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openntpd-openbsd
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Source code pulled from OpenBSD for OpenNTPD. The place to contribute to this code is via the OpenBSD CVS tree.
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openntpd-openbsd/src/usr.sbin/ntpd/ntp.c

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/* $OpenBSD: ntp.c,v 1.145 2017/01/20 01:21:18 phessler Exp $ */
/*
* Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
* Copyright (c) 2004 Alexander Guy <alexander.guy@andern.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <poll.h>
#include <pwd.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <time.h>
#include <unistd.h>
#include <err.h>
#include "ntpd.h"
#define PFD_PIPE_MAIN 0
#define PFD_PIPE_DNS 1
#define PFD_SOCK_CTL 2
#define PFD_MAX 3
volatile sig_atomic_t ntp_quit = 0;
struct imsgbuf *ibuf_main;
struct imsgbuf *ibuf_dns;
struct ntpd_conf *conf;
struct ctl_conns ctl_conns;
u_int peer_cnt;
u_int sensors_cnt;
extern u_int constraint_cnt;
void ntp_sighdlr(int);
int ntp_dispatch_imsg(void);
int ntp_dispatch_imsg_dns(void);
void peer_add(struct ntp_peer *);
void peer_remove(struct ntp_peer *);
void
ntp_sighdlr(int sig)
{
switch (sig) {
case SIGINT:
case SIGTERM:
ntp_quit = 1;
break;
}
}
void
ntp_main(struct ntpd_conf *nconf, struct passwd *pw, int argc, char **argv)
{
int a, b, nfds, i, j, idx_peers, timeout;
int nullfd, pipe_dns[2], idx_clients;
int ctls;
int fd_ctl;
u_int pfd_elms = 0, idx2peer_elms = 0;
u_int listener_cnt, new_cnt, sent_cnt, trial_cnt;
u_int ctl_cnt;
struct pollfd *pfd = NULL;
struct servent *se;
struct listen_addr *la;
struct ntp_peer *p;
struct ntp_peer **idx2peer = NULL;
struct ntp_sensor *s, *next_s;
struct constraint *cstr;
struct timespec tp;
struct stat stb;
struct ctl_conn *cc;
time_t nextaction, last_sensor_scan = 0, now;
void *newp;
if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, PF_UNSPEC,
pipe_dns) == -1)
fatal("socketpair");
start_child(NTPDNS_PROC_NAME, pipe_dns[1], argc, argv);
/* in this case the parent didn't init logging and didn't daemonize */
if (nconf->settime && !nconf->debug) {
log_init(nconf->debug, LOG_DAEMON);
if (setsid() == -1)
fatal("setsid");
}
log_procinit("ntp");
if ((se = getservbyname("ntp", "udp")) == NULL)
fatal("getservbyname");
/* Start control socket. */
if ((fd_ctl = control_init(CTLSOCKET)) == -1)
fatalx("control socket init failed");
if (control_listen(fd_ctl) == -1)
fatalx("control socket listen failed");
if ((nullfd = open("/dev/null", O_RDWR, 0)) == -1)
fatal(NULL);
if (stat(pw->pw_dir, &stb) == -1) {
fatal("privsep dir %s could not be opened", pw->pw_dir);
}
if (stb.st_uid != 0 || (stb.st_mode & (S_IWGRP|S_IWOTH)) != 0) {
fatalx("bad privsep dir %s permissions: %o",
pw->pw_dir, stb.st_mode);
}
if (chroot(pw->pw_dir) == -1)
fatal("chroot");
if (chdir("/") == -1)
fatal("chdir(\"/\")");
if (!nconf->debug) {
dup2(nullfd, STDIN_FILENO);
dup2(nullfd, STDOUT_FILENO);
dup2(nullfd, STDERR_FILENO);
}
close(nullfd);
setproctitle("ntp engine");
conf = nconf;
setup_listeners(se, conf, &listener_cnt);
if (setgroups(1, &pw->pw_gid) ||
setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) ||
setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid))
fatal("can't drop privileges");
endservent();
/* The ntp process will want to open NTP client sockets -> "inet" */
if (pledge("stdio inet", NULL) == -1)
err(1, "pledge");
signal(SIGTERM, ntp_sighdlr);
signal(SIGINT, ntp_sighdlr);
signal(SIGPIPE, SIG_IGN);
signal(SIGHUP, SIG_IGN);
signal(SIGCHLD, SIG_DFL);
if ((ibuf_main = malloc(sizeof(struct imsgbuf))) == NULL)
fatal(NULL);
imsg_init(ibuf_main, PARENT_SOCK_FILENO);
if ((ibuf_dns = malloc(sizeof(struct imsgbuf))) == NULL)
fatal(NULL);
imsg_init(ibuf_dns, pipe_dns[0]);
constraint_cnt = 0;
conf->constraint_median = 0;
conf->constraint_last = getmonotime();
TAILQ_FOREACH(cstr, &conf->constraints, entry)
constraint_cnt += constraint_init(cstr);
TAILQ_FOREACH(p, &conf->ntp_peers, entry)
client_peer_init(p);
memset(&conf->status, 0, sizeof(conf->status));
conf->freq.num = 0;
conf->freq.samples = 0;
conf->freq.x = 0.0;
conf->freq.xx = 0.0;
conf->freq.xy = 0.0;
conf->freq.y = 0.0;
conf->freq.overall_offset = 0.0;
conf->status.synced = 0;
clock_getres(CLOCK_REALTIME, &tp);
b = 1000000000 / tp.tv_nsec; /* convert to Hz */
for (a = 0; b > 1; a--, b >>= 1)
;
conf->status.precision = a;
conf->scale = 1;
TAILQ_INIT(&ctl_conns);
sensor_init();
log_info("ntp engine ready");
ctl_cnt = 0;
peer_cnt = 0;
TAILQ_FOREACH(p, &conf->ntp_peers, entry)
peer_cnt++;
while (ntp_quit == 0) {
if (peer_cnt > idx2peer_elms) {
if ((newp = reallocarray(idx2peer, peer_cnt,
sizeof(*idx2peer))) == NULL) {
/* panic for now */
log_warn("could not resize idx2peer from %u -> "
"%u entries", idx2peer_elms, peer_cnt);
fatalx("exiting");
}
idx2peer = newp;
idx2peer_elms = peer_cnt;
}
new_cnt = PFD_MAX +
peer_cnt + listener_cnt + ctl_cnt;
if (new_cnt > pfd_elms) {
if ((newp = reallocarray(pfd, new_cnt,
sizeof(*pfd))) == NULL) {
/* panic for now */
log_warn("could not resize pfd from %u -> "
"%u entries", pfd_elms, new_cnt);
fatalx("exiting");
}
pfd = newp;
pfd_elms = new_cnt;
}
memset(pfd, 0, sizeof(*pfd) * pfd_elms);
memset(idx2peer, 0, sizeof(*idx2peer) * idx2peer_elms);
nextaction = getmonotime() + 3600;
pfd[PFD_PIPE_MAIN].fd = ibuf_main->fd;
pfd[PFD_PIPE_MAIN].events = POLLIN;
pfd[PFD_PIPE_DNS].fd = ibuf_dns->fd;
pfd[PFD_PIPE_DNS].events = POLLIN;
pfd[PFD_SOCK_CTL].fd = fd_ctl;
pfd[PFD_SOCK_CTL].events = POLLIN;
i = PFD_MAX;
TAILQ_FOREACH(la, &conf->listen_addrs, entry) {
pfd[i].fd = la->fd;
pfd[i].events = POLLIN;
i++;
}
idx_peers = i;
sent_cnt = trial_cnt = 0;
TAILQ_FOREACH(p, &conf->ntp_peers, entry) {
if (constraint_cnt && conf->constraint_median == 0)
continue;
if (p->next > 0 && p->next <= getmonotime()) {
if (p->state > STATE_DNS_INPROGRESS)
trial_cnt++;
if (client_query(p) == 0)
sent_cnt++;
}
if (p->deadline > 0 && p->deadline <= getmonotime()) {
timeout = 300;
log_debug("no reply from %s received in time, "
"next query %ds", log_sockaddr(
(struct sockaddr *)&p->addr->ss), timeout);
if (p->trustlevel >= TRUSTLEVEL_BADPEER &&
(p->trustlevel /= 2) < TRUSTLEVEL_BADPEER)
log_info("peer %s now invalid",
log_sockaddr(
(struct sockaddr *)&p->addr->ss));
client_nextaddr(p);
set_next(p, timeout);
}
if (p->senderrors > MAX_SEND_ERRORS) {
log_debug("failed to send query to %s, "
"next query %ds", log_sockaddr(
(struct sockaddr *)&p->addr->ss),
INTERVAL_QUERY_PATHETIC);
p->senderrors = 0;
client_nextaddr(p);
set_next(p, INTERVAL_QUERY_PATHETIC);
}
if (p->next > 0 && p->next < nextaction)
nextaction = p->next;
if (p->deadline > 0 && p->deadline < nextaction)
nextaction = p->deadline;
if (p->state == STATE_QUERY_SENT &&
p->query->fd != -1) {
pfd[i].fd = p->query->fd;
pfd[i].events = POLLIN;
idx2peer[i - idx_peers] = p;
i++;
}
}
idx_clients = i;
if (!TAILQ_EMPTY(&conf->ntp_conf_sensors)) {
if (last_sensor_scan == 0 ||
last_sensor_scan + SENSOR_SCAN_INTERVAL <= getmonotime()) {
sensors_cnt = sensor_scan();
last_sensor_scan = getmonotime();
}
if (sensors_cnt == 0 &&
nextaction > last_sensor_scan + SENSOR_SCAN_INTERVAL)
nextaction = last_sensor_scan + SENSOR_SCAN_INTERVAL;
sensors_cnt = 0;
TAILQ_FOREACH(s, &conf->ntp_sensors, entry) {
if (conf->settime && s->offsets[0].offset)
priv_settime(s->offsets[0].offset);
sensors_cnt++;
if (s->next > 0 && s->next < nextaction)
nextaction = s->next;
}
}
if (conf->settime &&
((trial_cnt > 0 && sent_cnt == 0) ||
(peer_cnt == 0 && sensors_cnt == 0)))
priv_settime(0); /* no good peers, don't wait */
if (ibuf_main->w.queued > 0)
pfd[PFD_PIPE_MAIN].events |= POLLOUT;
if (ibuf_dns->w.queued > 0)
pfd[PFD_PIPE_DNS].events |= POLLOUT;
TAILQ_FOREACH(cc, &ctl_conns, entry) {
pfd[i].fd = cc->ibuf.fd;
pfd[i].events = POLLIN;
if (cc->ibuf.w.queued > 0)
pfd[i].events |= POLLOUT;
i++;
}
ctls = i;
TAILQ_FOREACH(cstr, &conf->constraints, entry) {
if (constraint_query(cstr) == -1)
continue;
}
now = getmonotime();
if (constraint_cnt)
nextaction = now + 1;
timeout = nextaction - now;
if (timeout < 0)
timeout = 0;
if ((nfds = poll(pfd, i, timeout * 1000)) == -1)
if (errno != EINTR) {
log_warn("poll error");
ntp_quit = 1;
}
if (nfds > 0 && (pfd[PFD_PIPE_MAIN].revents & POLLOUT))
if (msgbuf_write(&ibuf_main->w) <= 0 &&
errno != EAGAIN) {
log_warn("pipe write error (to parent)");
ntp_quit = 1;
}
if (nfds > 0 && pfd[PFD_PIPE_MAIN].revents & (POLLIN|POLLERR)) {
nfds--;
if (ntp_dispatch_imsg() == -1) {
log_warn("pipe write error (from main)");
ntp_quit = 1;
}
}
if (nfds > 0 && (pfd[PFD_PIPE_DNS].revents & POLLOUT))
if (msgbuf_write(&ibuf_dns->w) <= 0 &&
errno != EAGAIN) {
log_warn("pipe write error (to dns engine)");
ntp_quit = 1;
}
if (nfds > 0 && pfd[PFD_PIPE_DNS].revents & (POLLIN|POLLERR)) {
nfds--;
if (ntp_dispatch_imsg_dns() == -1) {
log_warn("pipe write error (from dns engine)");
ntp_quit = 1;
}
}
if (nfds > 0 && pfd[PFD_SOCK_CTL].revents & (POLLIN|POLLERR)) {
nfds--;
ctl_cnt += control_accept(fd_ctl);
}
for (j = PFD_MAX; nfds > 0 && j < idx_peers; j++)
if (pfd[j].revents & (POLLIN|POLLERR)) {
nfds--;
if (server_dispatch(pfd[j].fd, conf) == -1) {
log_warn("pipe write error (conf)");
ntp_quit = 1;
}
}
for (; nfds > 0 && j < idx_clients; j++) {
if (pfd[j].revents & (POLLIN|POLLERR)) {
nfds--;
if (client_dispatch(idx2peer[j - idx_peers],
conf->settime) == -1) {
log_warn("pipe write error (settime)");
ntp_quit = 1;
}
}
}
for (; nfds > 0 && j < ctls; j++) {
nfds -= control_dispatch_msg(&pfd[j], &ctl_cnt);
}
for (s = TAILQ_FIRST(&conf->ntp_sensors); s != NULL;
s = next_s) {
next_s = TAILQ_NEXT(s, entry);
if (s->next <= getmonotime())
sensor_query(s);
}
}
msgbuf_write(&ibuf_main->w);
msgbuf_clear(&ibuf_main->w);
free(ibuf_main);
msgbuf_write(&ibuf_dns->w);
msgbuf_clear(&ibuf_dns->w);
free(ibuf_dns);
log_info("ntp engine exiting");
exit(0);
}
int
ntp_dispatch_imsg(void)
{
struct imsg imsg;
int n;
if (((n = imsg_read(ibuf_main)) == -1 && errno != EAGAIN) || n == 0)
return (-1);
for (;;) {
if ((n = imsg_get(ibuf_main, &imsg)) == -1)
return (-1);
if (n == 0)
break;
switch (imsg.hdr.type) {
case IMSG_ADJTIME:
memcpy(&n, imsg.data, sizeof(n));
if (n == 1 && !conf->status.synced) {
log_info("clock is now synced");
conf->status.synced = 1;
} else if (n == 0 && conf->status.synced) {
log_info("clock is now unsynced");
conf->status.synced = 0;
}
break;
case IMSG_CONSTRAINT_RESULT:
constraint_msg_result(imsg.hdr.peerid,
imsg.data, imsg.hdr.len - IMSG_HEADER_SIZE);
break;
case IMSG_CONSTRAINT_CLOSE:
constraint_msg_close(imsg.hdr.peerid,
imsg.data, imsg.hdr.len - IMSG_HEADER_SIZE);
break;
default:
break;
}
imsg_free(&imsg);
}
return (0);
}
int
ntp_dispatch_imsg_dns(void)
{
struct imsg imsg;
struct ntp_peer *peer, *npeer;
u_int16_t dlen;
u_char *p;
struct ntp_addr *h;
int n;
if (((n = imsg_read(ibuf_dns)) == -1 && errno != EAGAIN) || n == 0)
return (-1);
for (;;) {
if ((n = imsg_get(ibuf_dns, &imsg)) == -1)
return (-1);
if (n == 0)
break;
switch (imsg.hdr.type) {
case IMSG_HOST_DNS:
TAILQ_FOREACH(peer, &conf->ntp_peers, entry)
if (peer->id == imsg.hdr.peerid)
break;
if (peer == NULL) {
log_warnx("IMSG_HOST_DNS with invalid peerID");
break;
}
if (peer->addr != NULL) {
log_warnx("IMSG_HOST_DNS but addr != NULL!");
break;
}
dlen = imsg.hdr.len - IMSG_HEADER_SIZE;
if (dlen == 0) { /* no data -> temp error */
peer->state = STATE_DNS_TEMPFAIL;
break;
}
p = (u_char *)imsg.data;
while (dlen >= sizeof(struct sockaddr_storage)) {
if ((h = calloc(1, sizeof(struct ntp_addr))) ==
NULL)
fatal(NULL);
memcpy(&h->ss, p, sizeof(h->ss));
p += sizeof(h->ss);
dlen -= sizeof(h->ss);
if (peer->addr_head.pool) {
npeer = new_peer();
npeer->weight = peer->weight;
h->next = NULL;
npeer->addr = h;
npeer->addr_head.a = h;
npeer->addr_head.name =
peer->addr_head.name;
npeer->addr_head.pool = 1;
client_peer_init(npeer);
npeer->state = STATE_DNS_DONE;
peer_add(npeer);
} else {
h->next = peer->addr;
peer->addr = h;
peer->addr_head.a = peer->addr;
peer->state = STATE_DNS_DONE;
}
}
if (dlen != 0)
fatalx("IMSG_HOST_DNS: dlen != 0");
if (peer->addr_head.pool)
peer_remove(peer);
else
client_addr_init(peer);
break;
case IMSG_CONSTRAINT_DNS:
constraint_msg_dns(imsg.hdr.peerid,
imsg.data, imsg.hdr.len - IMSG_HEADER_SIZE);
break;
default:
break;
}
imsg_free(&imsg);
}
return (0);
}
void
peer_add(struct ntp_peer *p)
{
TAILQ_INSERT_TAIL(&conf->ntp_peers, p, entry);
peer_cnt++;
}
void
peer_remove(struct ntp_peer *p)
{
TAILQ_REMOVE(&conf->ntp_peers, p, entry);
free(p);
peer_cnt--;
}
static void
priv_adjfreq(double offset)
{
double curtime, freq;
if (!conf->status.synced){
conf->freq.samples = 0;
return;
}
conf->freq.samples++;
if (conf->freq.samples <= 0)
return;
conf->freq.overall_offset += offset;
offset = conf->freq.overall_offset;
curtime = gettime_corrected();
conf->freq.xy += offset * curtime;
conf->freq.x += curtime;
conf->freq.y += offset;
conf->freq.xx += curtime * curtime;
if (conf->freq.samples % FREQUENCY_SAMPLES != 0)
return;
freq =
(conf->freq.xy - conf->freq.x * conf->freq.y / conf->freq.samples)
/
(conf->freq.xx - conf->freq.x * conf->freq.x / conf->freq.samples);
if (freq > MAX_FREQUENCY_ADJUST)
freq = MAX_FREQUENCY_ADJUST;
else if (freq < -MAX_FREQUENCY_ADJUST)
freq = -MAX_FREQUENCY_ADJUST;
imsg_compose(ibuf_main, IMSG_ADJFREQ, 0, 0, -1, &freq, sizeof(freq));
conf->filters |= FILTER_ADJFREQ;
conf->freq.xy = 0.0;
conf->freq.x = 0.0;
conf->freq.y = 0.0;
conf->freq.xx = 0.0;
conf->freq.samples = 0;
conf->freq.overall_offset = 0.0;
conf->freq.num++;
}
int
priv_adjtime(void)
{
struct ntp_peer *p;
struct ntp_sensor *s;
int offset_cnt = 0, i = 0, j;
struct ntp_offset **offsets;
double offset_median;
TAILQ_FOREACH(p, &conf->ntp_peers, entry) {
if (p->trustlevel < TRUSTLEVEL_BADPEER)
continue;
if (!p->update.good)
return (1);
offset_cnt += p->weight;
}
TAILQ_FOREACH(s, &conf->ntp_sensors, entry) {
if (!s->update.good)
continue;
offset_cnt += s->weight;
}
if (offset_cnt == 0)
return (1);
if ((offsets = calloc(offset_cnt, sizeof(struct ntp_offset *))) == NULL)
fatal("calloc priv_adjtime");
TAILQ_FOREACH(p, &conf->ntp_peers, entry) {
if (p->trustlevel < TRUSTLEVEL_BADPEER)
continue;
for (j = 0; j < p->weight; j++)
offsets[i++] = &p->update;
}
TAILQ_FOREACH(s, &conf->ntp_sensors, entry) {
if (!s->update.good)
continue;
for (j = 0; j < s->weight; j++)
offsets[i++] = &s->update;
}
qsort(offsets, offset_cnt, sizeof(struct ntp_offset *), offset_compare);
i = offset_cnt / 2;
if (offset_cnt % 2 == 0)
if (offsets[i - 1]->delay < offsets[i]->delay)
i -= 1;
offset_median = offsets[i]->offset;
conf->status.rootdelay = offsets[i]->delay;
conf->status.stratum = offsets[i]->status.stratum;
conf->status.leap = offsets[i]->status.leap;
imsg_compose(ibuf_main, IMSG_ADJTIME, 0, 0, -1,
&offset_median, sizeof(offset_median));
priv_adjfreq(offset_median);
conf->status.reftime = gettime();
conf->status.stratum++; /* one more than selected peer */
if (conf->status.stratum > NTP_MAXSTRATUM)
conf->status.stratum = NTP_MAXSTRATUM;
update_scale(offset_median);
conf->status.refid = offsets[i]->status.send_refid;
free(offsets);
TAILQ_FOREACH(p, &conf->ntp_peers, entry) {
for (i = 0; i < OFFSET_ARRAY_SIZE; i++)
p->reply[i].offset -= offset_median;
p->update.good = 0;
}
TAILQ_FOREACH(s, &conf->ntp_sensors, entry) {
for (i = 0; i < SENSOR_OFFSETS; i++)
s->offsets[i].offset -= offset_median;
s->update.offset -= offset_median;
}
return (0);
}
int
offset_compare(const void *aa, const void *bb)
{
const struct ntp_offset * const *a;
const struct ntp_offset * const *b;
a = aa;
b = bb;
if ((*a)->offset < (*b)->offset)
return (-1);
else if ((*a)->offset > (*b)->offset)
return (1);
else
return (0);
}
void
priv_settime(double offset)
{
imsg_compose(ibuf_main, IMSG_SETTIME, 0, 0, -1,
&offset, sizeof(offset));
conf->settime = 0;
}
void
priv_dns(int cmd, char *name, u_int32_t peerid)
{
u_int16_t dlen;
dlen = strlen(name) + 1;
imsg_compose(ibuf_dns, cmd, peerid, 0, -1, name, dlen);
}
void
update_scale(double offset)
{
offset += getoffset();
if (offset < 0)
offset = -offset;
if (offset > QSCALE_OFF_MAX || !conf->status.synced ||
conf->freq.num < 3)
conf->scale = 1;
else if (offset < QSCALE_OFF_MIN)
conf->scale = QSCALE_OFF_MAX / QSCALE_OFF_MIN;
else
conf->scale = QSCALE_OFF_MAX / offset;
}
time_t
scale_interval(time_t requested)
{
time_t interval, r;
interval = requested * conf->scale;
r = arc4random_uniform(MAXIMUM(5, interval / 10));
return (interval + r);
}
time_t
error_interval(void)
{
time_t interval, r;
interval = INTERVAL_QUERY_PATHETIC * QSCALE_OFF_MAX / QSCALE_OFF_MIN;
r = arc4random_uniform(interval / 10);
return (interval + r);
}