresses);
781
782 return manager_begin(m);
783 }
784
manager_retry_connect(sd_event_source * source,usec_t usec,void * userdata)785 static int manager_retry_connect(sd_event_source *source, usec_t usec, void *userdata) {
786 Manager *m = userdata;
787
788 assert(m);
789
790 return manager_connect(m);
791 }
792
manager_connect(Manager * m)793 int manager_connect(Manager *m) {
794 int r;
795
796 assert(m);
797
798 manager_disconnect(m);
799
800 m->event_retry = sd_event_source_unref(m->event_retry);
801 if (!ratelimit_below(&m->ratelimit)) {
802 log_debug("Delaying attempts to contact servers.");
803
804 r = sd_event_add_time_relative(m->event, &m->event_retry, CLOCK_BOOTTIME, m->connection_retry_usec,
805 0, manager_retry_connect, m);
806 if (r < 0)
807 return log_error_errno(r, "Failed to create retry timer: %m");
808
809 return 0;
810 }
811
812 /* If we already are operating on some address, switch to the
813 * next one. */
814 if (m->current_server_address && m->current_server_address->addresses_next)
815 manager_set_server_address(m, m->current_server_address->addresses_next);
816 else {
817 static const struct addrinfo hints = {
818 .ai_flags = AI_NUMERICSERV|AI_ADDRCONFIG,
819 .ai_socktype = SOCK_DGRAM,
820 };
821
822 /* Hmm, we are through all addresses, let's look for the next host instead */
823 if (m->current_server_name && m->current_server_name->names_next)
824 manager_set_server_name(m, m->current_server_name->names_next);
825 else {
826 ServerName *f;
827 bool restart = true;
828
829 /* Our current server name list is exhausted,
830 * let's find the next one to iterate. First we try the runtime list, then the system list,
831 * then the link list. After having processed the link list we jump back to the system list
832 * if no runtime server list.
833 * However, if all lists are empty, we change to the fallback list. */
834 if (!m->current_server_name || m->current_server_name->type == SERVER_LINK) {
835 f = m->runtime_servers;
836 if (!f)
837 f = m->system_servers;
838 if (!f)
839 f = m->link_servers;
840 } else {
841 f = m->link_servers;
842 if (f)
843 restart = false;
844 else {
845 f = m->runtime_servers;
846 if (!f)
847 f = m->system_servers;
848 }
849 }
850
851 if (!f)
852 f = m->fallback_servers;
853
854 if (!f) {
855 manager_set_server_name(m, NULL);
856 log_debug("No server found.");
857 return 0;
858 }
859
860 if (restart && !m->exhausted_servers && m->poll_interval_usec > 0) {
861 log_debug("Waiting after exhausting servers.");
862 r = sd_event_add_time_relative(m->event, &m->event_retry, CLOCK_BOOTTIME, m->poll_interval_usec, 0, manager_retry_connect, m);
863 if (r < 0)
864 return log_error_errno(r, "Failed to create retry timer: %m");
865
866 m->exhausted_servers = true;
867
868 /* Increase the polling interval */
869 if (m->poll_interval_usec < m->poll_interval_max_usec)
870 m->poll_interval_usec *= 2;
871
872 return 0;
873 }
874
875 m->exhausted_servers = false;
876
877 manager_set_server_name(m, f);
878 }
879
880 /* Tell the resolver to reread /etc/resolv.conf, in
881 * case it changed. */
882 res_init();
883
884 /* Flush out any previously resolved addresses */
885 server_name_flush_addresses(m->current_server_name);
886
887 log_debug("Resolving %s...", m->current_server_name->string);
888
889 r = resolve_getaddrinfo(m->resolve, &m->resolve_query, m->current_server_name->string, "123", &hints, manager_resolve_handler, NULL, m);
890 if (r < 0)
891 return log_error_errno(r, "Failed to create resolver: %m");
892
893 return 1;
894 }
895
896 r = manager_begin(m);
897 if (r < 0)
898 return r;
899
900 return 1;
901 }
902
manager_disconnect(Manager * m)903 void manager_disconnect(Manager *m) {
904 assert(m);
905
906 m->resolve_query = sd_resolve_query_unref(m->resolve_query);
907
908 m->event_timer = sd_event_source_unref(m->event_timer);
909
910 manager_listen_stop(m);
911
912 m->event_clock_watch = sd_event_source_disable_unref(m->event_clock_watch);
913
914 m->event_timeout = sd_event_source_unref(m->event_timeout);
915
916 (void) sd_notify(false, "STATUS=Idle.");
917 }
918
manager_flush_server_names(Manager * m,ServerType t)919 void manager_flush_server_names(Manager *m, ServerType t) {
920 assert(m);
921
922 if (t == SERVER_SYSTEM)
923 while (m->system_servers)
924 server_name_free(m->system_servers);
925
926 if (t == SERVER_LINK)
927 while (m->link_servers)
928 server_name_free(m->link_servers);
929
930 if (t == SERVER_FALLBACK)
931 while (m->fallback_servers)
932 server_name_free(m->fallback_servers);
933
934 if (t == SERVER_RUNTIME)
935 manager_flush_runtime_servers(m);
936 }
937
manager_flush_runtime_servers(Manager * m)938 void manager_flush_runtime_servers(Manager *m) {
939 assert(m);
940
941 while (m->runtime_servers)
942 server_name_free(m->runtime_servers);
943 }
944
manager_free(Manager * m)945 Manager* manager_free(Manager *m) {
946 if (!m)
947 return NULL;
948
949 manager_disconnect(m);
950 manager_flush_server_names(m, SERVER_SYSTEM);
951 manager_flush_server_names(m, SERVER_LINK);
952 manager_flush_server_names(m, SERVER_RUNTIME);
953 manager_flush_server_names(m, SERVER_FALLBACK);
954
955 sd_event_source_unref(m->event_retry);
956
957 sd_event_source_unref(m->network_event_source);
958 sd_network_monitor_unref(m->network_monitor);
959
960 sd_event_source_unref(m->event_save_time);
961
962 sd_resolve_unref(m->resolve);
963 sd_event_unref(m->event);
964
965 sd_bus_flush_close_unref(m->bus);
966
967 bus_verify_polkit_async_registry_free(m->polkit_registry);
968
969 return mfree(m);
970 }
971
manager_network_read_link_servers(Manager * m)972 static int manager_network_read_link_servers(Manager *m) {
973 _cleanup_strv_free_ char **ntp = NULL;
974 bool changed = false;
975 int r;
976
977 assert(m);
978
979 r = sd_network_get_ntp(&ntp);
980 if (r < 0) {
981 if (r == -ENOMEM)
982 log_oom();
983 else
984 log_debug_errno(r, "Failed to get link NTP servers: %m");
985 goto clear;
986 }
987
988 LIST_FOREACH(names, n, m->link_servers)
989 n->marked = true;
990
991 STRV_FOREACH(i, ntp) {
992 bool found = false;
993
994 r = dns_name_is_valid_or_address(*i);
995 if (r < 0) {
996 log_error_errno(r, "Failed to check validity of NTP server name or address '%s': %m", *i);
997 goto clear;
998 } else if (r == 0) {
999 log_error("Invalid NTP server name or address, ignoring: %s", *i);
1000 continue;
1001 }
1002
1003 LIST_FOREACH(names, n, m->link_servers)
1004 if (streq(n->string, *i)) {
1005 n->marked = false;
1006 found = true;
1007 break;
1008 }
1009
1010 if (!found) {
1011 r = server_name_new(m, NULL, SERVER_LINK, *i);
1012 if (r < 0) {
1013 log_oom();
1014 goto clear;
1015 }
1016
1017 changed = true;
1018 }
1019 }
1020
1021 LIST_FOREACH(names, n, m->link_servers)
1022 if (n->marked) {
1023 server_name_free(n);
1024 changed = true;
1025 }
1026
1027 return changed;
1028
1029 clear:
1030 manager_flush_server_names(m, SERVER_LINK);
1031 return r;
1032 }
1033
manager_is_connected(Manager * m)1034 bool manager_is_connected(Manager *m) {
1035 assert(m);
1036
1037 /* Return true when the manager is sending a request, resolving a server name, or
1038 * in a poll interval. */
1039 return m->server_socket >= 0 || m->resolve_query || m->event_timer;
1040 }
1041
manager_network_event_handler(sd_event_source * s,int fd,uint32_t revents,void * userdata)1042 static int manager_network_event_handler(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
1043 Manager *m = userdata;
1044 bool changed, connected, online;
1045 int r;
1046
1047 assert(m);
1048
1049 sd_network_monitor_flush(m->network_monitor);
1050
1051 /* When manager_network_read_link_servers() failed, we assume that the servers are changed. */
1052 changed = manager_network_read_link_servers(m);
1053
1054 /* check if the machine is online */
1055 online = network_is_online();
1056
1057 /* check if the client is currently connected */
1058 connected = manager_is_connected(m);
1059
1060 if (connected && !online) {
1061 log_info("No network connectivity, watching for changes.");
1062 manager_disconnect(m);
1063
1064 } else if ((!connected || changed) && online) {
1065 log_info("Network configuration changed, trying to establish connection.");
1066
1067 if (m->current_server_address)
1068 r = manager_begin(m);
1069 else
1070 r = manager_connect(m);
1071 if (r < 0)
1072 return r;
1073 }
1074
1075 return 0;
1076 }
1077
manager_network_monitor_listen(Manager * m)1078 static int manager_network_monitor_listen(Manager *m) {
1079 int r, fd, events;
1080
1081 assert(m);
1082
1083 r = sd_network_monitor_new(&m->network_monitor, NULL);
1084 if (r == -ENOENT) {
1085 log_info("systemd does not appear to be running, not listening for systemd-networkd events.");
1086 return 0;
1087 }
1088 if (r < 0)
1089 return r;
1090
1091 fd = sd_network_monitor_get_fd(m->network_monitor);
1092 if (fd < 0)
1093 return fd;
1094
1095 events = sd_network_monitor_get_events(m->network_monitor);
1096 if (events < 0)
1097 return events;
1098
1099 r = sd_event_add_io(m->event, &m->network_event_source, fd, events, manager_network_event_handler, m);
1100 if (r < 0)
1101 return r;
1102
1103 return 0;
1104 }
1105
manager_new(Manager ** ret)1106 int manager_new(Manager **ret) {
1107 _cleanup_(manager_freep) Manager *m = NULL;
1108 int r;
1109
1110 assert(ret);
1111
1112 m = new(Manager, 1);
1113 if (!m)
1114 return -ENOMEM;
1115
1116 *m = (Manager) {
1117 .root_distance_max_usec = NTP_ROOT_DISTANCE_MAX_USEC,
1118 .poll_interval_min_usec = NTP_POLL_INTERVAL_MIN_USEC,
1119 .poll_interval_max_usec = NTP_POLL_INTERVAL_MAX_USEC,
1120
1121 .connection_retry_usec = DEFAULT_CONNECTION_RETRY_USEC,
1122
1123 .server_socket = -1,
1124
1125 .ratelimit = (RateLimit) {
1126 RATELIMIT_INTERVAL_USEC,
1127 RATELIMIT_BURST
1128 },
1129
1130 .save_time_interval_usec = DEFAULT_SAVE_TIME_INTERVAL_USEC,
1131 };
1132
1133 r = sd_event_default(&m->event);
1134 if (r < 0)
1135 return r;
1136
1137 (void) sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL);
1138 (void) sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL);
1139
1140 (void) sd_event_set_watchdog(m->event, true);
1141
1142 /* Load previous synchronization state */
1143 r = access("/run/systemd/timesync/synchronized", F_OK);
1144 if (r < 0 && errno != ENOENT)
1145 log_debug_errno(errno, "Failed to determine whether /run/systemd/timesync/synchronized exists, ignoring: %m");
1146 m->synchronized = r >= 0;
1147
1148 r = sd_resolve_default(&m->resolve);
1149 if (r < 0)
1150 return r;
1151
1152 r = sd_resolve_attach_event(m->resolve, m->event, 0);
1153 if (r < 0)
1154 return r;
1155
1156 r = manager_network_monitor_listen(m);
1157 if (r < 0)
1158 return r;
1159
1160 (void) manager_network_read_link_servers(m);
1161
1162 *ret = TAKE_PTR(m);
1163
1164 return 0;
1165 }
1166
manager_save_time_handler(sd_event_source * s,uint64_t usec,void * userdata)1167 static int manager_save_time_handler(sd_event_source *s, uint64_t usec, void *userdata) {
1168 Manager *m = userdata;
1169
1170 assert(m);
1171
1172 (void) manager_save_time_and_rearm(m, USEC_INFINITY);
1173 return 0;
1174 }
1175
manager_setup_save_time_event(Manager * m)1176 int manager_setup_save_time_event(Manager *m) {
1177 int r;
1178
1179 assert(m);
1180 assert(!m->event_save_time);
1181
1182 if (m->save_time_interval_usec == USEC_INFINITY)
1183 return 0;
1184
1185 /* NB: we'll accumulate scheduling latencies here, but this doesn't matter */
1186 r = sd_event_add_time_relative(
1187 m->event, &m->event_save_time,
1188 CLOCK_BOOTTIME,
1189 m->save_time_interval_usec,
1190 10 * USEC_PER_SEC,
1191 manager_save_time_handler, m);
1192 if (r < 0)
1193 return log_error_errno(r, "Failed to add save time event: %m");
1194
1195 (void) sd_event_source_set_description(m->event_save_time, "save-time");
1196
1197 return 0;
1198 }
1199
manager_save_time_and_rearm(Manager * m,usec_t t)1200 static int manager_save_time_and_rearm(Manager *m, usec_t t) {
1201 int r;
1202
1203 assert(m);
1204
1205 /* Updates the timestamp file to the specified time. If 't' is USEC_INFINITY uses the current system
1206 * clock, but otherwise uses the specified timestamp. Note that whenever we acquire an NTP sync the
1207 * specified timestamp value might be more accurate than the system clock, since the latter is
1208 * subject to slow adjustments. */
1209 r = touch_file(CLOCK_FILE, false, t, UID_INVALID, GID_INVALID, MODE_INVALID);
1210 if (r < 0)
1211 log_debug_errno(r, "Failed to update " CLOCK_FILE ", ignoring: %m");
1212
1213 m->save_on_exit = true;
1214
1215 if (m->save_time_interval_usec != USEC_INFINITY) {
1216 r = sd_event_source_set_time_relative(m->event_save_time, m->save_time_interval_usec);
1217 if (r < 0)
1218 return log_error_errno(r, "Failed to rearm save time event: %m");
1219
1220 r = sd_event_source_set_enabled(m->event_save_time, SD_EVENT_ONESHOT);
1221 if (r < 0)
1222 return log_error_errno(r, "Failed to enable save time event: %m");
1223 }
1224
1225 return 0;
1226 }
1227