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Systemd/src/timesync/timesyncd-manager.c
Lennart Poettering 3691bcf3c5 tree-wide: use recvmsg_safe() at various places 
Let's be extra careful whenever we return from recvmsg() and see
MSG_CTRUNC set. This generally means we ran into a programming error, as
we didn't size the control buffer large enough. It's an error condition
we should at least log about, or propagate up. Hence do that.

This is particularly important when receiving fds, since for those the
control data can be of any size. In particular on stream sockets that's
nasty, because if we miss an fd because of control data truncation we
cannot recover, we might not even realize that we are one off.

(Also, when failing early, if there's any chance the socket might be
AF_UNIX let's close all received fds, all the time. We got this right
most of the time, but there were a few cases missing. God, UNIX is hard
to use)
2020-04-23 09:41:47 +02:00

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/* SPDX-License-Identifier: LGPL-2.1+ */
#include <errno.h>
#include <math.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <resolv.h>
#include <stdlib.h>
#include <sys/timerfd.h>
#include <sys/timex.h>
#include <sys/types.h>
#include "sd-daemon.h"
#include "alloc-util.h"
#include "dns-domain.h"
#include "fd-util.h"
#include "format-util.h"
#include "fs-util.h"
#include "list.h"
#include "log.h"
#include "network-util.h"
#include "ratelimit.h"
#include "resolve-private.h"
#include "socket-util.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
/*
* Maximum delta in seconds which the system clock is gradually adjusted
* (slewed) 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
/* Default of maximum acceptable root distance in microseconds. */
#define NTP_MAX_ROOT_DISTANCE (5 * USEC_PER_SEC)
/* Maximum number of missed replies before selecting another source. */
#define NTP_MAX_MISSED_REPLIES 2
#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)
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 set up 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 < m->poll_interval_max_usec)
m->retry_interval *= 2;
} else
m->retry_interval = m->poll_interval_min_usec;
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) {
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 = time_change_fd();
if (m->clock_watch_fd < 0)
return log_error_errno(m->clock_watch_fd, "Failed to create 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/timesync/clock");
(void) touch("/run/systemd/timesync/synchronized");
m->drift_freq = tmx.freq;
log_debug(" status : %04i %s\n"
" time now : %"PRI_TIME".%03"PRI_USEC"\n"
" constant : %"PRI_TIMEX"\n"
" offset : %+.3f sec\n"
" freq offset : %+"PRI_TIMEX" (%+"PRI_TIMEX" 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, tmx.freq / 65536);
return 0;
}
static bool manager_sample_spike_detection(Manager *m, double offset, double delay) {
unsigned 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 = m->poll_interval_min_usec;
m->poll_resync = false;
return;
}
/* set to minimal poll interval */
if (!spike && fabs(offset) > NTP_ACCURACY_SEC) {
m->poll_interval_usec = m->poll_interval_min_usec;
return;
}
/* increase polling interval */
if (fabs(offset) < NTP_ACCURACY_SEC * 0.25) {
if (m->poll_interval_usec < m->poll_interval_max_usec)
m->poll_interval_usec *= 2;
return;
}
/* decrease polling interval */
if (spike || fabs(offset) > NTP_ACCURACY_SEC * 0.75) {
if (m->poll_interval_usec > m->poll_interval_min_usec)
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 = NULL;
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_safe(fd, &msghdr, MSG_DONTWAIT);
if (len == -EAGAIN)
return 0;
if (len < 0) {
log_warning_errno(len, "Error receiving message, disconnecting: %m");
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;
}
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)
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
"Invalid packet timestamp.");
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) != (unsigned long) 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 > (double) m->max_root_distance_usec / (double) USEC_PER_SEC) {
log_info("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");
}
/* Save NTP response */
m->ntpmsg = ntpmsg;
m->origin_time = m->trans_time;
m->dest_time = *recv_time;
m->spike = spike;
log_debug("interval/delta/delay/jitter/drift " USEC_FMT "s/%+.3fs/%.3fs/%.3fs/%+"PRIi64"ppm%s",
m->poll_interval_usec / USEC_PER_SEC, offset, delay, m->samples_jitter, m->drift_freq / 65536,
spike ? " (ignored)" : "");
(void) sd_bus_emit_properties_changed(m->bus, "/org/freedesktop/timesync1", "org.freedesktop.timesync1.Manager", "NTPMessage", NULL);
if (!m->good) {
_cleanup_free_ char *pretty = NULL;
m->good = true;
server_address_pretty(m->current_server_address, &pretty);
/* "Initial", as further successful syncs will not be logged. */
log_info("Initial synchronization to time server %s (%s).", strna(pretty), m->current_server_name->string);
sd_notifyf(false, "STATUS=Initial synchronization 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 = {};
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_int(m->server_socket, SOL_SOCKET, SO_TIMESTAMPNS, true);
if (r < 0)
return r;
(void) setsockopt_int(m->server_socket, IPPROTO_IP, IP_TOS, IPTOS_LOWDELAY);
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 = m->poll_interval_min_usec;
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, Manager *m) {
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_below(&m->ratelimit)) {
log_debug("Delaying 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 < m->poll_interval_max_usec)
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 = resolve_getaddrinfo(m->resolve, &m->resolve_query, m->current_server_name->string, "123", &hints, manager_resolve_handler, NULL, 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);
sd_bus_flush_close_unref(m->bus);
free(m);
}
static int manager_network_read_link_servers(Manager *m) {
_cleanup_strv_free_ char **ntp = NULL;
ServerName *n, *nx;
char **i;
bool changed = false;
int r;
assert(m);
r = sd_network_get_ntp(&ntp);
if (r < 0) {
if (r == -ENOMEM)
log_oom();
else
log_debug_errno(r, "Failed to get link NTP servers: %m");
goto clear;
}
LIST_FOREACH(names, n, m->link_servers)
n->marked = true;
STRV_FOREACH(i, ntp) {
bool found = false;
r = dns_name_is_valid_or_address(*i);
if (r < 0) {
log_error_errno(r, "Failed to check validity of NTP server name or address '%s': %m", *i);
goto clear;
} else if (r == 0) {
log_error("Invalid NTP server name or address, ignoring: %s", *i);
continue;
}
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) {
log_oom();
goto clear;
}
changed = true;
}
}
LIST_FOREACH_SAFE(names, n, nx, m->link_servers)
if (n->marked) {
server_name_free(n);
changed = true;
}
return changed;
clear:
manager_flush_server_names(m, SERVER_LINK);
return r;
}
static bool manager_is_connected(Manager *m) {
/* Return true when the manager is sending a request, resolving a server name, or
* in a poll interval. */
return m->server_socket >= 0 || m->resolve_query || m->event_timer;
}
static int manager_network_event_handler(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
Manager *m = userdata;
bool changed, connected, online;
int r;
assert(m);
sd_network_monitor_flush(m->network_monitor);
/* When manager_network_read_link_servers() failed, we assume that the servers are changed. */
changed = manager_network_read_link_servers(m);
/* check if the machine is online */
online = network_is_online();
/* check if the client is currently connected */
connected = manager_is_connected(m);
if (connected && !online) {
log_info("No network connectivity, watching for changes.");
manager_disconnect(m);
} else if ((!connected || changed) && 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 == -ENOENT) {
log_info("systemd does not appear to be running, not listening for systemd-networkd events.");
return 0;
}
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->max_root_distance_usec = NTP_MAX_ROOT_DISTANCE;
m->poll_interval_min_usec = NTP_POLL_INTERVAL_MIN_USEC;
m->poll_interval_max_usec = NTP_POLL_INTERVAL_MAX_USEC;
m->server_socket = m->clock_watch_fd = -1;
m->ratelimit = (RateLimit) { RATELIMIT_INTERVAL_USEC, RATELIMIT_BURST };
r = sd_event_default(&m->event);
if (r < 0)
return r;
(void) sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL);
(void) sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL);
(void) 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;
(void) manager_network_read_link_servers(m);
*ret = TAKE_PTR(m);
return 0;
}
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