2 * ntp_proto.c - NTP version 4 protocol machinery
4 * ATTENTION: Get approval from Dave Mills on all changes to this file!
12 #include "ntp_stdlib.h"
13 #include "ntp_unixtime.h"
14 #include "ntp_control.h"
15 #include "ntp_string.h"
16 #include "ntp_leapsec.h"
17 #include "refidsmear.h"
28 * This macro defines the authentication state. If x is 1 authentication
29 * is required; othewise it is optional.
31 #define AUTH(x, y) ((x) ? (y) == AUTH_OK \
32 : (y) == AUTH_OK || (y) == AUTH_NONE)
34 #define AUTH_NONE 0 /* authentication not required */
35 #define AUTH_OK 1 /* authentication OK */
36 #define AUTH_ERROR 2 /* authentication error */
37 #define AUTH_CRYPTO 3 /* crypto_NAK */
40 * Set up Kiss Code values
44 NOKISS, /* No Kiss Code */
45 RATEKISS, /* Rate limit Kiss Code */
46 DENYKISS, /* Deny Kiss */
47 RSTRKISS, /* Restricted Kiss */
48 XKISS, /* Experimental Kiss */
49 UNKNOWNKISS /* Unknown Kiss Code */
53 * traffic shaping parameters
55 #define NTP_IBURST 6 /* packets in iburst */
56 #define RESP_DELAY 1 /* refclock burst delay (s) */
59 * pool soliciting restriction duration (s)
61 #define POOL_SOLICIT_WINDOW 8
64 * peer_select groups statistics for a peer used by clock_select() and
67 typedef struct peer_select_tag {
69 double synch; /* sync distance */
70 double error; /* jitter */
71 double seljit; /* selection jitter */
75 * System variables are declared here. Unless specified otherwise, all
76 * times are in seconds.
78 u_char sys_leap; /* system leap indicator, use set_sys_leap() to change this */
79 u_char xmt_leap; /* leap indicator sent in client requests, set up by set_sys_leap() */
80 u_char sys_stratum; /* system stratum */
81 s_char sys_precision; /* local clock precision (log2 s) */
82 double sys_rootdelay; /* roundtrip delay to primary source */
83 double sys_rootdisp; /* dispersion to primary source */
84 u_int32 sys_refid; /* reference id (network byte order) */
85 l_fp sys_reftime; /* last update time */
86 struct peer *sys_peer; /* current peer */
89 struct leap_smear_info leap_smear;
91 int leap_sec_in_progress;
94 * Rate controls. Leaky buckets are used to throttle the packet
95 * transmission rates in order to protect busy servers such as at NIST
96 * and USNO. There is a counter for each association and another for KoD
97 * packets. The association counter decrements each second, but not
98 * below zero. Each time a packet is sent the counter is incremented by
99 * a configurable value representing the average interval between
100 * packets. A packet is delayed as long as the counter is greater than
101 * zero. Note this does not affect the time value computations.
104 * Nonspecified system state variables
106 int sys_bclient; /* broadcast client enable */
107 double sys_bdelay; /* broadcast client default delay */
108 int sys_authenticate; /* requre authentication for config */
109 l_fp sys_authdelay; /* authentication delay */
110 double sys_offset; /* current local clock offset */
111 double sys_mindisp = MINDISPERSE; /* minimum distance (s) */
112 double sys_maxdist = MAXDISTANCE; /* selection threshold */
113 double sys_jitter; /* system jitter */
114 u_long sys_epoch; /* last clock update time */
115 static double sys_clockhop; /* clockhop threshold */
116 static int leap_vote_ins; /* leap consensus for insert */
117 static int leap_vote_del; /* leap consensus for delete */
118 keyid_t sys_private; /* private value for session seed */
119 int sys_manycastserver; /* respond to manycast client pkts */
120 int ntp_mode7; /* respond to ntpdc (mode7) */
121 int peer_ntpdate; /* active peers in ntpdate mode */
122 int sys_survivors; /* truest of the truechimers */
123 char *sys_ident = NULL; /* identity scheme */
126 * TOS and multicast mapping stuff
128 int sys_floor = 0; /* cluster stratum floor */
129 int sys_ceiling = STRATUM_UNSPEC - 1; /* cluster stratum ceiling */
130 int sys_minsane = 1; /* minimum candidates */
131 int sys_minclock = NTP_MINCLOCK; /* minimum candidates */
132 int sys_maxclock = NTP_MAXCLOCK; /* maximum candidates */
133 int sys_cohort = 0; /* cohort switch */
134 int sys_orphan = STRATUM_UNSPEC + 1; /* orphan stratum */
135 int sys_orphwait = NTP_ORPHWAIT; /* orphan wait */
136 int sys_beacon = BEACON; /* manycast beacon interval */
137 int sys_ttlmax; /* max ttl mapping vector index */
138 u_char sys_ttl[MAX_TTL]; /* ttl mapping vector */
141 * Statistics counters - first the good, then the bad
143 u_long sys_stattime; /* elapsed time */
144 u_long sys_received; /* packets received */
145 u_long sys_processed; /* packets for this host */
146 u_long sys_newversion; /* current version */
147 u_long sys_oldversion; /* old version */
148 u_long sys_restricted; /* access denied */
149 u_long sys_badlength; /* bad length or format */
150 u_long sys_badauth; /* bad authentication */
151 u_long sys_declined; /* declined */
152 u_long sys_limitrejected; /* rate exceeded */
153 u_long sys_kodsent; /* KoD sent */
155 static int kiss_code_check(u_char hisleap, u_char hisstratum, u_char hismode, u_int32 refid);
156 static double root_distance (struct peer *);
157 static void clock_combine (peer_select *, int, int);
158 static void peer_xmit (struct peer *);
159 static void fast_xmit (struct recvbuf *, int, keyid_t, int);
160 static void pool_xmit (struct peer *);
161 static void clock_update (struct peer *);
162 static void measure_precision(void);
163 static double measure_tick_fuzz(void);
164 static int local_refid (struct peer *);
165 static int peer_unfit (struct peer *);
167 static int group_test (char *, char *);
170 void pool_name_resolved (int, int, void *, const char *,
171 const char *, const struct addrinfo *,
172 const struct addrinfo *);
176 set_sys_leap(u_char new_sys_leap) {
177 sys_leap = new_sys_leap;
181 * Under certain conditions we send faked leap bits to clients, so
182 * eventually change xmt_leap below, but never change LEAP_NOTINSYNC.
184 if (xmt_leap != LEAP_NOTINSYNC) {
185 if (leap_sec_in_progress) {
186 /* always send "not sync" */
187 xmt_leap = LEAP_NOTINSYNC;
192 * If leap smear is enabled in general we must never send a leap second warning
193 * to clients, so make sure we only send "in sync".
195 if (leap_smear.enabled)
196 xmt_leap = LEAP_NOWARNING;
198 #endif /* LEAP_SMEAR */
205 int kiss_code_check(u_char hisleap, u_char hisstratum, u_char hismode, u_int32 refid) {
207 if ( hismode == MODE_SERVER
208 && hisleap == LEAP_NOTINSYNC
209 && hisstratum == STRATUM_UNSPEC) {
210 if(memcmp(&refid,"RATE", 4) == 0) {
213 else if(memcmp(&refid,"DENY", 4) == 0) {
216 else if(memcmp(&refid,"RSTR", 4) == 0) {
219 else if(memcmp(&refid,"X", 1) == 0) {
223 return (UNKNOWNKISS);
231 * transmit - transmit procedure called by poll timeout
235 struct peer *peer /* peer structure pointer */
241 * The polling state machine. There are two kinds of machines,
242 * those that never expect a reply (broadcast and manycast
243 * server modes) and those that do (all other modes). The dance
249 * In broadcast mode the poll interval is never changed from
252 if (peer->cast_flags & (MDF_BCAST | MDF_MCAST)) {
253 peer->outdate = current_time;
254 if (sys_leap != LEAP_NOTINSYNC)
256 poll_update(peer, hpoll);
261 * In manycast mode we start with unity ttl. The ttl is
262 * increased by one for each poll until either sys_maxclock
263 * servers have been found or the maximum ttl is reached. When
264 * sys_maxclock servers are found we stop polling until one or
265 * more servers have timed out or until less than sys_minclock
266 * associations turn up. In this case additional better servers
267 * are dragged in and preempt the existing ones. Once every
268 * sys_beacon seconds we are to transmit unconditionally, but
269 * this code is not quite right -- peer->unreach counts polls
270 * and is being compared with sys_beacon, so the beacons happen
271 * every sys_beacon polls.
273 if (peer->cast_flags & MDF_ACAST) {
274 peer->outdate = current_time;
275 if (peer->unreach > sys_beacon) {
279 } else if ( sys_survivors < sys_minclock
280 || peer_associations < sys_maxclock) {
281 if (peer->ttl < (u_int32)sys_ttlmax)
286 poll_update(peer, hpoll);
291 * Pool associations transmit unicast solicitations when there
292 * are less than a hard limit of 2 * sys_maxclock associations,
293 * and either less than sys_minclock survivors or less than
294 * sys_maxclock associations. The hard limit prevents unbounded
295 * growth in associations if the system clock or network quality
296 * result in survivor count dipping below sys_minclock often.
297 * This was observed testing with pool, where sys_maxclock == 12
298 * resulted in 60 associations without the hard limit. A
299 * similar hard limit on manycastclient ephemeral associations
300 * may be appropriate.
302 if (peer->cast_flags & MDF_POOL) {
303 peer->outdate = current_time;
304 if ( (peer_associations <= 2 * sys_maxclock)
305 && ( peer_associations < sys_maxclock
306 || sys_survivors < sys_minclock))
308 poll_update(peer, hpoll);
313 * In unicast modes the dance is much more intricate. It is
314 * designed to back off whenever possible to minimize network
317 if (peer->burst == 0) {
321 * Update the reachability status. If not heard for
322 * three consecutive polls, stuff infinity in the clock
325 oreach = peer->reach;
326 peer->outdate = current_time;
332 * Here the peer is unreachable. If it was
333 * previously reachable raise a trap. Send a
336 clock_filter(peer, 0., 0., MAXDISPERSE);
339 report_event(PEVNT_UNREACH, peer, NULL);
341 if ( (peer->flags & FLAG_IBURST)
343 peer->retry = NTP_RETRY;
347 * Here the peer is reachable. Send a burst if
348 * enabled and the peer is fit. Reset unreach
349 * for persistent and ephemeral associations.
350 * Unreach is also reset for survivors in
354 if (!(peer->flags & FLAG_PREEMPT))
356 if ( (peer->flags & FLAG_BURST)
358 && !peer_unfit(peer))
359 peer->retry = NTP_RETRY;
363 * Watch for timeout. If ephemeral, toss the rascal;
364 * otherwise, bump the poll interval. Note the
365 * poll_update() routine will clamp it to maxpoll.
366 * If preemptible and we have more peers than maxclock,
367 * and this peer has the minimum score of preemptibles,
370 if (peer->unreach >= NTP_UNREACH) {
372 /* ephemeral: no FLAG_CONFIG nor FLAG_PREEMPT */
373 if (!(peer->flags & (FLAG_CONFIG | FLAG_PREEMPT))) {
374 report_event(PEVNT_RESTART, peer, "timeout");
375 peer_clear(peer, "TIME");
379 if ( (peer->flags & FLAG_PREEMPT)
380 && (peer_associations > sys_maxclock)
381 && score_all(peer)) {
382 report_event(PEVNT_RESTART, peer, "timeout");
383 peer_clear(peer, "TIME");
390 if (peer->burst == 0) {
393 * If ntpdate mode and the clock has not been
394 * set and all peers have completed the burst,
395 * we declare a successful failure.
399 if (peer_ntpdate == 0) {
401 "ntpd: no servers found");
404 "ntpd: no servers found\n");
414 * Do not transmit if in broadcast client mode.
416 if (peer->hmode != MODE_BCLIENT)
418 poll_update(peer, hpoll);
423 * receive - receive procedure called for each packet received
427 struct recvbuf *rbufp
430 register struct peer *peer; /* peer structure pointer */
431 register struct pkt *pkt; /* receive packet pointer */
432 u_char hisversion; /* packet version */
433 u_char hisleap; /* packet leap indicator */
434 u_char hismode; /* packet mode */
435 u_char hisstratum; /* packet stratum */
436 u_short restrict_mask; /* restrict bits */
437 int kissCode = NOKISS; /* Kiss Code */
438 int has_mac; /* length of MAC field */
439 int authlen; /* offset of MAC field */
440 int is_authentic = 0; /* cryptosum ok */
441 int retcode = AM_NOMATCH; /* match code */
442 keyid_t skeyid = 0; /* key IDs */
443 u_int32 opcode = 0; /* extension field opcode */
444 sockaddr_u *dstadr_sin; /* active runway */
445 struct peer *peer2; /* aux peer structure pointer */
446 endpt * match_ep; /* newpeer() local address */
447 l_fp p_org; /* origin timestamp */
448 l_fp p_rec; /* receive timestamp */
449 l_fp p_xmt; /* transmit timestamp */
451 char hostname[NTP_MAXSTRLEN + 1];
452 char *groupname = NULL;
453 struct autokey *ap; /* autokey structure pointer */
454 int rval; /* cookie snatcher */
455 keyid_t pkeyid = 0, tkeyid = 0; /* key IDs */
457 #ifdef HAVE_NTP_SIGND
458 static unsigned char zero_key[16];
459 #endif /* HAVE_NTP_SIGND */
462 * Monitor the packet and get restrictions. Note that the packet
463 * length for control and private mode packets must be checked
464 * by the service routines. Some restrictions have to be handled
465 * later in order to generate a kiss-o'-death packet.
468 * Bogus port check is before anything, since it probably
469 * reveals a clogging attack.
472 if (0 == SRCPORT(&rbufp->recv_srcadr)) {
474 return; /* bogus port */
476 restrict_mask = restrictions(&rbufp->recv_srcadr);
477 DPRINTF(2, ("receive: at %ld %s<-%s flags %x restrict %03x\n",
478 current_time, stoa(&rbufp->dstadr->sin),
479 stoa(&rbufp->recv_srcadr),
480 rbufp->dstadr->flags, restrict_mask));
481 pkt = &rbufp->recv_pkt;
482 hisversion = PKT_VERSION(pkt->li_vn_mode);
483 hisleap = PKT_LEAP(pkt->li_vn_mode);
484 hismode = (int)PKT_MODE(pkt->li_vn_mode);
485 hisstratum = PKT_TO_STRATUM(pkt->stratum);
486 if (restrict_mask & RES_IGNORE) {
488 return; /* ignore everything */
490 if (hismode == MODE_PRIVATE) {
491 if (!ntp_mode7 || (restrict_mask & RES_NOQUERY)) {
493 return; /* no query private */
495 process_private(rbufp, ((restrict_mask &
496 RES_NOMODIFY) == 0));
499 if (hismode == MODE_CONTROL) {
500 if (restrict_mask & RES_NOQUERY) {
502 return; /* no query control */
504 process_control(rbufp, restrict_mask);
507 if (restrict_mask & RES_DONTSERVE) {
509 return; /* no time serve */
513 * This is for testing. If restricted drop ten percent of
516 if (restrict_mask & RES_FLAKE) {
517 if ((double)ntp_random() / 0x7fffffff < .1) {
519 return; /* no flakeway */
524 * Version check must be after the query packets, since they
525 * intentionally use an early version.
527 if (hisversion == NTP_VERSION) {
528 sys_newversion++; /* new version */
529 } else if ( !(restrict_mask & RES_VERSION)
530 && hisversion >= NTP_OLDVERSION) {
531 sys_oldversion++; /* previous version */
534 return; /* old version */
538 * Figure out his mode and validate the packet. This has some
539 * legacy raunch that probably should be removed. In very early
540 * NTP versions mode 0 was equivalent to what later versions
541 * would interpret as client mode.
543 if (hismode == MODE_UNSPEC) {
544 if (hisversion == NTP_OLDVERSION) {
545 hismode = MODE_CLIENT;
548 return; /* invalid mode */
553 * Parse the extension field if present. We figure out whether
554 * an extension field is present by measuring the MAC size. If
555 * the number of words following the packet header is 0, no MAC
556 * is present and the packet is not authenticated. If 1, the
557 * packet is a crypto-NAK; if 3, the packet is authenticated
558 * with DES; if 5, the packet is authenticated with MD5; if 6,
559 * the packet is authenticated with SHA. If 2 or * 4, the packet
560 * is a runt and discarded forthwith. If greater than 6, an
561 * extension field is present, so we subtract the length of the
562 * field and go around again.
564 authlen = LEN_PKT_NOMAC;
565 has_mac = rbufp->recv_length - authlen;
566 while (has_mac > 0) {
573 if (has_mac % 4 != 0 || has_mac < (int)MIN_MAC_LEN) {
575 return; /* bad length */
577 if (has_mac <= (int)MAX_MAC_LEN) {
578 skeyid = ntohl(((u_int32 *)pkt)[authlen / 4]);
582 opcode = ntohl(((u_int32 *)pkt)[authlen / 4]);
583 len = opcode & 0xffff;
586 || (int)len + authlen > rbufp->recv_length) {
588 return; /* bad length */
592 * Extract calling group name for later. If
593 * sys_groupname is non-NULL, there must be
594 * a group name provided to elicit a response.
596 if ( (opcode & 0x3fff0000) == CRYPTO_ASSOC
597 && sys_groupname != NULL) {
598 ep = (struct exten *)&((u_int32 *)pkt)[authlen / 4];
599 hostlen = ntohl(ep->vallen);
600 if ( hostlen >= sizeof(hostname)
602 offsetof(struct exten, pkt)) {
604 return; /* bad length */
606 memcpy(hostname, &ep->pkt, hostlen);
607 hostname[hostlen] = '\0';
608 groupname = strchr(hostname, '@');
609 if (groupname == NULL) {
622 * If has_mac is < 0 we had a malformed packet.
626 return; /* bad length */
630 * If authentication required, a MAC must be present.
632 if (restrict_mask & RES_DONTTRUST && has_mac == 0) {
634 return; /* access denied */
638 * Update the MRU list and finger the cloggers. It can be a
639 * little expensive, so turn it off for production use.
640 * RES_LIMITED and RES_KOD will be cleared in the returned
641 * restrict_mask unless one or both actions are warranted.
643 restrict_mask = ntp_monitor(rbufp, restrict_mask);
644 if (restrict_mask & RES_LIMITED) {
646 if ( !(restrict_mask & RES_KOD)
647 || MODE_BROADCAST == hismode
648 || MODE_SERVER == hismode) {
649 if (MODE_SERVER == hismode)
650 DPRINTF(1, ("Possibly self-induced rate limiting of MODE_SERVER from %s\n",
651 stoa(&rbufp->recv_srcadr)));
652 return; /* rate exceeded */
654 if (hismode == MODE_CLIENT)
655 fast_xmit(rbufp, MODE_SERVER, skeyid,
658 fast_xmit(rbufp, MODE_ACTIVE, skeyid,
660 return; /* rate exceeded */
662 restrict_mask &= ~RES_KOD;
665 * We have tossed out as many buggy packets as possible early in
666 * the game to reduce the exposure to a clogging attack. Now we
667 * have to burn some cycles to find the association and
668 * authenticate the packet if required. Note that we burn only
669 * digest cycles, again to reduce exposure. There may be no
670 * matching association and that's okay.
672 * More on the autokey mambo. Normally the local interface is
673 * found when the association was mobilized with respect to a
674 * designated remote address. We assume packets arriving from
675 * the remote address arrive via this interface and the local
676 * address used to construct the autokey is the unicast address
677 * of the interface. However, if the sender is a broadcaster,
678 * the interface broadcast address is used instead.
679 * Notwithstanding this technobabble, if the sender is a
680 * multicaster, the broadcast address is null, so we use the
681 * unicast address anyway. Don't ask.
683 peer = findpeer(rbufp, hismode, &retcode);
684 dstadr_sin = &rbufp->dstadr->sin;
685 NTOHL_FP(&pkt->org, &p_org);
686 NTOHL_FP(&pkt->rec, &p_rec);
687 NTOHL_FP(&pkt->xmt, &p_xmt);
690 * Authentication is conditioned by three switches:
692 * NOPEER (RES_NOPEER) do not mobilize an association unless
694 * NOTRUST (RES_DONTTRUST) do not allow access unless
695 * authenticated (implies NOPEER)
696 * enable (sys_authenticate) master NOPEER switch, by default
699 * The NOPEER and NOTRUST can be specified on a per-client basis
700 * using the restrict command. The enable switch if on implies
701 * NOPEER for all clients. There are four outcomes:
703 * NONE The packet has no MAC.
704 * OK the packet has a MAC and authentication succeeds
705 * ERROR the packet has a MAC and authentication fails
706 * CRYPTO crypto-NAK. The MAC has four octets only.
708 * Note: The AUTH(x, y) macro is used to filter outcomes. If x
709 * is zero, acceptable outcomes of y are NONE and OK. If x is
710 * one, the only acceptable outcome of y is OK.
714 restrict_mask &= ~RES_MSSNTP;
715 is_authentic = AUTH_NONE; /* not required */
719 "receive: at %ld %s<-%s mode %d len %d\n",
720 current_time, stoa(dstadr_sin),
721 stoa(&rbufp->recv_srcadr), hismode,
724 } else if (has_mac == 4) {
725 restrict_mask &= ~RES_MSSNTP;
726 is_authentic = AUTH_CRYPTO; /* crypto-NAK */
730 "receive: at %ld %s<-%s mode %d keyid %08x len %d auth %d\n",
731 current_time, stoa(dstadr_sin),
732 stoa(&rbufp->recv_srcadr), hismode, skeyid,
733 authlen + has_mac, is_authentic);
736 #ifdef HAVE_NTP_SIGND
738 * If the signature is 20 bytes long, the last 16 of
739 * which are zero, then this is a Microsoft client
740 * wanting AD-style authentication of the server's
743 * This is described in Microsoft's WSPP docs, in MS-SNTP:
744 * http://msdn.microsoft.com/en-us/library/cc212930.aspx
746 } else if ( has_mac == MAX_MD5_LEN
747 && (restrict_mask & RES_MSSNTP)
748 && (retcode == AM_FXMIT || retcode == AM_NEWPASS)
749 && (memcmp(zero_key, (char *)pkt + authlen + 4,
750 MAX_MD5_LEN - 4) == 0)) {
751 is_authentic = AUTH_NONE;
752 #endif /* HAVE_NTP_SIGND */
755 restrict_mask &= ~RES_MSSNTP;
758 * For autokey modes, generate the session key
759 * and install in the key cache. Use the socket
760 * broadcast or unicast address as appropriate.
762 if (crypto_flags && skeyid > NTP_MAXKEY) {
765 * More on the autokey dance (AKD). A cookie is
766 * constructed from public and private values.
767 * For broadcast packets, the cookie is public
768 * (zero). For packets that match no
769 * association, the cookie is hashed from the
770 * addresses and private value. For server
771 * packets, the cookie was previously obtained
772 * from the server. For symmetric modes, the
773 * cookie was previously constructed using an
774 * agreement protocol; however, should PKI be
775 * unavailable, we construct a fake agreement as
776 * the EXOR of the peer and host cookies.
778 * hismode ephemeral persistent
779 * =======================================
782 * client sys cookie 0%
783 * server 0% sys cookie
789 if (has_mac < (int)MAX_MD5_LEN) {
793 if (hismode == MODE_BROADCAST) {
796 * For broadcaster, use the interface
797 * broadcast address when available;
798 * otherwise, use the unicast address
799 * found when the association was
800 * mobilized. However, if this is from
801 * the wildcard interface, game over.
805 ANY_INTERFACE_CHOOSE(&rbufp->recv_srcadr)) {
807 return; /* no wildcard */
810 if (!SOCK_UNSPEC(&rbufp->dstadr->bcast))
812 &rbufp->dstadr->bcast;
813 } else if (peer == NULL) {
814 pkeyid = session_key(
815 &rbufp->recv_srcadr, dstadr_sin, 0,
818 pkeyid = peer->pcookie;
822 * The session key includes both the public
823 * values and cookie. In case of an extension
824 * field, the cookie used for authentication
825 * purposes is zero. Note the hash is saved for
826 * use later in the autokey mambo.
828 if (authlen > (int)LEN_PKT_NOMAC && pkeyid != 0) {
829 session_key(&rbufp->recv_srcadr,
830 dstadr_sin, skeyid, 0, 2);
831 tkeyid = session_key(
832 &rbufp->recv_srcadr, dstadr_sin,
835 tkeyid = session_key(
836 &rbufp->recv_srcadr, dstadr_sin,
844 * Compute the cryptosum. Note a clogging attack may
845 * succeed in bloating the key cache. If an autokey,
846 * purge it immediately, since we won't be needing it
847 * again. If the packet is authentic, it can mobilize an
848 * association. Note that there is no key zero.
850 if (!authdecrypt(skeyid, (u_int32 *)pkt, authlen,
852 is_authentic = AUTH_ERROR;
854 is_authentic = AUTH_OK;
856 if (crypto_flags && skeyid > NTP_MAXKEY)
857 authtrust(skeyid, 0);
862 "receive: at %ld %s<-%s mode %d keyid %08x len %d auth %d\n",
863 current_time, stoa(dstadr_sin),
864 stoa(&rbufp->recv_srcadr), hismode, skeyid,
865 authlen + has_mac, is_authentic);
870 * The association matching rules are implemented by a set of
871 * routines and an association table. A packet matching an
872 * association is processed by the peer process for that
873 * association. If there are no errors, an ephemeral association
874 * is mobilized: a broadcast packet mobilizes a broadcast client
875 * aassociation; a manycast server packet mobilizes a manycast
876 * client association; a symmetric active packet mobilizes a
877 * symmetric passive association.
882 * This is a client mode packet not matching any association. If
883 * an ordinary client, simply toss a server mode packet back
884 * over the fence. If a manycast client, we have to work a
890 * If authentication OK, send a server reply; otherwise,
893 if (!(rbufp->dstadr->flags & INT_MCASTOPEN)) {
894 if (AUTH(restrict_mask & RES_DONTTRUST,
896 fast_xmit(rbufp, MODE_SERVER, skeyid,
898 } else if (is_authentic == AUTH_ERROR) {
899 fast_xmit(rbufp, MODE_SERVER, 0,
909 * This must be manycast. Do not respond if not
910 * configured as a manycast server.
912 if (!sys_manycastserver) {
914 return; /* not enabled */
919 * Do not respond if not the same group.
921 if (group_test(groupname, NULL)) {
928 * Do not respond if we are not synchronized or our
929 * stratum is greater than the manycaster or the
930 * manycaster has already synchronized to us.
932 if ( sys_leap == LEAP_NOTINSYNC
933 || sys_stratum >= hisstratum
934 || (!sys_cohort && sys_stratum == hisstratum + 1)
935 || rbufp->dstadr->addr_refid == pkt->refid) {
937 return; /* no help */
941 * Respond only if authentication succeeds. Don't do a
942 * crypto-NAK, as that would not be useful.
944 if (AUTH(restrict_mask & RES_DONTTRUST, is_authentic))
945 fast_xmit(rbufp, MODE_SERVER, skeyid,
950 * This is a server mode packet returned in response to a client
951 * mode packet sent to a multicast group address (for
952 * manycastclient) or to a unicast address (for pool). The
953 * origin timestamp is a good nonce to reliably associate the
954 * reply with what was sent. If there is no match, that's
955 * curious and could be an intruder attempting to clog, so we
958 * If the packet is authentic and the manycastclient or pool
959 * association is found, we mobilize a client association and
960 * copy pertinent variables from the manycastclient or pool
961 * association to the new client association. If not, just
964 * There is an implosion hazard at the manycast client, since
965 * the manycast servers send the server packet immediately. If
966 * the guy is already here, don't fire up a duplicate.
972 * Do not respond if not the same group.
974 if (group_test(groupname, NULL)) {
979 if ((peer2 = findmanycastpeer(rbufp)) == NULL) {
981 return; /* not enabled */
983 if (!AUTH( (!(peer2->cast_flags & MDF_POOL)
985 || (restrict_mask & (RES_NOPEER |
986 RES_DONTTRUST)), is_authentic)) {
988 return; /* access denied */
992 * Do not respond if unsynchronized or stratum is below
993 * the floor or at or above the ceiling.
995 if ( hisleap == LEAP_NOTINSYNC
996 || hisstratum < sys_floor
997 || hisstratum >= sys_ceiling) {
999 return; /* no help */
1001 peer = newpeer(&rbufp->recv_srcadr, NULL, rbufp->dstadr,
1002 MODE_CLIENT, hisversion, peer2->minpoll,
1003 peer2->maxpoll, FLAG_PREEMPT |
1004 (FLAG_IBURST & peer2->flags), MDF_UCAST |
1005 MDF_UCLNT, 0, skeyid, sys_ident);
1008 return; /* ignore duplicate */
1012 * After each ephemeral pool association is spun,
1013 * accelerate the next poll for the pool solicitor so
1014 * the pool will fill promptly.
1016 if (peer2->cast_flags & MDF_POOL)
1017 peer2->nextdate = current_time + 1;
1020 * Further processing of the solicitation response would
1021 * simply detect its origin timestamp as bogus for the
1022 * brand-new association (it matches the prototype
1023 * association) and tinker with peer->nextdate delaying
1026 return; /* solicitation response handled */
1029 * This is the first packet received from a broadcast server. If
1030 * the packet is authentic and we are enabled as broadcast
1031 * client, mobilize a broadcast client association. We don't
1032 * kiss any frogs here.
1038 * Do not respond if not the same group.
1040 if (group_test(groupname, sys_ident)) {
1044 #endif /* AUTOKEY */
1045 if (sys_bclient == 0) {
1047 return; /* not enabled */
1049 if (!AUTH(sys_authenticate | (restrict_mask &
1050 (RES_NOPEER | RES_DONTTRUST)), is_authentic)) {
1052 return; /* access denied */
1056 * Do not respond if unsynchronized or stratum is below
1057 * the floor or at or above the ceiling.
1059 if ( hisleap == LEAP_NOTINSYNC
1060 || hisstratum < sys_floor
1061 || hisstratum >= sys_ceiling) {
1063 return; /* no help */
1068 * Do not respond if Autokey and the opcode is not a
1069 * CRYPTO_ASSOC response with association ID.
1071 if ( crypto_flags && skeyid > NTP_MAXKEY
1072 && (opcode & 0xffff0000) != (CRYPTO_ASSOC | CRYPTO_RESP)) {
1074 return; /* protocol error */
1076 #endif /* AUTOKEY */
1079 * Broadcasts received via a multicast address may
1080 * arrive after a unicast volley has begun
1081 * with the same remote address. newpeer() will not
1082 * find duplicate associations on other local endpoints
1083 * if a non-NULL endpoint is supplied. multicastclient
1084 * ephemeral associations are unique across all local
1087 if (!(INT_MCASTOPEN & rbufp->dstadr->flags))
1088 match_ep = rbufp->dstadr;
1093 * Determine whether to execute the initial volley.
1095 if (sys_bdelay != 0) {
1098 * If a two-way exchange is not possible,
1099 * neither is Autokey.
1101 if (crypto_flags && skeyid > NTP_MAXKEY) {
1103 return; /* no autokey */
1105 #endif /* AUTOKEY */
1108 * Do not execute the volley. Start out in
1109 * broadcast client mode.
1111 peer = newpeer(&rbufp->recv_srcadr, NULL,
1112 match_ep, MODE_BCLIENT, hisversion,
1113 pkt->ppoll, pkt->ppoll, FLAG_PREEMPT,
1114 MDF_BCLNT, 0, skeyid, sys_ident);
1117 return; /* ignore duplicate */
1120 peer->delay = sys_bdelay;
1126 * Execute the initial volley in order to calibrate the
1127 * propagation delay and run the Autokey protocol.
1129 * Note that the minpoll is taken from the broadcast
1130 * packet, normally 6 (64 s) and that the poll interval
1131 * is fixed at this value.
1133 peer = newpeer(&rbufp->recv_srcadr, NULL, match_ep,
1134 MODE_CLIENT, hisversion, pkt->ppoll, pkt->ppoll,
1135 FLAG_BC_VOL | FLAG_IBURST | FLAG_PREEMPT, MDF_BCLNT,
1136 0, skeyid, sys_ident);
1139 return; /* ignore duplicate */
1142 if (skeyid > NTP_MAXKEY)
1143 crypto_recv(peer, rbufp);
1144 #endif /* AUTOKEY */
1146 return; /* hooray */
1149 * This is the first packet received from a symmetric active
1150 * peer. If the packet is authentic and the first he sent,
1151 * mobilize a passive association. If not, kiss the frog.
1157 * Do not respond if not the same group.
1159 if (group_test(groupname, sys_ident)) {
1163 #endif /* AUTOKEY */
1164 if (!AUTH(sys_authenticate | (restrict_mask &
1165 (RES_NOPEER | RES_DONTTRUST)), is_authentic)) {
1168 * If authenticated but cannot mobilize an
1169 * association, send a symmetric passive
1170 * response without mobilizing an association.
1171 * This is for drat broken Windows clients. See
1172 * Microsoft KB 875424 for preferred workaround.
1174 if (AUTH(restrict_mask & RES_DONTTRUST,
1176 fast_xmit(rbufp, MODE_PASSIVE, skeyid,
1178 return; /* hooray */
1180 if (is_authentic == AUTH_ERROR) {
1181 fast_xmit(rbufp, MODE_ACTIVE, 0,
1187 * If we got here, the packet isn't part of an
1188 * existing association, it isn't correctly
1189 * authenticated, and it didn't meet either of
1190 * the previous two special cases so we should
1191 * just drop it on the floor. For example,
1192 * crypto-NAKs (is_authentic == AUTH_CRYPTO)
1193 * will make it this far. This is just
1194 * debug-printed and not logged to avoid log
1197 DPRINTF(1, ("receive: at %ld refusing to mobilize passive association"
1198 " with unknown peer %s mode %d keyid %08x len %d auth %d\n",
1199 current_time, stoa(&rbufp->recv_srcadr),
1200 hismode, skeyid, (authlen + has_mac),
1207 * Do not respond if synchronized and if stratum is
1208 * below the floor or at or above the ceiling. Note,
1209 * this allows an unsynchronized peer to synchronize to
1210 * us. It would be very strange if he did and then was
1211 * nipped, but that could only happen if we were
1212 * operating at the top end of the range. It also means
1213 * we will spin an ephemeral association in response to
1214 * MODE_ACTIVE KoDs, which will time out eventually.
1216 if ( hisleap != LEAP_NOTINSYNC
1217 && (hisstratum < sys_floor || hisstratum >= sys_ceiling)) {
1219 return; /* no help */
1223 * The message is correctly authenticated and allowed.
1224 * Mobilize a symmetric passive association.
1226 if ((peer = newpeer(&rbufp->recv_srcadr, NULL,
1227 rbufp->dstadr, MODE_PASSIVE, hisversion, pkt->ppoll,
1228 NTP_MAXDPOLL, 0, MDF_UCAST, 0, skeyid,
1229 sys_ident)) == NULL) {
1231 return; /* ignore duplicate */
1237 * Process regular packet. Nothing special.
1243 * Do not respond if not the same group.
1245 if (group_test(groupname, peer->ident)) {
1249 #endif /* AUTOKEY */
1253 * A passive packet matches a passive association. This is
1254 * usually the result of reconfiguring a client on the fly. As
1255 * this association might be legitimate and this packet an
1256 * attempt to deny service, just ignore it.
1263 * For everything else there is the bit bucket.
1272 * If the association is configured for Autokey, the packet must
1273 * have a public key ID; if not, the packet must have a
1276 if ( is_authentic != AUTH_CRYPTO
1277 && ( ((peer->flags & FLAG_SKEY) && skeyid <= NTP_MAXKEY)
1278 || (!(peer->flags & FLAG_SKEY) && skeyid > NTP_MAXKEY))) {
1282 #endif /* AUTOKEY */
1284 peer->flash &= ~PKT_TEST_MASK;
1285 if (peer->flags & FLAG_XBOGUS) {
1286 peer->flags &= ~FLAG_XBOGUS;
1287 peer->flash |= TEST3;
1291 * Next comes a rigorous schedule of timestamp checking. If the
1292 * transmit timestamp is zero, the server has not initialized in
1293 * interleaved modes or is horribly broken.
1295 if (L_ISZERO(&p_xmt)) {
1296 peer->flash |= TEST3; /* unsynch */
1299 * If the transmit timestamp duplicates a previous one, the
1300 * packet is a replay. This prevents the bad guys from replaying
1301 * the most recent packet, authenticated or not.
1303 } else if (L_ISEQU(&peer->xmt, &p_xmt)) {
1304 peer->flash |= TEST1; /* duplicate */
1309 * If this is a broadcast mode packet, skip further checking. If
1310 * an initial volley, bail out now and let the client do its
1311 * stuff. If the origin timestamp is nonzero, this is an
1312 * interleaved broadcast. so restart the protocol.
1314 } else if (hismode == MODE_BROADCAST) {
1315 if (!L_ISZERO(&p_org) && !(peer->flags & FLAG_XB)) {
1316 peer->flags |= FLAG_XB;
1318 peer->borg = rbufp->recv_time;
1319 report_event(PEVNT_XLEAVE, peer, NULL);
1324 * Check for bogus packet in basic mode. If found, switch to
1325 * interleaved mode and resynchronize, but only after confirming
1326 * the packet is not bogus in symmetric interleaved mode.
1328 * This could also mean somebody is forging packets claiming to
1329 * be from us, attempting to cause our server to KoD us.
1331 } else if (peer->flip == 0) {
1332 if (!L_ISEQU(&p_org, &peer->aorg)) {
1334 peer->flash |= TEST2; /* bogus */
1336 "receive: Unexpected origin timestamp from %s",
1337 ntoa(&peer->srcadr));
1338 if ( !L_ISZERO(&peer->dst)
1339 && L_ISEQU(&p_org, &peer->dst)) {
1341 report_event(PEVNT_XLEAVE, peer, NULL);
1343 return; /* Bogus packet, we are done */
1349 * Check for valid nonzero timestamp fields.
1351 } else if (L_ISZERO(&p_org) || L_ISZERO(&p_rec) ||
1352 L_ISZERO(&peer->dst)) {
1353 peer->flash |= TEST3; /* unsynch */
1356 * Check for bogus packet in interleaved symmetric mode. This
1357 * can happen if a packet is lost, duplicated or crossed. If
1358 * found, flip and resynchronize.
1360 } else if ( !L_ISZERO(&peer->dst)
1361 && !L_ISEQU(&p_org, &peer->dst)) {
1363 peer->flags |= FLAG_XBOGUS;
1364 peer->flash |= TEST2; /* bogus */
1365 return; /* Bogus packet, we are done */
1369 * If this is a crypto_NAK, the server cannot authenticate a
1370 * client packet. The server might have just changed keys. Clear
1371 * the association and restart the protocol.
1373 if (is_authentic == AUTH_CRYPTO) {
1374 report_event(PEVNT_AUTH, peer, "crypto_NAK");
1375 peer->flash |= TEST5; /* bad auth */
1377 if (peer->flags & FLAG_PREEMPT) {
1383 peer_clear(peer, "AUTH");
1384 #endif /* AUTOKEY */
1388 * If the digest fails or it's missing for authenticated
1389 * associations, the client cannot authenticate a server
1390 * reply to a client packet previously sent. The loopback check
1391 * is designed to avoid a bait-and-switch attack, which was
1392 * possible in past versions. If symmetric modes, return a
1393 * crypto-NAK. The peer should restart the protocol.
1395 } else if (!AUTH(peer->keyid || has_mac ||
1396 (restrict_mask & RES_DONTTRUST), is_authentic)) {
1397 report_event(PEVNT_AUTH, peer, "digest");
1398 peer->flash |= TEST5; /* bad auth */
1401 && (hismode == MODE_ACTIVE || hismode == MODE_PASSIVE))
1402 fast_xmit(rbufp, MODE_ACTIVE, 0, restrict_mask);
1403 if (peer->flags & FLAG_PREEMPT) {
1409 peer_clear(peer, "AUTH");
1410 #endif /* AUTOKEY */
1415 * Update the state variables.
1417 if (peer->flip == 0) {
1418 if (hismode != MODE_BROADCAST)
1420 peer->dst = rbufp->recv_time;
1425 * Set the peer ppoll to the maximum of the packet ppoll and the
1426 * peer minpoll. If a kiss-o'-death, set the peer minpoll to
1427 * this maximum and advance the headway to give the sender some
1428 * headroom. Very intricate.
1432 * Check for any kiss codes. Note this is only used when a server
1433 * responds to a packet request
1436 kissCode = kiss_code_check(hisleap, hisstratum, hismode, pkt->refid);
1439 * Check to see if this is a RATE Kiss Code
1440 * Currently this kiss code will accept whatever poll
1441 * rate that the server sends
1443 peer->ppoll = max(peer->minpoll, pkt->ppoll);
1444 if (kissCode == RATEKISS) {
1445 peer->selbroken++; /* Increment the KoD count */
1446 report_event(PEVNT_RATE, peer, NULL);
1447 if (pkt->ppoll > peer->minpoll)
1448 peer->minpoll = peer->ppoll;
1449 peer->burst = peer->retry = 0;
1450 peer->throttle = (NTP_SHIFT + 1) * (1 << peer->minpoll);
1451 poll_update(peer, pkt->ppoll);
1452 return; /* kiss-o'-death */
1454 if (kissCode != NOKISS) {
1455 peer->selbroken++; /* Increment the KoD count */
1456 return; /* Drop any other kiss code packets */
1461 * That was hard and I am sweaty, but the packet is squeaky
1462 * clean. Get on with real work.
1464 peer->timereceived = current_time;
1465 if (is_authentic == AUTH_OK)
1466 peer->flags |= FLAG_AUTHENTIC;
1468 peer->flags &= ~FLAG_AUTHENTIC;
1472 * More autokey dance. The rules of the cha-cha are as follows:
1474 * 1. If there is no key or the key is not auto, do nothing.
1476 * 2. If this packet is in response to the one just previously
1477 * sent or from a broadcast server, do the extension fields.
1478 * Otherwise, assume bogosity and bail out.
1480 * 3. If an extension field contains a verified signature, it is
1481 * self-authenticated and we sit the dance.
1483 * 4. If this is a server reply, check only to see that the
1484 * transmitted key ID matches the received key ID.
1486 * 5. Check to see that one or more hashes of the current key ID
1487 * matches the previous key ID or ultimate original key ID
1488 * obtained from the broadcaster or symmetric peer. If no
1489 * match, sit the dance and call for new autokey values.
1491 * In case of crypto error, fire the orchestra, stop dancing and
1492 * restart the protocol.
1494 if (peer->flags & FLAG_SKEY) {
1496 * Decrement remaining autokey hashes. This isn't
1497 * perfect if a packet is lost, but results in no harm.
1499 ap = (struct autokey *)peer->recval.ptr;
1504 peer->flash |= TEST8;
1505 rval = crypto_recv(peer, rbufp);
1506 if (rval == XEVNT_OK) {
1509 if (rval == XEVNT_ERR) {
1510 report_event(PEVNT_RESTART, peer,
1512 peer_clear(peer, "CRYP");
1513 peer->flash |= TEST9; /* bad crypt */
1514 if (peer->flags & FLAG_PREEMPT)
1521 * If server mode, verify the receive key ID matches
1522 * the transmit key ID.
1524 if (hismode == MODE_SERVER) {
1525 if (skeyid == peer->keyid)
1526 peer->flash &= ~TEST8;
1529 * If an extension field is present, verify only that it
1530 * has been correctly signed. We don't need a sequence
1531 * check here, but the sequence continues.
1533 } else if (!(peer->flash & TEST8)) {
1534 peer->pkeyid = skeyid;
1537 * Now the fun part. Here, skeyid is the current ID in
1538 * the packet, pkeyid is the ID in the last packet and
1539 * tkeyid is the hash of skeyid. If the autokey values
1540 * have not been received, this is an automatic error.
1541 * If so, check that the tkeyid matches pkeyid. If not,
1542 * hash tkeyid and try again. If the number of hashes
1543 * exceeds the number remaining in the sequence, declare
1544 * a successful failure and refresh the autokey values.
1546 } else if (ap != NULL) {
1549 for (i = 0; ; i++) {
1550 if ( tkeyid == peer->pkeyid
1551 || tkeyid == ap->key) {
1552 peer->flash &= ~TEST8;
1553 peer->pkeyid = skeyid;
1562 tkeyid = session_key(
1563 &rbufp->recv_srcadr, dstadr_sin,
1566 if (peer->flash & TEST8)
1567 report_event(PEVNT_AUTH, peer, "keylist");
1569 if (!(peer->crypto & CRYPTO_FLAG_PROV)) /* test 9 */
1570 peer->flash |= TEST8; /* bad autokey */
1573 * The maximum lifetime of the protocol is about one
1574 * week before restarting the Autokey protocol to
1575 * refresh certificates and leapseconds values.
1577 if (current_time > peer->refresh) {
1578 report_event(PEVNT_RESTART, peer,
1580 peer_clear(peer, "TIME");
1584 #endif /* AUTOKEY */
1587 * The dance is complete and the flash bits have been lit. Toss
1588 * the packet over the fence for processing, which may light up
1591 process_packet(peer, pkt, rbufp->recv_length);
1594 * In interleaved mode update the state variables. Also adjust the
1595 * transmit phase to avoid crossover.
1597 if (peer->flip != 0) {
1599 peer->dst = rbufp->recv_time;
1600 if (peer->nextdate - current_time < (1U << min(peer->ppoll,
1610 * process_packet - Packet Procedure, a la Section 3.4.4 of the
1611 * specification. Or almost, at least. If we're in here we have a
1612 * reasonable expectation that we will be having a long term
1613 * relationship with this host.
1617 register struct peer *peer,
1618 register struct pkt *pkt,
1623 double p_offset, p_del, p_disp;
1624 l_fp p_rec, p_xmt, p_org, p_reftime, ci;
1625 u_char pmode, pleap, pversion, pstratum;
1626 char statstr[NTP_MAXSTRLEN];
1629 double etemp, ftemp, td;
1634 p_del = FPTOD(NTOHS_FP(pkt->rootdelay));
1636 p_disp = FPTOD(NTOHS_FP(pkt->rootdisp));
1637 NTOHL_FP(&pkt->reftime, &p_reftime);
1638 NTOHL_FP(&pkt->org, &p_org);
1639 NTOHL_FP(&pkt->rec, &p_rec);
1640 NTOHL_FP(&pkt->xmt, &p_xmt);
1641 pmode = PKT_MODE(pkt->li_vn_mode);
1642 pleap = PKT_LEAP(pkt->li_vn_mode);
1643 pversion = PKT_VERSION(pkt->li_vn_mode);
1644 pstratum = PKT_TO_STRATUM(pkt->stratum);
1647 * Capture the header values in the client/peer association..
1649 record_raw_stats(&peer->srcadr, peer->dstadr ?
1650 &peer->dstadr->sin : NULL,
1651 &p_org, &p_rec, &p_xmt, &peer->dst,
1652 pleap, pversion, pmode, pstratum, pkt->ppoll, pkt->precision,
1653 p_del, p_disp, pkt->refid);
1655 peer->stratum = min(pstratum, STRATUM_UNSPEC);
1656 peer->pmode = pmode;
1657 peer->precision = pkt->precision;
1658 peer->rootdelay = p_del;
1659 peer->rootdisp = p_disp;
1660 peer->refid = pkt->refid; /* network byte order */
1661 peer->reftime = p_reftime;
1664 * First, if either burst mode is armed, enable the burst.
1665 * Compute the headway for the next packet and delay if
1666 * necessary to avoid exceeding the threshold.
1668 if (peer->retry > 0) {
1671 peer->burst = min(1 << (peer->hpoll -
1672 peer->minpoll), NTP_SHIFT) - 1;
1674 peer->burst = NTP_IBURST - 1;
1675 if (peer->burst > 0)
1676 peer->nextdate = current_time;
1678 poll_update(peer, peer->hpoll);
1681 * Verify the server is synchronized; that is, the leap bits,
1682 * stratum and root distance are valid.
1684 if ( pleap == LEAP_NOTINSYNC /* test 6 */
1685 || pstratum < sys_floor || pstratum >= sys_ceiling)
1686 peer->flash |= TEST6; /* bad synch or strat */
1687 if (p_del / 2 + p_disp >= MAXDISPERSE) /* test 7 */
1688 peer->flash |= TEST7; /* bad header */
1691 * If any tests fail at this point, the packet is discarded.
1692 * Note that some flashers may have already been set in the
1693 * receive() routine.
1695 if (peer->flash & PKT_TEST_MASK) {
1696 peer->seldisptoolarge++;
1699 printf("packet: flash header %04x\n",
1706 * If the peer was previously unreachable, raise a trap. In any
1707 * case, mark it reachable.
1710 report_event(PEVNT_REACH, peer, NULL);
1711 peer->timereachable = current_time;
1716 * For a client/server association, calculate the clock offset,
1717 * roundtrip delay and dispersion. The equations are reordered
1718 * from the spec for more efficient use of temporaries. For a
1719 * broadcast association, offset the last measurement by the
1720 * computed delay during the client/server volley. Note the
1721 * computation of dispersion includes the system precision plus
1722 * that due to the frequency error since the origin time.
1724 * It is very important to respect the hazards of overflow. The
1725 * only permitted operation on raw timestamps is subtraction,
1726 * where the result is a signed quantity spanning from 68 years
1727 * in the past to 68 years in the future. To avoid loss of
1728 * precision, these calculations are done using 64-bit integer
1729 * arithmetic. However, the offset and delay calculations are
1730 * sums and differences of these first-order differences, which
1731 * if done using 64-bit integer arithmetic, would be valid over
1732 * only half that span. Since the typical first-order
1733 * differences are usually very small, they are converted to 64-
1734 * bit doubles and all remaining calculations done in floating-
1735 * double arithmetic. This preserves the accuracy while
1736 * retaining the 68-year span.
1738 * There are three interleaving schemes, basic, interleaved
1739 * symmetric and interleaved broadcast. The timestamps are
1740 * idioscyncratically different. See the onwire briefing/white
1741 * paper at www.eecis.udel.edu/~mills for details.
1743 * Interleaved symmetric mode
1744 * t1 = peer->aorg/borg, t2 = peer->rec, t3 = p_xmt,
1747 if (peer->flip != 0) {
1748 ci = p_xmt; /* t3 - t4 */
1749 L_SUB(&ci, &peer->dst);
1751 ci = p_rec; /* t2 - t1 */
1753 L_SUB(&ci, &peer->borg);
1755 L_SUB(&ci, &peer->aorg);
1758 p_offset = (t21 + t34) / 2.;
1759 if (p_del < 0 || p_del > 1.) {
1760 snprintf(statstr, sizeof(statstr),
1761 "t21 %.6f t34 %.6f", t21, t34);
1762 report_event(PEVNT_XERR, peer, statstr);
1769 } else if (peer->pmode == MODE_BROADCAST) {
1772 * Interleaved broadcast mode. Use interleaved timestamps.
1773 * t1 = peer->borg, t2 = p_org, t3 = p_org, t4 = aorg
1775 if (peer->flags & FLAG_XB) {
1776 ci = p_org; /* delay */
1777 L_SUB(&ci, &peer->aorg);
1779 ci = p_org; /* t2 - t1 */
1780 L_SUB(&ci, &peer->borg);
1783 peer->borg = peer->dst;
1784 if (t34 < 0 || t34 > 1.) {
1785 snprintf(statstr, sizeof(statstr),
1786 "offset %.6f delay %.6f", t21, t34);
1787 report_event(PEVNT_XERR, peer, statstr);
1794 * Basic broadcast - use direct timestamps.
1795 * t3 = p_xmt, t4 = peer->dst
1798 ci = p_xmt; /* t3 - t4 */
1799 L_SUB(&ci, &peer->dst);
1805 * When calibration is complete and the clock is
1806 * synchronized, the bias is calculated as the difference
1807 * between the unicast timestamp and the broadcast
1808 * timestamp. This works for both basic and interleaved
1811 if (FLAG_BC_VOL & peer->flags) {
1812 peer->flags &= ~FLAG_BC_VOL;
1813 peer->delay = fabs(peer->offset - p_offset) * 2;
1815 p_del = peer->delay;
1816 p_offset += p_del / 2;
1820 * Basic mode, otherwise known as the old fashioned way.
1822 * t1 = p_org, t2 = p_rec, t3 = p_xmt, t4 = peer->dst
1825 ci = p_xmt; /* t3 - t4 */
1826 L_SUB(&ci, &peer->dst);
1828 ci = p_rec; /* t2 - t1 */
1831 p_del = fabs(t21 - t34);
1832 p_offset = (t21 + t34) / 2.;
1834 p_del = max(p_del, LOGTOD(sys_precision));
1835 p_disp = LOGTOD(sys_precision) + LOGTOD(peer->precision) +
1840 * This code calculates the outbound and inbound data rates by
1841 * measuring the differences between timestamps at different
1842 * packet lengths. This is helpful in cases of large asymmetric
1843 * delays commonly experienced on deep space communication
1846 if (peer->t21_last > 0 && peer->t34_bytes > 0) {
1847 itemp = peer->t21_bytes - peer->t21_last;
1849 etemp = t21 - peer->t21;
1850 if (fabs(etemp) > 1e-6) {
1851 ftemp = itemp / etemp;
1856 itemp = len - peer->t34_bytes;
1858 etemp = -t34 - peer->t34;
1859 if (fabs(etemp) > 1e-6) {
1860 ftemp = itemp / etemp;
1868 * The following section compensates for different data rates on
1869 * the outbound (d21) and inbound (t34) directions. To do this,
1870 * it finds t such that r21 * t - r34 * (d - t) = 0, where d is
1871 * the roundtrip delay. Then it calculates the correction as a
1875 peer->t21_last = peer->t21_bytes;
1877 peer->t34_bytes = len;
1880 printf("packet: t21 %.9lf %d t34 %.9lf %d\n", peer->t21,
1881 peer->t21_bytes, peer->t34, peer->t34_bytes);
1883 if (peer->r21 > 0 && peer->r34 > 0 && p_del > 0) {
1884 if (peer->pmode != MODE_BROADCAST)
1885 td = (peer->r34 / (peer->r21 + peer->r34) -
1891 * Unfortunately, in many cases the errors are
1892 * unacceptable, so for the present the rates are not
1893 * used. In future, we might find conditions where the
1894 * calculations are useful, so this should be considered
1895 * a work in progress.
1901 printf("packet: del %.6lf r21 %.1lf r34 %.1lf %.6lf\n",
1902 p_del, peer->r21 / 1e3, peer->r34 / 1e3,
1909 * That was awesome. Now hand off to the clock filter.
1911 clock_filter(peer, p_offset + peer->bias, p_del, p_disp);
1914 * If we are in broadcast calibrate mode, return to broadcast
1915 * client mode when the client is fit and the autokey dance is
1918 if ( (FLAG_BC_VOL & peer->flags)
1919 && MODE_CLIENT == peer->hmode
1920 && !(TEST11 & peer_unfit(peer))) { /* distance exceeded */
1922 if (peer->flags & FLAG_SKEY) {
1923 if (!(~peer->crypto & CRYPTO_FLAG_ALL))
1924 peer->hmode = MODE_BCLIENT;
1926 peer->hmode = MODE_BCLIENT;
1928 #else /* !AUTOKEY follows */
1929 peer->hmode = MODE_BCLIENT;
1930 #endif /* !AUTOKEY */
1936 * clock_update - Called at system process update intervals.
1940 struct peer *peer /* peer structure pointer */
1945 #ifdef HAVE_LIBSCF_H
1947 #endif /* HAVE_LIBSCF_H */
1950 * Update the system state variables. We do this very carefully,
1951 * as the poll interval might need to be clamped differently.
1954 sys_epoch = peer->epoch;
1955 if (sys_poll < peer->minpoll)
1956 sys_poll = peer->minpoll;
1957 if (sys_poll > peer->maxpoll)
1958 sys_poll = peer->maxpoll;
1959 poll_update(peer, sys_poll);
1960 sys_stratum = min(peer->stratum + 1, STRATUM_UNSPEC);
1961 if ( peer->stratum == STRATUM_REFCLOCK
1962 || peer->stratum == STRATUM_UNSPEC)
1963 sys_refid = peer->refid;
1965 sys_refid = addr2refid(&peer->srcadr);
1967 * Root Dispersion (E) is defined (in RFC 5905) as:
1969 * E = p.epsilon_r + p.epsilon + p.psi + PHI*(s.t - p.t) + |THETA|
1972 * p.epsilon_r is the PollProc's root dispersion
1973 * p.epsilon is the PollProc's dispersion
1974 * p.psi is the PollProc's jitter
1975 * THETA is the combined offset
1977 * NB: Think Hard about where these numbers come from and
1978 * what they mean. When did peer->update happen? Has anything
1979 * interesting happened since then? What values are the most
1982 * DLM thinks this equation is probably the best of all worse choices.
1984 dtemp = peer->rootdisp
1987 + clock_phi * (current_time - peer->update)
1990 if (dtemp > sys_mindisp)
1991 sys_rootdisp = dtemp;
1993 sys_rootdisp = sys_mindisp;
1994 sys_rootdelay = peer->delay + peer->rootdelay;
1995 sys_reftime = peer->dst;
2000 "clock_update: at %lu sample %lu associd %d\n",
2001 current_time, peer->epoch, peer->associd);
2005 * Comes now the moment of truth. Crank the clock discipline and
2006 * see what comes out.
2008 switch (local_clock(peer, sys_offset)) {
2011 * Clock exceeds panic threshold. Life as we know it ends.
2014 #ifdef HAVE_LIBSCF_H
2016 * For Solaris enter the maintenance mode.
2018 if ((fmri = getenv("SMF_FMRI")) != NULL) {
2019 if (smf_maintain_instance(fmri, 0) < 0) {
2020 printf("smf_maintain_instance: %s\n",
2021 scf_strerror(scf_error()));
2025 * Sleep until SMF kills us.
2030 #endif /* HAVE_LIBSCF_H */
2035 * Clock was stepped. Flush all time values of all peers.
2039 set_sys_leap(LEAP_NOTINSYNC);
2040 sys_stratum = STRATUM_UNSPEC;
2041 memcpy(&sys_refid, "STEP", 4);
2044 L_CLR(&sys_reftime);
2045 sys_jitter = LOGTOD(sys_precision);
2046 leapsec_reset_frame();
2050 * Clock was slewed. Handle the leapsecond stuff.
2055 * If this is the first time the clock is set, reset the
2056 * leap bits. If crypto, the timer will goose the setup
2059 if (sys_leap == LEAP_NOTINSYNC) {
2060 set_sys_leap(LEAP_NOWARNING);
2064 #endif /* AUTOKEY */
2066 * If our parent process is waiting for the
2067 * first clock sync, send them home satisfied.
2069 #ifdef HAVE_WORKING_FORK
2070 if (waitsync_fd_to_close != -1) {
2071 close(waitsync_fd_to_close);
2072 waitsync_fd_to_close = -1;
2073 DPRINTF(1, ("notified parent --wait-sync is done\n"));
2075 #endif /* HAVE_WORKING_FORK */
2080 * If there is no leap second pending and the number of
2081 * survivor leap bits is greater than half the number of
2082 * survivors, try to schedule a leap for the end of the
2083 * current month. (This only works if no leap second for
2084 * that range is in the table, so doing this more than
2085 * once is mostly harmless.)
2087 if (leapsec == LSPROX_NOWARN) {
2088 if ( leap_vote_ins > leap_vote_del
2089 && leap_vote_ins > sys_survivors / 2) {
2091 leapsec_add_dyn(TRUE, now.l_ui, NULL);
2093 if ( leap_vote_del > leap_vote_ins
2094 && leap_vote_del > sys_survivors / 2) {
2096 leapsec_add_dyn(FALSE, now.l_ui, NULL);
2102 * Popcorn spike or step threshold exceeded. Pretend it never
2112 * poll_update - update peer poll interval
2116 struct peer *peer, /* peer structure pointer */
2124 * This routine figures out when the next poll should be sent.
2125 * That turns out to be wickedly complicated. One problem is
2126 * that sometimes the time for the next poll is in the past when
2127 * the poll interval is reduced. We watch out for races here
2128 * between the receive process and the poll process.
2130 * Clamp the poll interval between minpoll and maxpoll.
2132 hpoll = max(min(peer->maxpoll, mpoll), peer->minpoll);
2136 * If during the crypto protocol the poll interval has changed,
2137 * the lifetimes in the key list are probably bogus. Purge the
2138 * the key list and regenerate it later.
2140 if ((peer->flags & FLAG_SKEY) && hpoll != peer->hpoll)
2142 #endif /* AUTOKEY */
2143 peer->hpoll = hpoll;
2146 * There are three variables important for poll scheduling, the
2147 * current time (current_time), next scheduled time (nextdate)
2148 * and the earliest time (utemp). The earliest time is 2 s
2149 * seconds, but could be more due to rate management. When
2150 * sending in a burst, use the earliest time. When not in a
2151 * burst but with a reply pending, send at the earliest time
2152 * unless the next scheduled time has not advanced. This can
2153 * only happen if multiple replies are pending in the same
2154 * response interval. Otherwise, send at the later of the next
2155 * scheduled time and the earliest time.
2157 * Now we figure out if there is an override. If a burst is in
2158 * progress and we get called from the receive process, just
2159 * slink away. If called from the poll process, delay 1 s for a
2160 * reference clock, otherwise 2 s.
2162 utemp = current_time + max(peer->throttle - (NTP_SHIFT - 1) *
2163 (1 << peer->minpoll), ntp_minpkt);
2164 if (peer->burst > 0) {
2165 if (peer->nextdate > current_time)
2168 else if (peer->flags & FLAG_REFCLOCK)
2169 peer->nextdate = current_time + RESP_DELAY;
2170 #endif /* REFCLOCK */
2172 peer->nextdate = utemp;
2176 * If a burst is not in progress and a crypto response message
2177 * is pending, delay 2 s, but only if this is a new interval.
2179 } else if (peer->cmmd != NULL) {
2180 if (peer->nextdate > current_time) {
2181 if (peer->nextdate + ntp_minpkt != utemp)
2182 peer->nextdate = utemp;
2184 peer->nextdate = utemp;
2186 #endif /* AUTOKEY */
2189 * The ordinary case. If a retry, use minpoll; if unreachable,
2190 * use host poll; otherwise, use the minimum of host and peer
2191 * polls; In other words, oversampling is okay but
2192 * understampling is evil. Use the maximum of this value and the
2193 * headway. If the average headway is greater than the headway
2194 * threshold, increase the headway by the minimum interval.
2197 if (peer->retry > 0)
2198 hpoll = peer->minpoll;
2199 else if (!(peer->reach))
2200 hpoll = peer->hpoll;
2202 hpoll = min(peer->ppoll, peer->hpoll);
2204 if (peer->flags & FLAG_REFCLOCK)
2207 #endif /* REFCLOCK */
2208 next = ((0x1000UL | (ntp_random() & 0x0ff)) <<
2210 next += peer->outdate;
2212 peer->nextdate = next;
2214 peer->nextdate = utemp;
2215 if (peer->throttle > (1 << peer->minpoll))
2216 peer->nextdate += ntp_minpkt;
2218 DPRINTF(2, ("poll_update: at %lu %s poll %d burst %d retry %d head %d early %lu next %lu\n",
2219 current_time, ntoa(&peer->srcadr), peer->hpoll,
2220 peer->burst, peer->retry, peer->throttle,
2221 utemp - current_time, peer->nextdate -
2227 * peer_clear - clear peer filter registers. See Section 3.4.8 of the
2232 struct peer *peer, /* peer structure */
2233 const char *ident /* tally lights */
2240 * If cryptographic credentials have been acquired, toss them to
2241 * Valhalla. Note that autokeys are ephemeral, in that they are
2242 * tossed immediately upon use. Therefore, the keylist can be
2243 * purged anytime without needing to preserve random keys. Note
2244 * that, if the peer is purged, the cryptographic variables are
2245 * purged, too. This makes it much harder to sneak in some
2246 * unauthenticated data in the clock filter.
2249 if (peer->iffval != NULL)
2250 BN_free(peer->iffval);
2251 value_free(&peer->cookval);
2252 value_free(&peer->recval);
2253 value_free(&peer->encrypt);
2254 value_free(&peer->sndval);
2255 if (peer->cmmd != NULL)
2257 if (peer->subject != NULL)
2258 free(peer->subject);
2259 if (peer->issuer != NULL)
2261 #endif /* AUTOKEY */
2264 * Clear all values, including the optional crypto values above.
2266 memset(CLEAR_TO_ZERO(peer), 0, LEN_CLEAR_TO_ZERO(peer));
2267 peer->ppoll = peer->maxpoll;
2268 peer->hpoll = peer->minpoll;
2269 peer->disp = MAXDISPERSE;
2270 peer->flash = peer_unfit(peer);
2271 peer->jitter = LOGTOD(sys_precision);
2274 * If interleave mode, initialize the alternate origin switch.
2276 if (peer->flags & FLAG_XLEAVE)
2278 for (u = 0; u < NTP_SHIFT; u++) {
2279 peer->filter_order[u] = u;
2280 peer->filter_disp[u] = MAXDISPERSE;
2283 if (!(peer->flags & FLAG_REFCLOCK)) {
2285 peer->leap = LEAP_NOTINSYNC;
2286 peer->stratum = STRATUM_UNSPEC;
2287 memcpy(&peer->refid, ident, 4);
2293 * During initialization use the association count to spread out
2294 * the polls at one-second intervals. Passive associations'
2295 * first poll is delayed by the "discard minimum" to avoid rate
2296 * limiting. Other post-startup new or cleared associations
2297 * randomize the first poll over the minimum poll interval to
2300 peer->nextdate = peer->update = peer->outdate = current_time;
2302 peer->nextdate += peer_associations;
2303 } else if (MODE_PASSIVE == peer->hmode) {
2304 peer->nextdate += ntp_minpkt;
2306 peer->nextdate += ntp_random() % peer->minpoll;
2309 peer->refresh = current_time + (1 << NTP_REFRESH);
2310 #endif /* AUTOKEY */
2314 "peer_clear: at %ld next %ld associd %d refid %s\n",
2315 current_time, peer->nextdate, peer->associd,
2322 * clock_filter - add incoming clock sample to filter register and run
2323 * the filter procedure to find the best sample.
2327 struct peer *peer, /* peer structure pointer */
2328 double sample_offset, /* clock offset */
2329 double sample_delay, /* roundtrip delay */
2330 double sample_disp /* dispersion */
2333 double dst[NTP_SHIFT]; /* distance vector */
2334 int ord[NTP_SHIFT]; /* index vector */
2336 double dtemp, etemp;
2340 * A sample consists of the offset, delay, dispersion and epoch
2341 * of arrival. The offset and delay are determined by the on-
2342 * wire protocol. The dispersion grows from the last outbound
2343 * packet to the arrival of this one increased by the sum of the
2344 * peer precision and the system precision as required by the
2345 * error budget. First, shift the new arrival into the shift
2346 * register discarding the oldest one.
2348 j = peer->filter_nextpt;
2349 peer->filter_offset[j] = sample_offset;
2350 peer->filter_delay[j] = sample_delay;
2351 peer->filter_disp[j] = sample_disp;
2352 peer->filter_epoch[j] = current_time;
2353 j = (j + 1) % NTP_SHIFT;
2354 peer->filter_nextpt = j;
2357 * Update dispersions since the last update and at the same
2358 * time initialize the distance and index lists. Since samples
2359 * become increasingly uncorrelated beyond the Allan intercept,
2360 * only under exceptional cases will an older sample be used.
2361 * Therefore, the distance list uses a compound metric. If the
2362 * dispersion is greater than the maximum dispersion, clamp the
2363 * distance at that value. If the time since the last update is
2364 * less than the Allan intercept use the delay; otherwise, use
2365 * the sum of the delay and dispersion.
2367 dtemp = clock_phi * (current_time - peer->update);
2368 peer->update = current_time;
2369 for (i = NTP_SHIFT - 1; i >= 0; i--) {
2371 peer->filter_disp[j] += dtemp;
2372 if (peer->filter_disp[j] >= MAXDISPERSE) {
2373 peer->filter_disp[j] = MAXDISPERSE;
2374 dst[i] = MAXDISPERSE;
2375 } else if (peer->update - peer->filter_epoch[j] >
2376 (u_long)ULOGTOD(allan_xpt)) {
2377 dst[i] = peer->filter_delay[j] +
2378 peer->filter_disp[j];
2380 dst[i] = peer->filter_delay[j];
2383 j = (j + 1) % NTP_SHIFT;
2387 * If the clock has stabilized, sort the samples by distance.
2389 if (freq_cnt == 0) {
2390 for (i = 1; i < NTP_SHIFT; i++) {
2391 for (j = 0; j < i; j++) {
2392 if (dst[j] > dst[i]) {
2405 * Copy the index list to the association structure so ntpq
2406 * can see it later. Prune the distance list to leave only
2407 * samples less than the maximum dispersion, which disfavors
2408 * uncorrelated samples older than the Allan intercept. To
2409 * further improve the jitter estimate, of the remainder leave
2410 * only samples less than the maximum distance, but keep at
2411 * least two samples for jitter calculation.
2414 for (i = 0; i < NTP_SHIFT; i++) {
2415 peer->filter_order[i] = (u_char) ord[i];
2416 if ( dst[i] >= MAXDISPERSE
2417 || (m >= 2 && dst[i] >= sys_maxdist))
2423 * Compute the dispersion and jitter. The dispersion is weighted
2424 * exponentially by NTP_FWEIGHT (0.5) so it is normalized close
2425 * to 1.0. The jitter is the RMS differences relative to the
2426 * lowest delay sample.
2428 peer->disp = peer->jitter = 0;
2430 for (i = NTP_SHIFT - 1; i >= 0; i--) {
2432 peer->disp = NTP_FWEIGHT * (peer->disp +
2433 peer->filter_disp[j]);
2435 peer->jitter += DIFF(peer->filter_offset[j],
2436 peer->filter_offset[k]);
2440 * If no acceptable samples remain in the shift register,
2441 * quietly tiptoe home leaving only the dispersion. Otherwise,
2442 * save the offset, delay and jitter. Note the jitter must not
2443 * be less than the precision.
2449 etemp = fabs(peer->offset - peer->filter_offset[k]);
2450 peer->offset = peer->filter_offset[k];
2451 peer->delay = peer->filter_delay[k];
2453 peer->jitter /= m - 1;
2454 peer->jitter = max(SQRT(peer->jitter), LOGTOD(sys_precision));
2457 * If the the new sample and the current sample are both valid
2458 * and the difference between their offsets exceeds CLOCK_SGATE
2459 * (3) times the jitter and the interval between them is less
2460 * than twice the host poll interval, consider the new sample
2461 * a popcorn spike and ignore it.
2463 if ( peer->disp < sys_maxdist
2464 && peer->filter_disp[k] < sys_maxdist
2465 && etemp > CLOCK_SGATE * peer->jitter
2466 && peer->filter_epoch[k] - peer->epoch
2467 < 2. * ULOGTOD(peer->hpoll)) {
2468 snprintf(tbuf, sizeof(tbuf), "%.6f s", etemp);
2469 report_event(PEVNT_POPCORN, peer, tbuf);
2474 * A new minimum sample is useful only if it is later than the
2475 * last one used. In this design the maximum lifetime of any
2476 * sample is not greater than eight times the poll interval, so
2477 * the maximum interval between minimum samples is eight
2480 if (peer->filter_epoch[k] <= peer->epoch) {
2483 printf("clock_filter: old sample %lu\n", current_time -
2484 peer->filter_epoch[k]);
2488 peer->epoch = peer->filter_epoch[k];
2491 * The mitigated sample statistics are saved for later
2492 * processing. If not synchronized or not in a burst, tickle the
2493 * clock select algorithm.
2495 record_peer_stats(&peer->srcadr, ctlpeerstatus(peer),
2496 peer->offset, peer->delay, peer->disp, peer->jitter);
2500 "clock_filter: n %d off %.6f del %.6f dsp %.6f jit %.6f\n",
2501 m, peer->offset, peer->delay, peer->disp,
2504 if (peer->burst == 0 || sys_leap == LEAP_NOTINSYNC)
2510 * clock_select - find the pick-of-the-litter clock
2512 * LOCKCLOCK: (1) If the local clock is the prefer peer, it will always
2513 * be enabled, even if declared falseticker, (2) only the prefer peer
2514 * can be selected as the system peer, (3) if the external source is
2515 * down, the system leap bits are set to 11 and the stratum set to
2529 double orphmet = 2.0 * U_INT32_MAX; /* 2x is greater than */
2530 struct endpoint endp;
2531 struct peer *osys_peer;
2532 struct peer *sys_prefer = NULL; /* prefer peer */
2533 struct peer *typesystem = NULL;
2534 struct peer *typeorphan = NULL;
2536 struct peer *typeacts = NULL;
2537 struct peer *typelocal = NULL;
2538 struct peer *typepps = NULL;
2539 #endif /* REFCLOCK */
2540 static struct endpoint *endpoint = NULL;
2541 static int *indx = NULL;
2542 static peer_select *peers = NULL;
2543 static u_int endpoint_size = 0;
2544 static u_int peers_size = 0;
2545 static u_int indx_size = 0;
2549 * Initialize and create endpoint, index and peer lists big
2550 * enough to handle all associations.
2552 osys_peer = sys_peer;
2555 set_sys_leap(LEAP_NOTINSYNC);
2556 sys_stratum = STRATUM_UNSPEC;
2557 memcpy(&sys_refid, "DOWN", 4);
2558 #endif /* LOCKCLOCK */
2561 * Allocate dynamic space depending on the number of
2565 for (peer = peer_list; peer != NULL; peer = peer->p_link)
2567 endpoint_size = ALIGNED_SIZE(nlist * 2 * sizeof(*endpoint));
2568 peers_size = ALIGNED_SIZE(nlist * sizeof(*peers));
2569 indx_size = ALIGNED_SIZE(nlist * 2 * sizeof(*indx));
2570 octets = endpoint_size + peers_size + indx_size;
2571 endpoint = erealloc(endpoint, octets);
2572 peers = INC_ALIGNED_PTR(endpoint, endpoint_size);
2573 indx = INC_ALIGNED_PTR(peers, peers_size);
2576 * Initially, we populate the island with all the rifraff peers
2577 * that happen to be lying around. Those with seriously
2578 * defective clocks are immediately booted off the island. Then,
2579 * the falsetickers are culled and put to sea. The truechimers
2580 * remaining are subject to repeated rounds where the most
2581 * unpopular at each round is kicked off. When the population
2582 * has dwindled to sys_minclock, the survivors split a million
2583 * bucks and collectively crank the chimes.
2585 nlist = nl2 = 0; /* none yet */
2586 for (peer = peer_list; peer != NULL; peer = peer->p_link) {
2587 peer->new_status = CTL_PST_SEL_REJECT;
2590 * Leave the island immediately if the peer is
2591 * unfit to synchronize.
2593 if (peer_unfit(peer))
2597 * If this peer is an orphan parent, elect the
2598 * one with the lowest metric defined as the
2599 * IPv4 address or the first 64 bits of the
2600 * hashed IPv6 address. To ensure convergence
2601 * on the same selected orphan, consider as
2602 * well that this system may have the lowest
2603 * metric and be the orphan parent. If this
2604 * system wins, sys_peer will be NULL to trigger
2605 * orphan mode in timer().
2607 if (peer->stratum == sys_orphan) {
2611 if (peer->dstadr != NULL)
2612 localmet = ntohl(peer->dstadr->addr_refid);
2614 localmet = U_INT32_MAX;
2615 peermet = ntohl(addr2refid(&peer->srcadr));
2616 if (peermet < localmet && peermet < orphmet) {
2624 * If this peer could have the orphan parent
2625 * as a synchronization ancestor, exclude it
2626 * from selection to avoid forming a
2627 * synchronization loop within the orphan mesh,
2628 * triggering stratum climb to infinity
2629 * instability. Peers at stratum higher than
2630 * the orphan stratum could have the orphan
2631 * parent in ancestry so are excluded.
2632 * See http://bugs.ntp.org/2050
2634 if (peer->stratum > sys_orphan)
2638 * The following are special cases. We deal
2641 if (!(peer->flags & FLAG_PREFER)) {
2642 switch (peer->refclktype) {
2643 case REFCLK_LOCALCLOCK:
2644 if ( current_time > orphwait
2645 && typelocal == NULL)
2650 if ( current_time > orphwait
2651 && typeacts == NULL)
2656 #endif /* REFCLOCK */
2659 * If we get this far, the peer can stay on the
2660 * island, but does not yet have the immunity
2663 peer->new_status = CTL_PST_SEL_SANE;
2664 f = root_distance(peer);
2665 peers[nlist].peer = peer;
2666 peers[nlist].error = peer->jitter;
2667 peers[nlist].synch = f;
2671 * Insert each interval endpoint on the unsorted
2675 endpoint[nl2].type = -1; /* lower end */
2676 endpoint[nl2].val = e - f;
2678 endpoint[nl2].type = 1; /* upper end */
2679 endpoint[nl2].val = e + f;
2683 * Construct sorted indx[] of endpoint[] indexes ordered by
2686 for (i = 0; i < nl2; i++)
2688 for (i = 0; i < nl2; i++) {
2689 endp = endpoint[indx[i]];
2692 for (j = i + 1; j < nl2; j++) {
2693 endp = endpoint[indx[j]];
2705 for (i = 0; i < nl2; i++)
2706 DPRINTF(3, ("select: endpoint %2d %.6f\n",
2707 endpoint[indx[i]].type, endpoint[indx[i]].val));
2710 * This is the actual algorithm that cleaves the truechimers
2711 * from the falsetickers. The original algorithm was described
2712 * in Keith Marzullo's dissertation, but has been modified for
2715 * Briefly put, we first assume there are no falsetickers, then
2716 * scan the candidate list first from the low end upwards and
2717 * then from the high end downwards. The scans stop when the
2718 * number of intersections equals the number of candidates less
2719 * the number of falsetickers. If this doesn't happen for a
2720 * given number of falsetickers, we bump the number of
2721 * falsetickers and try again. If the number of falsetickers
2722 * becomes equal to or greater than half the number of
2723 * candidates, the Albanians have won the Byzantine wars and
2724 * correct synchronization is not possible.
2726 * Here, nlist is the number of candidates and allow is the
2727 * number of falsetickers. Upon exit, the truechimers are the
2728 * survivors with offsets not less than low and not greater than
2729 * high. There may be none of them.
2733 for (allow = 0; 2 * allow < nlist; allow++) {
2736 * Bound the interval (low, high) as the smallest
2737 * interval containing points from the most sources.
2740 for (i = 0; i < nl2; i++) {
2741 low = endpoint[indx[i]].val;
2742 n -= endpoint[indx[i]].type;
2743 if (n >= nlist - allow)
2747 for (j = nl2 - 1; j >= 0; j--) {
2748 high = endpoint[indx[j]].val;
2749 n += endpoint[indx[j]].type;
2750 if (n >= nlist - allow)
2755 * If an interval containing truechimers is found, stop.
2756 * If not, increase the number of falsetickers and go
2764 * Clustering algorithm. Whittle candidate list of falsetickers,
2765 * who leave the island immediately. The TRUE peer is always a
2766 * truechimer. We must leave at least one peer to collect the
2769 * We assert the correct time is contained in the interval, but
2770 * the best offset estimate for the interval might not be
2771 * contained in the interval. For this purpose, a truechimer is
2772 * defined as the midpoint of an interval that overlaps the
2773 * intersection interval.
2776 for (i = 0; i < nlist; i++) {
2779 peer = peers[i].peer;
2782 || peer->offset + h < low
2783 || peer->offset - h > high
2784 ) && !(peer->flags & FLAG_TRUE))
2789 * Eligible PPS peers must survive the intersection
2790 * algorithm. Use the first one found, but don't
2791 * include any of them in the cluster population.
2793 if (peer->flags & FLAG_PPS) {
2794 if (typepps == NULL)
2796 if (!(peer->flags & FLAG_TSTAMP_PPS))
2799 #endif /* REFCLOCK */
2802 peers[j] = peers[i];
2808 * If no survivors remain at this point, check if the modem
2809 * driver, local driver or orphan parent in that order. If so,
2810 * nominate the first one found as the only survivor.
2811 * Otherwise, give up and leave the island to the rats.
2815 peers[0].synch = sys_mindisp;
2817 if (typeacts != NULL) {
2818 peers[0].peer = typeacts;
2820 } else if (typelocal != NULL) {
2821 peers[0].peer = typelocal;
2824 #endif /* REFCLOCK */
2825 if (typeorphan != NULL) {
2826 peers[0].peer = typeorphan;
2832 * Mark the candidates at this point as truechimers.
2834 for (i = 0; i < nlist; i++) {
2835 peers[i].peer->new_status = CTL_PST_SEL_SELCAND;
2836 DPRINTF(2, ("select: survivor %s %f\n",
2837 stoa(&peers[i].peer->srcadr), peers[i].synch));
2841 * Now, vote outliers off the island by select jitter weighted
2842 * by root distance. Continue voting as long as there are more
2843 * than sys_minclock survivors and the select jitter of the peer
2844 * with the worst metric is greater than the minimum peer
2845 * jitter. Stop if we are about to discard a TRUE or PREFER
2846 * peer, who of course have the immunity idol.
2853 for (i = 0; i < nlist; i++) {
2854 if (peers[i].error < d)
2856 peers[i].seljit = 0;
2859 for (j = 0; j < nlist; j++)
2860 f += DIFF(peers[j].peer->offset,
2861 peers[i].peer->offset);
2862 peers[i].seljit = SQRT(f / (nlist - 1));
2864 if (peers[i].seljit * peers[i].synch > e) {
2865 g = peers[i].seljit;
2866 e = peers[i].seljit * peers[i].synch;
2870 g = max(g, LOGTOD(sys_precision));
2871 if ( nlist <= max(1, sys_minclock)
2873 || ((FLAG_TRUE | FLAG_PREFER) & peers[k].peer->flags))
2876 DPRINTF(3, ("select: drop %s seljit %.6f jit %.6f\n",
2877 ntoa(&peers[k].peer->srcadr), g, d));
2878 if (nlist > sys_maxclock)
2879 peers[k].peer->new_status = CTL_PST_SEL_EXCESS;
2880 for (j = k + 1; j < nlist; j++)
2881 peers[j - 1] = peers[j];
2886 * What remains is a list usually not greater than sys_minclock
2887 * peers. Note that unsynchronized peers cannot survive this
2888 * far. Count and mark these survivors.
2890 * While at it, count the number of leap warning bits found.
2891 * This will be used later to vote the system leap warning bit.
2892 * If a leap warning bit is found on a reference clock, the vote
2895 * Choose the system peer using a hybrid metric composed of the
2896 * selection jitter scaled by the root distance augmented by
2897 * stratum scaled by sys_mindisp (.001 by default). The goal of
2898 * the small stratum factor is to avoid clockhop between a
2899 * reference clock and a network peer which has a refclock and
2900 * is using an older ntpd, which does not floor sys_rootdisp at
2903 * In contrast, ntpd 4.2.6 and earlier used stratum primarily
2904 * in selecting the system peer, using a weight of 1 second of
2905 * additional root distance per stratum. This heavy bias is no
2906 * longer appropriate, as the scaled root distance provides a
2907 * more rational metric carrying the cumulative error budget.
2913 for (i = 0; i < nlist; i++) {
2914 peer = peers[i].peer;
2916 peer->new_status = CTL_PST_SEL_SYNCCAND;
2918 if (peer->leap == LEAP_ADDSECOND) {
2919 if (peer->flags & FLAG_REFCLOCK)
2920 leap_vote_ins = nlist;
2921 else if (leap_vote_ins < nlist)
2924 if (peer->leap == LEAP_DELSECOND) {
2925 if (peer->flags & FLAG_REFCLOCK)
2926 leap_vote_del = nlist;
2927 else if (leap_vote_del < nlist)
2930 if (peer->flags & FLAG_PREFER)
2932 speermet = peers[i].seljit * peers[i].synch +
2933 peer->stratum * sys_mindisp;
2941 * Unless there are at least sys_misane survivors, leave the
2942 * building dark. Otherwise, do a clockhop dance. Ordinarily,
2943 * use the selected survivor speer. However, if the current
2944 * system peer is not speer, stay with the current system peer
2945 * as long as it doesn't get too old or too ugly.
2947 if (nlist > 0 && nlist >= sys_minsane) {
2950 typesystem = peers[speer].peer;
2951 if (osys_peer == NULL || osys_peer == typesystem) {
2953 } else if ((x = fabs(typesystem->offset -
2954 osys_peer->offset)) < sys_mindisp) {
2955 if (sys_clockhop == 0)
2956 sys_clockhop = sys_mindisp;
2959 DPRINTF(1, ("select: clockhop %d %.6f %.6f\n",
2960 j, x, sys_clockhop));
2961 if (fabs(x) < sys_clockhop)
2962 typesystem = osys_peer;
2971 * Mitigation rules of the game. We have the pick of the
2972 * litter in typesystem if any survivors are left. If
2973 * there is a prefer peer, use its offset and jitter.
2974 * Otherwise, use the combined offset and jitter of all kitters.
2976 if (typesystem != NULL) {
2977 if (sys_prefer == NULL) {
2978 typesystem->new_status = CTL_PST_SEL_SYSPEER;
2979 clock_combine(peers, sys_survivors, speer);
2981 typesystem = sys_prefer;
2983 typesystem->new_status = CTL_PST_SEL_SYSPEER;
2984 sys_offset = typesystem->offset;
2985 sys_jitter = typesystem->jitter;
2987 DPRINTF(1, ("select: combine offset %.9f jitter %.9f\n",
2988 sys_offset, sys_jitter));
2992 * If a PPS driver is lit and the combined offset is less than
2993 * 0.4 s, select the driver as the PPS peer and use its offset
2994 * and jitter. However, if this is the atom driver, use it only
2995 * if there is a prefer peer or there are no survivors and none
2998 if ( typepps != NULL
2999 && fabs(sys_offset) < 0.4
3000 && ( typepps->refclktype != REFCLK_ATOM_PPS
3001 || ( typepps->refclktype == REFCLK_ATOM_PPS
3002 && ( sys_prefer != NULL
3003 || (typesystem == NULL && sys_minsane == 0))))) {
3004 typesystem = typepps;
3006 typesystem->new_status = CTL_PST_SEL_PPS;
3007 sys_offset = typesystem->offset;
3008 sys_jitter = typesystem->jitter;
3009 DPRINTF(1, ("select: pps offset %.9f jitter %.9f\n",
3010 sys_offset, sys_jitter));
3012 #endif /* REFCLOCK */
3015 * If there are no survivors at this point, there is no
3016 * system peer. If so and this is an old update, keep the
3017 * current statistics, but do not update the clock.
3019 if (typesystem == NULL) {
3020 if (osys_peer != NULL) {
3021 if (sys_orphwait > 0)
3022 orphwait = current_time + sys_orphwait;
3023 report_event(EVNT_NOPEER, NULL, NULL);
3026 for (peer = peer_list; peer != NULL; peer = peer->p_link)
3027 peer->status = peer->new_status;
3032 * Do not use old data, as this may mess up the clock discipline
3035 if (typesystem->epoch <= sys_epoch)
3039 * We have found the alpha male. Wind the clock.
3041 if (osys_peer != typesystem)
3042 report_event(PEVNT_NEWPEER, typesystem, NULL);
3043 for (peer = peer_list; peer != NULL; peer = peer->p_link)
3044 peer->status = peer->new_status;
3045 clock_update(typesystem);
3051 peer_select * peers, /* survivor list */
3052 int npeers, /* number of survivors */
3053 int syspeer /* index of sys.peer */
3060 for (i = 0; i < npeers; i++) {
3061 x = 1. / peers[i].synch;
3063 z += x * peers[i].peer->offset;
3064 w += x * DIFF(peers[i].peer->offset,
3065 peers[syspeer].peer->offset);
3068 sys_jitter = SQRT(w / y + SQUARE(peers[syspeer].seljit));
3073 * root_distance - compute synchronization distance from peer to root
3077 struct peer *peer /* peer structure pointer */
3083 * Root Distance (LAMBDA) is defined as:
3084 * (delta + DELTA)/2 + epsilon + EPSILON + phi
3087 * delta is the round-trip delay
3088 * DELTA is the root delay
3089 * epsilon is the remote server precision + local precision
3090 * + (15 usec each second)
3091 * EPSILON is the root dispersion
3092 * phi is the peer jitter statistic
3094 * NB: Think hard about why we are using these values, and what
3095 * the alternatives are, and the various pros/cons.
3097 * DLM thinks these are probably the best choices from any of the
3098 * other worse choices.
3100 dtemp = (peer->delay + peer->rootdelay) / 2
3101 + LOGTOD(peer->precision)
3102 + LOGTOD(sys_precision)
3103 + clock_phi * (current_time - peer->update)
3107 * Careful squeak here. The value returned must be greater than
3108 * the minimum root dispersion in order to avoid clockhop with
3109 * highly precise reference clocks. Note that the root distance
3110 * cannot exceed the sys_maxdist, as this is the cutoff by the
3111 * selection algorithm.
3113 if (dtemp < sys_mindisp)
3114 dtemp = sys_mindisp;
3120 * peer_xmit - send packet for persistent association.
3124 struct peer *peer /* peer structure pointer */
3127 struct pkt xpkt; /* transmit packet */
3128 size_t sendlen, authlen;
3129 keyid_t xkeyid = 0; /* transmit key ID */
3130 l_fp xmt_tx, xmt_ty;
3132 if (!peer->dstadr) /* drop peers without interface */
3135 xpkt.li_vn_mode = PKT_LI_VN_MODE(sys_leap, peer->version,
3137 xpkt.stratum = STRATUM_TO_PKT(sys_stratum);
3138 xpkt.ppoll = peer->hpoll;
3139 xpkt.precision = sys_precision;
3140 xpkt.refid = sys_refid;
3141 xpkt.rootdelay = HTONS_FP(DTOFP(sys_rootdelay));
3142 xpkt.rootdisp = HTONS_FP(DTOUFP(sys_rootdisp));
3143 HTONL_FP(&sys_reftime, &xpkt.reftime);
3144 HTONL_FP(&peer->rec, &xpkt.org);
3145 HTONL_FP(&peer->dst, &xpkt.rec);
3148 * If the received packet contains a MAC, the transmitted packet
3149 * is authenticated and contains a MAC. If not, the transmitted
3150 * packet is not authenticated.
3152 * It is most important when autokey is in use that the local
3153 * interface IP address be known before the first packet is
3154 * sent. Otherwise, it is not possible to compute a correct MAC
3155 * the recipient will accept. Thus, the I/O semantics have to do
3156 * a little more work. In particular, the wildcard interface
3157 * might not be usable.
3159 sendlen = LEN_PKT_NOMAC;
3161 if (!(peer->flags & FLAG_SKEY) && peer->keyid == 0) {
3162 #else /* !AUTOKEY follows */
3163 if (peer->keyid == 0) {
3164 #endif /* !AUTOKEY */
3167 * Transmit a-priori timestamps
3169 get_systime(&xmt_tx);
3170 if (peer->flip == 0) { /* basic mode */
3171 peer->aorg = xmt_tx;
3172 HTONL_FP(&xmt_tx, &xpkt.xmt);
3173 } else { /* interleaved modes */
3174 if (peer->hmode == MODE_BROADCAST) { /* bcst */
3175 HTONL_FP(&xmt_tx, &xpkt.xmt);
3177 HTONL_FP(&peer->borg,
3180 HTONL_FP(&peer->aorg,
3182 } else { /* symmetric */
3184 HTONL_FP(&peer->borg,
3187 HTONL_FP(&peer->aorg,
3191 peer->t21_bytes = sendlen;
3192 sendpkt(&peer->srcadr, peer->dstadr, sys_ttl[peer->ttl],
3195 peer->throttle += (1 << peer->minpoll) - 2;
3198 * Capture a-posteriori timestamps
3200 get_systime(&xmt_ty);
3201 if (peer->flip != 0) { /* interleaved modes */
3203 peer->aorg = xmt_ty;
3205 peer->borg = xmt_ty;
3206 peer->flip = -peer->flip;
3208 L_SUB(&xmt_ty, &xmt_tx);
3209 LFPTOD(&xmt_ty, peer->xleave);
3212 printf("transmit: at %ld %s->%s mode %d len %zu\n",
3213 current_time, peer->dstadr ?
3214 stoa(&peer->dstadr->sin) : "-",
3215 stoa(&peer->srcadr), peer->hmode, sendlen);
3221 * Authentication is enabled, so the transmitted packet must be
3222 * authenticated. If autokey is enabled, fuss with the various
3223 * modes; otherwise, symmetric key cryptography is used.
3226 if (peer->flags & FLAG_SKEY) {
3227 struct exten *exten; /* extension field */
3230 * The Public Key Dance (PKD): Cryptographic credentials
3231 * are contained in extension fields, each including a
3232 * 4-octet length/code word followed by a 4-octet
3233 * association ID and optional additional data. Optional
3234 * data includes a 4-octet data length field followed by
3235 * the data itself. Request messages are sent from a
3236 * configured association; response messages can be sent
3237 * from a configured association or can take the fast
3238 * path without ever matching an association. Response
3239 * messages have the same code as the request, but have
3240 * a response bit and possibly an error bit set. In this
3241 * implementation, a message may contain no more than
3242 * one command and one or more responses.
3244 * Cryptographic session keys include both a public and
3245 * a private componet. Request and response messages
3246 * using extension fields are always sent with the
3247 * private component set to zero. Packets without
3248 * extension fields indlude the private component when
3249 * the session key is generated.
3254 * Allocate and initialize a keylist if not
3255 * already done. Then, use the list in inverse
3256 * order, discarding keys once used. Keep the
3257 * latest key around until the next one, so
3258 * clients can use client/server packets to
3259 * compute propagation delay.
3261 * Note that once a key is used from the list,
3262 * it is retained in the key cache until the
3263 * next key is used. This is to allow a client
3264 * to retrieve the encrypted session key
3265 * identifier to verify authenticity.
3267 * If for some reason a key is no longer in the
3268 * key cache, a birthday has happened or the key
3269 * has expired, so the pseudo-random sequence is
3270 * broken. In that case, purge the keylist and
3273 if (peer->keynumber == 0)
3274 make_keylist(peer, peer->dstadr);
3277 xkeyid = peer->keylist[peer->keynumber];
3278 if (authistrusted(xkeyid))
3283 peer->keyid = xkeyid;
3285 switch (peer->hmode) {
3288 * In broadcast server mode the autokey values are
3289 * required by the broadcast clients. Push them when a
3290 * new keylist is generated; otherwise, push the
3291 * association message so the client can request them at
3294 case MODE_BROADCAST:
3295 if (peer->flags & FLAG_ASSOC)
3296 exten = crypto_args(peer, CRYPTO_AUTO |
3297 CRYPTO_RESP, peer->associd, NULL);
3299 exten = crypto_args(peer, CRYPTO_ASSOC |
3300 CRYPTO_RESP, peer->associd, NULL);
3304 * In symmetric modes the parameter, certificate,
3305 * identity, cookie and autokey exchanges are
3306 * required. The leapsecond exchange is optional. But, a
3307 * peer will not believe the other peer until the other
3308 * peer has synchronized, so the certificate exchange
3309 * might loop until then. If a peer finds a broken
3310 * autokey sequence, it uses the autokey exchange to
3311 * retrieve the autokey values. In any case, if a new
3312 * keylist is generated, the autokey values are pushed.
3318 * Parameter, certificate and identity.
3321 exten = crypto_args(peer, CRYPTO_ASSOC,
3322 peer->associd, hostval.ptr);
3323 else if (!(peer->crypto & CRYPTO_FLAG_CERT))
3324 exten = crypto_args(peer, CRYPTO_CERT,
3325 peer->associd, peer->issuer);
3326 else if (!(peer->crypto & CRYPTO_FLAG_VRFY))
3327 exten = crypto_args(peer,
3328 crypto_ident(peer), peer->associd,
3332 * Cookie and autokey. We request the cookie
3333 * only when the this peer and the other peer
3334 * are synchronized. But, this peer needs the
3335 * autokey values when the cookie is zero. Any
3336 * time we regenerate the key list, we offer the
3337 * autokey values without being asked. If for
3338 * some reason either peer finds a broken
3339 * autokey sequence, the autokey exchange is
3340 * used to retrieve the autokey values.
3342 else if ( sys_leap != LEAP_NOTINSYNC
3343 && peer->leap != LEAP_NOTINSYNC
3344 && !(peer->crypto & CRYPTO_FLAG_COOK))
3345 exten = crypto_args(peer, CRYPTO_COOK,
3346 peer->associd, NULL);
3347 else if (!(peer->crypto & CRYPTO_FLAG_AUTO))
3348 exten = crypto_args(peer, CRYPTO_AUTO,
3349 peer->associd, NULL);
3350 else if ( peer->flags & FLAG_ASSOC
3351 && peer->crypto & CRYPTO_FLAG_SIGN)
3352 exten = crypto_args(peer, CRYPTO_AUTO |
3353 CRYPTO_RESP, peer->assoc, NULL);
3356 * Wait for clock sync, then sign the
3357 * certificate and retrieve the leapsecond
3360 else if (sys_leap == LEAP_NOTINSYNC)
3363 else if (!(peer->crypto & CRYPTO_FLAG_SIGN))
3364 exten = crypto_args(peer, CRYPTO_SIGN,
3365 peer->associd, hostval.ptr);
3366 else if (!(peer->crypto & CRYPTO_FLAG_LEAP))
3367 exten = crypto_args(peer, CRYPTO_LEAP,
3368 peer->associd, NULL);
3372 * In client mode the parameter, certificate, identity,
3373 * cookie and sign exchanges are required. The
3374 * leapsecond exchange is optional. If broadcast client
3375 * mode the same exchanges are required, except that the
3376 * autokey exchange is substitutes for the cookie
3377 * exchange, since the cookie is always zero. If the
3378 * broadcast client finds a broken autokey sequence, it
3379 * uses the autokey exchange to retrieve the autokey
3385 * Parameter, certificate and identity.
3388 exten = crypto_args(peer, CRYPTO_ASSOC,
3389 peer->associd, hostval.ptr);
3390 else if (!(peer->crypto & CRYPTO_FLAG_CERT))
3391 exten = crypto_args(peer, CRYPTO_CERT,
3392 peer->associd, peer->issuer);
3393 else if (!(peer->crypto & CRYPTO_FLAG_VRFY))
3394 exten = crypto_args(peer,
3395 crypto_ident(peer), peer->associd,
3399 * Cookie and autokey. These are requests, but
3400 * we use the peer association ID with autokey
3401 * rather than our own.
3403 else if (!(peer->crypto & CRYPTO_FLAG_COOK))
3404 exten = crypto_args(peer, CRYPTO_COOK,
3405 peer->associd, NULL);
3406 else if (!(peer->crypto & CRYPTO_FLAG_AUTO))
3407 exten = crypto_args(peer, CRYPTO_AUTO,
3411 * Wait for clock sync, then sign the
3412 * certificate and retrieve the leapsecond
3415 else if (sys_leap == LEAP_NOTINSYNC)
3418 else if (!(peer->crypto & CRYPTO_FLAG_SIGN))
3419 exten = crypto_args(peer, CRYPTO_SIGN,
3420 peer->associd, hostval.ptr);
3421 else if (!(peer->crypto & CRYPTO_FLAG_LEAP))
3422 exten = crypto_args(peer, CRYPTO_LEAP,
3423 peer->associd, NULL);
3428 * Add a queued extension field if present. This is
3429 * always a request message, so the reply ID is already
3430 * in the message. If an error occurs, the error bit is
3431 * lit in the response.
3433 if (peer->cmmd != NULL) {
3436 temp32 = CRYPTO_RESP;
3437 peer->cmmd->opcode |= htonl(temp32);
3438 sendlen += crypto_xmit(peer, &xpkt, NULL,
3439 sendlen, peer->cmmd, 0);
3445 * Add an extension field created above. All but the
3446 * autokey response message are request messages.
3448 if (exten != NULL) {
3449 if (exten->opcode != 0)
3450 sendlen += crypto_xmit(peer, &xpkt,
3451 NULL, sendlen, exten, 0);
3456 * Calculate the next session key. Since extension
3457 * fields are present, the cookie value is zero.
3459 if (sendlen > (int)LEN_PKT_NOMAC) {
3460 session_key(&peer->dstadr->sin, &peer->srcadr,
3464 #endif /* AUTOKEY */
3467 * Transmit a-priori timestamps
3469 get_systime(&xmt_tx);
3470 if (peer->flip == 0) { /* basic mode */
3471 peer->aorg = xmt_tx;
3472 HTONL_FP(&xmt_tx, &xpkt.xmt);
3473 } else { /* interleaved modes */
3474 if (peer->hmode == MODE_BROADCAST) { /* bcst */
3475 HTONL_FP(&xmt_tx, &xpkt.xmt);
3477 HTONL_FP(&peer->borg, &xpkt.org);
3479 HTONL_FP(&peer->aorg, &xpkt.org);
3480 } else { /* symmetric */
3482 HTONL_FP(&peer->borg, &xpkt.xmt);
3484 HTONL_FP(&peer->aorg, &xpkt.xmt);
3487 xkeyid = peer->keyid;
3488 authlen = authencrypt(xkeyid, (u_int32 *)&xpkt, sendlen);
3490 report_event(PEVNT_AUTH, peer, "no key");
3491 peer->flash |= TEST5; /* auth error */
3497 if (xkeyid > NTP_MAXKEY)
3498 authtrust(xkeyid, 0);
3499 #endif /* AUTOKEY */
3500 if (sendlen > sizeof(xpkt)) {
3501 msyslog(LOG_ERR, "proto: buffer overflow %zu", sendlen);
3504 peer->t21_bytes = sendlen;
3505 sendpkt(&peer->srcadr, peer->dstadr, sys_ttl[peer->ttl], &xpkt,
3508 peer->throttle += (1 << peer->minpoll) - 2;
3511 * Capture a-posteriori timestamps
3513 get_systime(&xmt_ty);
3514 if (peer->flip != 0) { /* interleaved modes */
3516 peer->aorg = xmt_ty;
3518 peer->borg = xmt_ty;
3519 peer->flip = -peer->flip;
3521 L_SUB(&xmt_ty, &xmt_tx);
3522 LFPTOD(&xmt_ty, peer->xleave);
3526 printf("transmit: at %ld %s->%s mode %d keyid %08x len %zu index %d\n",
3527 current_time, latoa(peer->dstadr),
3528 ntoa(&peer->srcadr), peer->hmode, xkeyid, sendlen,
3531 #else /* !AUTOKEY follows */
3534 printf("transmit: at %ld %s->%s mode %d keyid %08x len %d\n",
3535 current_time, peer->dstadr ?
3536 ntoa(&peer->dstadr->sin) : "-",
3537 ntoa(&peer->srcadr), peer->hmode, xkeyid, sendlen);
3539 #endif /* !AUTOKEY */
3546 leap_smear_add_offs(l_fp *t, l_fp *t_recv) {
3547 L_ADD(t, &leap_smear.offset);
3550 #endif /* LEAP_SMEAR */
3554 * fast_xmit - Send packet for nonpersistent association. Note that
3555 * neither the source or destination can be a broadcast address.
3559 struct recvbuf *rbufp, /* receive packet pointer */
3560 int xmode, /* receive mode */
3561 keyid_t xkeyid, /* transmit key ID */
3562 int flags /* restrict mask */
3565 struct pkt xpkt; /* transmit packet structure */
3566 struct pkt *rpkt; /* receive packet structure */
3567 l_fp xmt_tx, xmt_ty;
3574 * Initialize transmit packet header fields from the receive
3575 * buffer provided. We leave the fields intact as received, but
3576 * set the peer poll at the maximum of the receive peer poll and
3577 * the system minimum poll (ntp_minpoll). This is for KoD rate
3578 * control and not strictly specification compliant, but doesn't
3581 * If the gazinta was from a multicast address, the gazoutta
3582 * must go out another way.
3584 rpkt = &rbufp->recv_pkt;
3585 if (rbufp->dstadr->flags & INT_MCASTOPEN)
3586 rbufp->dstadr = findinterface(&rbufp->recv_srcadr);
3589 * If this is a kiss-o'-death (KoD) packet, show leap
3590 * unsynchronized, stratum zero, reference ID the four-character
3591 * kiss code and system root delay. Note we don't reveal the
3592 * local time, so these packets can't be used for
3595 if (flags & RES_KOD) {
3597 xpkt.li_vn_mode = PKT_LI_VN_MODE(LEAP_NOTINSYNC,
3598 PKT_VERSION(rpkt->li_vn_mode), xmode);
3599 xpkt.stratum = STRATUM_PKT_UNSPEC;
3600 xpkt.ppoll = max(rpkt->ppoll, ntp_minpoll);
3601 xpkt.precision = rpkt->precision;
3602 memcpy(&xpkt.refid, "RATE", 4);
3603 xpkt.rootdelay = rpkt->rootdelay;
3604 xpkt.rootdisp = rpkt->rootdisp;
3605 xpkt.reftime = rpkt->reftime;
3606 xpkt.org = rpkt->xmt;
3607 xpkt.rec = rpkt->xmt;
3608 xpkt.xmt = rpkt->xmt;
3611 * This is a normal packet. Use the system variables.
3616 * Make copies of the variables which can be affected by smearing.
3619 l_fp this_recv_time;
3623 * If we are inside the leap smear interval we add the current smear offset to
3624 * the packet receive time, to the packet transmit time, and eventually to the
3625 * reftime to make sure the reftime isn't later than the transmit/receive times.
3627 xpkt.li_vn_mode = PKT_LI_VN_MODE(xmt_leap,
3628 PKT_VERSION(rpkt->li_vn_mode), xmode);
3630 xpkt.stratum = STRATUM_TO_PKT(sys_stratum);
3631 xpkt.ppoll = max(rpkt->ppoll, ntp_minpoll);
3632 xpkt.precision = sys_precision;
3633 xpkt.refid = sys_refid;
3634 xpkt.rootdelay = HTONS_FP(DTOFP(sys_rootdelay));
3635 xpkt.rootdisp = HTONS_FP(DTOUFP(sys_rootdisp));
3638 this_ref_time = sys_reftime;
3639 if (leap_smear.in_progress) {
3640 leap_smear_add_offs(&this_ref_time, NULL);
3641 xpkt.refid = convertLFPToRefID(leap_smear.offset);
3642 DPRINTF(2, ("fast_xmit: leap_smear.in_progress: refid %8x, smear %s\n",
3644 lfptoa(&leap_smear.offset, 8)
3647 HTONL_FP(&this_ref_time, &xpkt.reftime);
3649 HTONL_FP(&sys_reftime, &xpkt.reftime);
3652 xpkt.org = rpkt->xmt;
3655 this_recv_time = rbufp->recv_time;
3656 if (leap_smear.in_progress)
3657 leap_smear_add_offs(&this_recv_time, NULL);
3658 HTONL_FP(&this_recv_time, &xpkt.rec);
3660 HTONL_FP(&rbufp->recv_time, &xpkt.rec);
3663 get_systime(&xmt_tx);
3665 if (leap_smear.in_progress)
3666 leap_smear_add_offs(&xmt_tx, &this_recv_time);
3668 HTONL_FP(&xmt_tx, &xpkt.xmt);
3671 #ifdef HAVE_NTP_SIGND
3672 if (flags & RES_MSSNTP) {
3673 send_via_ntp_signd(rbufp, xmode, xkeyid, flags, &xpkt);
3676 #endif /* HAVE_NTP_SIGND */
3679 * If the received packet contains a MAC, the transmitted packet
3680 * is authenticated and contains a MAC. If not, the transmitted
3681 * packet is not authenticated.
3683 sendlen = LEN_PKT_NOMAC;
3684 if (rbufp->recv_length == sendlen) {
3685 sendpkt(&rbufp->recv_srcadr, rbufp->dstadr, 0, &xpkt,
3690 "transmit: at %ld %s->%s mode %d len %d\n",
3691 current_time, stoa(&rbufp->dstadr->sin),
3692 stoa(&rbufp->recv_srcadr), xmode, sendlen);
3698 * The received packet contains a MAC, so the transmitted packet
3699 * must be authenticated. For symmetric key cryptography, use
3700 * the predefined and trusted symmetric keys to generate the
3701 * cryptosum. For autokey cryptography, use the server private
3702 * value to generate the cookie, which is unique for every
3703 * source-destination-key ID combination.
3706 if (xkeyid > NTP_MAXKEY) {
3710 * The only way to get here is a reply to a legitimate
3711 * client request message, so the mode must be
3712 * MODE_SERVER. If an extension field is present, there
3713 * can be only one and that must be a command. Do what
3714 * needs, but with private value of zero so the poor
3715 * jerk can decode it. If no extension field is present,
3716 * use the cookie to generate the session key.
3718 cookie = session_key(&rbufp->recv_srcadr,
3719 &rbufp->dstadr->sin, 0, sys_private, 0);
3720 if (rbufp->recv_length > sendlen + (int)MAX_MAC_LEN) {
3721 session_key(&rbufp->dstadr->sin,
3722 &rbufp->recv_srcadr, xkeyid, 0, 2);
3723 temp32 = CRYPTO_RESP;
3724 rpkt->exten[0] |= htonl(temp32);
3725 sendlen += crypto_xmit(NULL, &xpkt, rbufp,
3726 sendlen, (struct exten *)rpkt->exten,
3729 session_key(&rbufp->dstadr->sin,
3730 &rbufp->recv_srcadr, xkeyid, cookie, 2);
3733 #endif /* AUTOKEY */
3734 get_systime(&xmt_tx);
3735 sendlen += authencrypt(xkeyid, (u_int32 *)&xpkt, sendlen);
3737 if (xkeyid > NTP_MAXKEY)
3738 authtrust(xkeyid, 0);
3739 #endif /* AUTOKEY */
3740 sendpkt(&rbufp->recv_srcadr, rbufp->dstadr, 0, &xpkt, sendlen);
3741 get_systime(&xmt_ty);
3742 L_SUB(&xmt_ty, &xmt_tx);
3743 sys_authdelay = xmt_ty;
3747 "transmit: at %ld %s->%s mode %d keyid %08x len %d\n",
3748 current_time, ntoa(&rbufp->dstadr->sin),
3749 ntoa(&rbufp->recv_srcadr), xmode, xkeyid, sendlen);
3755 * pool_xmit - resolve hostname or send unicast solicitation for pool.
3759 struct peer *pool /* pool solicitor association */
3763 struct pkt xpkt; /* transmit packet structure */
3764 struct addrinfo hints;
3766 struct interface * lcladr;
3767 sockaddr_u * rmtadr;
3772 if (NULL == pool->ai) {
3773 if (pool->addrs != NULL) {
3774 /* free() is used with copy_addrinfo_list() */
3779 hints.ai_family = AF(&pool->srcadr);
3780 hints.ai_socktype = SOCK_DGRAM;
3781 hints.ai_protocol = IPPROTO_UDP;
3782 /* ignore getaddrinfo_sometime() errors, we will retry */
3783 rc = getaddrinfo_sometime(
3788 &pool_name_resolved,
3789 (void *)(intptr_t)pool->associd);
3791 DPRINTF(1, ("pool DNS lookup %s started\n",
3795 "unable to start pool DNS %s: %m",
3801 /* copy_addrinfo_list ai_addr points to a sockaddr_u */
3802 rmtadr = (sockaddr_u *)(void *)pool->ai->ai_addr;
3803 pool->ai = pool->ai->ai_next;
3804 p = findexistingpeer(rmtadr, NULL, NULL, MODE_CLIENT, 0);
3805 } while (p != NULL && pool->ai != NULL);
3807 return; /* out of addresses, re-query DNS next poll */
3808 restrict_mask = restrictions(rmtadr);
3809 if (RES_FLAGS & restrict_mask)
3810 restrict_source(rmtadr, 0,
3811 current_time + POOL_SOLICIT_WINDOW + 1);
3812 lcladr = findinterface(rmtadr);
3813 memset(&xpkt, 0, sizeof(xpkt));
3814 xpkt.li_vn_mode = PKT_LI_VN_MODE(sys_leap, pool->version,
3816 xpkt.stratum = STRATUM_TO_PKT(sys_stratum);
3817 xpkt.ppoll = pool->hpoll;
3818 xpkt.precision = sys_precision;
3819 xpkt.refid = sys_refid;
3820 xpkt.rootdelay = HTONS_FP(DTOFP(sys_rootdelay));
3821 xpkt.rootdisp = HTONS_FP(DTOUFP(sys_rootdisp));
3822 HTONL_FP(&sys_reftime, &xpkt.reftime);
3823 get_systime(&xmt_tx);
3824 pool->aorg = xmt_tx;
3825 HTONL_FP(&xmt_tx, &xpkt.xmt);
3826 sendpkt(rmtadr, lcladr, sys_ttl[pool->ttl], &xpkt,
3829 pool->throttle += (1 << pool->minpoll) - 2;
3832 printf("transmit: at %ld %s->%s pool\n",
3833 current_time, latoa(lcladr), stoa(rmtadr));
3835 msyslog(LOG_INFO, "Soliciting pool server %s", stoa(rmtadr));
3842 * group_test - test if this is the same group
3844 * host assoc return action
3845 * none none 0 mobilize *
3846 * none group 0 mobilize *
3847 * group none 0 mobilize *
3848 * group group 1 mobilize
3849 * group different 1 ignore
3850 * * ignore if notrust
3860 if (strcmp(grp, sys_groupname) == 0)
3866 if (strcmp(grp, ident) == 0)
3871 #endif /* AUTOKEY */
3880 const char * service,
3881 const struct addrinfo * hints,
3882 const struct addrinfo * res
3885 struct peer * pool; /* pool solicitor association */
3890 "error resolving pool %s: %s (%d)",
3891 name, gai_strerror(rescode), rescode);
3895 assoc = (associd_t)(intptr_t)context;
3896 pool = findpeerbyassoc(assoc);
3899 "Could not find assoc %u for pool DNS %s",
3903 DPRINTF(1, ("pool DNS %s completed\n", name));
3904 pool->addrs = copy_addrinfo_list(res);
3905 pool->ai = pool->addrs;
3914 * key_expire - purge the key list
3918 struct peer *peer /* peer structure pointer */
3923 if (peer->keylist != NULL) {
3924 for (i = 0; i <= peer->keynumber; i++)
3925 authtrust(peer->keylist[i], 0);
3926 free(peer->keylist);
3927 peer->keylist = NULL;
3929 value_free(&peer->sndval);
3930 peer->keynumber = 0;
3931 peer->flags &= ~FLAG_ASSOC;
3934 printf("key_expire: at %lu associd %d\n", current_time,
3938 #endif /* AUTOKEY */
3942 * local_refid(peer) - check peer refid to avoid selecting peers
3943 * currently synced to this ntpd.
3952 if (p->dstadr != NULL && !(INT_MCASTIF & p->dstadr->flags))
3953 unicast_ep = p->dstadr;
3955 unicast_ep = findinterface(&p->srcadr);
3957 if (unicast_ep != NULL && p->refid == unicast_ep->addr_refid)
3965 * Determine if the peer is unfit for synchronization
3967 * A peer is unfit for synchronization if
3968 * > TEST10 bad leap or stratum below floor or at or above ceiling
3969 * > TEST11 root distance exceeded for remote peer
3970 * > TEST12 a direct or indirect synchronization loop would form
3971 * > TEST13 unreachable or noselect
3973 int /* FALSE if fit, TRUE if unfit */
3975 struct peer *peer /* peer structure pointer */
3981 * A stratum error occurs if (1) the server has never been
3982 * synchronized, (2) the server stratum is below the floor or
3983 * greater than or equal to the ceiling.
3985 if ( peer->leap == LEAP_NOTINSYNC
3986 || peer->stratum < sys_floor
3987 || peer->stratum >= sys_ceiling)
3988 rval |= TEST10; /* bad synch or stratum */
3991 * A distance error for a remote peer occurs if the root
3992 * distance is greater than or equal to the distance threshold
3993 * plus the increment due to one host poll interval.
3995 if ( !(peer->flags & FLAG_REFCLOCK)
3996 && root_distance(peer) >= sys_maxdist
3997 + clock_phi * ULOGTOD(peer->hpoll))
3998 rval |= TEST11; /* distance exceeded */
4001 * A loop error occurs if the remote peer is synchronized to the
4002 * local peer or if the remote peer is synchronized to the same
4003 * server as the local peer but only if the remote peer is
4004 * neither a reference clock nor an orphan.
4006 if (peer->stratum > 1 && local_refid(peer))
4007 rval |= TEST12; /* synchronization loop */
4010 * An unreachable error occurs if the server is unreachable or
4011 * the noselect bit is set.
4013 if (!peer->reach || (peer->flags & FLAG_NOSELECT))
4014 rval |= TEST13; /* unreachable */
4016 peer->flash &= ~PEER_TEST_MASK;
4017 peer->flash |= rval;
4023 * Find the precision of this particular machine
4025 #define MINSTEP 20e-9 /* minimum clock increment (s) */
4026 #define MAXSTEP 1 /* maximum clock increment (s) */
4027 #define MINCHANGES 12 /* minimum number of step samples */
4028 #define MAXLOOPS ((int)(1. / MINSTEP)) /* avoid infinite loop */
4031 * This routine measures the system precision defined as the minimum of
4032 * a sequence of differences between successive readings of the system
4033 * clock. However, if a difference is less than MINSTEP, the clock has
4034 * been read more than once during a clock tick and the difference is
4035 * ignored. We set MINSTEP greater than zero in case something happens
4036 * like a cache miss, and to tolerate underlying system clocks which
4037 * ensure each reading is strictly greater than prior readings while
4038 * using an underlying stepping (not interpolated) clock.
4040 * sys_tick and sys_precision represent the time to read the clock for
4041 * systems with high-precision clocks, and the tick interval or step
4042 * size for lower-precision stepping clocks.
4044 * This routine also measures the time to read the clock on stepping
4045 * system clocks by counting the number of readings between changes of
4046 * the underlying clock. With either type of clock, the minimum time
4047 * to read the clock is saved as sys_fuzz, and used to ensure the
4048 * get_systime() readings always increase and are fuzzed below sys_fuzz.
4051 measure_precision(void)
4054 * With sys_fuzz set to zero, get_systime() fuzzing of low bits
4055 * is effectively disabled. trunc_os_clock is FALSE to disable
4056 * get_ostime() simulation of a low-precision system clock.
4059 trunc_os_clock = FALSE;
4060 measured_tick = measure_tick_fuzz();
4061 set_sys_tick_precision(measured_tick);
4062 msyslog(LOG_INFO, "proto: precision = %.3f usec (%d)",
4063 sys_tick * 1e6, sys_precision);
4064 if (sys_fuzz < sys_tick) {
4065 msyslog(LOG_NOTICE, "proto: fuzz beneath %.3f usec",
4072 * measure_tick_fuzz()
4074 * measures the minimum time to read the clock (stored in sys_fuzz)
4075 * and returns the tick, the larger of the minimum increment observed
4076 * between successive clock readings and the time to read the clock.
4079 measure_tick_fuzz(void)
4081 l_fp minstep; /* MINSTEP as l_fp */
4082 l_fp val; /* current seconds fraction */
4083 l_fp last; /* last seconds fraction */
4084 l_fp ldiff; /* val - last */
4085 double tick; /* computed tick value */
4090 int i; /* log2 precision */
4096 DTOLFP(MINSTEP, &minstep);
4098 for (i = 0; i < MAXLOOPS && changes < MINCHANGES; i++) {
4101 L_SUB(&ldiff, &last);
4103 if (L_ISGT(&ldiff, &minstep)) {
4104 max_repeats = max(repeats, max_repeats);
4107 LFPTOD(&ldiff, diff);
4108 tick = min(diff, tick);
4113 if (changes < MINCHANGES) {
4114 msyslog(LOG_ERR, "Fatal error: precision could not be measured (MINSTEP too large?)");
4118 if (0 == max_repeats) {
4121 set_sys_fuzz(tick / max_repeats);
4129 set_sys_tick_precision(
4137 "unsupported tick %.3f > 1s ignored", tick);
4140 if (tick < measured_tick) {
4142 "proto: tick %.3f less than measured tick %.3f, ignored",
4143 tick, measured_tick);
4145 } else if (tick > measured_tick) {
4146 trunc_os_clock = TRUE;
4148 "proto: truncating system clock to multiples of %.9f",
4154 * Find the nearest power of two.
4156 for (i = 0; tick <= 1; i--)
4158 if (tick - 1 > 1 - tick / 2)
4161 sys_precision = (s_char)i;
4166 * init_proto - initialize the protocol module's data
4175 * Fill in the sys_* stuff. Default is don't listen to
4176 * broadcasting, require authentication.
4178 set_sys_leap(LEAP_NOTINSYNC);
4179 sys_stratum = STRATUM_UNSPEC;
4180 memcpy(&sys_refid, "INIT", 4);
4184 L_CLR(&sys_reftime);
4186 measure_precision();
4187 get_systime(&dummy);
4189 sys_manycastserver = 0;
4192 sys_authenticate = 1;
4193 sys_stattime = current_time;
4194 orphwait = current_time + sys_orphwait;
4196 for (i = 0; i < MAX_TTL; i++) {
4197 sys_ttl[i] = (u_char)((i * 256) / MAX_TTL);
4206 * proto_config - configure the protocol module
4217 * Figure out what he wants to change, then do it
4219 DPRINTF(2, ("proto_config: code %d value %lu dvalue %lf\n",
4220 item, value, dvalue));
4225 * enable and disable commands - arguments are Boolean.
4227 case PROTO_AUTHENTICATE: /* authentication (auth) */
4228 sys_authenticate = value;
4231 case PROTO_BROADCLIENT: /* broadcast client (bclient) */
4232 sys_bclient = (int)value;
4233 if (sys_bclient == 0)
4240 case PROTO_CAL: /* refclock calibrate (calibrate) */
4243 #endif /* REFCLOCK */
4245 case PROTO_KERNEL: /* kernel discipline (kernel) */
4249 case PROTO_MONITOR: /* monitoring (monitor) */
4255 msyslog(LOG_WARNING,
4256 "restrict: 'monitor' cannot be disabled while 'limited' is enabled");
4260 case PROTO_NTP: /* NTP discipline (ntp) */
4264 case PROTO_MODE7: /* mode7 management (ntpdc) */
4268 case PROTO_PPS: /* PPS discipline (pps) */
4269 hardpps_enable = value;
4272 case PROTO_FILEGEN: /* statistics (stats) */
4273 stats_control = value;
4277 * tos command - arguments are double, sometimes cast to int
4279 case PROTO_BEACON: /* manycast beacon (beacon) */
4280 sys_beacon = (int)dvalue;
4283 case PROTO_BROADDELAY: /* default broadcast delay (bdelay) */
4284 sys_bdelay = dvalue;
4287 case PROTO_CEILING: /* stratum ceiling (ceiling) */
4288 sys_ceiling = (int)dvalue;
4291 case PROTO_COHORT: /* cohort switch (cohort) */
4292 sys_cohort = (int)dvalue;
4295 case PROTO_FLOOR: /* stratum floor (floor) */
4296 sys_floor = (int)dvalue;
4299 case PROTO_MAXCLOCK: /* maximum candidates (maxclock) */
4300 sys_maxclock = (int)dvalue;
4303 case PROTO_MAXDIST: /* select threshold (maxdist) */
4304 sys_maxdist = dvalue;
4307 case PROTO_CALLDELAY: /* modem call delay (mdelay) */
4308 break; /* NOT USED */
4310 case PROTO_MINCLOCK: /* minimum candidates (minclock) */
4311 sys_minclock = (int)dvalue;
4314 case PROTO_MINDISP: /* minimum distance (mindist) */
4315 sys_mindisp = dvalue;
4318 case PROTO_MINSANE: /* minimum survivors (minsane) */
4319 sys_minsane = (int)dvalue;
4322 case PROTO_ORPHAN: /* orphan stratum (orphan) */
4323 sys_orphan = (int)dvalue;
4326 case PROTO_ORPHWAIT: /* orphan wait (orphwait) */
4327 orphwait -= sys_orphwait;
4328 sys_orphwait = (int)dvalue;
4329 orphwait += sys_orphwait;
4333 * Miscellaneous commands
4335 case PROTO_MULTICAST_ADD: /* add group address */
4337 io_multicast_add(svalue);
4341 case PROTO_MULTICAST_DEL: /* delete group address */
4343 io_multicast_del(svalue);
4348 "proto: unsupported option %d", item);
4354 * proto_clr_stats - clear protocol stat counters
4357 proto_clr_stats(void)
4359 sys_stattime = current_time;
4368 sys_limitrejected = 0;
projects / FreeBSD / releng / 10.2.git / blob