/***
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_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;
/* 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.%03llu\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, (unsigned long long) (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;
}