2 * NTP client/server, based on OpenNTPD 3.9p1
4 * Author: Adam Tkac <vonsch@gmail.com>
6 * Licensed under GPLv2, see file LICENSE in this tarball for details.
9 #include <netinet/ip.h> /* For IPTOS_LOWDELAY definition */
12 # error "Sorry, your kernel has to support IP_PKTINFO"
15 #define INTERVAL_QUERY_NORMAL 30 /* sync to peers every n secs */
16 #define INTERVAL_QUERY_PATHETIC 60
17 #define INTERVAL_QUERY_AGRESSIVE 5
19 #define TRUSTLEVEL_BADPEER 6 /* bad if *less than* TRUSTLEVEL_BADPEER */
20 #define TRUSTLEVEL_PATHETIC 2
21 #define TRUSTLEVEL_AGRESSIVE 8
22 #define TRUSTLEVEL_MAX 10
24 #define QSCALE_OFF_MIN 0.05
25 #define QSCALE_OFF_MAX 0.50
27 #define QUERYTIME_MAX 15 /* single query might take n secs max */
28 #define OFFSET_ARRAY_SIZE 8
29 #define SETTIME_MIN_OFFSET 180 /* min offset for settime at start */
30 #define SETTIME_TIMEOUT 15 /* max seconds to wait with -s */
32 /* Style borrowed from NTP ref/tcpdump and updated for SNTPv4 (RFC2030). */
38 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
39 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
41 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
43 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
46 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
47 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
48 * | Integer Part | Fraction Part |
49 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
63 NTP_MSGSIZE_NOAUTH = 48,
64 NTP_MSGSIZE = (NTP_MSGSIZE_NOAUTH + 4 + NTP_DIGESTSIZE),
68 uint8_t status; /* status of local clock and leap info */
69 uint8_t stratum; /* stratum level */
70 uint8_t ppoll; /* poll value */
72 s_fixedpt_t rootdelay;
73 s_fixedpt_t dispersion;
80 uint8_t digest[NTP_DIGESTSIZE];
92 /* Leap Second Codes (high order two bits) */
93 LI_NOWARNING = (0 << 6), /* no warning */
94 LI_PLUSSEC = (1 << 6), /* add a second (61 seconds) */
95 LI_MINUSSEC = (2 << 6), /* minus a second (59 seconds) */
96 LI_ALARM = (3 << 6), /* alarm condition */
100 VERSION_MASK = (7 << 3),
105 MODE_RES0 = 0, /* reserved */
106 MODE_SYM_ACT = 1, /* symmetric active */
107 MODE_SYM_PAS = 2, /* symmetric passive */
108 MODE_CLIENT = 3, /* client */
109 MODE_SERVER = 4, /* server */
110 MODE_BROADCAST = 5, /* broadcast */
111 MODE_RES1 = 6, /* reserved for NTP control message */
112 MODE_RES2 = 7, /* reserved for private use */
115 #define JAN_1970 2208988800UL /* 1970 - 1900 in seconds */
120 STATE_REPLY_RECEIVED,
125 double rootdispersion;
147 // (1) store dotted addr str, to avoid constant translations
148 // (2) periodically re-resolve DNS names
149 len_and_sockaddr *lsa;
151 ntp_offset_t reply[OFFSET_ARRAY_SIZE];
153 enum client_state state;
164 /* Insert new options above this line. */
165 /* Non-compat options: */
173 #if ENABLE_FEATURE_NTPD_SERVER
183 #define G (*ptr_to_globals)
186 static const int const_IPTOS_LOWDELAY = IPTOS_LOWDELAY;
190 set_next(ntp_peer_t *p, time_t t)
192 p->next = time(NULL) + t;
197 add_peers(const char *s)
201 p = xzalloc(sizeof(*p));
202 //TODO: big ntpd uses all IPs, not just 1st, do we need to mimic that?
203 p->lsa = xhost2sockaddr(s, 123);
205 p->query.msg.status = MODE_CLIENT | (NTP_VERSION << 3);
207 p->state = STATE_NONE;
208 p->trustlevel = TRUSTLEVEL_PATHETIC;
212 llist_add_to(&G.ntp_peers, p);
220 gettimeofday(&tv, NULL); /* never fails */
221 return (tv.tv_sec + 1.0e-6 * tv.tv_usec + JAN_1970);
225 d_to_tv(double d, struct timeval *tv)
227 tv->tv_sec = (long)d;
228 tv->tv_usec = (d - tv->tv_sec) * 1000000;
232 lfp_to_d(l_fixedpt_t lfp)
235 lfp.int_partl = ntohl(lfp.int_partl);
236 lfp.fractionl = ntohl(lfp.fractionl);
237 ret = (double)lfp.int_partl + ((double)lfp.fractionl / UINT_MAX);
242 sfp_to_d(s_fixedpt_t sfp)
245 sfp.int_parts = ntohs(sfp.int_parts);
246 sfp.fractions = ntohs(sfp.fractions);
247 ret = (double)sfp.int_parts + ((double)sfp.fractions / USHRT_MAX);
251 #if ENABLE_FEATURE_NTPD_SERVER
256 lfp.int_partl = (uint32_t)d;
257 lfp.fractionl = (uint32_t)((d - lfp.int_partl) * UINT_MAX);
258 lfp.int_partl = htonl(lfp.int_partl);
259 lfp.fractionl = htonl(lfp.fractionl);
267 sfp.int_parts = (uint16_t)d;
268 sfp.fractions = (uint16_t)((d - sfp.int_parts) * USHRT_MAX);
269 sfp.int_parts = htons(sfp.int_parts);
270 sfp.fractions = htons(sfp.fractions);
276 set_deadline(ntp_peer_t *p, time_t t)
278 p->deadline = time(NULL) + t;
286 interval = INTERVAL_QUERY_PATHETIC * QSCALE_OFF_MAX / QSCALE_OFF_MIN;
287 r = (unsigned)random() % (unsigned long)(interval / 10);
288 return (interval + r);
293 const struct sockaddr *from, const struct sockaddr *to, socklen_t addrlen,
294 ntp_msg_t *msg, ssize_t len)
300 ret = sendto(fd, msg, len, MSG_DONTWAIT, to, addrlen);
302 ret = send_to_from(fd, msg, len, MSG_DONTWAIT, to, from, addrlen);
305 bb_perror_msg("send failed");
312 send_query_to_peer(ntp_peer_t *p)
314 if (p->query.fd == -1) {
315 p->query.fd = xsocket(p->lsa->u.sa.sa_family, SOCK_DGRAM, 0);
316 #if ENABLE_FEATURE_IPV6
317 if (p->lsa->u.sa.sa_family == AF_INET)
319 setsockopt(p->query.fd, IPPROTO_IP, IP_TOS, &const_IPTOS_LOWDELAY, sizeof(const_IPTOS_LOWDELAY));
323 * Send out a random 64-bit number as our transmit time. The NTP
324 * server will copy said number into the originate field on the
325 * response that it sends us. This is totally legal per the SNTP spec.
327 * The impact of this is two fold: we no longer send out the current
328 * system time for the world to see (which may aid an attacker), and
329 * it gives us a (not very secure) way of knowing that we're not
330 * getting spoofed by an attacker that can't capture our traffic
331 * but can spoof packets from the NTP server we're communicating with.
333 * Save the real transmit timestamp locally.
336 p->query.msg.xmttime.int_partl = random();
337 p->query.msg.xmttime.fractionl = random();
338 p->query.xmttime = gettime_fp();
340 if (sendmsg_wrap(p->query.fd, /*from:*/ NULL, /*to:*/ &p->lsa->u.sa, /*addrlen:*/ p->lsa->len,
341 &p->query.msg, NTP_MSGSIZE_NOAUTH) == -1) {
342 set_next(p, INTERVAL_QUERY_PATHETIC);
346 p->state = STATE_QUERY_SENT;
347 set_deadline(p, QUERYTIME_MAX);
353 offset_compare(const void *aa, const void *bb)
355 const ntp_peer_t *const *a = aa;
356 const ntp_peer_t *const *b = bb;
357 if ((*a)->update.offset < (*b)->update.offset)
359 return ((*a)->update.offset > (*b)->update.offset);
363 updated_scale(double offset)
367 if (offset > QSCALE_OFF_MAX)
369 if (offset < QSCALE_OFF_MIN)
370 return QSCALE_OFF_MAX / QSCALE_OFF_MIN;
371 return QSCALE_OFF_MAX / offset;
382 double offset_median;
384 len_and_sockaddr *lsa;
385 struct timeval tv, olddelta;
388 for (item = G.ntp_peers; item != NULL; item = item->link) {
389 p = (ntp_peer_t *) item->data;
390 if (p->trustlevel < TRUSTLEVEL_BADPEER)
400 peers = xzalloc(sizeof(peers[0]) * offset_cnt);
401 for (item = G.ntp_peers; item != NULL; item = item->link) {
402 p = (ntp_peer_t *) item->data;
403 if (p->trustlevel < TRUSTLEVEL_BADPEER)
408 qsort(peers, offset_cnt, sizeof(peers[0]), offset_compare);
410 middle = offset_cnt / 2;
411 if ((offset_cnt & 1) == 0) {
412 offset_median = (peers[middle-1]->update.offset + peers[middle]->update.offset) / 2;
413 G.status.rootdelay = (peers[middle-1]->update.delay + peers[middle]->update.delay) / 2;
414 G.status.stratum = MAX(peers[middle-1]->update.status.stratum, peers[middle]->update.status.stratum);
416 offset_median = peers[middle]->update.offset;
417 G.status.rootdelay = peers[middle]->update.delay;
418 G.status.stratum = peers[middle]->update.status.stratum;
420 G.status.leap = peers[middle]->update.status.leap;
422 bb_info_msg("adjusting local clock by %fs", offset_median);
424 d_to_tv(offset_median, &tv);
425 if (adjtime(&tv, &olddelta) == -1)
426 bb_error_msg("adjtime failed");
428 && olddelta.tv_sec == 0
429 && olddelta.tv_usec == 0
432 bb_info_msg("clock synced");
434 } else if (G.status.synced) {
435 bb_info_msg("clock unsynced");
440 G.status.reftime = gettime_fp();
441 G.status.stratum++; /* one more than selected peer */
442 G.scale = updated_scale(offset_median);
444 G.status.refid4 = peers[middle]->update.status.refid4;
446 lsa = peers[middle]->lsa;
448 #if ENABLE_FEATURE_IPV6
449 lsa->u.sa.sa_family != AF_INET ?
452 lsa->u.sin.sin_addr.s_addr;
457 for (item = G.ntp_peers; item != NULL; item = item->link) {
458 p = (ntp_peer_t *) item->data;
464 settime(double offset)
468 struct timeval tv, curtime;
477 /* if the offset is small, don't call settimeofday */
478 if (offset < SETTIME_MIN_OFFSET && offset > -SETTIME_MIN_OFFSET)
481 gettimeofday(&curtime, NULL); /* never fails */
483 d_to_tv(offset, &tv);
484 curtime.tv_usec += tv.tv_usec + 1000000;
485 curtime.tv_sec += tv.tv_sec - 1 + (curtime.tv_usec / 1000000);
486 curtime.tv_usec %= 1000000;
488 if (settimeofday(&curtime, NULL) == -1) {
489 bb_error_msg("settimeofday");
493 tval = curtime.tv_sec;
494 strftime(buf, sizeof(buf), "%a %b %e %H:%M:%S %Z %Y", localtime(&tval));
496 /* Do we want to print message below to system log when daemonized? */
497 bb_info_msg("set local clock to %s (offset %fs)", buf, offset);
499 for (item = G.ntp_peers; item != NULL; item = item->link) {
500 p = (ntp_peer_t *) item->data;
504 p->deadline -= offset;
508 if (option_mask32 & OPT_q)
513 update_peer_data(ntp_peer_t *p)
515 int i, best = 0, good = 0;
519 * find the offset which arrived with the lowest delay
520 * use that as the peer update
521 * invalidate it and all older ones
524 for (i = 0; good == 0 && i < OFFSET_ARRAY_SIZE; i++) {
525 if (p->reply[i].good) {
531 for (; i < OFFSET_ARRAY_SIZE; i++) {
532 if (p->reply[i].good) {
534 if (p->reply[i].delay < p->reply[best].delay)
542 memcpy(&p->update, &p->reply[best], sizeof(p->update));
545 for (i = 0; i < OFFSET_ARRAY_SIZE; i++)
546 if (p->reply[i].rcvd <= p->reply[best].rcvd)
547 p->reply[i].good = 0;
551 scale_interval(time_t requested)
554 interval = requested * G.scale;
555 r = (unsigned)random() % (unsigned long)(MAX(5, interval / 10));
556 return (interval + r);
560 recv_and_process_peer_pkt(ntp_peer_t *p)
565 double T1, T2, T3, T4;
567 ntp_offset_t *offset;
569 addr = xmalloc_sockaddr2dotted_noport(&p->lsa->u.sa);
571 size = recv(p->query.fd, &msg, sizeof(msg), MSG_DONTWAIT);
573 bb_perror_msg("recv(%s) error", addr);
574 if (errno == EHOSTUNREACH || errno == EHOSTDOWN
575 || errno == ENETUNREACH || errno == ENETDOWN
576 || errno == ECONNREFUSED || errno == EADDRNOTAVAIL
579 //TODO: always do this?
580 set_next(p, error_interval());
588 if (size != NTP_MSGSIZE_NOAUTH && size != NTP_MSGSIZE) {
589 bb_error_msg("malformed packet received from %s", addr);
593 if (msg.orgtime.int_partl != p->query.msg.xmttime.int_partl
594 || msg.orgtime.fractionl != p->query.msg.xmttime.fractionl
599 if ((msg.status & LI_ALARM) == LI_ALARM
601 || msg.stratum > NTP_MAXSTRATUM
603 interval = error_interval();
604 bb_info_msg("reply from %s: not synced, next query %ds", addr, (int) interval);
609 * From RFC 2030 (with a correction to the delay math):
611 * Timestamp Name ID When Generated
612 * ------------------------------------------------------------
613 * Originate Timestamp T1 time request sent by client
614 * Receive Timestamp T2 time request received by server
615 * Transmit Timestamp T3 time reply sent by server
616 * Destination Timestamp T4 time reply received by client
618 * The roundtrip delay d and local clock offset t are defined as
620 * d = (T4 - T1) - (T3 - T2) t = ((T2 - T1) + (T3 - T4)) / 2.
623 T1 = p->query.xmttime;
624 T2 = lfp_to_d(msg.rectime);
625 T3 = lfp_to_d(msg.xmttime);
627 offset = &p->reply[p->shift];
629 offset->offset = ((T2 - T1) + (T3 - T4)) / 2;
630 offset->delay = (T4 - T1) - (T3 - T2);
631 if (offset->delay < 0) {
632 interval = error_interval();
633 set_next(p, interval);
634 bb_info_msg("reply from %s: negative delay %f", addr, p->reply[p->shift].delay);
637 offset->error = (T2 - T1) - (T3 - T4);
638 // Can we use (T4 - JAN_1970) instead of time(NULL)?
639 offset->rcvd = time(NULL);
642 offset->status.leap = (msg.status & LI_MASK);
643 offset->status.precision = msg.precision;
644 offset->status.rootdelay = sfp_to_d(msg.rootdelay);
645 offset->status.rootdispersion = sfp_to_d(msg.dispersion);
646 offset->status.refid = ntohl(msg.refid);
647 offset->status.refid4 = msg.xmttime.fractionl;
648 offset->status.reftime = lfp_to_d(msg.reftime);
649 offset->status.poll = msg.ppoll;
650 offset->status.stratum = msg.stratum;
652 if (p->trustlevel < TRUSTLEVEL_PATHETIC)
653 interval = scale_interval(INTERVAL_QUERY_PATHETIC);
654 else if (p->trustlevel < TRUSTLEVEL_AGRESSIVE)
655 interval = scale_interval(INTERVAL_QUERY_AGRESSIVE);
657 interval = scale_interval(INTERVAL_QUERY_NORMAL);
659 set_next(p, interval);
660 p->state = STATE_REPLY_RECEIVED;
662 /* every received reply which we do not discard increases trust */
663 if (p->trustlevel < TRUSTLEVEL_MAX) {
665 if (p->trustlevel == TRUSTLEVEL_BADPEER)
666 bb_info_msg("peer %s now valid", addr);
669 bb_info_msg("reply from %s: offset %f delay %f, next query %ds", addr,
670 offset->offset, offset->delay, (int) interval);
673 settime(offset->offset);
676 if (p->shift >= OFFSET_ARRAY_SIZE)
683 #if ENABLE_FEATURE_NTPD_SERVER
685 recv_and_process_client_pkt(void /*int fd*/)
690 len_and_sockaddr *to;
691 struct sockaddr *from;
693 uint8_t query_status;
695 l_fixedpt_t query_xmttime;
697 to = get_sock_lsa(G.listen_fd);
698 from = xzalloc(to->len);
700 size = recv_from_to(G.listen_fd, &msg, sizeof(msg), MSG_DONTWAIT, from, &to->u.sa, to->len);
701 if (size != NTP_MSGSIZE_NOAUTH && size != NTP_MSGSIZE) {
706 bb_perror_msg_and_die("recv_from_to");
708 addr = xmalloc_sockaddr2dotted_noport(from);
709 bb_error_msg("malformed packet received from %s", addr);
714 query_status = msg.status;
715 query_ppoll = msg.ppoll;
716 query_xmttime = msg.xmttime;
718 /* Build a reply packet */
719 memset(&msg, 0, sizeof(msg));
720 msg.status = G.status.synced ? G.status.leap : LI_ALARM;
721 msg.status |= (query_status & VERSION_MASK);
722 msg.status |= ((query_status & MODE_MASK) == MODE_CLIENT) ?
723 MODE_SERVER : MODE_SYM_PAS;
724 msg.stratum = G.status.stratum;
725 msg.ppoll = query_ppoll;
726 msg.precision = G.status.precision;
727 rectime = gettime_fp();
728 msg.xmttime = msg.rectime = d_to_lfp(rectime);
729 msg.reftime = d_to_lfp(G.status.reftime);
730 //msg.xmttime = d_to_lfp(gettime_fp()); // = msg.rectime
731 msg.orgtime = query_xmttime;
732 msg.rootdelay = d_to_sfp(G.status.rootdelay);
733 version = (query_status & VERSION_MASK); /* ... >> VERSION_SHIFT - done below instead */
734 msg.refid = (version > (3 << VERSION_SHIFT)) ? G.status.refid4 : G.status.refid;
736 /* We reply from the local address packet was sent to,
737 * this makes to/from look swapped here: */
738 sendmsg_wrap(G.listen_fd,
739 /*from:*/ &to->u.sa, /*to:*/ from, /*addrlen:*/ to->len,
748 /* Upstream ntpd's options:
750 * -4 Force DNS resolution of host names to the IPv4 namespace.
751 * -6 Force DNS resolution of host names to the IPv6 namespace.
752 * -a Require cryptographic authentication for broadcast client,
753 * multicast client and symmetric passive associations.
754 * This is the default.
755 * -A Do not require cryptographic authentication for broadcast client,
756 * multicast client and symmetric passive associations.
757 * This is almost never a good idea.
758 * -b Enable the client to synchronize to broadcast servers.
760 * Specify the name and path of the configuration file,
761 * default /etc/ntp.conf
762 * -d Specify debugging mode. This option may occur more than once,
763 * with each occurrence indicating greater detail of display.
765 * Specify debugging level directly.
767 * Specify the name and path of the frequency file.
768 * This is the same operation as the "driftfile FILE"
769 * configuration command.
770 * -g Normally, ntpd exits with a message to the system log
771 * if the offset exceeds the panic threshold, which is 1000 s
772 * by default. This option allows the time to be set to any value
773 * without restriction; however, this can happen only once.
774 * If the threshold is exceeded after that, ntpd will exit
775 * with a message to the system log. This option can be used
776 * with the -q and -x options. See the tinker command for other options.
778 * Chroot the server to the directory jaildir. This option also implies
779 * that the server attempts to drop root privileges at startup
780 * (otherwise, chroot gives very little additional security).
781 * You may need to also specify a -u option.
783 * Specify the name and path of the symmetric key file,
784 * default /etc/ntp/keys. This is the same operation
785 * as the "keys FILE" configuration command.
787 * Specify the name and path of the log file. The default
788 * is the system log file. This is the same operation as
789 * the "logfile FILE" configuration command.
790 * -L Do not listen to virtual IPs. The default is to listen.
792 * -N To the extent permitted by the operating system,
793 * run the ntpd at the highest priority.
795 * Specify the name and path of the file used to record the ntpd
796 * process ID. This is the same operation as the "pidfile FILE"
797 * configuration command.
799 * To the extent permitted by the operating system,
800 * run the ntpd at the specified priority.
801 * -q Exit the ntpd just after the first time the clock is set.
802 * This behavior mimics that of the ntpdate program, which is
803 * to be retired. The -g and -x options can be used with this option.
804 * Note: The kernel time discipline is disabled with this option.
806 * Specify the default propagation delay from the broadcast/multicast
807 * server to this client. This is necessary only if the delay
808 * cannot be computed automatically by the protocol.
810 * Specify the directory path for files created by the statistics
811 * facility. This is the same operation as the "statsdir DIR"
812 * configuration command.
814 * Add a key number to the trusted key list. This option can occur
817 * Specify a user, and optionally a group, to switch to.
820 * Add a system variable listed by default.
821 * -x Normally, the time is slewed if the offset is less than the step
822 * threshold, which is 128 ms by default, and stepped if above
823 * the threshold. This option sets the threshold to 600 s, which is
824 * well within the accuracy window to set the clock manually.
825 * Note: since the slew rate of typical Unix kernels is limited
826 * to 0.5 ms/s, each second of adjustment requires an amortization
827 * interval of 2000 s. Thus, an adjustment as much as 600 s
828 * will take almost 14 days to complete. This option can be used
829 * with the -g and -q options. See the tinker command for other options.
830 * Note: The kernel time discipline is disabled with this option.
833 /* By doing init in a separate function we decrease stack usage
836 static NOINLINE void ntp_init(char **argv)
842 /* tzset(); - why? it's called automatically when needed, no? */
845 bb_error_msg_and_die("need root privileges");
848 opt_complementary = "dd:p::"; /* d: counter, p: list */
849 opts = getopt32(argv,
851 "p:"IF_FEATURE_NTPD_SERVER("l") /* NOT compat */
853 "46aAbLNx", /* compat, ignored */
855 #if ENABLE_FEATURE_NTPD_SERVER
858 G.listen_fd = create_and_bind_dgram_or_die(NULL, 123);
859 socket_want_pktinfo(G.listen_fd);
860 setsockopt(G.listen_fd, IPPROTO_IP, IP_TOS, &const_IPTOS_LOWDELAY, sizeof(const_IPTOS_LOWDELAY));
866 add_peers(llist_pop(&peers));
867 if (!(opts & OPT_n)) {
868 logmode = LOGMODE_NONE;
869 bb_daemonize(DAEMON_DEVNULL_STDIO);
872 /* Set some globals */
878 /* We can use sys_clock_getres but assuming 10ms tick should be fine */
879 clock_getres(CLOCK_REALTIME, &tp);
881 tp.tv_nsec = 10000000;
882 b = 1000000000 / tp.tv_nsec; /* convert to Hz */
884 b = 100; /* b = 1000000000/10000000 = 100 */
888 G.status.precision = prec;
893 bb_signals((1 << SIGTERM) | (1 << SIGINT), record_signo);
894 bb_signals((1 << SIGPIPE) | (1 << SIGHUP), SIG_IGN);
897 int ntpd_main(int argc UNUSED_PARAM, char **argv) MAIN_EXTERNALLY_VISIBLE;
898 int ntpd_main(int argc UNUSED_PARAM, char **argv)
902 ntp_peer_t **idx2peer;
904 memset(&g, 0, sizeof(g));
905 SET_PTR_TO_GLOBALS(&g);
910 unsigned cnt = g.peer_cnt;
911 /* if ENABLE_FEATURE_NTPD_SERVER, + 1 for listen_fd: */
912 idx2peer = xzalloc(sizeof(void *) * (cnt + ENABLE_FEATURE_NTPD_SERVER));
913 pfd = xzalloc(sizeof(pfd[0]) * (cnt + ENABLE_FEATURE_NTPD_SERVER));
916 while (!bb_got_signal) {
919 unsigned sent_cnt, trial_cnt;
921 time_t cur_time, nextaction;
923 /* Nothing between here and poll() blocks for any significant time */
925 cur_time = time(NULL);
926 nextaction = cur_time + 3600;
929 #if ENABLE_FEATURE_NTPD_SERVER
930 if (g.listen_fd != -1) {
931 pfd[0].fd = g.listen_fd;
932 pfd[0].events = POLLIN;
936 /* Pass over peer list, send requests, time out on receives */
937 sent_cnt = trial_cnt = 0;
938 for (item = g.ntp_peers; item != NULL; item = item->link) {
939 ntp_peer_t *p = (ntp_peer_t *) item->data;
941 if (p->next != 0 && p->next <= cur_time) {
942 /* Time to send new req */
944 if (send_query_to_peer(p) == 0)
947 if (p->deadline != 0 && p->deadline <= cur_time) {
948 /* Timed out waiting for reply */
949 char *addr = xmalloc_sockaddr2dotted_noport(&p->lsa->u.sa);
951 timeout = error_interval();
952 bb_info_msg("no reply from %s received in time, "
953 "next query %ds", addr, timeout);
954 if (p->trustlevel >= TRUSTLEVEL_BADPEER) {
956 if (p->trustlevel < TRUSTLEVEL_BADPEER)
957 bb_info_msg("peer %s now invalid", addr);
961 set_next(p, timeout);
964 if (p->next != 0 && p->next < nextaction)
965 nextaction = p->next;
966 if (p->deadline != 0 && p->deadline < nextaction)
967 nextaction = p->deadline;
969 if (p->state == STATE_QUERY_SENT) {
970 /* Wait for reply from this peer */
971 pfd[i].fd = p->query.fd;
972 pfd[i].events = POLLIN;
978 if ((trial_cnt > 0 && sent_cnt == 0) || g.peer_cnt == 0)
979 settime(0); /* no good peers, don't wait */
981 timeout = nextaction - cur_time;
985 /* Here we may block */
987 bb_error_msg("entering poll %u secs", timeout);
988 nfds = poll(pfd, i, timeout * 1000);
992 /* Process any received packets */
994 #if ENABLE_FEATURE_NTPD_SERVER
995 if (g.listen_fd != -1) {
996 if (pfd[0].revents /* & (POLLIN|POLLERR)*/) {
998 recv_and_process_client_pkt(/*g.listen_fd*/);
1003 for (; nfds != 0 && j < i; j++) {
1004 if (pfd[j].revents /* & (POLLIN|POLLERR)*/) {
1006 recv_and_process_peer_pkt(idx2peer[j]);
1009 } /* while (!bb_got_signal) */
1011 kill_myself_with_sig(bb_got_signal);