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) {
log_error("Failed to add server address: %s", strerror(-r));
return r;
}
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);
}
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);
}
int main(int argc, char *argv[]) {
_cleanup_(manager_freep) Manager *m = NULL;
const char *user = "******";
uid_t uid;
gid_t gid;
int r;
log_set_target(LOG_TARGET_AUTO);
log_set_facility(LOG_CRON);
log_parse_environment();
log_open();
umask(0022);
if (argc != 1) {
log_error("This program does not take arguments.");
r = -EINVAL;
goto finish;
}
r = get_user_creds(&user, &uid, &gid, NULL, NULL);
if (r < 0) {
log_error_errno(r, "Cannot resolve user name %s: %m", user);
goto finish;
}
r = load_clock_timestamp(uid, gid);
if (r < 0)
goto finish;
r = drop_privileges(uid, gid, (1ULL << CAP_SYS_TIME));
if (r < 0)
goto finish;
/* We need one process for ourselves, plus one thread for the asynchronous resolver */
if (setrlimit(RLIMIT_NPROC, &RLIMIT_MAKE_CONST(2)) < 0)
log_warning_errno(errno, "Failed to lower RLIMIT_NPROC to 2: %m");
assert_se(sigprocmask_many(SIG_BLOCK, SIGTERM, SIGINT, -1) == 0);
r = manager_new(&m);
if (r < 0) {
log_error_errno(r, "Failed to allocate manager: %m");
goto finish;
}
if (clock_is_localtime() > 0) {
log_info("The system is configured to read the RTC time in the local time zone. "
"This mode can not be fully supported. All system time to RTC updates are disabled.");
m->rtc_local_time = true;
}
r = manager_parse_config_file(m);
if (r < 0)
log_warning_errno(r, "Failed to parse configuration file: %m");
log_debug("systemd-timesyncd running as pid %lu", (unsigned long) getpid());
sd_notify(false,
"READY=1\n"
"STATUS=Daemon is running");
if (network_is_online()) {
r = manager_connect(m);
if (r < 0)
goto finish;
}
r = sd_event_loop(m->event);
if (r < 0) {
log_error_errno(r, "Failed to run event loop: %m");
goto finish;
}
/* if we got an authoritative time, store it in the file system */
if (m->sync)
touch("/var/lib/systemd/clock");
sd_event_get_exit_code(m->event, &r);
finish:
sd_notify(false,
"STOPPING=1\n"
"STATUS=Shutting down...");
return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
}
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 now_ts;
struct timeval *recv_time;
ssize_t len;
double origin, receive, trans, dest;
double delay, offset;
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);
}
if (iov.iov_len < sizeof(struct ntp_msg)) {
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;
for (cmsg = CMSG_FIRSTHDR(&msghdr); cmsg; cmsg = CMSG_NXTHDR(&msghdr, cmsg)) {
if (cmsg->cmsg_level != SOL_SOCKET)
continue;
switch (cmsg->cmsg_type) {
case SCM_TIMESTAMP:
recv_time = (struct timeval *) CMSG_DATA(cmsg);
break;
}
}
if (!recv_time) {
log_error("Invalid packet timestamp.");
return -EINVAL;
}
if (!m->pending) {
log_debug("Unexpected reply. Ignoring.");
return 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) {
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);
}
/* valid packet */
m->pending = false;
m->retry_interval = 0;
/* 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"
*/
assert_se(clock_gettime(clock_boottime_or_monotonic(), &now_ts) >= 0);
origin = tv_to_d(recv_time) - (ts_to_d(&now_ts) - ts_to_d(&m->trans_time_mon)) + OFFSET_1900_1970;
receive = ntp_ts_to_d(&ntpmsg.recv_time);
trans = ntp_ts_to_d(&ntpmsg.trans_time);
dest = tv_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"
" 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,
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("Failed to call clock_adjtime(): %m");
}
log_info("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)" : "");
r = manager_arm_timer(m, m->poll_interval_usec);
if (r < 0) {
log_error("Failed to rearm timer: %s", strerror(-r));
return r;
}
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);
assert(m->server_socket < 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_TIMESTAMP, &on, sizeof(on));
if (r < 0)
return -errno;
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 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->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
server_address_pretty(m->current_server_address, &pretty);
log_info("Using NTP server %s (%s).", strna(pretty), m->current_server_name->string);
sd_notifyf(false, "STATUS=Using Time Server %s (%s).", strna(pretty), m->current_server_name->string);
r = manager_listen_setup(m);
if (r < 0) {
log_warning("Failed to setup connection socket: %s", strerror(-r));
return r;
}
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);
}
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);
/*
* 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("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) {
log_error("Failed to rearm timer: %s", strerror(-r));
return r;
}
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) {
log_error("Failed to arm timeout timer: %s", strerror(-r));
return r;
}
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);
}
