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Systemd/src/timesync/timesyncd-manager.c
akochetkov 5f36e3d303 timesyncd: clear ADJ_MAXERROR to keep STA_UNSYNC cleared after jump adjust (#4626) 
NTP use jump adjust if system has incorrect time read from RTC during boot.
It is desireble to update RTC time as soon as NTP set correct system time.
Sometimes kernel failed to update RTC due to STA_UNSYNC get set before RTC
update finised. In that case RTC time wouldn't be updated within long time.
The commit makes RTC updates stable.

When NTP do jump time adjust using ADJ_SETOFFSET it clears STA_UNSYNC flag.
If don't clear ADJ_MAXERROR, STA_UNSYNC will be set again by kernel within
1 second (by second_overflow() function). STA_UNSYNC flag prevent RTC updates
in kernel. Sometimes the kernel is able to update RTC withing 1 second,
but sometimes it falied.
2016-11-11 18:50:46 +01:00

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/***
This file is part of systemd.
Copyright 2014 Kay Sievers, Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <errno.h>
#include <math.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <resolv.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <sys/timerfd.h>
#include <sys/timex.h>
#include <sys/types.h>
#include <time.h>
#include "sd-daemon.h"
#include "alloc-util.h"
#include "fd-util.h"
#include "fs-util.h"
#include "list.h"
#include "log.h"
#include "missing.h"
#include "network-util.h"
#include "ratelimit.h"
#include "socket-util.h"
#include "sparse-endian.h"
#include "string-util.h"
#include "strv.h"
#include "time-util.h"
#include "timesyncd-conf.h"
#include "timesyncd-manager.h"
#include "util.h"
#ifndef ADJ_SETOFFSET
#define ADJ_SETOFFSET 0x0100 /* add 'time' to current time */
#endif
/* expected accuracy of time synchronization; used to adjust the poll interval */
#define NTP_ACCURACY_SEC 0.2
/*
* "A client MUST NOT under any conditions use a poll interval less
* than 15 seconds."
*/
#define NTP_POLL_INTERVAL_MIN_SEC 32
#define NTP_POLL_INTERVAL_MAX_SEC 2048
/*
* Maximum delta in seconds which the system clock is gradually adjusted
* (slew) to approach the network time. Deltas larger that this are set by
* letting the system time jump. The kernel's limit for adjtime is 0.5s.
*/
#define NTP_MAX_ADJUST 0.4
/* NTP protocol, packet header */
#define NTP_LEAP_PLUSSEC 1
#define NTP_LEAP_MINUSSEC 2
#define NTP_LEAP_NOTINSYNC 3
#define NTP_MODE_CLIENT 3
#define NTP_MODE_SERVER 4
#define NTP_FIELD_LEAP(f) (((f) >> 6) & 3)
#define NTP_FIELD_VERSION(f) (((f) >> 3) & 7)
#define NTP_FIELD_MODE(f) ((f) & 7)
#define NTP_FIELD(l, v, m) (((l) << 6) | ((v) << 3) | (m))
/* Maximum acceptable root distance in seconds. */
#define NTP_MAX_ROOT_DISTANCE 5.0
/* Maximum number of missed replies before selecting another source. */
#define NTP_MAX_MISSED_REPLIES 2
/*
* "NTP timestamps are represented as a 64-bit unsigned fixed-point number,
* in seconds relative to 0h on 1 January 1900."
*/
#define OFFSET_1900_1970 UINT64_C(2208988800)
#define RETRY_USEC (30*USEC_PER_SEC)
#define RATELIMIT_INTERVAL_USEC (10*USEC_PER_SEC)
#define RATELIMIT_BURST 10
#define TIMEOUT_USEC (10*USEC_PER_SEC)
struct ntp_ts {
be32_t sec;
be32_t frac;
} _packed_;
struct ntp_ts_short {
be16_t sec;
be16_t frac;
} _packed_;
struct ntp_msg {
uint8_t field;
uint8_t stratum;
int8_t poll;
int8_t precision;
struct ntp_ts_short root_delay;
struct ntp_ts_short root_dispersion;
char refid[4];
struct ntp_ts reference_time;
struct ntp_ts origin_time;
struct ntp_ts recv_time;
struct ntp_ts trans_time;
} _packed_;
static int manager_arm_timer(Manager *m, usec_t next);
static int manager_clock_watch_setup(Manager *m);
static int manager_listen_setup(Manager *m);
static void manager_listen_stop(Manager *m);
static double ntp_ts_short_to_d(const struct ntp_ts_short *ts) {
return be16toh(ts->sec) + (be16toh(ts->frac) / 65536.0);
}
static double ntp_ts_to_d(const struct ntp_ts *ts) {
return be32toh(ts->sec) + ((double)be32toh(ts->frac) / UINT_MAX);
}
static double ts_to_d(const struct timespec *ts) {
return ts->tv_sec + (1.0e-9 * ts->tv_nsec);
}
static int manager_timeout(sd_event_source *source, usec_t usec, void *userdata) {
_cleanup_free_ char *pretty = NULL;
Manager *m = userdata;
assert(m);
assert(m->current_server_name);
assert(m->current_server_address);
server_address_pretty(m->current_server_address, &pretty);
log_info("Timed out waiting for reply from %s (%s).", strna(pretty), m->current_server_name->string);
return manager_connect(m);
}
static int manager_send_request(Manager *m) {
_cleanup_free_ char *pretty = NULL;
struct ntp_msg ntpmsg = {
/*
* "The client initializes the NTP message header, sends the request
* to the server, and strips the time of day from the Transmit
* Timestamp field of the reply. For this purpose, all the NTP
* header fields are set to 0, except the Mode, VN, and optional
* Transmit Timestamp fields."
*/
.field = NTP_FIELD(0, 4, NTP_MODE_CLIENT),
};
ssize_t len;
int r;
assert(m);
assert(m->current_server_name);
assert(m->current_server_address);
m->event_timeout = sd_event_source_unref(m->event_timeout);
r = manager_listen_setup(m);
if (r < 0)
return log_warning_errno(r, "Failed to setup connection socket: %m");
/*
* Set transmit timestamp, remember it; the server will send that back
* as the origin timestamp and we have an indication that this is the
* matching answer to our request.
*
* The actual value does not matter, We do not care about the correct
* NTP UINT_MAX fraction; we just pass the plain nanosecond value.
*/
assert_se(clock_gettime(clock_boottime_or_monotonic(), &m->trans_time_mon) >= 0);
assert_se(clock_gettime(CLOCK_REALTIME, &m->trans_time) >= 0);
ntpmsg.trans_time.sec = htobe32(m->trans_time.tv_sec + OFFSET_1900_1970);
ntpmsg.trans_time.frac = htobe32(m->trans_time.tv_nsec);
server_address_pretty(m->current_server_address, &pretty);
len = sendto(m->server_socket, &ntpmsg, sizeof(ntpmsg), MSG_DONTWAIT, &m->current_server_address->sockaddr.sa, m->current_server_address->socklen);
if (len == sizeof(ntpmsg)) {
m->pending = true;
log_debug("Sent NTP request to %s (%s).", strna(pretty), m->current_server_name->string);
} else {
log_debug_errno(errno, "Sending NTP request to %s (%s) failed: %m", strna(pretty), m->current_server_name->string);
return manager_connect(m);
}
/* re-arm timer with increasing timeout, in case the packets never arrive back */
if (m->retry_interval > 0) {
if (m->retry_interval < NTP_POLL_INTERVAL_MAX_SEC * USEC_PER_SEC)
m->retry_interval *= 2;
} else
m->retry_interval = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
r = manager_arm_timer(m, m->retry_interval);
if (r < 0)
return log_error_errno(r, "Failed to rearm timer: %m");
m->missed_replies++;
if (m->missed_replies > NTP_MAX_MISSED_REPLIES) {
r = sd_event_add_time(
m->event,
&m->event_timeout,
clock_boottime_or_monotonic(),
now(clock_boottime_or_monotonic()) + TIMEOUT_USEC, 0,
manager_timeout, m);
if (r < 0)
return log_error_errno(r, "Failed to arm timeout timer: %m");
}
return 0;
}
static int manager_timer(sd_event_source *source, usec_t usec, void *userdata) {
Manager *m = userdata;
assert(m);
return manager_send_request(m);
}
static int manager_arm_timer(Manager *m, usec_t next) {
int r;
assert(m);
if (next == 0) {
m->event_timer = sd_event_source_unref(m->event_timer);
return 0;
}
if (m->event_timer) {
r = sd_event_source_set_time(m->event_timer, now(clock_boottime_or_monotonic()) + next);
if (r < 0)
return r;
return sd_event_source_set_enabled(m->event_timer, SD_EVENT_ONESHOT);
}
return sd_event_add_time(
m->event,
&m->event_timer,
clock_boottime_or_monotonic(),
now(clock_boottime_or_monotonic()) + next, 0,
manager_timer, m);
}
static int manager_clock_watch(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
Manager *m = userdata;
assert(m);
/* rearm timer */
manager_clock_watch_setup(m);
/* skip our own jumps */
if (m->jumped) {
m->jumped = false;
return 0;
}
/* resync */
log_debug("System time changed. Resyncing.");
m->poll_resync = true;
return manager_send_request(m);
}
/* wake up when the system time changes underneath us */
static int manager_clock_watch_setup(Manager *m) {
struct itimerspec its = {
.it_value.tv_sec = TIME_T_MAX
};
int r;
assert(m);
m->event_clock_watch = sd_event_source_unref(m->event_clock_watch);
safe_close(m->clock_watch_fd);
m->clock_watch_fd = timerfd_create(CLOCK_REALTIME, TFD_NONBLOCK|TFD_CLOEXEC);
if (m->clock_watch_fd < 0)
return log_error_errno(errno, "Failed to create timerfd: %m");
if (timerfd_settime(m->clock_watch_fd, TFD_TIMER_ABSTIME|TFD_TIMER_CANCEL_ON_SET, &its, NULL) < 0)
return log_error_errno(errno, "Failed to set up timerfd: %m");
r = sd_event_add_io(m->event, &m->event_clock_watch, m->clock_watch_fd, EPOLLIN, manager_clock_watch, m);
if (r < 0)
return log_error_errno(r, "Failed to create clock watch event source: %m");
return 0;
}
static int manager_adjust_clock(Manager *m, double offset, int leap_sec) {
struct timex tmx = {};
int r;
assert(m);
/*
* For small deltas, tell the kernel to gradually adjust the system
* clock to the NTP time, larger deltas are just directly set.
*/
if (fabs(offset) < NTP_MAX_ADJUST) {
tmx.modes = ADJ_STATUS | ADJ_NANO | ADJ_OFFSET | ADJ_TIMECONST | ADJ_MAXERROR | ADJ_ESTERROR;
tmx.status = STA_PLL;
tmx.offset = offset * NSEC_PER_SEC;
tmx.constant = log2i(m->poll_interval_usec / USEC_PER_SEC) - 4;
tmx.maxerror = 0;
tmx.esterror = 0;
log_debug(" adjust (slew): %+.3f sec", offset);
} else {
tmx.modes = ADJ_STATUS | ADJ_NANO | ADJ_SETOFFSET | ADJ_MAXERROR | ADJ_ESTERROR;
/* ADJ_NANO uses nanoseconds in the microseconds field */
tmx.time.tv_sec = (long)offset;
tmx.time.tv_usec = (offset - tmx.time.tv_sec) * NSEC_PER_SEC;
tmx.maxerror = 0;
tmx.esterror = 0;
/* the kernel expects -0.3s as {-1, 7000.000.000} */
if (tmx.time.tv_usec < 0) {
tmx.time.tv_sec -= 1;
tmx.time.tv_usec += NSEC_PER_SEC;
}
m->jumped = true;
log_debug(" adjust (jump): %+.3f sec", offset);
}
/*
* An unset STA_UNSYNC will enable the kernel's 11-minute mode,
* which syncs the system time periodically to the RTC.
*
* In case the RTC runs in local time, never touch the RTC,
* we have no way to properly handle daylight saving changes and
* mobile devices moving between time zones.
*/
if (m->rtc_local_time)
tmx.status |= STA_UNSYNC;
switch (leap_sec) {
case 1:
tmx.status |= STA_INS;
break;
case -1:
tmx.status |= STA_DEL;
break;
}
r = clock_adjtime(CLOCK_REALTIME, &tmx);
if (r < 0)
return -errno;
/* If touch fails, there isn't much we can do. Maybe it'll work next time. */
(void) touch("/var/lib/systemd/clock");
m->drift_ppm = tmx.freq / 65536;
log_debug(" status : %04i %s\n"
" time now : %li.%03"PRI_USEC"\n"
" constant : %li\n"
" offset : %+.3f sec\n"
" freq offset : %+li (%i ppm)\n",
tmx.status, tmx.status & STA_UNSYNC ? "unsync" : "sync",
tmx.time.tv_sec, tmx.time.tv_usec / NSEC_PER_MSEC,
tmx.constant,
(double)tmx.offset / NSEC_PER_SEC,
tmx.freq, m->drift_ppm);
return 0;
}
static bool manager_sample_spike_detection(Manager *m, double offset, double delay) {
unsigned int i, idx_cur, idx_new, idx_min;
double jitter;
double j;
assert(m);
m->packet_count++;
/* ignore initial sample */
if (m->packet_count == 1)
return false;
/* store the current data in our samples array */
idx_cur = m->samples_idx;
idx_new = (idx_cur + 1) % ELEMENTSOF(m->samples);
m->samples_idx = idx_new;
m->samples[idx_new].offset = offset;
m->samples[idx_new].delay = delay;
/* calculate new jitter value from the RMS differences relative to the lowest delay sample */
jitter = m->samples_jitter;
for (idx_min = idx_cur, i = 0; i < ELEMENTSOF(m->samples); i++)
if (m->samples[i].delay > 0 && m->samples[i].delay < m->samples[idx_min].delay)
idx_min = i;
j = 0;
for (i = 0; i < ELEMENTSOF(m->samples); i++)
j += pow(m->samples[i].offset - m->samples[idx_min].offset, 2);
m->samples_jitter = sqrt(j / (ELEMENTSOF(m->samples) - 1));
/* ignore samples when resyncing */
if (m->poll_resync)
return false;
/* always accept offset if we are farther off than the round-trip delay */
if (fabs(offset) > delay)
return false;
/* we need a few samples before looking at them */
if (m->packet_count < 4)
return false;
/* do not accept anything worse than the maximum possible error of the best sample */
if (fabs(offset) > m->samples[idx_min].delay)
return true;
/* compare the difference between the current offset to the previous offset and jitter */
return fabs(offset - m->samples[idx_cur].offset) > 3 * jitter;
}
static void manager_adjust_poll(Manager *m, double offset, bool spike) {
assert(m);
if (m->poll_resync) {
m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
m->poll_resync = false;
return;
}
/* set to minimal poll interval */
if (!spike && fabs(offset) > NTP_ACCURACY_SEC) {
m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
return;
}
/* increase polling interval */
if (fabs(offset) < NTP_ACCURACY_SEC * 0.25) {
if (m->poll_interval_usec < NTP_POLL_INTERVAL_MAX_SEC * USEC_PER_SEC)
m->poll_interval_usec *= 2;
return;
}
/* decrease polling interval */
if (spike || fabs(offset) > NTP_ACCURACY_SEC * 0.75) {
if (m->poll_interval_usec > NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC)
m->poll_interval_usec /= 2;
return;
}
}
static int manager_receive_response(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
Manager *m = userdata;
struct ntp_msg ntpmsg;
struct iovec iov = {
.iov_base = &ntpmsg,
.iov_len = sizeof(ntpmsg),
};
union {
struct cmsghdr cmsghdr;
uint8_t buf[CMSG_SPACE(sizeof(struct timeval))];
} control;
union sockaddr_union server_addr;
struct msghdr msghdr = {
.msg_iov = &iov,
.msg_iovlen = 1,
.msg_control = &control,
.msg_controllen = sizeof(control),
.msg_name = &server_addr,
.msg_namelen = sizeof(server_addr),
};
struct cmsghdr *cmsg;
struct timespec *recv_time;
ssize_t len;
double origin, receive, trans, dest;
double delay, offset;
double root_distance;
bool spike;
int leap_sec;
int r;
assert(source);
assert(m);
if (revents & (EPOLLHUP|EPOLLERR)) {
log_warning("Server connection returned error.");
return manager_connect(m);
}
len = recvmsg(fd, &msghdr, MSG_DONTWAIT);
if (len < 0) {
if (errno == EAGAIN)
return 0;
log_warning("Error receiving message. Disconnecting.");
return manager_connect(m);
}
/* Too short or too long packet? */
if (iov.iov_len < sizeof(struct ntp_msg) || (msghdr.msg_flags & MSG_TRUNC)) {
log_warning("Invalid response from server. Disconnecting.");
return manager_connect(m);
}
if (!m->current_server_name ||
!m->current_server_address ||
!sockaddr_equal(&server_addr, &m->current_server_address->sockaddr)) {
log_debug("Response from unknown server.");
return 0;
}
recv_time = NULL;
CMSG_FOREACH(cmsg, &msghdr) {
if (cmsg->cmsg_level != SOL_SOCKET)
continue;
switch (cmsg->cmsg_type) {
case SCM_TIMESTAMPNS:
recv_time = (struct timespec *) CMSG_DATA(cmsg);
break;
}
}
if (!recv_time) {
log_error("Invalid packet timestamp.");
return -EINVAL;
}
if (!m->pending) {
log_debug("Unexpected reply. Ignoring.");
return 0;
}
m->missed_replies = 0;
/* check our "time cookie" (we just stored nanoseconds in the fraction field) */
if (be32toh(ntpmsg.origin_time.sec) != m->trans_time.tv_sec + OFFSET_1900_1970 ||
be32toh(ntpmsg.origin_time.frac) != m->trans_time.tv_nsec) {
log_debug("Invalid reply; not our transmit time. Ignoring.");
return 0;
}
m->event_timeout = sd_event_source_unref(m->event_timeout);
if (be32toh(ntpmsg.recv_time.sec) < TIME_EPOCH + OFFSET_1900_1970 ||
be32toh(ntpmsg.trans_time.sec) < TIME_EPOCH + OFFSET_1900_1970) {
log_debug("Invalid reply, returned times before epoch. Ignoring.");
return manager_connect(m);
}
if (NTP_FIELD_LEAP(ntpmsg.field) == NTP_LEAP_NOTINSYNC ||
ntpmsg.stratum == 0 || ntpmsg.stratum >= 16) {
log_debug("Server is not synchronized. Disconnecting.");
return manager_connect(m);
}
if (!IN_SET(NTP_FIELD_VERSION(ntpmsg.field), 3, 4)) {
log_debug("Response NTPv%d. Disconnecting.", NTP_FIELD_VERSION(ntpmsg.field));
return manager_connect(m);
}
if (NTP_FIELD_MODE(ntpmsg.field) != NTP_MODE_SERVER) {
log_debug("Unsupported mode %d. Disconnecting.", NTP_FIELD_MODE(ntpmsg.field));
return manager_connect(m);
}
root_distance = ntp_ts_short_to_d(&ntpmsg.root_delay) / 2 + ntp_ts_short_to_d(&ntpmsg.root_dispersion);
if (root_distance > NTP_MAX_ROOT_DISTANCE) {
log_debug("Server has too large root distance. Disconnecting.");
return manager_connect(m);
}
/* valid packet */
m->pending = false;
m->retry_interval = 0;
/* Stop listening */
manager_listen_stop(m);
/* announce leap seconds */
if (NTP_FIELD_LEAP(ntpmsg.field) & NTP_LEAP_PLUSSEC)
leap_sec = 1;
else if (NTP_FIELD_LEAP(ntpmsg.field) & NTP_LEAP_MINUSSEC)
leap_sec = -1;
else
leap_sec = 0;
/*
* "Timestamp Name ID When Generated
* ------------------------------------------------------------
* Originate Timestamp T1 time request sent by client
* Receive Timestamp T2 time request received by server
* Transmit Timestamp T3 time reply sent by server
* Destination Timestamp T4 time reply received by client
*
* The round-trip delay, d, and system clock offset, t, are defined as:
* d = (T4 - T1) - (T3 - T2) t = ((T2 - T1) + (T3 - T4)) / 2"
*/
origin = ts_to_d(&m->trans_time) + OFFSET_1900_1970;
receive = ntp_ts_to_d(&ntpmsg.recv_time);
trans = ntp_ts_to_d(&ntpmsg.trans_time);
dest = ts_to_d(recv_time) + OFFSET_1900_1970;
offset = ((receive - origin) + (trans - dest)) / 2;
delay = (dest - origin) - (trans - receive);
spike = manager_sample_spike_detection(m, offset, delay);
manager_adjust_poll(m, offset, spike);
log_debug("NTP response:\n"
" leap : %u\n"
" version : %u\n"
" mode : %u\n"
" stratum : %u\n"
" precision : %.6f sec (%d)\n"
" root distance: %.6f sec\n"
" reference : %.4s\n"
" origin : %.3f\n"
" receive : %.3f\n"
" transmit : %.3f\n"
" dest : %.3f\n"
" offset : %+.3f sec\n"
" delay : %+.3f sec\n"
" packet count : %"PRIu64"\n"
" jitter : %.3f%s\n"
" poll interval: " USEC_FMT "\n",
NTP_FIELD_LEAP(ntpmsg.field),
NTP_FIELD_VERSION(ntpmsg.field),
NTP_FIELD_MODE(ntpmsg.field),
ntpmsg.stratum,
exp2(ntpmsg.precision), ntpmsg.precision,
root_distance,
ntpmsg.stratum == 1 ? ntpmsg.refid : "n/a",
origin - OFFSET_1900_1970,
receive - OFFSET_1900_1970,
trans - OFFSET_1900_1970,
dest - OFFSET_1900_1970,
offset, delay,
m->packet_count,
m->samples_jitter, spike ? " spike" : "",
m->poll_interval_usec / USEC_PER_SEC);
if (!spike) {
m->sync = true;
r = manager_adjust_clock(m, offset, leap_sec);
if (r < 0)
log_error_errno(r, "Failed to call clock_adjtime(): %m");
}
log_debug("interval/delta/delay/jitter/drift " USEC_FMT "s/%+.3fs/%.3fs/%.3fs/%+ippm%s",
m->poll_interval_usec / USEC_PER_SEC, offset, delay, m->samples_jitter, m->drift_ppm,
spike ? " (ignored)" : "");
if (!m->good) {
_cleanup_free_ char *pretty = NULL;
m->good = true;
server_address_pretty(m->current_server_address, &pretty);
log_info("Synchronized to time server %s (%s).", strna(pretty), m->current_server_name->string);
sd_notifyf(false, "STATUS=Synchronized to time server %s (%s).", strna(pretty), m->current_server_name->string);
}
r = manager_arm_timer(m, m->poll_interval_usec);
if (r < 0)
return log_error_errno(r, "Failed to rearm timer: %m");
return 0;
}
static int manager_listen_setup(Manager *m) {
union sockaddr_union addr = {};
static const int tos = IPTOS_LOWDELAY;
static const int on = 1;
int r;
assert(m);
if (m->server_socket >= 0)
return 0;
assert(!m->event_receive);
assert(m->current_server_address);
addr.sa.sa_family = m->current_server_address->sockaddr.sa.sa_family;
m->server_socket = socket(addr.sa.sa_family, SOCK_DGRAM | SOCK_CLOEXEC, 0);
if (m->server_socket < 0)
return -errno;
r = bind(m->server_socket, &addr.sa, m->current_server_address->socklen);
if (r < 0)
return -errno;
r = setsockopt(m->server_socket, SOL_SOCKET, SO_TIMESTAMPNS, &on, sizeof(on));
if (r < 0)
return -errno;
(void) setsockopt(m->server_socket, IPPROTO_IP, IP_TOS, &tos, sizeof(tos));
return sd_event_add_io(m->event, &m->event_receive, m->server_socket, EPOLLIN, manager_receive_response, m);
}
static void manager_listen_stop(Manager *m) {
assert(m);
m->event_receive = sd_event_source_unref(m->event_receive);
m->server_socket = safe_close(m->server_socket);
}
static int manager_begin(Manager *m) {
_cleanup_free_ char *pretty = NULL;
int r;
assert(m);
assert_return(m->current_server_name, -EHOSTUNREACH);
assert_return(m->current_server_address, -EHOSTUNREACH);
m->good = false;
m->missed_replies = NTP_MAX_MISSED_REPLIES;
if (m->poll_interval_usec == 0)
m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
server_address_pretty(m->current_server_address, &pretty);
log_debug("Connecting to time server %s (%s).", strna(pretty), m->current_server_name->string);
sd_notifyf(false, "STATUS=Connecting to time server %s (%s).", strna(pretty), m->current_server_name->string);
r = manager_clock_watch_setup(m);
if (r < 0)
return r;
return manager_send_request(m);
}
void manager_set_server_name(Manager *m, ServerName *n) {
assert(m);
if (m->current_server_name == n)
return;
m->current_server_name = n;
m->current_server_address = NULL;
manager_disconnect(m);
if (n)
log_debug("Selected server %s.", n->string);
}
void manager_set_server_address(Manager *m, ServerAddress *a) {
assert(m);
if (m->current_server_address == a)
return;
m->current_server_address = a;
/* If a is NULL, we are just clearing the address, without
* changing the name. Keep the existing name in that case. */
if (a)
m->current_server_name = a->name;
manager_disconnect(m);
if (a) {
_cleanup_free_ char *pretty = NULL;
server_address_pretty(a, &pretty);
log_debug("Selected address %s of server %s.", strna(pretty), a->name->string);
}
}
static int manager_resolve_handler(sd_resolve_query *q, int ret, const struct addrinfo *ai, void *userdata) {
Manager *m = userdata;
int r;
assert(q);
assert(m);
assert(m->current_server_name);
m->resolve_query = sd_resolve_query_unref(m->resolve_query);
if (ret != 0) {
log_debug("Failed to resolve %s: %s", m->current_server_name->string, gai_strerror(ret));
/* Try next host */
return manager_connect(m);
}
for (; ai; ai = ai->ai_next) {
_cleanup_free_ char *pretty = NULL;
ServerAddress *a;
assert(ai->ai_addr);
assert(ai->ai_addrlen >= offsetof(struct sockaddr, sa_data));
if (!IN_SET(ai->ai_addr->sa_family, AF_INET, AF_INET6)) {
log_warning("Unsuitable address protocol for %s", m->current_server_name->string);
continue;
}
r = server_address_new(m->current_server_name, &a, (const union sockaddr_union*) ai->ai_addr, ai->ai_addrlen);
if (r < 0)
return log_error_errno(r, "Failed to add server address: %m");
server_address_pretty(a, &pretty);
log_debug("Resolved address %s for %s.", pretty, m->current_server_name->string);
}
if (!m->current_server_name->addresses) {
log_error("Failed to find suitable address for host %s.", m->current_server_name->string);
/* Try next host */
return manager_connect(m);
}
manager_set_server_address(m, m->current_server_name->addresses);
return manager_begin(m);
}
static int manager_retry_connect(sd_event_source *source, usec_t usec, void *userdata) {
Manager *m = userdata;
assert(m);
return manager_connect(m);
}
int manager_connect(Manager *m) {
int r;
assert(m);
manager_disconnect(m);
m->event_retry = sd_event_source_unref(m->event_retry);
if (!ratelimit_test(&m->ratelimit)) {
log_debug("Slowing down attempts to contact servers.");
r = sd_event_add_time(m->event, &m->event_retry, clock_boottime_or_monotonic(), now(clock_boottime_or_monotonic()) + RETRY_USEC, 0, manager_retry_connect, m);
if (r < 0)
return log_error_errno(r, "Failed to create retry timer: %m");
return 0;
}
/* If we already are operating on some address, switch to the
* next one. */
if (m->current_server_address && m->current_server_address->addresses_next)
manager_set_server_address(m, m->current_server_address->addresses_next);
else {
struct addrinfo hints = {
.ai_flags = AI_NUMERICSERV|AI_ADDRCONFIG,
.ai_socktype = SOCK_DGRAM,
};
/* Hmm, we are through all addresses, let's look for the next host instead */
if (m->current_server_name && m->current_server_name->names_next)
manager_set_server_name(m, m->current_server_name->names_next);
else {
ServerName *f;
bool restart = true;
/* Our current server name list is exhausted,
* let's find the next one to iterate. First
* we try the system list, then the link list.
* After having processed the link list we
* jump back to the system list. However, if
* both lists are empty, we change to the
* fallback list. */
if (!m->current_server_name || m->current_server_name->type == SERVER_LINK) {
f = m->system_servers;
if (!f)
f = m->link_servers;
} else {
f = m->link_servers;
if (!f)
f = m->system_servers;
else
restart = false;
}
if (!f)
f = m->fallback_servers;
if (!f) {
manager_set_server_name(m, NULL);
log_debug("No server found.");
return 0;
}
if (restart && !m->exhausted_servers && m->poll_interval_usec) {
log_debug("Waiting after exhausting servers.");
r = sd_event_add_time(m->event, &m->event_retry, clock_boottime_or_monotonic(), now(clock_boottime_or_monotonic()) + m->poll_interval_usec, 0, manager_retry_connect, m);
if (r < 0)
return log_error_errno(r, "Failed to create retry timer: %m");
m->exhausted_servers = true;
/* Increase the polling interval */
if (m->poll_interval_usec < NTP_POLL_INTERVAL_MAX_SEC * USEC_PER_SEC)
m->poll_interval_usec *= 2;
return 0;
}
m->exhausted_servers = false;
manager_set_server_name(m, f);
}
/* Tell the resolver to reread /etc/resolv.conf, in
* case it changed. */
res_init();
/* Flush out any previously resolved addresses */
server_name_flush_addresses(m->current_server_name);
log_debug("Resolving %s...", m->current_server_name->string);
r = sd_resolve_getaddrinfo(m->resolve, &m->resolve_query, m->current_server_name->string, "123", &hints, manager_resolve_handler, m);
if (r < 0)
return log_error_errno(r, "Failed to create resolver: %m");
return 1;
}
r = manager_begin(m);
if (r < 0)
return r;
return 1;
}
void manager_disconnect(Manager *m) {
assert(m);
m->resolve_query = sd_resolve_query_unref(m->resolve_query);
m->event_timer = sd_event_source_unref(m->event_timer);
manager_listen_stop(m);
m->event_clock_watch = sd_event_source_unref(m->event_clock_watch);
m->clock_watch_fd = safe_close(m->clock_watch_fd);
m->event_timeout = sd_event_source_unref(m->event_timeout);
sd_notifyf(false, "STATUS=Idle.");
}
void manager_flush_server_names(Manager *m, ServerType t) {
assert(m);
if (t == SERVER_SYSTEM)
while (m->system_servers)
server_name_free(m->system_servers);
if (t == SERVER_LINK)
while (m->link_servers)
server_name_free(m->link_servers);
if (t == SERVER_FALLBACK)
while (m->fallback_servers)
server_name_free(m->fallback_servers);
}
void manager_free(Manager *m) {
if (!m)
return;
manager_disconnect(m);
manager_flush_server_names(m, SERVER_SYSTEM);
manager_flush_server_names(m, SERVER_LINK);
manager_flush_server_names(m, SERVER_FALLBACK);
sd_event_source_unref(m->event_retry);
sd_event_source_unref(m->network_event_source);
sd_network_monitor_unref(m->network_monitor);
sd_resolve_unref(m->resolve);
sd_event_unref(m->event);
free(m);
}
static int manager_network_read_link_servers(Manager *m) {
_cleanup_strv_free_ char **ntp = NULL;
ServerName *n, *nx;
char **i;
int r;
assert(m);
r = sd_network_get_ntp(&ntp);
if (r < 0)
goto clear;
LIST_FOREACH(names, n, m->link_servers)
n->marked = true;
STRV_FOREACH(i, ntp) {
bool found = false;
LIST_FOREACH(names, n, m->link_servers)
if (streq(n->string, *i)) {
n->marked = false;
found = true;
break;
}
if (!found) {
r = server_name_new(m, NULL, SERVER_LINK, *i);
if (r < 0)
goto clear;
}
}
LIST_FOREACH_SAFE(names, n, nx, m->link_servers)
if (n->marked)
server_name_free(n);
return 0;
clear:
manager_flush_server_names(m, SERVER_LINK);
return r;
}
static int manager_network_event_handler(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
Manager *m = userdata;
bool connected, online;
int r;
assert(m);
sd_network_monitor_flush(m->network_monitor);
manager_network_read_link_servers(m);
/* check if the machine is online */
online = network_is_online();
/* check if the client is currently connected */
connected = m->server_socket >= 0 || m->resolve_query || m->exhausted_servers;
if (connected && !online) {
log_info("No network connectivity, watching for changes.");
manager_disconnect(m);
} else if (!connected && online) {
log_info("Network configuration changed, trying to establish connection.");
if (m->current_server_address)
r = manager_begin(m);
else
r = manager_connect(m);
if (r < 0)
return r;
}
return 0;
}
static int manager_network_monitor_listen(Manager *m) {
int r, fd, events;
assert(m);
r = sd_network_monitor_new(&m->network_monitor, NULL);
if (r < 0)
return r;
fd = sd_network_monitor_get_fd(m->network_monitor);
if (fd < 0)
return fd;
events = sd_network_monitor_get_events(m->network_monitor);
if (events < 0)
return events;
r = sd_event_add_io(m->event, &m->network_event_source, fd, events, manager_network_event_handler, m);
if (r < 0)
return r;
return 0;
}
int manager_new(Manager **ret) {
_cleanup_(manager_freep) Manager *m = NULL;
int r;
assert(ret);
m = new0(Manager, 1);
if (!m)
return -ENOMEM;
m->server_socket = m->clock_watch_fd = -1;
RATELIMIT_INIT(m->ratelimit, RATELIMIT_INTERVAL_USEC, RATELIMIT_BURST);
r = manager_parse_server_string(m, SERVER_FALLBACK, NTP_SERVERS);
if (r < 0)
return r;
r = sd_event_default(&m->event);
if (r < 0)
return r;
sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL);
sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL);
sd_event_set_watchdog(m->event, true);
r = sd_resolve_default(&m->resolve);
if (r < 0)
return r;
r = sd_resolve_attach_event(m->resolve, m->event, 0);
if (r < 0)
return r;
r = manager_network_monitor_listen(m);
if (r < 0)
return r;
manager_network_read_link_servers(m);
*ret = m;
m = NULL;
return 0;
}
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