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"
19 #if defined(VMS) && defined(VMS_LOCALUNIT) /*wjm*/
20 #include "ntp_refclock.h"
23 #if defined(__FreeBSD__) && __FreeBSD__ >= 3
24 #include <sys/sysctl.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 : (y) == AUTH_OK || \
35 * System variables are declared here. See Section 3.2 of the
38 u_char sys_leap; /* system leap indicator */
39 u_char sys_stratum; /* stratum of system */
40 s_char sys_precision; /* local clock precision (log2 s) */
41 double sys_rootdelay; /* roundtrip delay to primary source */
42 double sys_rootdispersion; /* dispersion to primary source */
43 u_int32 sys_refid; /* source/loop in network byte order */
44 static double sys_offset; /* current local clock offset */
45 l_fp sys_reftime; /* time we were last updated */
46 struct peer *sys_peer; /* our current peer */
47 struct peer *sys_pps; /* our PPS peer */
48 struct peer *sys_prefer; /* our cherished peer */
49 int sys_kod; /* kod credit */
50 int sys_kod_rate = 2; /* max kod packets per second */
52 u_long sys_automax; /* maximum session key lifetime */
56 * Nonspecified system state variables.
58 int sys_bclient; /* broadcast client enable */
59 double sys_bdelay; /* broadcast client default delay */
60 int sys_calldelay; /* modem callup delay (s) */
61 int sys_authenticate; /* requre authentication for config */
62 l_fp sys_authdelay; /* authentication delay */
63 static u_long sys_authdly[2]; /* authentication delay shift reg */
64 static double sys_mindisp = MINDISPERSE; /* min disp increment (s) */
65 static double sys_maxdist = MAXDISTANCE; /* selection threshold (s) */
66 double sys_jitter; /* system jitter (s) */
67 static int sys_hopper; /* anticlockhop counter */
68 static int sys_maxhop = MAXHOP; /* anticlockhop counter threshold */
69 int leap_next; /* leap consensus */
70 keyid_t sys_private; /* private value for session seed */
71 int sys_manycastserver; /* respond to manycast client pkts */
72 int peer_ntpdate; /* active peers in ntpdate mode */
73 int sys_survivors; /* truest of the truechimers */
75 char *sys_hostname; /* gethostname() name */
79 * TOS and multicast mapping stuff
81 int sys_floor = 0; /* cluster stratum floor */
82 int sys_ceiling = STRATUM_UNSPEC; /* cluster stratum ceiling */
83 int sys_minsane = 1; /* minimum candidates */
84 int sys_minclock = NTP_MINCLOCK; /* minimum survivors */
85 int sys_maxclock = NTP_MAXCLOCK; /* maximum candidates */
86 int sys_cohort = 0; /* cohort switch */
87 int sys_orphan = STRATUM_UNSPEC + 1; /* orphan stratum */
88 double sys_orphandelay = 0; /* orphan root delay */
89 int sys_beacon = BEACON; /* manycast beacon interval */
90 int sys_ttlmax; /* max ttl mapping vector index */
91 u_char sys_ttl[MAX_TTL]; /* ttl mapping vector */
96 u_long sys_stattime; /* time since reset */
97 u_long sys_received; /* packets received */
98 u_long sys_processed; /* packets processed */
99 u_long sys_newversionpkt; /* current version */
100 u_long sys_oldversionpkt; /* recent version */
101 u_long sys_unknownversion; /* invalid version */
102 u_long sys_restricted; /* access denied */
103 u_long sys_badlength; /* bad length or format */
104 u_long sys_badauth; /* bad authentication */
105 u_long sys_limitrejected; /* rate exceeded */
107 static double root_distance P((struct peer *));
108 static void clock_combine P((struct peer **, int));
109 static void peer_xmit P((struct peer *));
110 static void fast_xmit P((struct recvbuf *, int, keyid_t,
112 static void clock_update P((void));
113 static int default_get_precision P((void));
114 static int peer_unfit P((struct peer *));
118 * transmit - Transmit Procedure. See Section 3.4.2 of the
123 struct peer *peer /* peer structure pointer */
129 * The polling state machine. There are two kinds of machines,
130 * those that never expect a reply (broadcast and manycast
131 * server modes) and those that do (all other modes). The dance
135 * Orphan mode is active when enabled and when no servers less
136 * than the orphan statum are available. In this mode packets
137 * are sent at the orphan stratum. An orphan with no other
138 * synchronization source is an orphan parent. It assumes root
139 * delay zero and reference ID the loopback address. All others
140 * are orphan children with root delay randomized over a 1-s
141 * range. The root delay is used by the election algorithm to
142 * select the order of synchronization.
145 if (sys_orphan < STRATUM_UNSPEC && sys_peer == NULL) {
146 sys_leap = LEAP_NOWARNING;
147 sys_stratum = sys_orphan;
148 sys_refid = htonl(LOOPBACKADR);
150 sys_rootdispersion = 0;
154 * In broadcast mode the poll interval is never changed from
157 if (peer->cast_flags & (MDF_BCAST | MDF_MCAST)) {
158 peer->outdate = current_time;
160 poll_update(peer, hpoll);
165 * In manycast mode we start with unity ttl. The ttl is
166 * increased by one for each poll until either sys_maxclock
167 * servers have been found or the maximum ttl is reached. When
168 * sys_maxclock servers are found we stop polling until one or
169 * more servers have timed out or until less than minpoll
170 * associations turn up. In this case additional better servers
171 * are dragged in and preempt the existing ones.
173 if (peer->cast_flags & MDF_ACAST) {
174 peer->outdate = current_time;
175 if (peer->unreach > sys_beacon) {
179 } else if (sys_survivors < sys_minclock ||
180 peer_preempt < sys_maxclock) {
181 if (peer->ttl < sys_ttlmax)
186 poll_update(peer, hpoll);
191 * In unicast modes the dance is much more intricate. It is
192 * desigmed to back off whenever possible to minimize network
195 if (peer->burst == 0) {
199 * Update the reachability status. If not heard for
200 * three consecutive polls, stuff infinity in the clock
203 oreach = peer->reach;
204 peer->outdate = current_time;
205 if (peer == sys_peer)
208 if (!(peer->reach & 0x07))
209 clock_filter(peer, 0., 0., MAXDISPERSE);
213 * Here the peer is unreachable. If it was
214 * previously reachable, raise a trap.
217 report_event(EVNT_UNREACH, peer);
218 peer->timereachable = current_time;
222 * Send a burst if enabled, but only once after
223 * a peer becomes unreachable. If the prempt
224 * flag is dim, bump the unreach counter by one;
225 * otherwise, bump it by three.
227 if (peer->flags & FLAG_IBURST &&
228 peer->unreach == 0) {
229 peer->burst = NTP_BURST;
231 if (!(peer->flags & FLAG_PREEMPT))
238 * Here the peer is reachable. Set the poll
239 * interval to the system poll interval. Send a
240 * burst only if enabled and the peer is fit.
242 * Respond to the peer evaluation produced by
243 * the selection algorithm. If less than the
244 * outlyer level, up the unreach by three. If
245 * there are excess associations, up the unreach
246 * by two if not a candidate and by one if so.
248 if (!(peer->flags & FLAG_PREEMPT)) {
250 } else if (peer->status < CTL_PST_SEL_SELCAND) {
252 } else if (peer_preempt > sys_maxclock) {
253 if (peer->status < CTL_PST_SEL_SYNCCAND)
261 if (peer->flags & FLAG_BURST &&
263 peer->burst = NTP_BURST;
267 * Watch for timeout. If ephemeral or preemptable, toss
268 * the rascal; otherwise, bump the poll interval.
270 if (peer->unreach >= NTP_UNREACH) {
271 if (peer->flags & FLAG_PREEMPT ||
272 !(peer->flags & FLAG_CONFIG)) {
273 peer_clear(peer, "TIME");
284 * If a broadcast client at this point, the burst has
285 * concluded, so we switch to client mode and purge the
286 * keylist, since no further transmissions will be made.
288 if (peer->burst == 0) {
289 if (peer->cast_flags & MDF_BCLNT) {
290 peer->hmode = MODE_BCLIENT;
297 * If ntpdate mode and the clock has not been
298 * set and all peers have completed the burst,
299 * we declare a successful failure.
303 if (peer_ntpdate == 0) {
305 "no reply; clock not set");
313 * Do not transmit if in broadcast client mode.
315 if (peer->hmode != MODE_BCLIENT)
317 poll_update(peer, hpoll);
322 * receive - Receive Procedure. See section 3.4.3 in the specification.
326 struct recvbuf *rbufp
329 register struct peer *peer; /* peer structure pointer */
330 register struct pkt *pkt; /* receive packet pointer */
331 int hisversion; /* packet version */
332 int hisleap; /* packet leap indicator */
333 int hismode; /* packet mode */
334 int hisstratum; /* packet stratum */
335 int restrict_mask; /* restrict bits */
336 int has_mac; /* length of MAC field */
337 int authlen; /* offset of MAC field */
338 int is_authentic = 0; /* cryptosum ok */
339 keyid_t skeyid = 0; /* key ID */
340 struct sockaddr_storage *dstadr_sin; /* active runway */
341 struct peer *peer2; /* aux peer structure pointer */
342 l_fp p_org; /* origin timestamp */
343 l_fp p_rec; /* receive timestamp */
344 l_fp p_xmt; /* transmit timestamp */
346 keyid_t tkeyid = 0; /* temporary key ID */
347 keyid_t pkeyid = 0; /* previous key ID */
348 struct autokey *ap; /* autokey structure pointer */
349 int rval; /* cookie snatcher */
351 int retcode = AM_NOMATCH;
355 * Monitor the packet and get restrictions. Note that the packet
356 * length for control and private mode packets must be checked
357 * by the service routines. Note that no statistics counters are
358 * recorded for restrict violations, since these counters are in
359 * the restriction routine. Note the careful distinctions here
360 * between a packet with a format error and a packet that is
361 * simply discarded without prejudice. Some restrictions have to
362 * be handled later in order to generate a kiss-of-death packet.
365 * Bogus port check is before anything, since it probably
366 * reveals a clogging attack.
369 if (SRCPORT(&rbufp->recv_srcadr) == 0) {
371 return; /* bogus port */
373 at_listhead = ntp_monitor(rbufp);
374 restrict_mask = restrictions(&rbufp->recv_srcadr, at_listhead);
377 printf("receive: at %ld %s<-%s flags %x restrict %03x\n",
378 current_time, stoa(&rbufp->dstadr->sin),
379 stoa(&rbufp->recv_srcadr),
380 rbufp->dstadr->flags, restrict_mask);
382 if (restrict_mask & RES_IGNORE) {
384 return; /* ignore everything */
386 pkt = &rbufp->recv_pkt;
387 hisversion = PKT_VERSION(pkt->li_vn_mode);
388 hisleap = PKT_LEAP(pkt->li_vn_mode);
389 hismode = (int)PKT_MODE(pkt->li_vn_mode);
390 hisstratum = PKT_TO_STRATUM(pkt->stratum);
391 if (hismode == MODE_PRIVATE) {
392 if (restrict_mask & RES_NOQUERY) {
394 return; /* no query private */
396 process_private(rbufp, ((restrict_mask &
397 RES_NOMODIFY) == 0));
400 if (hismode == MODE_CONTROL) {
401 if (restrict_mask & RES_NOQUERY) {
403 return; /* no query control */
405 process_control(rbufp, restrict_mask);
408 if (restrict_mask & RES_DONTSERVE) {
410 return; /* no time */
412 if (rbufp->recv_length < LEN_PKT_NOMAC) {
414 return; /* runt packet */
418 * Version check must be after the query packets, since they
419 * intentionally use early version.
421 if (hisversion == NTP_VERSION) {
422 sys_newversionpkt++; /* new version */
423 } else if (!(restrict_mask & RES_VERSION) && hisversion >=
425 sys_oldversionpkt++; /* previous version */
427 sys_unknownversion++;
428 return; /* old version */
432 * Figure out his mode and validate the packet. This has some
433 * legacy raunch that probably should be removed. In very early
434 * NTP versions mode 0 was equivalent to what later versions
435 * would interpret as client mode.
437 if (hismode == MODE_UNSPEC) {
438 if (hisversion == NTP_OLDVERSION) {
439 hismode = MODE_CLIENT;
442 return; /* invalid mode */
447 * Parse the extension field if present. We figure out whether
448 * an extension field is present by measuring the MAC size. If
449 * the number of words following the packet header is 0, no MAC
450 * is present and the packet is not authenticated. If 1, the
451 * packet is a crypto-NAK; if 3, the packet is authenticated
452 * with DES; if 5, the packet is authenticated with MD5. If 2 or
453 * 4, the packet is a runt and discarded forthwith. If greater
454 * than 5, an extension field is present, so we subtract the
455 * length of the field and go around again.
457 authlen = LEN_PKT_NOMAC;
458 has_mac = rbufp->recv_length - authlen;
459 while (has_mac > 0) {
462 if (has_mac % 4 != 0 || has_mac < 0) {
464 return; /* bad MAC length */
466 if (has_mac == 1 * 4 || has_mac == 3 * 4 || has_mac ==
468 skeyid = ntohl(((u_int32 *)pkt)[authlen / 4]);
471 } else if (has_mac > MAX_MAC_LEN) {
472 temp = ntohl(((u_int32 *)pkt)[authlen / 4]) &
474 if (temp < 4 || temp > NTP_MAXEXTEN || temp % 4
477 return; /* bad MAC length */
483 return; /* bad MAC length */
491 * We have tossed out as many buggy packets as possible early in
492 * the game to reduce the exposure to a clogging attack. Now we
493 * have to burn some cycles to find the association and
494 * authenticate the packet if required. Note that we burn only
495 * MD5 cycles, again to reduce exposure. There may be no
496 * matching association and that's okay.
498 * More on the autokey mambo. Normally the local interface is
499 * found when the association was mobilized with respect to a
500 * designated remote address. We assume packets arriving from
501 * the remote address arrive via this interface and the local
502 * address used to construct the autokey is the unicast address
503 * of the interface. However, if the sender is a broadcaster,
504 * the interface broadcast address is used instead.
505 & Notwithstanding this technobabble, if the sender is a
506 * multicaster, the broadcast address is null, so we use the
507 * unicast address anyway. Don't ask.
509 peer = findpeer(&rbufp->recv_srcadr, rbufp->dstadr, hismode,
511 dstadr_sin = &rbufp->dstadr->sin;
512 NTOHL_FP(&pkt->org, &p_org);
513 NTOHL_FP(&pkt->rec, &p_rec);
514 NTOHL_FP(&pkt->xmt, &p_xmt);
517 * Authentication is conditioned by three switches:
519 * NOPEER (RES_NOPEER) do not mobilize an association unless
521 * NOTRUST (RES_DONTTRUST) do not allow access unless
522 * authenticated (implies NOPEER)
523 * enable (sys_authenticate) master NOPEER switch, by default
526 * The NOPEER and NOTRUST can be specified on a per-client basis
527 * using the restrict command. The enable switch if on implies
528 * NOPEER for all clients. There are four outcomes:
530 * NONE The packet has no MAC.
531 * OK the packet has a MAC and authentication succeeds
532 * ERROR the packet has a MAC and authentication fails
533 * CRYPTO crypto-NAK. The MAC has four octets only.
535 * Note: The AUTH(x, y) macro is used to filter outcomes. If x
536 * is zero, acceptable outcomes of y are NONE and OK. If x is
537 * one, the only acceptable outcome of y is OK.
540 is_authentic = AUTH_NONE; /* not required */
543 printf("receive: at %ld %s<-%s mode %d code %d auth %d\n",
544 current_time, stoa(dstadr_sin),
545 stoa(&rbufp->recv_srcadr), hismode, retcode,
548 } else if (has_mac == 4) {
549 is_authentic = AUTH_CRYPTO; /* crypto-NAK */
553 "receive: at %ld %s<-%s mode %d code %d keyid %08x len %d mac %d auth %d\n",
554 current_time, stoa(dstadr_sin),
555 stoa(&rbufp->recv_srcadr), hismode, retcode,
556 skeyid, authlen, has_mac, is_authentic);
561 * For autokey modes, generate the session key
562 * and install in the key cache. Use the socket
563 * broadcast or unicast address as appropriate.
565 if (skeyid > NTP_MAXKEY) {
568 * More on the autokey dance (AKD). A cookie is
569 * constructed from public and private values.
570 * For broadcast packets, the cookie is public
571 * (zero). For packets that match no
572 * association, the cookie is hashed from the
573 * addresses and private value. For server
574 * packets, the cookie was previously obtained
575 * from the server. For symmetric modes, the
576 * cookie was previously constructed using an
577 * agreement protocol; however, should PKI be
578 * unavailable, we construct a fake agreement as
579 * the EXOR of the peer and host cookies.
581 * hismode ephemeral persistent
582 * =======================================
585 * client sys cookie 0%
586 * server 0% sys cookie
592 if (hismode == MODE_BROADCAST) {
595 * For broadcaster, use the interface
596 * broadcast address when available;
597 * otherwise, use the unicast address
598 * found when the association was
599 * mobilized. However, if this is from
600 * the wildcard interface, game over.
602 if (crypto_flags && rbufp->dstadr ==
605 return; /* no wildcard */
608 if (!SOCKNUL(&rbufp->dstadr->bcast))
610 &rbufp->dstadr->bcast;
611 } else if (peer == NULL) {
612 pkeyid = session_key(
613 &rbufp->recv_srcadr, dstadr_sin, 0,
616 pkeyid = peer->pcookie;
620 * The session key includes both the public
621 * values and cookie. In case of an extension
622 * field, the cookie used for authentication
623 * purposes is zero. Note the hash is saved for
624 * use later in the autokey mambo.
626 if (authlen > LEN_PKT_NOMAC && pkeyid != 0) {
627 session_key(&rbufp->recv_srcadr,
628 dstadr_sin, skeyid, 0, 2);
629 tkeyid = session_key(
630 &rbufp->recv_srcadr, dstadr_sin,
633 tkeyid = session_key(
634 &rbufp->recv_srcadr, dstadr_sin,
642 * Compute the cryptosum. Note a clogging attack may
643 * succeed in bloating the key cache. If an autokey,
644 * purge it immediately, since we won't be needing it
645 * again. If the packet is authentic, it can mobilize an
646 * association. Note that there is no key zero.
648 if (!authdecrypt(skeyid, (u_int32 *)pkt, authlen,
650 is_authentic = AUTH_ERROR;
654 is_authentic = AUTH_OK;
657 if (skeyid > NTP_MAXKEY)
658 authtrust(skeyid, 0);
663 "receive: at %ld %s<-%s mode %d code %d keyid %08x len %d mac %d auth %d\n",
664 current_time, stoa(dstadr_sin),
665 stoa(&rbufp->recv_srcadr), hismode, retcode,
666 skeyid, authlen, has_mac, is_authentic);
671 * The association matching rules are implemented by a set of
672 * routines and an association table. A packet matching an
673 * association is processed by the peer process for that
674 * association. If there are no errors, an ephemeral association
675 * is mobilized: a broadcast packet mobilizes a broadcast client
676 * aassociation; a manycast server packet mobilizes a manycast
677 * client association; a symmetric active packet mobilizes a
678 * symmetric passive association.
683 * This is a client mode packet not matching any association. If
684 * an ordinary client, simply toss a server mode packet back
685 * over the fence. If a manycast client, we have to work a
691 * The vanilla case is when this is not a multicast
692 * interface. If authentication succeeds, return a
693 * server mode packet; if not and the key ID is nonzero,
694 * return a crypto-NAK.
696 if (!(rbufp->dstadr->flags & INT_MCASTOPEN)) {
697 if (AUTH(restrict_mask & RES_DONTTRUST,
699 fast_xmit(rbufp, MODE_SERVER, skeyid,
701 else if (is_authentic == AUTH_ERROR)
702 fast_xmit(rbufp, MODE_SERVER, 0,
708 * This must be manycast. Do not respond if not
709 * configured as a manycast server.
711 if (!sys_manycastserver) {
713 return; /* not enabled */
717 * Do not respond if unsynchronized or stratum is below
718 * the floor or at or above the ceiling.
720 if (sys_leap == LEAP_NOTINSYNC || sys_stratum <
721 sys_floor || sys_stratum >= sys_ceiling)
722 return; /* bad stratum */
725 * Do not respond if our stratum is greater than the
726 * manycaster or it has already synchronized to us.
728 if (sys_peer == NULL || hisstratum < sys_stratum ||
729 (sys_cohort && hisstratum == sys_stratum) ||
730 rbufp->dstadr->addr_refid == pkt->refid)
731 return; /* no help */
734 * Respond only if authentication succeeds. Don't do a
735 * crypto-NAK, as that would not be useful.
737 if (AUTH(restrict_mask & RES_DONTTRUST, is_authentic))
738 fast_xmit(rbufp, MODE_SERVER, skeyid,
744 * This is a server mode packet returned in response to a client
745 * mode packet sent to a multicast group address. The origin
746 * timestamp is a good nonce to reliably associate the reply
747 * with what was sent. If there is no match, that's curious and
748 * could be an intruder attempting to clog, so we just ignore
751 * If the packet is authentic and the manycast association is
752 * found, we mobilize a client association and copy pertinent
753 * variables from the manycast association to the new client
754 * association. If not, just ignore the packet.
756 * There is an implosion hazard at the manycast client, since
757 * the manycast servers send the server packet immediately. If
758 * the guy is already here, don't fire up a duplicate.
761 if (!AUTH(sys_authenticate | (restrict_mask &
762 (RES_NOPEER | RES_DONTTRUST)), is_authentic))
763 return; /* bad auth */
765 if ((peer2 = findmanycastpeer(rbufp)) == NULL) {
767 return; /* not enabled */
769 if ((peer = newpeer(&rbufp->recv_srcadr,
770 rbufp->dstadr, MODE_CLIENT,
771 hisversion, NTP_MINDPOLL, NTP_MAXDPOLL,
772 FLAG_IBURST | FLAG_PREEMPT, MDF_UCAST | MDF_ACLNT,
774 return; /* system error */
777 * We don't need these, but it warms the billboards.
779 peer->ttl = peer2->ttl;
783 * This is the first packet received from a broadcast server. If
784 * the packet is authentic and we are enabled as broadcast
785 * client, mobilize a broadcast client association. We don't
786 * kiss any frogs here.
789 if (!AUTH(sys_authenticate | (restrict_mask &
790 (RES_NOPEER | RES_DONTTRUST)), is_authentic))
791 return; /* bad auth */
794 * Do not respond if unsynchronized or stratum is below
795 * the floor or at or above the ceiling.
797 if (hisleap == LEAP_NOTINSYNC || hisstratum <
798 sys_floor || hisstratum >= sys_ceiling)
799 return; /* bad stratum */
801 switch (sys_bclient) {
804 * If not enabled, just skedaddle.
808 return; /* not enabled */
811 * Execute the initial volley in order to calibrate the
812 * propagation delay and run the Autokey protocol, if
816 if ((peer = newpeer(&rbufp->recv_srcadr,
817 rbufp->dstadr, MODE_CLIENT, hisversion,
818 NTP_MINDPOLL, NTP_MAXDPOLL, FLAG_MCAST |
819 FLAG_IBURST, MDF_BCLNT, 0, skeyid)) ==
821 return; /* system error */
823 if (skeyid > NTP_MAXKEY)
824 crypto_recv(peer, rbufp);
830 * Do not execute the initial volley.
835 * If a two-way exchange is not possible,
836 * neither is Autokey.
838 if (skeyid > NTP_MAXKEY) {
840 "receive: autokey requires two-way communication");
841 return; /* no autokey */
844 if ((peer = newpeer(&rbufp->recv_srcadr,
845 rbufp->dstadr, MODE_BCLIENT, hisversion,
846 NTP_MINDPOLL, NTP_MAXDPOLL, 0, MDF_BCLNT, 0,
848 return; /* system error */
853 * This is the first packet received from a symmetric active
854 * peer. If the packet is authentic and the first he sent,
855 * mobilize a passive association. If not, kiss the frog.
860 * If the inbound packet is correctly authenticated and
861 * enabled, a symmetric passive association is
862 * mobilized. If not but correctly authenticated, a
863 * symmetric active response is sent. If authentication
864 * fails, send a crypto-NAK packet.
866 if (!AUTH(restrict_mask & RES_DONTTRUST, is_authentic))
868 if (is_authentic == AUTH_ERROR)
869 fast_xmit(rbufp, MODE_ACTIVE, 0,
871 return; /* bad auth */
873 if (!AUTH(sys_authenticate | (restrict_mask &
874 RES_NOPEER), is_authentic)) {
875 fast_xmit(rbufp, MODE_ACTIVE, skeyid,
881 * Do not respond if stratum is below the floor.
883 if (hisstratum < sys_floor)
884 return; /* bad stratum */
886 if ((peer = newpeer(&rbufp->recv_srcadr,
887 rbufp->dstadr, MODE_PASSIVE, hisversion,
888 NTP_MINDPOLL, NTP_MAXDPOLL, 0, MDF_UCAST, 0,
890 return; /* system error */
894 * Process regular packet. Nothing special.
900 * A passive packet matches a passive association. This is
901 * usually the result of reconfiguring a client on the fly. As
902 * this association might be legitamate and this packet an
903 * attempt to deny service, just ignore it.
909 * For everything else there is the bit bucket.
914 peer->flash &= ~PKT_TEST_MASK;
917 * Next comes a rigorous schedule of timestamp checking. If the
918 * transmit timestamp is zero, the server is horribly broken.
920 if (L_ISZERO(&p_xmt)) {
921 return; /* read rfc1305 */
924 * If the transmit timestamp duplicates a previous one, the
925 * packet is a replay. This prevents the bad guys from replaying
926 * the most recent packet, authenticated or not.
928 } else if (L_ISEQU(&peer->org, &p_xmt)) {
929 peer->flash |= TEST1;
931 return; /* duplicate packet */
935 * If this is a broadcast mode packet, skip further checking.
937 } else if (hismode != MODE_BROADCAST) {
938 if (L_ISZERO(&p_org))
939 peer->flash |= TEST3; /* protocol unsynch */
940 else if (!L_ISEQU(&p_org, &peer->xmt))
941 peer->flash |= TEST2; /* bogus packet */
945 * Update the origin and destination timestamps. If
946 * unsynchronized or bogus abandon ship. If the crypto machine
947 * breaks, light the crypto bit and plaint the log.
950 peer->rec = rbufp->recv_time;
951 if (peer->flash & PKT_TEST_MASK) {
953 if (crypto_flags && (peer->flags & FLAG_SKEY)) {
954 rval = crypto_recv(peer, rbufp);
955 if (rval != XEVNT_OK) {
956 peer_clear(peer, "CRYP");
957 peer->flash |= TEST9; /* crypto error */
961 return; /* unsynch */
965 * The timestamps are valid and the receive packet matches the
966 * last one sent. If the packet is a crypto-NAK, the server
967 * might have just changed keys. We reset the association
968 * and restart the protocol.
970 if (is_authentic == AUTH_CRYPTO) {
971 peer_clear(peer, "AUTH");
972 return; /* crypto-NAK */
975 * If the association is authenticated, the key ID is nonzero
976 * and received packets must be authenticated. This is designed
977 * to avoid a bait-and-switch attack, which was possible in past
978 * versions. If symmetric modes, return a crypto-NAK. The peer
979 * should restart the protocol.
981 } else if (!AUTH(peer->keyid || (restrict_mask & RES_DONTTRUST),
983 peer->flash |= TEST5;
984 if (hismode == MODE_ACTIVE || hismode == MODE_PASSIVE)
985 fast_xmit(rbufp, MODE_ACTIVE, 0, restrict_mask);
986 return; /* bad auth */
990 * That was hard and I am sweaty, but the packet is squeaky
991 * clean. Get on with real work.
994 peer->timereceived = current_time;
995 if (is_authentic == AUTH_OK)
996 peer->flags |= FLAG_AUTHENTIC;
998 peer->flags &= ~FLAG_AUTHENTIC;
1001 * More autokey dance. The rules of the cha-cha are as follows:
1003 * 1. If there is no key or the key is not auto, do nothing.
1005 * 2. If this packet is in response to the one just previously
1006 * sent or from a broadcast server, do the extension fields.
1007 * Otherwise, assume bogosity and bail out.
1009 * 3. If an extension field contains a verified signature, it is
1010 * self-authenticated and we sit the dance.
1012 * 4. If this is a server reply, check only to see that the
1013 * transmitted key ID matches the received key ID.
1015 * 5. Check to see that one or more hashes of the current key ID
1016 * matches the previous key ID or ultimate original key ID
1017 * obtained from the broadcaster or symmetric peer. If no
1018 * match, sit the dance and wait for timeout.
1020 * In case of crypto error, fire the orchestra and stop dancing.
1021 * This is considered a permanant error, so light the crypto bit
1022 * to suppress further requests. If preemptable or ephemeral,
1025 if (crypto_flags && (peer->flags & FLAG_SKEY)) {
1026 peer->flash |= TEST8;
1027 rval = crypto_recv(peer, rbufp);
1028 if (rval != XEVNT_OK) {
1029 peer_clear(peer, "CRYP");
1030 peer->flash |= TEST9; /* crypto error */
1031 if (peer->flags & FLAG_PREEMPT ||
1032 !(peer->flags & FLAG_CONFIG))
1036 } else if (hismode == MODE_SERVER) {
1037 if (skeyid == peer->keyid)
1038 peer->flash &= ~TEST8;
1039 } else if (!(peer->flash & TEST8)) {
1040 peer->pkeyid = skeyid;
1041 } else if ((ap = (struct autokey *)peer->recval.ptr) !=
1045 for (i = 0; ; i++) {
1046 if (tkeyid == peer->pkeyid ||
1047 tkeyid == ap->key) {
1048 peer->flash &= ~TEST8;
1049 peer->pkeyid = skeyid;
1054 tkeyid = session_key(
1055 &rbufp->recv_srcadr, dstadr_sin,
1059 if (!(peer->crypto & CRYPTO_FLAG_PROV)) /* test 9 */
1060 peer->flash |= TEST8; /* not proventic */
1063 * If the transmit queue is nonempty, clamp the host
1064 * poll interval to the packet poll interval.
1066 if (peer->cmmd != 0) {
1067 peer->ppoll = pkt->ppoll;
1068 poll_update(peer, peer->hpoll);
1071 #endif /* OPENSSL */
1074 * The dance is complete and the flash bits have been lit. Toss
1075 * the packet over the fence for processing, which may light up
1078 process_packet(peer, pkt);
1081 * Well, that was nice. If TEST4 is lit, either the crypto
1082 * machine jammed or a kiss-o'-death packet flew in, either of
1085 if (peer->flash & TEST4) {
1086 msyslog(LOG_INFO, "receive: fatal error %04x for %s",
1087 peer->flash, stoa(&peer->srcadr));
1094 * process_packet - Packet Procedure, a la Section 3.4.4 of the
1095 * specification. Or almost, at least. If we're in here we have a
1096 * reasonable expectation that we will be having a long term
1097 * relationship with this host.
1101 register struct peer *peer,
1102 register struct pkt *pkt
1106 double p_offset, p_del, p_disp;
1107 l_fp p_rec, p_xmt, p_org, p_reftime;
1109 u_char pmode, pleap, pstratum;
1113 p_del = FPTOD(NTOHS_FP(pkt->rootdelay));
1114 p_disp = FPTOD(NTOHS_FP(pkt->rootdispersion));
1115 NTOHL_FP(&pkt->reftime, &p_reftime);
1116 NTOHL_FP(&pkt->rec, &p_rec);
1117 NTOHL_FP(&pkt->xmt, &p_xmt);
1118 pmode = PKT_MODE(pkt->li_vn_mode);
1119 pleap = PKT_LEAP(pkt->li_vn_mode);
1120 if (pmode != MODE_BROADCAST)
1121 NTOHL_FP(&pkt->org, &p_org);
1124 pstratum = PKT_TO_STRATUM(pkt->stratum);
1127 * Test for kiss-o'death packet)
1129 if (pleap == LEAP_NOTINSYNC && pstratum == STRATUM_UNSPEC) {
1130 if (memcmp(&pkt->refid, "DENY", 4) == 0) {
1131 peer_clear(peer, "DENY");
1132 peer->flash |= TEST4; /* access denied */
1137 * Capture the header values.
1139 record_raw_stats(&peer->srcadr, peer->dstadr ? &peer->dstadr->sin : NULL, &p_org,
1140 &p_rec, &p_xmt, &peer->rec);
1142 peer->stratum = min(pstratum, STRATUM_UNSPEC);
1143 peer->pmode = pmode;
1144 peer->ppoll = pkt->ppoll;
1145 peer->precision = pkt->precision;
1146 peer->rootdelay = p_del;
1147 peer->rootdispersion = p_disp;
1148 peer->refid = pkt->refid; /* network byte order */
1149 peer->reftime = p_reftime;
1152 * Verify the server is synchronized; that is, the leap bits and
1153 * stratum are valid, the root delay and root dispersion are
1154 * valid and the reference timestamp is not later than the
1155 * transmit timestamp.
1157 if (pleap == LEAP_NOTINSYNC || /* test 6 */
1158 pstratum < sys_floor || pstratum >= sys_ceiling)
1159 peer->flash |= TEST6; /* peer not synch */
1160 if (p_del < 0 || p_disp < 0 || p_del / /* test 7 */
1161 2 + p_disp >= MAXDISPERSE || !L_ISHIS(&p_xmt, &p_reftime))
1162 peer->flash |= TEST7; /* bad header */
1165 * If any tests fail at this point, the packet is discarded.
1166 * Note that some flashers may have already been set in the
1167 * receive() routine.
1169 if (peer->flash & PKT_TEST_MASK) {
1172 printf("packet: flash header %04x\n",
1177 if (!(peer->reach)) {
1178 report_event(EVNT_REACH, peer);
1179 peer->timereachable = current_time;
1181 poll_update(peer, peer->hpoll);
1185 * For a client/server association, calculate the clock offset,
1186 * roundtrip delay and dispersion. The equations are reordered
1187 * from the spec for more efficient use of temporaries. For a
1188 * broadcast association, offset the last measurement by the
1189 * computed delay during the client/server volley. Note that
1190 * org has been set to the time of last reception. Note the
1191 * computation of dispersion includes the system precision plus
1192 * that due to the frequency error since the origin time.
1194 * It is very important to respect the hazards of overflow. The
1195 * only permitted operation on raw timestamps is subtraction,
1196 * where the result is a signed quantity spanning from 68 years
1197 * in the past to 68 years in the future. To avoid loss of
1198 * precision, these calculations are done using 64-bit integer
1199 * arithmetic. However, the offset and delay calculations are
1200 * sums and differences of these first-order differences, which
1201 * if done using 64-bit integer arithmetic, would be valid over
1202 * only half that span. Since the typical first-order
1203 * differences are usually very small, they are converted to 64-
1204 * bit doubles and all remaining calculations done in floating-
1205 * point arithmetic. This preserves the accuracy while retaining
1208 * Let t1 = p_org, t2 = p_rec, t3 = p_xmt, t4 = peer->rec:
1210 ci = p_xmt; /* t3 - t4 */
1211 L_SUB(&ci, &peer->rec);
1213 ci = p_rec; /* t2 - t1 */
1216 ci = peer->rec; /* t4 - t1 */
1220 * If running in a broadcast association, the clock offset is
1221 * (t1 - t0) corrected by the one-way delay, but we can't
1222 * measure that directly. Therefore, we start up in MODE_CLIENT
1223 * mode, set FLAG_MCAST and exchange eight messages to determine
1224 * the clock offset. When the last message is sent, we switch to
1225 * MODE_BCLIENT mode. The next broadcast message after that
1226 * computes the broadcast offset and clears FLAG_MCAST.
1228 if (pmode == MODE_BROADCAST) {
1230 if (peer->flags & FLAG_MCAST) {
1231 peer->estbdelay = peer->offset - p_offset;
1232 if (peer->hmode == MODE_CLIENT)
1235 peer->flags &= ~(FLAG_MCAST | FLAG_BURST);
1237 p_offset += peer->estbdelay;
1238 p_del = peer->delay;
1241 p_offset = (t21 + t34) / 2.;
1243 LFPTOD(&ci, p_disp);
1244 p_disp = LOGTOD(sys_precision) +
1245 LOGTOD(peer->precision) + clock_phi * p_disp;
1247 p_del = max(p_del, LOGTOD(sys_precision));
1248 clock_filter(peer, p_offset, p_del, p_disp);
1249 record_peer_stats(&peer->srcadr, ctlpeerstatus(peer),
1250 peer->offset, peer->delay, peer->disp, peer->jitter);
1255 * clock_update - Called at system process update intervals.
1265 * There must be a system peer at this point. If we just changed
1266 * the system peer, but have a newer sample from the old one,
1267 * wait until newer data are available.
1269 if (sys_poll < sys_peer->minpoll)
1270 sys_poll = sys_peer->minpoll;
1271 if (sys_poll > sys_peer->maxpoll)
1272 sys_poll = sys_peer->maxpoll;
1273 poll_update(sys_peer, sys_poll);
1274 if (sys_peer->epoch <= sys_clocktime)
1279 printf("clock_update: at %ld assoc %d \n", current_time,
1283 ostratum = sys_stratum;
1284 switch (local_clock(sys_peer, sys_offset)) {
1287 * Clock exceeds panic threshold. Life as we know it ends.
1290 report_event(EVNT_SYSFAULT, NULL);
1295 * Clock was stepped. Flush all time values of all peers.
1299 sys_leap = LEAP_NOTINSYNC;
1300 sys_stratum = STRATUM_UNSPEC;
1303 sys_rootdispersion = 0;
1304 memcpy(&sys_refid, "STEP", 4);
1305 report_event(EVNT_CLOCKRESET, NULL);
1309 * Clock was slewed. Update the system stratum, leap bits, root
1310 * delay, root dispersion, reference ID and reference time. If
1311 * the leap changes, we gotta reroll the keys. Except for
1312 * reference clocks, the minimum dispersion increment is not
1313 * less than sys_mindisp.
1316 sys_leap = leap_next;
1317 sys_stratum = min(sys_peer->stratum + 1,
1319 sys_reftime = sys_peer->rec;
1322 * In orphan mode the stratum defaults to the orphan
1323 * stratum. The root delay is set to a random value
1324 * generated at startup. The root dispersion is set from
1325 * the peer dispersion; the peer root dispersion is
1328 dtemp = sys_peer->disp + clock_phi * (current_time -
1329 sys_peer->update) + sys_jitter +
1330 fabs(sys_peer->offset);
1332 if (!(sys_peer->flags & FLAG_REFCLOCK) && dtemp <
1334 dtemp = sys_mindisp;
1336 if (dtemp < sys_mindisp)
1337 dtemp = sys_mindisp;
1338 #endif /* REFCLOCK */
1339 if (sys_stratum >= sys_orphan) {
1340 sys_stratum = sys_orphan;
1341 sys_rootdelay = sys_peer->delay;
1342 sys_rootdispersion = dtemp;
1344 sys_rootdelay = sys_peer->delay +
1345 sys_peer->rootdelay;
1346 sys_rootdispersion = dtemp +
1347 sys_peer->rootdispersion;
1349 if (oleap == LEAP_NOTINSYNC) {
1350 report_event(EVNT_SYNCCHG, NULL);
1354 #endif /* OPENSSL */
1358 * Popcorn spike or step threshold exceeded. Pretend it never
1364 if (ostratum != sys_stratum)
1365 report_event(EVNT_PEERSTCHG, NULL);
1370 * poll_update - update peer poll interval
1381 * This routine figures out when the next poll should be sent.
1382 * That turns out to be wickedly complicated. The big problem is
1383 * that sometimes the time for the next poll is in the past.
1384 * Watch out for races here between the receive process and the
1385 * poll process. The key assertion is that, if nextdate equals
1386 * current_time, the call is from the poll process; otherwise,
1387 * it is from the receive process.
1389 * First, bracket the poll interval according to the type of
1390 * association and options. If a fixed interval is configured,
1391 * use minpoll. This primarily is for reference clocks, but
1392 * works for any association.
1394 if (peer->flags & FLAG_FIXPOLL) {
1395 hpoll = peer->minpoll;
1398 * The ordinary case; clamp the poll interval between minpoll
1402 hpoll = max(min(peer->maxpoll, mpoll), peer->minpoll);
1406 * Bit of crass arrogance at this point. If the poll interval
1407 * has changed and we have a keylist, the lifetimes in the
1408 * keylist are probably bogus. In this case purge the keylist
1409 * and regenerate it later.
1411 if (hpoll != peer->hpoll)
1413 #endif /* OPENSSL */
1414 peer->hpoll = hpoll;
1417 * Now we figure out if there is an override. If during the
1418 * crypto protocol and a message is pending, make it wait not
1419 * more than two seconds.
1422 if (peer->cmmd != NULL && (sys_leap != LEAP_NOTINSYNC ||
1424 peer->nextdate = current_time + RESP_DELAY;
1427 * If we get called from the receive routine while a burst is
1428 * pending, just slink away. If from the poll routine and a
1429 * reference clock or a pending crypto response, delay for one
1430 * second. If this is the first sent in a burst, wait for the
1431 * modem to come up. For others in the burst, delay two seconds.
1433 } else if (peer->burst > 0) {
1435 if (peer->burst > 0) {
1436 #endif /* OPENSSL */
1437 if (peer->nextdate != current_time)
1440 else if (peer->flags & FLAG_REFCLOCK)
1441 peer->nextdate += RESP_DELAY;
1442 #endif /* REFCLOCK */
1443 else if (peer->flags & (FLAG_IBURST | FLAG_BURST) &&
1444 peer->burst == NTP_BURST)
1445 peer->nextdate += sys_calldelay;
1447 peer->nextdate += BURST_DELAY;
1449 * The ordinary case; use the minimum of the host and peer
1450 * intervals, but not less than minpoll. In other words,
1451 * oversampling is okay but understampling is evil.
1454 peer->nextdate = peer->outdate +
1455 RANDPOLL(max(min(peer->ppoll, hpoll),
1460 * If the time for the next poll has already happened, bring it
1461 * up to the next second after this one. This way the only way
1462 * to get nexdate == current time is from the poll routine.
1464 if (peer->nextdate <= current_time)
1465 peer->nextdate = current_time + 1;
1468 printf("poll_update: at %lu %s flags %04x poll %d burst %d last %lu next %lu\n",
1469 current_time, ntoa(&peer->srcadr), peer->flags,
1470 peer->hpoll, peer->burst, peer->outdate,
1476 * peer_crypto_clear - discard crypto information
1484 * If cryptographic credentials have been acquired, toss them to
1485 * Valhalla. Note that autokeys are ephemeral, in that they are
1486 * tossed immediately upon use. Therefore, the keylist can be
1487 * purged anytime without needing to preserve random keys. Note
1488 * that, if the peer is purged, the cryptographic variables are
1489 * purged, too. This makes it much harder to sneak in some
1490 * unauthenticated data in the clock filter.
1492 DPRINTF(1, ("peer_crypto_clear: at %ld next %ld assoc ID %d\n",
1493 current_time, peer->nextdate, peer->associd));
1499 if (peer->pkey != NULL)
1500 EVP_PKEY_free(peer->pkey);
1503 peer->digest = NULL; /* XXX MEMLEAK? check whether this needs to be freed in any way - never was freed */
1505 if (peer->subject != NULL)
1506 free(peer->subject);
1507 peer->subject = NULL;
1509 if (peer->issuer != NULL)
1511 peer->issuer = NULL;
1517 if (peer->ident_pkey != NULL)
1518 EVP_PKEY_free(peer->ident_pkey);
1519 peer->ident_pkey = NULL;
1521 memset(&peer->fstamp, 0, sizeof(peer->fstamp));
1523 if (peer->iffval != NULL)
1524 BN_free(peer->iffval);
1525 peer->iffval = NULL;
1527 if (peer->grpkey != NULL)
1528 BN_free(peer->grpkey);
1529 peer->grpkey = NULL;
1531 value_free(&peer->cookval);
1532 value_free(&peer->recval);
1534 if (peer->cmmd != NULL) {
1541 value_free(&peer->encrypt);
1542 #endif /* OPENSSL */
1546 * peer_clear - clear peer filter registers. See Section 3.4.8 of the spec.
1550 struct peer *peer, /* peer structure */
1551 char *ident /* tally lights */
1556 peer_crypto_clear(peer);
1558 if (peer == sys_peer)
1562 * Wipe the association clean and initialize the nonzero values.
1564 memset(CLEAR_TO_ZERO(peer), 0, LEN_CLEAR_TO_ZERO);
1565 peer->estbdelay = sys_bdelay;
1566 peer->ppoll = peer->maxpoll;
1567 peer->hpoll = peer->minpoll;
1568 peer->disp = MAXDISPERSE;
1569 peer->jitter = LOGTOD(sys_precision);
1570 for (i = 0; i < NTP_SHIFT; i++) {
1571 peer->filter_order[i] = i;
1572 peer->filter_disp[i] = MAXDISPERSE;
1575 if (!(peer->flags & FLAG_REFCLOCK)) {
1576 peer->leap = LEAP_NOTINSYNC;
1577 peer->stratum = STRATUM_UNSPEC;
1578 memcpy(&peer->refid, ident, 4);
1581 peer->leap = LEAP_NOTINSYNC;
1582 peer->stratum = STRATUM_UNSPEC;
1583 memcpy(&peer->refid, ident, 4);
1584 #endif /* REFCLOCK */
1587 * During initialization use the association count to spread out
1588 * the polls at one-second intervals. Othersie, randomize over
1589 * the minimum poll interval in order to avoid broadcast
1592 peer->nextdate = peer->update = peer->outdate = current_time;
1594 peer->nextdate += peer_associations;
1595 else if (peer->hmode == MODE_PASSIVE)
1596 peer->nextdate += RESP_DELAY;
1598 peer->nextdate += (ntp_random() & ((1 << NTP_MINDPOLL) -
1601 DPRINTF(1, ("peer_clear: at %ld next %ld assoc ID %d refid %s\n",
1602 current_time, peer->nextdate, peer->associd, ident));
1607 * clock_filter - add incoming clock sample to filter register and run
1608 * the filter procedure to find the best sample.
1612 struct peer *peer, /* peer structure pointer */
1613 double sample_offset, /* clock offset */
1614 double sample_delay, /* roundtrip delay */
1615 double sample_disp /* dispersion */
1618 double dst[NTP_SHIFT]; /* distance vector */
1619 int ord[NTP_SHIFT]; /* index vector */
1621 double dtemp, etemp;
1624 * Shift the new sample into the register and discard the oldest
1625 * one. The new offset and delay come directly from the
1626 * timestamp calculations. The dispersion grows from the last
1627 * outbound packet or reference clock update to the present time
1628 * and increased by the sum of the peer precision and the system
1629 * precision. The delay can sometimes swing negative due to
1630 * frequency skew, so it is clamped non-negative.
1632 j = peer->filter_nextpt;
1633 peer->filter_offset[j] = sample_offset;
1634 peer->filter_delay[j] = max(0, sample_delay);
1635 peer->filter_disp[j] = sample_disp;
1636 peer->filter_epoch[j] = current_time;
1637 j = (j + 1) % NTP_SHIFT;
1638 peer->filter_nextpt = j;
1641 * Update dispersions since the last update and at the same
1642 * time initialize the distance and index lists. The distance
1643 * list uses a compound metric. If the sample is valid and
1644 * younger than the minimum Allan intercept, use delay;
1645 * otherwise, use biased dispersion.
1647 dtemp = clock_phi * (current_time - peer->update);
1648 peer->update = current_time;
1649 for (i = NTP_SHIFT - 1; i >= 0; i--) {
1651 peer->filter_disp[j] += dtemp;
1652 if (peer->filter_disp[j] >= MAXDISPERSE)
1653 peer->filter_disp[j] = MAXDISPERSE;
1654 if (peer->filter_disp[j] >= MAXDISPERSE)
1655 dst[i] = MAXDISPERSE;
1656 else if (peer->update - peer->filter_epoch[j] >
1658 dst[i] = sys_maxdist + peer->filter_disp[j];
1660 dst[i] = peer->filter_delay[j];
1662 j++; j %= NTP_SHIFT;
1666 * If the clock discipline has stabilized, sort the samples in
1667 * both lists by distance. Note, we do not displace a higher
1668 * distance sample by a lower distance one unless lower by at
1669 * least the precision.
1672 for (i = 1; i < NTP_SHIFT; i++) {
1673 for (j = 0; j < i; j++) {
1674 if (dst[j] > dst[i] +
1675 LOGTOD(sys_precision)) {
1688 * Copy the index list to the association structure so ntpq
1689 * can see it later. Prune the distance list to samples less
1690 * than max distance, but keep at least two valid samples for
1691 * jitter calculation.
1694 for (i = 0; i < NTP_SHIFT; i++) {
1695 peer->filter_order[i] = (u_char) ord[i];
1696 if (dst[i] >= MAXDISPERSE || (m >= 2 && dst[i] >=
1703 * Compute the dispersion and jitter. The dispersion is weighted
1704 * exponentially by NTP_FWEIGHT (0.5) so it is normalized close
1705 * to 1.0. The jitter is the RMS differences relative to the
1706 * lowest delay sample. If no acceptable samples remain in the
1707 * shift register, quietly tiptoe home leaving only the
1710 peer->disp = peer->jitter = 0;
1712 for (i = NTP_SHIFT - 1; i >= 0; i--) {
1714 peer->disp = NTP_FWEIGHT * (peer->disp +
1715 peer->filter_disp[j]);
1717 peer->jitter += DIFF(peer->filter_offset[j],
1718 peer->filter_offset[k]);
1722 * If no acceptable samples remain in the shift register,
1723 * quietly tiptoe home leaving only the dispersion. Otherwise,
1724 * save the offset, delay and jitter. Note the jitter must not
1725 * be less than the precision.
1730 etemp = fabs(peer->offset - peer->filter_offset[k]);
1731 peer->offset = peer->filter_offset[k];
1732 peer->delay = peer->filter_delay[k];
1734 peer->jitter /= m - 1;
1735 peer->jitter = max(SQRT(peer->jitter), LOGTOD(sys_precision));
1738 * A new sample is useful only if it is younger than the last
1739 * one used. Note the order is FIFO if the clock discipline has
1742 if (peer->filter_epoch[k] <= peer->epoch) {
1745 printf("clock_filter: discard %lu\n",
1746 peer->epoch - peer->filter_epoch[k]);
1752 * If the difference between the last offset and the current one
1753 * exceeds the jitter by CLOCK_SGATE and the interval since the
1754 * last update is less than twice the system poll interval,
1755 * consider the update a popcorn spike and ignore it.
1757 if (etemp > CLOCK_SGATE * peer->jitter && m > 1 &&
1758 peer->filter_epoch[k] - peer->epoch < 2. *
1759 ULOGTOD(sys_poll)) {
1762 printf("clock_filter: popcorn %.6f %.6f\n",
1769 * The mitigated sample statistics are saved for later
1770 * processing. If not in a burst, tickle the select.
1772 peer->epoch = peer->filter_epoch[k];
1776 "clock_filter: n %d off %.6f del %.6f dsp %.6f jit %.6f, age %lu\n",
1777 m, peer->offset, peer->delay, peer->disp,
1778 peer->jitter, current_time - peer->epoch);
1780 if (peer->burst == 0 || sys_leap == LEAP_NOTINSYNC)
1786 * clock_select - find the pick-of-the-litter clock
1788 * LOCKCLOCK: If the local clock is the prefer peer, it will always be
1789 * enabled, even if declared falseticker, (2) only the prefer peer can
1790 * be selected as the system peer, (3) if the external source is down,
1791 * the system leap bits are set to 11 and the stratum set to infinity.
1803 double synch[NTP_MAXASSOC], error[NTP_MAXASSOC];
1804 struct peer *osys_peer;
1805 struct peer *typeacts = NULL;
1806 struct peer *typelocal = NULL;
1807 struct peer *typesystem = NULL;
1809 static int list_alloc = 0;
1810 static struct endpoint *endpoint = NULL;
1811 static int *indx = NULL;
1812 static struct peer **peer_list = NULL;
1813 static u_int endpoint_size = 0;
1814 static u_int indx_size = 0;
1815 static u_int peer_list_size = 0;
1818 * Initialize and create endpoint, index and peer lists big
1819 * enough to handle all associations.
1821 osys_peer = sys_peer;
1825 osurv = sys_survivors;
1828 sys_leap = LEAP_NOTINSYNC;
1829 sys_stratum = STRATUM_UNSPEC;
1830 memcpy(&sys_refid, "DOWN", 4);
1831 #endif /* LOCKCLOCK */
1833 for (n = 0; n < NTP_HASH_SIZE; n++)
1834 nlist += peer_hash_count[n];
1835 if (nlist > list_alloc) {
1836 if (list_alloc > 0) {
1841 while (list_alloc < nlist) {
1843 endpoint_size += 5 * 3 * sizeof(*endpoint);
1844 indx_size += 5 * 3 * sizeof(*indx);
1845 peer_list_size += 5 * sizeof(*peer_list);
1847 endpoint = (struct endpoint *)emalloc(endpoint_size);
1848 indx = (int *)emalloc(indx_size);
1849 peer_list = (struct peer **)emalloc(peer_list_size);
1853 * Initially, we populate the island with all the rifraff peers
1854 * that happen to be lying around. Those with seriously
1855 * defective clocks are immediately booted off the island. Then,
1856 * the falsetickers are culled and put to sea. The truechimers
1857 * remaining are subject to repeated rounds where the most
1858 * unpopular at each round is kicked off. When the population
1859 * has dwindled to sys_minclock, the survivors split a million
1860 * bucks and collectively crank the chimes.
1862 nlist = nl3 = 0; /* none yet */
1863 for (n = 0; n < NTP_HASH_SIZE; n++) {
1864 for (peer = peer_hash[n]; peer != NULL; peer =
1866 peer->flags &= ~FLAG_SYSPEER;
1867 peer->status = CTL_PST_SEL_REJECT;
1870 * Leave the island immediately if the peer is
1871 * unfit to synchronize.
1873 if (peer_unfit(peer))
1877 * Don't allow the local clock or modem drivers
1878 * in the kitchen at this point, unless the
1879 * prefer peer. Do that later, but only if
1880 * nobody else is around. These guys are all
1881 * configured, so we never throw them away.
1884 if (peer->refclktype == REFCLK_LOCALCLOCK
1885 #if defined(VMS) && defined(VMS_LOCALUNIT)
1886 /* wjm: VMS_LOCALUNIT taken seriously */
1887 && REFCLOCKUNIT(&peer->srcadr) !=
1889 #endif /* VMS && VMS_LOCALUNIT */
1893 if (!(peer->flags & FLAG_PREFER))
1894 continue; /* no local clock */
1895 #endif /* LOCKCLOCK */
1897 if (peer->sstclktype == CTL_SST_TS_TELEPHONE) {
1899 if (!(peer->flags & FLAG_PREFER))
1900 continue; /* no acts */
1902 #endif /* REFCLOCK */
1905 * If we get this far, the peer can stay on the
1906 * island, but does not yet have the immunity
1909 peer->status = CTL_PST_SEL_SANE;
1910 peer_list[nlist++] = peer;
1913 * Insert each interval endpoint on the sorted
1916 e = peer->offset; /* Upper end */
1917 f = root_distance(peer);
1919 for (i = nl3 - 1; i >= 0; i--) {
1920 if (e >= endpoint[indx[i]].val)
1923 indx[i + 3] = indx[i];
1926 endpoint[nl3].type = 1;
1927 endpoint[nl3++].val = e;
1929 e = e - f; /* Center point */
1930 for (; i >= 0; i--) {
1931 if (e >= endpoint[indx[i]].val)
1934 indx[i + 2] = indx[i];
1937 endpoint[nl3].type = 0;
1938 endpoint[nl3++].val = e;
1940 e = e - f; /* Lower end */
1941 for (; i >= 0; i--) {
1942 if (e >= endpoint[indx[i]].val)
1945 indx[i + 1] = indx[i];
1948 endpoint[nl3].type = -1;
1949 endpoint[nl3++].val = e;
1954 for (i = 0; i < nl3; i++)
1955 printf("select: endpoint %2d %.6f\n",
1956 endpoint[indx[i]].type,
1957 endpoint[indx[i]].val);
1960 * This is the actual algorithm that cleaves the truechimers
1961 * from the falsetickers. The original algorithm was described
1962 * in Keith Marzullo's dissertation, but has been modified for
1965 * Briefly put, we first assume there are no falsetickers, then
1966 * scan the candidate list first from the low end upwards and
1967 * then from the high end downwards. The scans stop when the
1968 * number of intersections equals the number of candidates less
1969 * the number of falsetickers. If this doesn't happen for a
1970 * given number of falsetickers, we bump the number of
1971 * falsetickers and try again. If the number of falsetickers
1972 * becomes equal to or greater than half the number of
1973 * candidates, the Albanians have won the Byzantine wars and
1974 * correct synchronization is not possible.
1976 * Here, nlist is the number of candidates and allow is the
1977 * number of falsetickers. Upon exit, the truechimers are the
1978 * susvivors with offsets not less than low and not greater than
1979 * high. There may be none of them.
1983 for (allow = 0; 2 * allow < nlist; allow++) {
1987 * Bound the interval (low, high) as the largest
1988 * interval containing points from presumed truechimers.
1992 for (i = 0; i < nl3; i++) {
1993 low = endpoint[indx[i]].val;
1994 n -= endpoint[indx[i]].type;
1995 if (n >= nlist - allow)
1997 if (endpoint[indx[i]].type == 0)
2001 for (j = nl3 - 1; j >= 0; j--) {
2002 high = endpoint[indx[j]].val;
2003 n += endpoint[indx[j]].type;
2004 if (n >= nlist - allow)
2006 if (endpoint[indx[j]].type == 0)
2011 * If the number of candidates found outside the
2012 * interval is greater than the number of falsetickers,
2013 * then at least one truechimer is outside the interval,
2014 * so go around again. This is what makes this algorithm
2015 * different than Marzullo's.
2021 * If an interval containing truechimers is found, stop.
2022 * If not, increase the number of falsetickers and go
2030 * Clustering algorithm. Construct candidate list in order first
2031 * by stratum then by root distance, but keep only the best
2032 * NTP_MAXASSOC of them. Scan the list to find falsetickers, who
2033 * leave the island immediately. The TRUE peer is always a
2034 * truechimer. We must leave at least one peer to collect the
2035 * million bucks. If in orphan mode, rascals found with lower
2036 * stratum are guaranteed a seat on the bus.
2039 for (i = 0; i < nlist; i++) {
2040 peer = peer_list[i];
2041 if (nlist > 1 && (peer->offset <= low || peer->offset >=
2042 high) && !(peer->flags & FLAG_TRUE) &&
2043 !(sys_stratum >= sys_orphan && peer->stratum <
2047 peer->status = CTL_PST_SEL_DISTSYSPEER;
2050 * The order metric is formed from the stratum times
2051 * max distance (1.) plus the root distance. It strongly
2052 * favors the lowest stratum, but a higher stratum peer
2053 * can capture the clock if the low stratum dominant
2054 * hasn't been heard for awhile.
2056 d = root_distance(peer) + peer->stratum * sys_maxdist;
2057 if (j >= NTP_MAXASSOC) {
2058 if (d >= synch[j - 1])
2063 for (k = j; k > 0; k--) {
2064 if (d >= synch[k - 1])
2067 peer_list[k] = peer_list[k - 1];
2068 error[k] = error[k - 1];
2069 synch[k] = synch[k - 1];
2071 peer_list[k] = peer;
2072 error[k] = peer->jitter;
2079 * If no survivors remain at this point, check if the local
2080 * clock or modem drivers have been found. If so, nominate one
2081 * of them as the only survivor. Otherwise, give up and leave
2082 * the island to the rats.
2085 if (typeacts != 0) {
2086 typeacts->status = CTL_PST_SEL_DISTSYSPEER;
2087 peer_list[0] = typeacts;
2089 } else if (typelocal != 0) {
2090 typelocal->status = CTL_PST_SEL_DISTSYSPEER;
2091 peer_list[0] = typelocal;
2094 if (osys_peer != NULL) {
2095 NLOG(NLOG_SYNCSTATUS)
2097 "no servers reachable");
2098 report_event(EVNT_PEERSTCHG, NULL);
2104 * We can only trust the survivors if the number of candidates
2105 * sys_minsane is at least the number required to detect and
2106 * cast out one falsticker. For the Byzantine agreement
2107 * algorithm used here, that number is 4; however, the default
2108 * sys_minsane is 1 to speed initial synchronization. Careful
2109 * operators will tinker a higher value and use at least that
2110 * number of synchronization sources.
2112 if (nlist < sys_minsane)
2115 for (i = 0; i < nlist; i++)
2116 peer_list[i]->status = CTL_PST_SEL_SELCAND;
2119 * Now, vote outlyers off the island by select jitter weighted
2120 * by root distance. Continue voting as long as there are more
2121 * than sys_minclock survivors and the minimum select jitter is
2122 * greater than the maximum peer jitter. Stop if we are about to
2123 * discard a TRUE or PREFER peer, who of course has the
2131 for (i = 0; i < nlist; i++) {
2136 for (j = 0; j < nlist; j++)
2137 f += DIFF(peer_list[j]->offset,
2138 peer_list[i]->offset);
2139 f = SQRT(f / (nlist - 1));
2141 if (f * synch[i] > e) {
2147 f = max(f, LOGTOD(sys_precision));
2148 if (nlist <= sys_minclock || f <= d ||
2149 peer_list[k]->flags & (FLAG_TRUE | FLAG_PREFER))
2154 "select: drop %s select %.6f jitter %.6f\n",
2155 ntoa(&peer_list[k]->srcadr), g, d);
2157 for (j = k + 1; j < nlist; j++) {
2158 peer_list[j - 1] = peer_list[j];
2159 error[j - 1] = error[j];
2165 * What remains is a list usually not greater than sys_minclock
2166 * peers. We want only a peer at the lowest stratum to become
2167 * the system peer, although all survivors are eligible for the
2168 * combining algorithm. Consider each peer in turn and OR the
2169 * leap bits on the assumption that, if some of them honk
2170 * nonzero bits, they must know what they are doing. Check for
2171 * prefer and pps peers at any stratum. Note that the head of
2172 * the list is at the lowest stratum and that unsynchronized
2173 * peers cannot survive this far.
2176 for (i = 0; i < nlist; i++) {
2177 peer = peer_list[i];
2179 leap_next |= peer->leap;
2180 peer->status = CTL_PST_SEL_SYNCCAND;
2181 if (peer->flags & FLAG_PREFER)
2183 if (peer == osys_peer)
2186 if (peer->refclktype == REFCLK_ATOM_PPS)
2188 #endif /* REFCLOCK */
2191 printf("cluster: survivor %s metric %.6f\n",
2192 ntoa(&peer_list[i]->srcadr), synch[i]);
2197 * Anticlockhop provision. Keep the current system peer if it is
2198 * a survivor but not first in the list. But do that only HOPPER
2201 if (osys_peer == NULL || typesystem == NULL || typesystem ==
2202 peer_list[0] || sys_hopper > sys_maxhop) {
2203 typesystem = peer_list[0];
2210 * Mitigation rules of the game. There are several types of
2211 * peers that can be selected here: (1) orphan, (2) prefer peer
2212 * (flag FLAG_PREFER) (3) pps peers (type REFCLK_ATOM_PPS), (4)
2213 * the existing system peer, if any, and (5) the head of the
2216 if (typesystem->stratum >= sys_orphan) {
2219 * If in orphan mode, choose the system peer. If the
2220 * lowest distance, we are the orphan parent and the
2223 sys_peer = typesystem;
2224 sys_peer->status = CTL_PST_SEL_SYSPEER;
2225 if (sys_orphandelay < sys_peer->rootdelay) {
2227 sys_refid = htonl(LOOPBACKADR);
2229 sys_offset = sys_peer->offset;
2230 sys_refid = addr2refid(&sys_peer->srcadr);
2232 sys_jitter = LOGTOD(sys_precision);
2235 printf("select: orphan offset %.6f\n",
2238 } else if (sys_prefer) {
2241 * If a pps peer is present, choose it; otherwise,
2242 * choose the prefer peer.
2246 sys_peer->status = CTL_PST_SEL_PPS;
2247 sys_offset = sys_peer->offset;
2251 "pps sync enabled");
2252 pps_control = current_time;
2255 printf("select: pps offset %.6f\n",
2259 sys_peer = sys_prefer;
2260 sys_peer->status = CTL_PST_SEL_SYSPEER;
2261 sys_offset = sys_peer->offset;
2264 printf("select: prefer offset %.6f\n",
2268 if (sys_peer->stratum == STRATUM_REFCLOCK ||
2269 sys_peer->stratum == STRATUM_UNSPEC)
2270 sys_refid = sys_peer->refid;
2272 sys_refid = addr2refid(&sys_peer->srcadr);
2273 sys_jitter = sys_peer->jitter;
2277 * Otherwise, choose the anticlockhopper.
2279 sys_peer = typesystem;
2280 sys_peer->status = CTL_PST_SEL_SYSPEER;
2281 clock_combine(peer_list, nlist);
2282 if (sys_peer->stratum == STRATUM_REFCLOCK ||
2283 sys_peer->stratum == STRATUM_UNSPEC)
2284 sys_refid = sys_peer->refid;
2286 sys_refid = addr2refid(&sys_peer->srcadr);
2287 sys_jitter = SQRT(SQUARE(sys_peer->jitter) +
2288 SQUARE(sys_jitter));
2291 printf("select: combine offset %.6f\n",
2297 * We have found the alpha male.
2299 sys_peer->flags |= FLAG_SYSPEER;
2300 if (osys_peer != sys_peer) {
2303 report_event(EVNT_PEERSTCHG, NULL);
2306 if (sys_peer->flags & FLAG_REFCLOCK)
2307 src = refnumtoa(&sys_peer->srcadr);
2309 #endif /* REFCLOCK */
2310 src = ntoa(&sys_peer->srcadr);
2311 NLOG(NLOG_SYNCSTATUS)
2312 msyslog(LOG_INFO, "synchronized to %s, stratum %d",
2313 src, sys_peer->stratum);
2320 * clock_combine - compute system offset and jitter from selected peers
2324 struct peer **peers, /* survivor list */
2325 int npeers /* number of survivors */
2332 for (i = 0; i < npeers; i++) {
2333 x = root_distance(peers[i]);
2335 z += peers[i]->offset / x;
2336 w += SQUARE(peers[i]->offset - peers[0]->offset) / x;
2339 sys_jitter = SQRT(w / y);
2343 * root_distance - compute synchronization distance from peer to root
2353 * Careful squeak here. The value returned must be greater than
2354 * the minimum root dispersion in order to avoid clockhop with
2355 * highly precise reference clocks. In orphan mode lose the peer
2356 * root delay, as that is used by the election algorithm.
2358 if (peer->stratum >= sys_orphan)
2361 dist = peer->rootdelay;
2362 dist += max(sys_mindisp, dist + peer->delay) / 2 +
2363 peer->rootdispersion + peer->disp + clock_phi *
2364 (current_time - peer->update) + peer->jitter;
2369 * peer_xmit - send packet for persistent association.
2373 struct peer *peer /* peer structure pointer */
2376 struct pkt xpkt; /* transmit packet */
2377 int sendlen, authlen;
2378 keyid_t xkeyid = 0; /* transmit key ID */
2381 if (!peer->dstadr) /* don't bother with peers without interface */
2385 * This is deliciously complicated. There are three cases.
2387 * case leap stratum refid delay dispersion
2389 * normal system system system system system
2390 * orphan child 00 orphan system orphan system
2391 * orphan parent 00 orphan loopbk 0 0
2394 * This is a normal packet. Use the system variables.
2396 if (sys_stratum < sys_orphan) {
2397 xpkt.li_vn_mode = PKT_LI_VN_MODE(sys_leap,
2398 peer->version, peer->hmode);
2399 xpkt.stratum = STRATUM_TO_PKT(sys_stratum);
2400 xpkt.refid = sys_refid;
2401 xpkt.rootdelay = HTONS_FP(DTOFP(sys_rootdelay));
2402 xpkt.rootdispersion =
2403 HTONS_FP(DTOUFP(sys_rootdispersion));
2406 * This is a orphan child packet. The host is synchronized to an
2407 * orphan parent. Show leap synchronized, orphan stratum, system
2408 * reference ID, orphan root delay and system root dispersion.
2410 } else if (sys_peer != NULL) {
2411 xpkt.li_vn_mode = PKT_LI_VN_MODE(LEAP_NOWARNING,
2412 peer->version, peer->hmode);
2413 xpkt.stratum = STRATUM_TO_PKT(sys_orphan);
2414 xpkt.refid = htonl(LOOPBACKADR);
2415 xpkt.rootdelay = HTONS_FP(DTOFP(sys_orphandelay));
2416 xpkt.rootdispersion =
2417 HTONS_FP(DTOUFP(sys_rootdispersion));
2420 * This is an orphan parent. Show leap synchronized, orphan
2421 * stratum, loopack reference ID and zero root delay and root
2425 xpkt.li_vn_mode = PKT_LI_VN_MODE(LEAP_NOWARNING,
2426 peer->version, peer->hmode);
2427 xpkt.stratum = STRATUM_TO_PKT(sys_orphan);
2428 xpkt.refid = sys_refid;
2430 xpkt.rootdispersion = 0;
2432 xpkt.ppoll = peer->hpoll;
2433 xpkt.precision = sys_precision;
2434 HTONL_FP(&sys_reftime, &xpkt.reftime);
2435 HTONL_FP(&peer->org, &xpkt.org);
2436 HTONL_FP(&peer->rec, &xpkt.rec);
2439 * If the received packet contains a MAC, the transmitted packet
2440 * is authenticated and contains a MAC. If not, the transmitted
2441 * packet is not authenticated.
2443 * It is most important when autokey is in use that the local
2444 * interface IP address be known before the first packet is
2445 * sent. Otherwise, it is not possible to compute a correct MAC
2446 * the recipient will accept. Thus, the I/O semantics have to do
2447 * a little more work. In particular, the wildcard interface
2448 * might not be usable.
2450 sendlen = LEN_PKT_NOMAC;
2451 if (!(peer->flags & FLAG_AUTHENABLE)) {
2452 get_systime(&peer->xmt);
2453 HTONL_FP(&peer->xmt, &xpkt.xmt);
2454 sendpkt(&peer->srcadr, peer->dstadr, sys_ttl[peer->ttl],
2459 printf("transmit: at %ld %s->%s mode %d\n",
2460 current_time, peer->dstadr ? stoa(&peer->dstadr->sin) : "-",
2461 stoa(&peer->srcadr), peer->hmode);
2467 * The received packet contains a MAC, so the transmitted packet
2468 * must be authenticated. If autokey is enabled, fuss with the
2469 * various modes; otherwise, symmetric key cryptography is used.
2472 if (crypto_flags && (peer->flags & FLAG_SKEY)) {
2473 struct exten *exten; /* extension field */
2476 * The Public Key Dance (PKD): Cryptographic credentials
2477 * are contained in extension fields, each including a
2478 * 4-octet length/code word followed by a 4-octet
2479 * association ID and optional additional data. Optional
2480 * data includes a 4-octet data length field followed by
2481 * the data itself. Request messages are sent from a
2482 * configured association; response messages can be sent
2483 * from a configured association or can take the fast
2484 * path without ever matching an association. Response
2485 * messages have the same code as the request, but have
2486 * a response bit and possibly an error bit set. In this
2487 * implementation, a message may contain no more than
2488 * one command and no more than one response.
2490 * Cryptographic session keys include both a public and
2491 * a private componet. Request and response messages
2492 * using extension fields are always sent with the
2493 * private component set to zero. Packets without
2494 * extension fields indlude the private component when
2495 * the session key is generated.
2500 * Allocate and initialize a keylist if not
2501 * already done. Then, use the list in inverse
2502 * order, discarding keys once used. Keep the
2503 * latest key around until the next one, so
2504 * clients can use client/server packets to
2505 * compute propagation delay.
2507 * Note that once a key is used from the list,
2508 * it is retained in the key cache until the
2509 * next key is used. This is to allow a client
2510 * to retrieve the encrypted session key
2511 * identifier to verify authenticity.
2513 * If for some reason a key is no longer in the
2514 * key cache, a birthday has happened and the
2515 * pseudo-random sequence is probably broken. In
2516 * that case, purge the keylist and regenerate
2519 if (peer->keynumber == 0)
2520 make_keylist(peer, peer->dstadr);
2523 xkeyid = peer->keylist[peer->keynumber];
2524 if (authistrusted(xkeyid))
2529 peer->keyid = xkeyid;
2531 switch (peer->hmode) {
2534 * In broadcast server mode the autokey values are
2535 * required by the broadcast clients. Push them when a
2536 * new keylist is generated; otherwise, push the
2537 * association message so the client can request them at
2540 case MODE_BROADCAST:
2541 if (peer->flags & FLAG_ASSOC)
2542 exten = crypto_args(peer, CRYPTO_AUTO |
2545 exten = crypto_args(peer, CRYPTO_ASSOC |
2550 * In symmetric modes the digest, certificate, agreement
2551 * parameters, cookie and autokey values are required.
2552 * The leapsecond table is optional. But, a passive peer
2553 * will not believe the active peer until the latter has
2554 * synchronized, so the agreement must be postponed
2555 * until then. In any case, if a new keylist is
2556 * generated, the autokey values are pushed.
2558 * If the crypto bit is lit, don't send requests.
2562 if (peer->flash & TEST9)
2565 * Parameter and certificate.
2568 exten = crypto_args(peer, CRYPTO_ASSOC,
2570 else if (!(peer->crypto & CRYPTO_FLAG_VALID))
2571 exten = crypto_args(peer, CRYPTO_CERT,
2575 * Identity. Note we have to sign the
2576 * certificate before the cookie to avoid a
2577 * deadlock when the passive peer is walking the
2578 * certificate trail. Awesome.
2580 else if (!(peer->crypto & CRYPTO_FLAG_VRFY))
2581 exten = crypto_args(peer,
2582 crypto_ident(peer), NULL);
2583 else if (sys_leap != LEAP_NOTINSYNC &&
2584 !(peer->crypto & CRYPTO_FLAG_SIGN))
2585 exten = crypto_args(peer, CRYPTO_SIGN,
2589 * Autokey. We request the cookie only when the
2590 * server and client are synchronized and
2591 * signatures work both ways. On the other hand,
2592 * the active peer needs the autokey values
2593 * before then and when the passive peer is
2594 * waiting for the active peer to synchronize.
2595 * Any time we regenerate the key list, we offer
2596 * the autokey values without being asked.
2598 else if (sys_leap != LEAP_NOTINSYNC &&
2599 peer->leap != LEAP_NOTINSYNC &&
2600 !(peer->crypto & CRYPTO_FLAG_AGREE))
2601 exten = crypto_args(peer, CRYPTO_COOK,
2603 else if (peer->flags & FLAG_ASSOC)
2604 exten = crypto_args(peer, CRYPTO_AUTO |
2606 else if (!(peer->crypto & CRYPTO_FLAG_AUTO))
2607 exten = crypto_args(peer, CRYPTO_AUTO,
2611 * Postamble. We trade leapseconds only when the
2612 * server and client are synchronized.
2614 else if (sys_leap != LEAP_NOTINSYNC &&
2615 peer->leap != LEAP_NOTINSYNC &&
2616 peer->crypto & CRYPTO_FLAG_TAI &&
2617 !(peer->crypto & CRYPTO_FLAG_LEAP))
2618 exten = crypto_args(peer, CRYPTO_TAI,
2623 * In client mode the digest, certificate, agreement
2624 * parameters and cookie are required. The leapsecond
2625 * table is optional. If broadcast client mode, the
2626 * autokey values are required as well. In broadcast
2627 * client mode, these values must be acquired during the
2628 * client/server exchange to avoid having to wait until
2629 * the next key list regeneration. Otherwise, the poor
2630 * dude may die a lingering death until becoming
2631 * unreachable and attempting rebirth.
2633 * If neither the server or client have the agreement
2634 * parameters, the protocol transmits the cookie in the
2635 * clear. If the server has the parameters, the client
2636 * requests them and the protocol blinds it using the
2637 * agreed key. It is a protocol error if the client has
2638 * the parameters but the server does not.
2640 * If the crypto bit is lit, don't send requests.
2643 if (peer->flash & TEST9)
2646 * Parameter and certificate.
2649 exten = crypto_args(peer, CRYPTO_ASSOC,
2651 else if (!(peer->crypto & CRYPTO_FLAG_VALID))
2652 exten = crypto_args(peer, CRYPTO_CERT,
2658 else if (!(peer->crypto & CRYPTO_FLAG_VRFY))
2659 exten = crypto_args(peer,
2660 crypto_ident(peer), NULL);
2665 else if (!(peer->crypto & CRYPTO_FLAG_AGREE))
2666 exten = crypto_args(peer, CRYPTO_COOK,
2668 else if (!(peer->crypto & CRYPTO_FLAG_AUTO) &&
2669 (peer->cast_flags & MDF_BCLNT))
2670 exten = crypto_args(peer, CRYPTO_AUTO,
2674 * Postamble. We can sign the certificate here,
2675 * since there is no chance of deadlock.
2677 else if (sys_leap != LEAP_NOTINSYNC &&
2678 !(peer->crypto & CRYPTO_FLAG_SIGN))
2679 exten = crypto_args(peer, CRYPTO_SIGN,
2681 else if (sys_leap != LEAP_NOTINSYNC &&
2682 peer->crypto & CRYPTO_FLAG_TAI &&
2683 !(peer->crypto & CRYPTO_FLAG_LEAP))
2684 exten = crypto_args(peer, CRYPTO_TAI,
2690 * Build the extension fields as directed. A response to
2691 * a request is always sent, even if an error. If an
2692 * error occurs when sending a request, the crypto
2693 * machinery broke or was misconfigured. In that case
2694 * light the crypto bit to suppress further requests.
2696 if (peer->cmmd != NULL) {
2697 peer->cmmd->associd = htonl(peer->associd);
2698 sendlen += crypto_xmit(&xpkt, &peer->srcadr,
2699 sendlen, peer->cmmd, 0);
2703 if (exten != NULL) {
2706 if (exten->opcode != 0) {
2707 ltemp = crypto_xmit(&xpkt,
2708 &peer->srcadr, sendlen, exten, 0);
2710 peer->flash |= TEST9; /* crypto error */
2720 * If extension fields are present, we must use a
2721 * private cookie value of zero. Don't send if the
2722 * crypto bit is set and no extension field is present,
2723 * but in that case give back the key. Most intricate.
2725 if (sendlen > LEN_PKT_NOMAC) {
2726 session_key(&peer->dstadr->sin, &peer->srcadr,
2728 } else if (peer->flash & TEST9) {
2729 authtrust(xkeyid, 0);
2733 #endif /* OPENSSL */
2736 * Stash the transmit timestamp corrected for the encryption
2737 * delay. If autokey, give back the key, as we use keys only
2738 * once. Check for errors such as missing keys, buffer overflow,
2741 xkeyid = peer->keyid;
2742 get_systime(&peer->xmt);
2743 L_ADD(&peer->xmt, &sys_authdelay);
2744 HTONL_FP(&peer->xmt, &xpkt.xmt);
2745 authlen = authencrypt(xkeyid, (u_int32 *)&xpkt, sendlen);
2747 msyslog(LOG_INFO, "transmit: %s key %u not found",
2748 stoa(&peer->srcadr), xkeyid);
2749 peer->flash |= TEST9; /* no key found */
2754 if (xkeyid > NTP_MAXKEY)
2755 authtrust(xkeyid, 0);
2756 #endif /* OPENSSL */
2757 get_systime(&xmt_tx);
2758 if (sendlen > sizeof(xpkt)) {
2759 msyslog(LOG_ERR, "buffer overflow %u", sendlen);
2762 sendpkt(&peer->srcadr, peer->dstadr, sys_ttl[peer->ttl], &xpkt,
2766 * Calculate the encryption delay. Keep the minimum over
2767 * the latest two samples.
2769 L_SUB(&xmt_tx, &peer->xmt);
2770 L_ADD(&xmt_tx, &sys_authdelay);
2771 sys_authdly[1] = sys_authdly[0];
2772 sys_authdly[0] = xmt_tx.l_uf;
2773 if (sys_authdly[0] < sys_authdly[1])
2774 sys_authdelay.l_uf = sys_authdly[0];
2776 sys_authdelay.l_uf = sys_authdly[1];
2782 "transmit: at %ld %s->%s mode %d keyid %08x len %d mac %d index %d\n",
2783 current_time, peer->dstadr ? ntoa(&peer->dstadr->sin) : "-",
2784 ntoa(&peer->srcadr), peer->hmode, xkeyid, sendlen -
2785 authlen, authlen, peer->keynumber);
2791 "transmit: at %ld %s->%s mode %d keyid %08x len %d mac %d\n",
2792 current_time, peer->dstadr ? ntoa(&peer->dstadr->sin) : "-",
2793 ntoa(&peer->srcadr), peer->hmode, xkeyid, sendlen -
2796 #endif /* OPENSSL */
2801 * fast_xmit - Send packet for nonpersistent association. Note that
2802 * neither the source or destination can be a broadcast address.
2806 struct recvbuf *rbufp, /* receive packet pointer */
2807 int xmode, /* transmit mode */
2808 keyid_t xkeyid, /* transmit key ID */
2809 int mask /* restrict mask */
2812 struct pkt xpkt; /* transmit packet structure */
2813 struct pkt *rpkt; /* receive packet structure */
2814 l_fp xmt_ts; /* timestamp */
2815 l_fp xmt_tx; /* timestamp after authent */
2816 int sendlen, authlen;
2822 * Initialize transmit packet header fields from the receive
2823 * buffer provided. We leave some fields intact as received. If
2824 * the gazinta was from a multicast address, the gazoutta must
2825 * go out another way.
2827 * The root delay field is special. If the system stratum is
2828 * less than the orphan stratum, send the real root delay.
2829 * Otherwise, if there is no system peer, send the orphan delay.
2830 * Otherwise, we must be an orphan parent, so send zero.
2832 rpkt = &rbufp->recv_pkt;
2833 if (rbufp->dstadr->flags & INT_MCASTOPEN)
2834 rbufp->dstadr = findinterface(&rbufp->recv_srcadr);
2837 * This is deliciously complicated. There are four cases.
2839 * case leap stratum refid delay dispersion
2841 * KoD 11 16 KISS system system
2842 * normal system system system system system
2843 * orphan child 00 orphan system orphan system
2844 * orphan parent 00 orphan loopbk 0 0
2847 * This is a kiss-of-death (KoD) packet. Show leap
2848 * unsynchronized, stratum zero, reference ID the four-character
2849 * kiss code and system root delay. Note the rate limit on these
2850 * packets. Once a second initialize a bucket counter. Every
2851 * packet sent decrements the counter until reaching zero. If
2852 * the counter is zero, drop the kiss.
2854 if (mask & RES_LIMITED) {
2855 sys_limitrejected++;
2856 if (sys_kod == 0 || !(mask & RES_DEMOBILIZE))
2860 xpkt.li_vn_mode = PKT_LI_VN_MODE(LEAP_NOTINSYNC,
2861 PKT_VERSION(rpkt->li_vn_mode), xmode);
2862 xpkt.stratum = STRATUM_UNSPEC;
2863 memcpy(&xpkt.refid, "RATE", 4);
2864 xpkt.rootdelay = HTONS_FP(DTOFP(sys_rootdelay));
2865 xpkt.rootdispersion =
2866 HTONS_FP(DTOUFP(sys_rootdispersion));
2869 * This is a normal packet. Use the system variables.
2871 } else if (sys_stratum < sys_orphan) {
2872 xpkt.li_vn_mode = PKT_LI_VN_MODE(sys_leap,
2873 PKT_VERSION(rpkt->li_vn_mode), xmode);
2874 xpkt.stratum = STRATUM_TO_PKT(sys_stratum);
2875 xpkt.refid = sys_refid;
2876 xpkt.rootdelay = HTONS_FP(DTOFP(sys_rootdelay));
2877 xpkt.rootdispersion =
2878 HTONS_FP(DTOUFP(sys_rootdispersion));
2881 * This is a orphan child packet. The host is synchronized to an
2882 * orphan parent. Show leap synchronized, orphan stratum, system
2883 * reference ID and orphan root delay.
2885 } else if (sys_peer != NULL) {
2886 xpkt.li_vn_mode = PKT_LI_VN_MODE(LEAP_NOWARNING,
2887 PKT_VERSION(rpkt->li_vn_mode), xmode);
2888 xpkt.stratum = STRATUM_TO_PKT(sys_orphan);
2889 xpkt.refid = sys_refid;
2890 xpkt.rootdelay = HTONS_FP(DTOFP(sys_orphandelay));
2891 xpkt.rootdispersion =
2892 HTONS_FP(DTOUFP(sys_rootdispersion));
2895 * This is an orphan parent. Show leap synchronized, orphan
2896 * stratum, loopack reference ID and zero root delay.
2899 xpkt.li_vn_mode = PKT_LI_VN_MODE(LEAP_NOWARNING,
2900 PKT_VERSION(rpkt->li_vn_mode), xmode);
2901 xpkt.stratum = STRATUM_TO_PKT(sys_orphan);
2902 xpkt.refid = htonl(LOOPBACKADR);
2903 xpkt.rootdelay = HTONS_FP(DTOFP(0));
2904 xpkt.rootdispersion = HTONS_FP(DTOFP(0));
2906 xpkt.ppoll = rpkt->ppoll;
2907 xpkt.precision = sys_precision;
2908 xpkt.rootdispersion = HTONS_FP(DTOUFP(sys_rootdispersion));
2909 HTONL_FP(&sys_reftime, &xpkt.reftime);
2910 xpkt.org = rpkt->xmt;
2911 HTONL_FP(&rbufp->recv_time, &xpkt.rec);
2914 * If the received packet contains a MAC, the transmitted packet
2915 * is authenticated and contains a MAC. If not, the transmitted
2916 * packet is not authenticated.
2918 sendlen = LEN_PKT_NOMAC;
2919 if (rbufp->recv_length == sendlen) {
2920 get_systime(&xmt_ts);
2921 HTONL_FP(&xmt_ts, &xpkt.xmt);
2922 sendpkt(&rbufp->recv_srcadr, rbufp->dstadr, 0, &xpkt,
2926 printf("transmit: at %ld %s->%s mode %d\n",
2927 current_time, stoa(&rbufp->dstadr->sin),
2928 stoa(&rbufp->recv_srcadr), xmode);
2934 * The received packet contains a MAC, so the transmitted packet
2935 * must be authenticated. For symmetric key cryptography, use
2936 * the predefined and trusted symmetric keys to generate the
2937 * cryptosum. For autokey cryptography, use the server private
2938 * value to generate the cookie, which is unique for every
2939 * source-destination-key ID combination.
2942 if (xkeyid > NTP_MAXKEY) {
2946 * The only way to get here is a reply to a legitimate
2947 * client request message, so the mode must be
2948 * MODE_SERVER. If an extension field is present, there
2949 * can be only one and that must be a command. Do what
2950 * needs, but with private value of zero so the poor
2951 * jerk can decode it. If no extension field is present,
2952 * use the cookie to generate the session key.
2954 cookie = session_key(&rbufp->recv_srcadr,
2955 &rbufp->dstadr->sin, 0, sys_private, 0);
2956 if (rbufp->recv_length >= (int)(sendlen + MAX_MAC_LEN +
2957 2 * sizeof(u_int32))) {
2958 session_key(&rbufp->dstadr->sin,
2959 &rbufp->recv_srcadr, xkeyid, 0, 2);
2960 temp32 = CRYPTO_RESP;
2961 rpkt->exten[0] |= htonl(temp32);
2962 sendlen += crypto_xmit(&xpkt,
2963 &rbufp->recv_srcadr, sendlen,
2964 (struct exten *)rpkt->exten, cookie);
2966 session_key(&rbufp->dstadr->sin,
2967 &rbufp->recv_srcadr, xkeyid, cookie, 2);
2970 #endif /* OPENSSL */
2971 get_systime(&xmt_ts);
2972 L_ADD(&xmt_ts, &sys_authdelay);
2973 HTONL_FP(&xmt_ts, &xpkt.xmt);
2974 authlen = authencrypt(xkeyid, (u_int32 *)&xpkt, sendlen);
2977 if (xkeyid > NTP_MAXKEY)
2978 authtrust(xkeyid, 0);
2979 #endif /* OPENSSL */
2980 get_systime(&xmt_tx);
2981 if (sendlen > sizeof(xpkt)) {
2982 msyslog(LOG_ERR, "buffer overflow %u", sendlen);
2985 sendpkt(&rbufp->recv_srcadr, rbufp->dstadr, 0, &xpkt, sendlen);
2988 * Calculate the encryption delay. Keep the minimum over the
2989 * latest two samples.
2991 L_SUB(&xmt_tx, &xmt_ts);
2992 L_ADD(&xmt_tx, &sys_authdelay);
2993 sys_authdly[1] = sys_authdly[0];
2994 sys_authdly[0] = xmt_tx.l_uf;
2995 if (sys_authdly[0] < sys_authdly[1])
2996 sys_authdelay.l_uf = sys_authdly[0];
2998 sys_authdelay.l_uf = sys_authdly[1];
3002 "transmit: at %ld %s->%s mode %d keyid %08x len %d mac %d\n",
3003 current_time, ntoa(&rbufp->dstadr->sin),
3004 ntoa(&rbufp->recv_srcadr), xmode, xkeyid, sendlen -
3012 * key_expire - purge the key list
3016 struct peer *peer /* peer structure pointer */
3021 if (peer->keylist != NULL) {
3022 for (i = 0; i <= peer->keynumber; i++)
3023 authtrust(peer->keylist[i], 0);
3024 free(peer->keylist);
3025 peer->keylist = NULL;
3027 value_free(&peer->sndval);
3028 peer->keynumber = 0;
3031 printf("key_expire: at %lu\n", current_time);
3034 #endif /* OPENSSL */
3038 * Determine if the peer is unfit for synchronization
3040 * A peer is unfit for synchronization if
3041 * > TEST10 bad leap or stratum below floor or at or above ceiling
3042 * > TEST11 root distance exceeded
3043 * > TEST12 a direct or indirect synchronization loop would form
3044 * > TEST13 unreachable or noselect
3046 int /* FALSE if fit, TRUE if unfit */
3048 struct peer *peer /* peer structure pointer */
3054 * A stratum error occurs if (1) the server has never been
3055 * synchronized, (2) the server stratum is below the floor or
3056 * greater than or equal to the ceiling, (3) the system stratum
3057 * is below the orphan stratum and the server stratum is greater
3058 * than or equal to the orphan stratum.
3060 if (peer->leap == LEAP_NOTINSYNC || peer->stratum < sys_floor ||
3061 peer->stratum >= sys_ceiling || (sys_stratum < sys_orphan &&
3062 peer->stratum >= sys_orphan))
3063 rval |= TEST10; /* stratum out of bounds */
3066 * A distance error occurs if the root distance is greater than
3067 * or equal to the distance threshold plus the increment due to
3068 * one poll interval.
3070 if (root_distance(peer) >= sys_maxdist + clock_phi *
3072 rval |= TEST11; /* distance exceeded */
3075 * A loop error occurs if the remote peer is synchronized to the
3076 * local peer of if the remote peer is synchronized to the same
3077 * server as the local peer, but only if the remote peer is not
3078 * the orphan parent.
3080 if (peer->stratum > 1 && peer->refid != htonl(LOOPBACKADR) &&
3081 ((!peer->dstadr || peer->refid == peer->dstadr->addr_refid) ||
3082 peer->refid == sys_refid))
3083 rval |= TEST12; /* synch loop */
3086 * An unreachable error occurs if the server is unreachable or
3087 * the noselect bit is set.
3089 if (!peer->reach || peer->flags & FLAG_NOSELECT)
3090 rval |= TEST13; /* unreachable */
3092 peer->flash &= ~PEER_TEST_MASK;
3093 peer->flash |= rval;
3099 * Find the precision of this particular machine
3101 #define MINSTEP 100e-9 /* minimum clock increment (s) */
3102 #define MAXSTEP 20e-3 /* maximum clock increment (s) */
3103 #define MINLOOPS 5 /* minimum number of step samples */
3106 * This routine calculates the system precision, defined as the minimum
3107 * of a sequence of differences between successive readings of the
3108 * system clock. However, if the system clock can be read more than once
3109 * during a tick interval, the difference can be zero or one LSB unit,
3110 * where the LSB corresponds to one nanosecond or one microsecond.
3111 * Conceivably, if some other process preempts this one and reads the
3112 * clock, the difference can be more than one LSB unit.
3114 * For hardware clock frequencies of 10 MHz or less, we assume the
3115 * logical clock advances only at the hardware clock tick. For higher
3116 * frequencies, we assume the logical clock can advance no more than 100
3117 * nanoseconds between ticks.
3120 default_get_precision(void)
3122 l_fp val; /* current seconds fraction */
3123 l_fp last; /* last seconds fraction */
3124 l_fp diff; /* difference */
3125 double tick; /* computed tick value */
3126 double dtemp; /* scratch */
3127 int i; /* log2 precision */
3130 * Loop to find tick value in nanoseconds. Toss out outlyer
3131 * values less than the minimun tick value. In wacky cases, use
3132 * the default maximum value.
3136 for (i = 0; i < MINLOOPS;) {
3139 L_SUB(&diff, &last);
3141 LFPTOD(&diff, dtemp);
3142 if (dtemp < MINSTEP)
3150 * Find the nearest power of two.
3153 msyslog(LOG_INFO, "precision = %.3f usec", tick * 1e6);
3154 for (i = 0; tick <= 1; i++)
3156 if (tick - 1. > 1. - tick / 2)
3163 * kod_proto - called once per second to limit kiss-of-death packets
3168 sys_kod = sys_kod_rate;
3173 * init_proto - initialize the protocol module's data
3182 * Fill in the sys_* stuff. Default is don't listen to
3183 * broadcasting, authenticate.
3185 sys_leap = LEAP_NOTINSYNC;
3186 sys_stratum = STRATUM_UNSPEC;
3187 memcpy(&sys_refid, "INIT", 4);
3188 sys_precision = (s_char)default_get_precision();
3189 sys_jitter = LOGTOD(sys_precision);
3191 sys_orphandelay = (double)(ntp_random() & 0xffff) / 65536. *
3193 sys_rootdispersion = 0;
3194 L_CLR(&sys_reftime);
3197 get_systime(&dummy);
3198 sys_manycastserver = 0;
3200 sys_bdelay = DEFBROADDELAY;
3201 sys_calldelay = BURST_DELAY;
3202 sys_authenticate = 1;
3203 L_CLR(&sys_authdelay);
3204 sys_authdly[0] = sys_authdly[1] = 0;
3207 for (i = 0; i < MAX_TTL; i++) {
3208 sys_ttl[i] = (u_char)((i * 256) / MAX_TTL);
3212 sys_automax = 1 << NTP_AUTOMAX;
3213 #endif /* OPENSSL */
3216 * Default these to enable
3219 #ifndef KERNEL_FLL_BUG
3228 * proto_config - configure the protocol module
3235 struct sockaddr_storage* svalue
3239 * Figure out what he wants to change, then do it
3244 * Turn on/off kernel discipline.
3247 kern_enable = (int)value;
3251 * Turn on/off clock discipline.
3254 ntp_enable = (int)value;
3258 * Turn on/off monitoring.
3268 * Turn on/off statistics.
3271 stats_control = (int)value;
3275 * Turn on/off enable broadcasts.
3277 case PROTO_BROADCLIENT:
3278 sys_bclient = (int)value;
3279 if (sys_bclient == 0)
3286 * Turn on/off PPS discipline.
3289 pps_enable = (int)value;
3293 * Add muliticast group address.
3295 case PROTO_MULTICAST_ADD:
3297 io_multicast_add(*svalue);
3302 * Delete multicast group address.
3304 case PROTO_MULTICAST_DEL:
3306 io_multicast_del(*svalue);
3310 * Set default broadcast delay.
3312 case PROTO_BROADDELAY:
3313 sys_bdelay = dvalue;
3317 * Set modem call delay.
3319 case PROTO_CALLDELAY:
3320 sys_calldelay = (int)value;
3324 * Turn on/off authentication to mobilize ephemeral
3327 case PROTO_AUTHENTICATE:
3328 sys_authenticate = (int)value;
3332 * Set minimum number of survivors.
3334 case PROTO_MINCLOCK:
3335 sys_minclock = (int)dvalue;
3339 * Set maximum number of preemptable associations.
3341 case PROTO_MAXCLOCK:
3342 sys_maxclock = (int)dvalue;
3346 * Set minimum number of survivors.
3349 sys_minsane = (int)dvalue;
3353 * Set stratum floor.
3356 sys_floor = (int)dvalue;
3360 * Set stratum ceiling.
3363 sys_ceiling = (int)dvalue;
3367 * Set orphan stratum.
3370 sys_orphan = (int)dvalue;
3374 * Set cohort switch.
3377 sys_cohort = (int)dvalue;
3381 * Set minimum dispersion increment.
3384 sys_mindisp = dvalue;
3388 * Set maximum distance (select threshold).
3391 sys_maxdist = dvalue;
3395 * Set anticlockhop threshold.
3398 sys_maxhop = (int)dvalue;
3402 * Set adjtime() resolution (s).
3409 * Set manycast beacon interval.
3412 sys_beacon = (int)dvalue;
3417 * Turn on/off refclock calibrate
3420 cal_enable = (int)value;
3422 #endif /* REFCLOCK */
3429 "proto_config: illegal item %d, value %ld", item,
3436 * proto_clr_stats - clear protocol stat counters
3439 proto_clr_stats(void)
3441 sys_stattime = current_time;
3444 sys_newversionpkt = 0;
3445 sys_oldversionpkt = 0;
3446 sys_unknownversion = 0;
3450 sys_limitrejected = 0;
projects / FreeBSD / releng / 9.1.git / blob