2 * ntp_proto.c - NTP version 4 protocol machinery
4 * ATTENTION: Get approval from Harlan on all changes to this file!
5 * (Harlan will be discussing these changes with Dave Mills.)
13 #include "ntp_stdlib.h"
14 #include "ntp_unixtime.h"
15 #include "ntp_control.h"
16 #include "ntp_string.h"
17 #include "ntp_leapsec.h"
18 #include "refidsmear.h"
19 #include "lib_strbuf.h"
29 /* [Bug 3031] define automatic broadcastdelay cutoff preset */
30 #ifndef BDELAY_DEFAULT
31 # define BDELAY_DEFAULT (-0.050)
35 * This macro defines the authentication state. If x is 1 authentication
36 * is required; othewise it is optional.
38 #define AUTH(x, y) ((x) ? (y) == AUTH_OK \
39 : (y) == AUTH_OK || (y) == AUTH_NONE)
43 AUTH_UNKNOWN = -1, /* Unknown */
44 AUTH_NONE, /* authentication not required */
45 AUTH_OK, /* authentication OK */
46 AUTH_ERROR, /* authentication error */
47 AUTH_CRYPTO /* crypto_NAK */
51 * Set up Kiss Code values
56 NOKISS, /* No Kiss Code */
57 RATEKISS, /* Rate limit Kiss Code */
58 DENYKISS, /* Deny Kiss */
59 RSTRKISS, /* Restricted Kiss */
60 XKISS /* Experimental Kiss */
65 NONAK, /* No NAK seen */
66 INVALIDNAK, /* NAK cannot be used */
67 VALIDNAK /* NAK is valid */
71 * traffic shaping parameters
73 #define NTP_IBURST 6 /* packets in iburst */
74 #define RESP_DELAY 1 /* refclock burst delay (s) */
77 * pool soliciting restriction duration (s)
79 #define POOL_SOLICIT_WINDOW 8
82 * peer_select groups statistics for a peer used by clock_select() and
85 typedef struct peer_select_tag {
87 double synch; /* sync distance */
88 double error; /* jitter */
89 double seljit; /* selection jitter */
93 * System variables are declared here. Unless specified otherwise, all
94 * times are in seconds.
96 u_char sys_leap; /* system leap indicator, use set_sys_leap() to change this */
97 u_char xmt_leap; /* leap indicator sent in client requests, set up by set_sys_leap() */
98 u_char sys_stratum; /* system stratum */
99 s_char sys_precision; /* local clock precision (log2 s) */
100 double sys_rootdelay; /* roundtrip delay to primary source */
101 double sys_rootdisp; /* dispersion to primary source */
102 u_int32 sys_refid; /* reference id (network byte order) */
103 l_fp sys_reftime; /* last update time */
104 struct peer *sys_peer; /* current peer */
107 struct leap_smear_info leap_smear;
109 int leap_sec_in_progress;
112 * Rate controls. Leaky buckets are used to throttle the packet
113 * transmission rates in order to protect busy servers such as at NIST
114 * and USNO. There is a counter for each association and another for KoD
115 * packets. The association counter decrements each second, but not
116 * below zero. Each time a packet is sent the counter is incremented by
117 * a configurable value representing the average interval between
118 * packets. A packet is delayed as long as the counter is greater than
119 * zero. Note this does not affect the time value computations.
122 * Nonspecified system state variables
124 int sys_bclient; /* broadcast client enable */
125 double sys_bdelay; /* broadcast client default delay */
126 int sys_authenticate; /* requre authentication for config */
127 l_fp sys_authdelay; /* authentication delay */
128 double sys_offset; /* current local clock offset */
129 double sys_mindisp = MINDISPERSE; /* minimum distance (s) */
130 double sys_maxdist = MAXDISTANCE; /* selection threshold */
131 double sys_jitter; /* system jitter */
132 u_long sys_epoch; /* last clock update time */
133 static double sys_clockhop; /* clockhop threshold */
134 static int leap_vote_ins; /* leap consensus for insert */
135 static int leap_vote_del; /* leap consensus for delete */
136 keyid_t sys_private; /* private value for session seed */
137 int sys_manycastserver; /* respond to manycast client pkts */
138 int ntp_mode7; /* respond to ntpdc (mode7) */
139 int peer_ntpdate; /* active peers in ntpdate mode */
140 int sys_survivors; /* truest of the truechimers */
141 char *sys_ident = NULL; /* identity scheme */
144 * TOS and multicast mapping stuff
146 int sys_floor = 0; /* cluster stratum floor */
147 u_char sys_bcpollbstep = 0; /* Broadcast Poll backstep gate */
148 int sys_ceiling = STRATUM_UNSPEC - 1; /* cluster stratum ceiling */
149 int sys_minsane = 1; /* minimum candidates */
150 int sys_minclock = NTP_MINCLOCK; /* minimum candidates */
151 int sys_maxclock = NTP_MAXCLOCK; /* maximum candidates */
152 int sys_cohort = 0; /* cohort switch */
153 int sys_orphan = STRATUM_UNSPEC + 1; /* orphan stratum */
154 int sys_orphwait = NTP_ORPHWAIT; /* orphan wait */
155 int sys_beacon = BEACON; /* manycast beacon interval */
156 u_int sys_ttlmax; /* max ttl mapping vector index */
157 u_char sys_ttl[MAX_TTL]; /* ttl mapping vector */
160 * Statistics counters - first the good, then the bad
162 u_long sys_stattime; /* elapsed time */
163 u_long sys_received; /* packets received */
164 u_long sys_processed; /* packets for this host */
165 u_long sys_newversion; /* current version */
166 u_long sys_oldversion; /* old version */
167 u_long sys_restricted; /* access denied */
168 u_long sys_badlength; /* bad length or format */
169 u_long sys_badauth; /* bad authentication */
170 u_long sys_declined; /* declined */
171 u_long sys_limitrejected; /* rate exceeded */
172 u_long sys_kodsent; /* KoD sent */
175 * Mechanism knobs: how soon do we peer_clear() or unpeer()?
177 * The default way is "on-receipt". If this was a packet from a
178 * well-behaved source, on-receipt will offer the fastest recovery.
179 * If this was from a DoS attack, the default way makes it easier
180 * for a bad-guy to DoS us. So look and see what bites you harder
181 * and choose according to your environment.
183 int peer_clear_digest_early = 1; /* bad digest (TEST5) and Autokey */
184 int unpeer_crypto_early = 1; /* bad crypto (TEST9) */
185 int unpeer_crypto_nak_early = 1; /* crypto_NAK (TEST5) */
186 int unpeer_digest_early = 1; /* bad digest (TEST5) */
188 int dynamic_interleave = DYNAMIC_INTERLEAVE; /* Bug 2978 mitigation */
190 int kiss_code_check(u_char hisleap, u_char hisstratum, u_char hismode, u_int32 refid);
191 nak_code valid_NAK (struct peer *peer, struct recvbuf *rbufp, u_char hismode);
192 static double root_distance (struct peer *);
193 static void clock_combine (peer_select *, int, int);
194 static void peer_xmit (struct peer *);
195 static void fast_xmit (struct recvbuf *, int, keyid_t, int);
196 static void pool_xmit (struct peer *);
197 static void clock_update (struct peer *);
198 static void measure_precision(void);
199 static double measure_tick_fuzz(void);
200 static int local_refid (struct peer *);
201 static int peer_unfit (struct peer *);
203 static int group_test (char *, char *);
206 void pool_name_resolved (int, int, void *, const char *,
207 const char *, const struct addrinfo *,
208 const struct addrinfo *);
211 const char * amtoa (int am);
219 sys_leap = new_sys_leap;
223 * Under certain conditions we send faked leap bits to clients, so
224 * eventually change xmt_leap below, but never change LEAP_NOTINSYNC.
226 if (xmt_leap != LEAP_NOTINSYNC) {
227 if (leap_sec_in_progress) {
228 /* always send "not sync" */
229 xmt_leap = LEAP_NOTINSYNC;
234 * If leap smear is enabled in general we must
235 * never send a leap second warning to clients,
236 * so make sure we only send "in sync".
238 if (leap_smear.enabled)
239 xmt_leap = LEAP_NOWARNING;
241 #endif /* LEAP_SMEAR */
258 if ( hismode == MODE_SERVER
259 && hisleap == LEAP_NOTINSYNC
260 && hisstratum == STRATUM_UNSPEC) {
261 if(memcmp(&refid,"RATE", 4) == 0) {
263 } else if(memcmp(&refid,"DENY", 4) == 0) {
265 } else if(memcmp(&refid,"RSTR", 4) == 0) {
267 } else if(memcmp(&refid,"X", 1) == 0) {
276 * Check that NAK is valid
281 struct recvbuf *rbufp,
285 int base_packet_length = MIN_V4_PKT_LEN;
289 l_fp p_org; /* origin timestamp */
290 const l_fp * myorg; /* selected peer origin */
293 * Check to see if there is something beyond the basic packet
295 if (rbufp->recv_length == base_packet_length) {
299 remainder_size = rbufp->recv_length - base_packet_length;
301 * Is this a potential NAK?
303 if (remainder_size != 4) {
308 * Only server responses can contain NAK's
311 if (hismode != MODE_SERVER &&
312 hismode != MODE_ACTIVE &&
313 hismode != MODE_PASSIVE
319 * Make sure that the extra field in the packet is all zeros
321 rpkt = &rbufp->recv_pkt;
322 keyid = ntohl(((u_int32 *)rpkt)[base_packet_length / 4]);
328 * Only valid if peer uses a key
330 if (!peer || !peer->keyid || !(peer->flags & FLAG_SKEY)) {
335 * The ORIGIN must match, or this cannot be a valid NAK, either.
337 NTOHL_FP(&rpkt->org, &p_org);
343 if (L_ISZERO(&p_org) ||
345 !L_ISEQU(&p_org, myorg)) {
349 /* If we ever passed all that checks, we should be safe. Well,
350 * as safe as we can ever be with an unauthenticated crypto-nak.
357 * transmit - transmit procedure called by poll timeout
361 struct peer *peer /* peer structure pointer */
367 * The polling state machine. There are two kinds of machines,
368 * those that never expect a reply (broadcast and manycast
369 * server modes) and those that do (all other modes). The dance
375 * In broadcast mode the poll interval is never changed from
378 if (peer->cast_flags & (MDF_BCAST | MDF_MCAST)) {
379 peer->outdate = current_time;
380 if (sys_leap != LEAP_NOTINSYNC)
382 poll_update(peer, hpoll);
387 * In manycast mode we start with unity ttl. The ttl is
388 * increased by one for each poll until either sys_maxclock
389 * servers have been found or the maximum ttl is reached. When
390 * sys_maxclock servers are found we stop polling until one or
391 * more servers have timed out or until less than sys_minclock
392 * associations turn up. In this case additional better servers
393 * are dragged in and preempt the existing ones. Once every
394 * sys_beacon seconds we are to transmit unconditionally, but
395 * this code is not quite right -- peer->unreach counts polls
396 * and is being compared with sys_beacon, so the beacons happen
397 * every sys_beacon polls.
399 if (peer->cast_flags & MDF_ACAST) {
400 peer->outdate = current_time;
401 if (peer->unreach > sys_beacon) {
405 } else if ( sys_survivors < sys_minclock
406 || peer_associations < sys_maxclock) {
407 if (peer->ttl < sys_ttlmax)
412 poll_update(peer, hpoll);
417 * Pool associations transmit unicast solicitations when there
418 * are less than a hard limit of 2 * sys_maxclock associations,
419 * and either less than sys_minclock survivors or less than
420 * sys_maxclock associations. The hard limit prevents unbounded
421 * growth in associations if the system clock or network quality
422 * result in survivor count dipping below sys_minclock often.
423 * This was observed testing with pool, where sys_maxclock == 12
424 * resulted in 60 associations without the hard limit. A
425 * similar hard limit on manycastclient ephemeral associations
426 * may be appropriate.
428 if (peer->cast_flags & MDF_POOL) {
429 peer->outdate = current_time;
430 if ( (peer_associations <= 2 * sys_maxclock)
431 && ( peer_associations < sys_maxclock
432 || sys_survivors < sys_minclock))
434 poll_update(peer, hpoll);
439 * In unicast modes the dance is much more intricate. It is
440 * designed to back off whenever possible to minimize network
443 if (peer->burst == 0) {
447 * Update the reachability status. If not heard for
448 * three consecutive polls, stuff infinity in the clock
451 oreach = peer->reach;
452 peer->outdate = current_time;
458 * Here the peer is unreachable. If it was
459 * previously reachable raise a trap. Send a
462 clock_filter(peer, 0., 0., MAXDISPERSE);
465 report_event(PEVNT_UNREACH, peer, NULL);
467 if ( (peer->flags & FLAG_IBURST)
469 peer->retry = NTP_RETRY;
473 * Here the peer is reachable. Send a burst if
474 * enabled and the peer is fit. Reset unreach
475 * for persistent and ephemeral associations.
476 * Unreach is also reset for survivors in
480 if (!(peer->flags & FLAG_PREEMPT))
482 if ( (peer->flags & FLAG_BURST)
484 && !peer_unfit(peer))
485 peer->retry = NTP_RETRY;
489 * Watch for timeout. If ephemeral, toss the rascal;
490 * otherwise, bump the poll interval. Note the
491 * poll_update() routine will clamp it to maxpoll.
492 * If preemptible and we have more peers than maxclock,
493 * and this peer has the minimum score of preemptibles,
496 if (peer->unreach >= NTP_UNREACH) {
498 /* ephemeral: no FLAG_CONFIG nor FLAG_PREEMPT */
499 if (!(peer->flags & (FLAG_CONFIG | FLAG_PREEMPT))) {
500 report_event(PEVNT_RESTART, peer, "timeout");
501 peer_clear(peer, "TIME");
505 if ( (peer->flags & FLAG_PREEMPT)
506 && (peer_associations > sys_maxclock)
507 && score_all(peer)) {
508 report_event(PEVNT_RESTART, peer, "timeout");
509 peer_clear(peer, "TIME");
516 if (peer->burst == 0) {
519 * If ntpdate mode and the clock has not been
520 * set and all peers have completed the burst,
521 * we declare a successful failure.
525 if (peer_ntpdate == 0) {
527 "ntpd: no servers found");
530 "ntpd: no servers found\n");
540 * Do not transmit if in broadcast client mode.
542 if (peer->hmode != MODE_BCLIENT)
544 poll_update(peer, hpoll);
558 case AM_ERR: return "AM_ERR";
559 case AM_NOMATCH: return "AM_NOMATCH";
560 case AM_PROCPKT: return "AM_PROCPKT";
561 case AM_BCST: return "AM_BCST";
562 case AM_FXMIT: return "AM_FXMIT";
563 case AM_MANYCAST: return "AM_MANYCAST";
564 case AM_NEWPASS: return "AM_NEWPASS";
565 case AM_NEWBCL: return "AM_NEWBCL";
566 case AM_POSSBCL: return "AM_POSSBCL";
569 snprintf(bp, LIB_BUFLENGTH, "AM_#%d", am);
576 * receive - receive procedure called for each packet received
580 struct recvbuf *rbufp
583 register struct peer *peer; /* peer structure pointer */
584 register struct pkt *pkt; /* receive packet pointer */
585 u_char hisversion; /* packet version */
586 u_char hisleap; /* packet leap indicator */
587 u_char hismode; /* packet mode */
588 u_char hisstratum; /* packet stratum */
589 r4addr r4a; /* address restrictions */
590 u_short restrict_mask; /* restrict bits */
591 const char *hm_str; /* hismode string */
592 const char *am_str; /* association match string */
593 int kissCode = NOKISS; /* Kiss Code */
594 int has_mac; /* length of MAC field */
595 int authlen; /* offset of MAC field */
596 auth_code is_authentic = AUTH_UNKNOWN; /* Was AUTH_NONE */
597 nak_code crypto_nak_test; /* result of crypto-NAK check */
598 int retcode = AM_NOMATCH; /* match code */
599 keyid_t skeyid = 0; /* key IDs */
600 u_int32 opcode = 0; /* extension field opcode */
601 sockaddr_u *dstadr_sin; /* active runway */
602 struct peer *peer2; /* aux peer structure pointer */
603 endpt *match_ep; /* newpeer() local address */
604 l_fp p_org; /* origin timestamp */
605 l_fp p_rec; /* receive timestamp */
606 l_fp p_xmt; /* transmit timestamp */
608 char hostname[NTP_MAXSTRLEN + 1];
609 char *groupname = NULL;
610 struct autokey *ap; /* autokey structure pointer */
611 int rval; /* cookie snatcher */
612 keyid_t pkeyid = 0, tkeyid = 0; /* key IDs */
614 #ifdef HAVE_NTP_SIGND
615 static unsigned char zero_key[16];
616 #endif /* HAVE_NTP_SIGND */
619 * Note that there are many places we do not call record_raw_stats().
621 * We only want to call it *after* we've sent a response, or perhaps
622 * when we've decided to drop a packet.
626 * Monitor the packet and get restrictions. Note that the packet
627 * length for control and private mode packets must be checked
628 * by the service routines. Some restrictions have to be handled
629 * later in order to generate a kiss-o'-death packet.
632 * Bogus port check is before anything, since it probably
633 * reveals a clogging attack.
636 if (0 == SRCPORT(&rbufp->recv_srcadr)) {
638 return; /* bogus port */
640 restrictions(&rbufp->recv_srcadr, &r4a);
641 restrict_mask = r4a.rflags;
643 pkt = &rbufp->recv_pkt;
644 hisversion = PKT_VERSION(pkt->li_vn_mode);
645 hisleap = PKT_LEAP(pkt->li_vn_mode);
646 hismode = (int)PKT_MODE(pkt->li_vn_mode);
647 hisstratum = PKT_TO_STRATUM(pkt->stratum);
648 DPRINTF(2, ("receive: at %ld %s<-%s ippeerlimit %d mode %d iflags %s restrict %s org %#010x.%08x xmt %#010x.%08x\n",
649 current_time, stoa(&rbufp->dstadr->sin),
650 stoa(&rbufp->recv_srcadr), r4a.ippeerlimit, hismode,
651 build_iflags(rbufp->dstadr->flags),
652 build_rflags(restrict_mask),
653 ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf),
654 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf)));
656 /* See basic mode and broadcast checks, below */
657 INSIST(0 != hisstratum);
659 if (restrict_mask & RES_IGNORE) {
660 DPRINTF(2, ("receive: drop: RES_IGNORE\n"));
662 return; /* ignore everything */
664 if (hismode == MODE_PRIVATE) {
665 if (!ntp_mode7 || (restrict_mask & RES_NOQUERY)) {
666 DPRINTF(2, ("receive: drop: RES_NOQUERY\n"));
668 return; /* no query private */
670 process_private(rbufp, ((restrict_mask &
671 RES_NOMODIFY) == 0));
674 if (hismode == MODE_CONTROL) {
675 if (restrict_mask & RES_NOQUERY) {
676 DPRINTF(2, ("receive: drop: RES_NOQUERY\n"));
678 return; /* no query control */
680 process_control(rbufp, restrict_mask);
683 if (restrict_mask & RES_DONTSERVE) {
684 DPRINTF(2, ("receive: drop: RES_DONTSERVE\n"));
686 return; /* no time serve */
690 * This is for testing. If restricted drop ten percent of
693 if (restrict_mask & RES_FLAKE) {
694 if ((double)ntp_random() / 0x7fffffff < .1) {
695 DPRINTF(2, ("receive: drop: RES_FLAKE\n"));
697 return; /* no flakeway */
702 ** Format Layer Checks
704 ** Validate the packet format. The packet size, packet header,
705 ** and any extension field lengths are checked. We identify
706 ** the beginning of the MAC, to identify the upper limit of
707 ** of the hash computation.
709 ** In case of a format layer check violation, the packet is
710 ** discarded with no further processing.
714 * Version check must be after the query packets, since they
715 * intentionally use an early version.
717 if (hisversion == NTP_VERSION) {
718 sys_newversion++; /* new version */
719 } else if ( !(restrict_mask & RES_VERSION)
720 && hisversion >= NTP_OLDVERSION) {
721 sys_oldversion++; /* previous version */
723 DPRINTF(2, ("receive: drop: RES_VERSION\n"));
725 return; /* old version */
729 * Figure out his mode and validate the packet. This has some
730 * legacy raunch that probably should be removed. In very early
731 * NTP versions mode 0 was equivalent to what later versions
732 * would interpret as client mode.
734 if (hismode == MODE_UNSPEC) {
735 if (hisversion == NTP_OLDVERSION) {
736 hismode = MODE_CLIENT;
738 DPRINTF(2, ("receive: drop: MODE_UNSPEC\n"));
740 return; /* invalid mode */
745 * Parse the extension field if present. We figure out whether
746 * an extension field is present by measuring the MAC size. If
747 * the number of words following the packet header is 0, no MAC
748 * is present and the packet is not authenticated. If 1, the
749 * packet is a crypto-NAK; if 3, the packet is authenticated
750 * with DES; if 5, the packet is authenticated with MD5; if 6,
751 * the packet is authenticated with SHA. If 2 or * 4, the packet
752 * is a runt and discarded forthwith. If greater than 6, an
753 * extension field is present, so we subtract the length of the
754 * field and go around again.
756 * Note the above description is lame. We should/could also check
757 * the two bytes that make up the EF type and subtype, and then
758 * check the two bytes that tell us the EF length. A legacy MAC
759 * has a 4 byte keyID, and for conforming symmetric keys its value
760 * must be <= 64k, meaning the top two bytes will always be zero.
761 * Since the EF Type of 0 is reserved/unused, there's no way a
762 * conforming legacy MAC could ever be misinterpreted as an EF.
764 * There is more, but this isn't the place to document it.
767 authlen = LEN_PKT_NOMAC;
768 has_mac = rbufp->recv_length - authlen;
769 while (has_mac > 0) {
776 if (has_mac % 4 != 0 || has_mac < (int)MIN_MAC_LEN) {
777 DPRINTF(2, ("receive: drop: bad post-packet length\n"));
779 return; /* bad length */
782 * This next test is clearly wrong - it needlessly
783 * prohibits short EFs (which don't yet exist)
785 if (has_mac <= (int)MAX_MAC_LEN) {
786 skeyid = ntohl(((u_int32 *)pkt)[authlen / 4]);
790 opcode = ntohl(((u_int32 *)pkt)[authlen / 4]);
791 len = opcode & 0xffff;
794 || (int)len + authlen > rbufp->recv_length) {
795 DPRINTF(2, ("receive: drop: bad EF length\n"));
797 return; /* bad length */
801 * Extract calling group name for later. If
802 * sys_groupname is non-NULL, there must be
803 * a group name provided to elicit a response.
805 if ( (opcode & 0x3fff0000) == CRYPTO_ASSOC
806 && sys_groupname != NULL) {
807 ep = (struct exten *)&((u_int32 *)pkt)[authlen / 4];
808 hostlen = ntohl(ep->vallen);
809 if ( hostlen >= sizeof(hostname)
811 offsetof(struct exten, pkt)) {
812 DPRINTF(2, ("receive: drop: bad autokey hostname length\n"));
814 return; /* bad length */
816 memcpy(hostname, &ep->pkt, hostlen);
817 hostname[hostlen] = '\0';
818 groupname = strchr(hostname, '@');
819 if (groupname == NULL) {
820 DPRINTF(2, ("receive: drop: empty autokey groupname\n"));
833 * If has_mac is < 0 we had a malformed packet.
836 DPRINTF(2, ("receive: drop: post-packet under-read\n"));
838 return; /* bad length */
842 ** Packet Data Verification Layer
844 ** This layer verifies the packet data content. If
845 ** authentication is required, a MAC must be present.
846 ** If a MAC is present, it must validate.
847 ** Crypto-NAK? Look - a shiny thing!
849 ** If authentication fails, we're done.
853 * If authentication is explicitly required, a MAC must be present.
855 if (restrict_mask & RES_DONTTRUST && has_mac == 0) {
856 DPRINTF(2, ("receive: drop: RES_DONTTRUST\n"));
858 return; /* access denied */
862 * Update the MRU list and finger the cloggers. It can be a
863 * little expensive, so turn it off for production use.
864 * RES_LIMITED and RES_KOD will be cleared in the returned
865 * restrict_mask unless one or both actions are warranted.
867 restrict_mask = ntp_monitor(rbufp, restrict_mask);
868 if (restrict_mask & RES_LIMITED) {
870 if ( !(restrict_mask & RES_KOD)
871 || MODE_BROADCAST == hismode
872 || MODE_SERVER == hismode) {
873 if (MODE_SERVER == hismode) {
874 DPRINTF(1, ("Possibly self-induced rate limiting of MODE_SERVER from %s\n",
875 stoa(&rbufp->recv_srcadr)));
877 DPRINTF(2, ("receive: drop: RES_KOD\n"));
879 return; /* rate exceeded */
881 if (hismode == MODE_CLIENT)
882 fast_xmit(rbufp, MODE_SERVER, skeyid,
885 fast_xmit(rbufp, MODE_ACTIVE, skeyid,
887 return; /* rate exceeded */
889 restrict_mask &= ~RES_KOD;
892 * We have tossed out as many buggy packets as possible early in
893 * the game to reduce the exposure to a clogging attack. Now we
894 * have to burn some cycles to find the association and
895 * authenticate the packet if required. Note that we burn only
896 * digest cycles, again to reduce exposure. There may be no
897 * matching association and that's okay.
899 * More on the autokey mambo. Normally the local interface is
900 * found when the association was mobilized with respect to a
901 * designated remote address. We assume packets arriving from
902 * the remote address arrive via this interface and the local
903 * address used to construct the autokey is the unicast address
904 * of the interface. However, if the sender is a broadcaster,
905 * the interface broadcast address is used instead.
906 * Notwithstanding this technobabble, if the sender is a
907 * multicaster, the broadcast address is null, so we use the
908 * unicast address anyway. Don't ask.
911 peer = findpeer(rbufp, hismode, &retcode);
912 dstadr_sin = &rbufp->dstadr->sin;
913 NTOHL_FP(&pkt->org, &p_org);
914 NTOHL_FP(&pkt->rec, &p_rec);
915 NTOHL_FP(&pkt->xmt, &p_xmt);
916 hm_str = modetoa(hismode);
917 am_str = amtoa(retcode);
920 * Authentication is conditioned by three switches:
922 * NOPEER (RES_NOPEER) do not mobilize an association unless
924 * NOTRUST (RES_DONTTRUST) do not allow access unless
925 * authenticated (implies NOPEER)
926 * enable (sys_authenticate) master NOPEER switch, by default
929 * The NOPEER and NOTRUST can be specified on a per-client basis
930 * using the restrict command. The enable switch if on implies
931 * NOPEER for all clients. There are four outcomes:
933 * NONE The packet has no MAC.
934 * OK the packet has a MAC and authentication succeeds
935 * ERROR the packet has a MAC and authentication fails
936 * CRYPTO crypto-NAK. The MAC has four octets only.
938 * Note: The AUTH(x, y) macro is used to filter outcomes. If x
939 * is zero, acceptable outcomes of y are NONE and OK. If x is
940 * one, the only acceptable outcome of y is OK.
942 crypto_nak_test = valid_NAK(peer, rbufp, hismode);
945 * Drop any invalid crypto-NAKs
947 if (crypto_nak_test == INVALIDNAK) {
948 report_event(PEVNT_AUTH, peer, "Invalid_NAK");
952 msyslog(LOG_ERR, "Invalid-NAK error at %ld %s<-%s",
953 current_time, stoa(dstadr_sin), stoa(&rbufp->recv_srcadr));
958 restrict_mask &= ~RES_MSSNTP;
959 is_authentic = AUTH_NONE; /* not required */
960 DPRINTF(2, ("receive: at %ld %s<-%s mode %d/%s:%s len %d org %#010x.%08x xmt %#010x.%08x NOMAC\n",
961 current_time, stoa(dstadr_sin),
962 stoa(&rbufp->recv_srcadr), hismode, hm_str, am_str,
964 ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf),
965 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf)));
966 } else if (crypto_nak_test == VALIDNAK) {
967 restrict_mask &= ~RES_MSSNTP;
968 is_authentic = AUTH_CRYPTO; /* crypto-NAK */
969 DPRINTF(2, ("receive: at %ld %s<-%s mode %d/%s:%s keyid %08x len %d auth %d org %#010x.%08x xmt %#010x.%08x MAC4\n",
970 current_time, stoa(dstadr_sin),
971 stoa(&rbufp->recv_srcadr), hismode, hm_str, am_str,
972 skeyid, authlen + has_mac, is_authentic,
973 ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf),
974 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf)));
976 #ifdef HAVE_NTP_SIGND
978 * If the signature is 20 bytes long, the last 16 of
979 * which are zero, then this is a Microsoft client
980 * wanting AD-style authentication of the server's
983 * This is described in Microsoft's WSPP docs, in MS-SNTP:
984 * http://msdn.microsoft.com/en-us/library/cc212930.aspx
986 } else if ( has_mac == MAX_MD5_LEN
987 && (restrict_mask & RES_MSSNTP)
988 && (retcode == AM_FXMIT || retcode == AM_NEWPASS)
989 && (memcmp(zero_key, (char *)pkt + authlen + 4,
990 MAX_MD5_LEN - 4) == 0)) {
991 is_authentic = AUTH_NONE;
992 #endif /* HAVE_NTP_SIGND */
998 * Not an MS-SNTP SIGND packet
1000 * So there is a MAC here.
1003 restrict_mask &= ~RES_MSSNTP;
1006 * For autokey modes, generate the session key
1007 * and install in the key cache. Use the socket
1008 * broadcast or unicast address as appropriate.
1010 if (crypto_flags && skeyid > NTP_MAXKEY) {
1013 * More on the autokey dance (AKD). A cookie is
1014 * constructed from public and private values.
1015 * For broadcast packets, the cookie is public
1016 * (zero). For packets that match no
1017 * association, the cookie is hashed from the
1018 * addresses and private value. For server
1019 * packets, the cookie was previously obtained
1020 * from the server. For symmetric modes, the
1021 * cookie was previously constructed using an
1022 * agreement protocol; however, should PKI be
1023 * unavailable, we construct a fake agreement as
1024 * the EXOR of the peer and host cookies.
1026 * hismode ephemeral persistent
1027 * =======================================
1029 * passive 0% cookie#
1030 * client sys cookie 0%
1031 * server 0% sys cookie
1037 if (has_mac < (int)MAX_MD5_LEN) {
1038 DPRINTF(2, ("receive: drop: MD5 digest too short\n"));
1042 if (hismode == MODE_BROADCAST) {
1045 * For broadcaster, use the interface
1046 * broadcast address when available;
1047 * otherwise, use the unicast address
1048 * found when the association was
1049 * mobilized. However, if this is from
1050 * the wildcard interface, game over.
1054 ANY_INTERFACE_CHOOSE(&rbufp->recv_srcadr)) {
1055 DPRINTF(2, ("receive: drop: BCAST from wildcard\n"));
1057 return; /* no wildcard */
1060 if (!SOCK_UNSPEC(&rbufp->dstadr->bcast))
1062 &rbufp->dstadr->bcast;
1063 } else if (peer == NULL) {
1064 pkeyid = session_key(
1065 &rbufp->recv_srcadr, dstadr_sin, 0,
1068 pkeyid = peer->pcookie;
1072 * The session key includes both the public
1073 * values and cookie. In case of an extension
1074 * field, the cookie used for authentication
1075 * purposes is zero. Note the hash is saved for
1076 * use later in the autokey mambo.
1078 if (authlen > (int)LEN_PKT_NOMAC && pkeyid != 0) {
1079 session_key(&rbufp->recv_srcadr,
1080 dstadr_sin, skeyid, 0, 2);
1081 tkeyid = session_key(
1082 &rbufp->recv_srcadr, dstadr_sin,
1085 tkeyid = session_key(
1086 &rbufp->recv_srcadr, dstadr_sin,
1091 #endif /* AUTOKEY */
1094 * Compute the cryptosum. Note a clogging attack may
1095 * succeed in bloating the key cache. If an autokey,
1096 * purge it immediately, since we won't be needing it
1097 * again. If the packet is authentic, it can mobilize an
1098 * association. Note that there is no key zero.
1100 if (!authdecrypt(skeyid, (u_int32 *)pkt, authlen,
1102 is_authentic = AUTH_ERROR;
1104 is_authentic = AUTH_OK;
1106 if (crypto_flags && skeyid > NTP_MAXKEY)
1107 authtrust(skeyid, 0);
1108 #endif /* AUTOKEY */
1109 DPRINTF(2, ("receive: at %ld %s<-%s mode %d/%s:%s keyid %08x len %d auth %d org %#010x.%08x xmt %#010x.%08x\n",
1110 current_time, stoa(dstadr_sin),
1111 stoa(&rbufp->recv_srcadr), hismode, hm_str, am_str,
1112 skeyid, authlen + has_mac, is_authentic,
1113 ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf),
1114 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf)));
1121 * Now come at this from a different perspective:
1122 * - If we expect a MAC and it's not there, we drop it.
1123 * - If we expect one keyID and get another, we drop it.
1124 * - If we have a MAC ahd it hasn't been validated yet, try.
1125 * - if the provided MAC doesn't validate, we drop it.
1127 * There might be more to this.
1129 if (0 != peer && 0 != peer->keyid) {
1130 /* Should we msyslog() any of these? */
1133 * This should catch:
1134 * - no keyID where one is expected,
1135 * - different keyID than what we expect.
1137 if (peer->keyid != skeyid) {
1138 DPRINTF(2, ("receive: drop: Wanted keyID %d, got %d from %s\n",
1139 peer->keyid, skeyid,
1140 stoa(&rbufp->recv_srcadr)));
1142 return; /* drop: access denied */
1146 * if has_mac != 0 ...
1147 * - If it has not yet been validated, do so.
1148 * (under what circumstances might that happen?)
1149 * - if missing or bad MAC, log and drop.
1152 if (is_authentic == AUTH_UNKNOWN) {
1153 /* How can this happen? */
1154 DPRINTF(2, ("receive: 3454 check: AUTH_UNKNOWN from %s\n",
1155 stoa(&rbufp->recv_srcadr)));
1156 if (!authdecrypt(skeyid, (u_int32 *)pkt, authlen,
1158 /* MAC invalid or not found */
1159 is_authentic = AUTH_ERROR;
1161 is_authentic = AUTH_OK;
1164 if (is_authentic != AUTH_OK) {
1165 DPRINTF(2, ("receive: drop: missing or bad MAC from %s\n",
1166 stoa(&rbufp->recv_srcadr)));
1168 return; /* drop: access denied */
1175 ** On-Wire Protocol Layer
1177 ** Verify protocol operations consistent with the on-wire protocol.
1178 ** The protocol discards bogus and duplicate packets as well as
1179 ** minimizes disruptions doe to protocol restarts and dropped
1180 ** packets. The operations are controlled by two timestamps:
1181 ** the transmit timestamp saved in the client state variables,
1182 ** and the origin timestamp in the server packet header. The
1183 ** comparison of these two timestamps is called the loopback test.
1184 ** The transmit timestamp functions as a nonce to verify that the
1185 ** response corresponds to the original request. The transmit
1186 ** timestamp also serves to discard replays of the most recent
1187 ** packet. Upon failure of either test, the packet is discarded
1188 ** with no further action.
1192 * The association matching rules are implemented by a set of
1193 * routines and an association table. A packet matching an
1194 * association is processed by the peer process for that
1195 * association. If there are no errors, an ephemeral association
1196 * is mobilized: a broadcast packet mobilizes a broadcast client
1197 * aassociation; a manycast server packet mobilizes a manycast
1198 * client association; a symmetric active packet mobilizes a
1199 * symmetric passive association.
1204 * This is a client mode packet not matching any association. If
1205 * an ordinary client, simply toss a server mode packet back
1206 * over the fence. If a manycast client, we have to work a
1209 * There are cases here where we do not call record_raw_stats().
1214 * If authentication OK, send a server reply; otherwise,
1215 * send a crypto-NAK.
1217 if (!(rbufp->dstadr->flags & INT_MCASTOPEN)) {
1218 /* HMS: would be nice to log FAST_XMIT|BADAUTH|RESTRICTED */
1219 record_raw_stats(&rbufp->recv_srcadr,
1220 &rbufp->dstadr->sin,
1221 &p_org, &p_rec, &p_xmt, &rbufp->recv_time,
1222 PKT_LEAP(pkt->li_vn_mode),
1223 PKT_VERSION(pkt->li_vn_mode),
1224 PKT_MODE(pkt->li_vn_mode),
1225 PKT_TO_STRATUM(pkt->stratum),
1228 FPTOD(NTOHS_FP(pkt->rootdelay)),
1229 FPTOD(NTOHS_FP(pkt->rootdisp)),
1231 rbufp->recv_length - MIN_V4_PKT_LEN, (u_char *)&pkt->exten);
1233 if (AUTH(restrict_mask & RES_DONTTRUST,
1235 fast_xmit(rbufp, MODE_SERVER, skeyid,
1237 } else if (is_authentic == AUTH_ERROR) {
1238 fast_xmit(rbufp, MODE_SERVER, 0,
1242 DPRINTF(2, ("receive: AM_FXMIT drop: !mcast restricted\n"));
1246 return; /* hooray */
1250 * This must be manycast. Do not respond if not
1251 * configured as a manycast server.
1253 if (!sys_manycastserver) {
1254 DPRINTF(2, ("receive: AM_FXMIT drop: Not manycastserver\n"));
1256 return; /* not enabled */
1261 * Do not respond if not the same group.
1263 if (group_test(groupname, NULL)) {
1264 DPRINTF(2, ("receive: AM_FXMIT drop: empty groupname\n"));
1268 #endif /* AUTOKEY */
1271 * Do not respond if we are not synchronized or our
1272 * stratum is greater than the manycaster or the
1273 * manycaster has already synchronized to us.
1275 if ( sys_leap == LEAP_NOTINSYNC
1276 || sys_stratum >= hisstratum
1277 || (!sys_cohort && sys_stratum == hisstratum + 1)
1278 || rbufp->dstadr->addr_refid == pkt->refid) {
1279 DPRINTF(2, ("receive: AM_FXMIT drop: LEAP_NOTINSYNC || stratum || loop\n"));
1281 return; /* no help */
1285 * Respond only if authentication succeeds. Don't do a
1286 * crypto-NAK, as that would not be useful.
1288 if (AUTH(restrict_mask & RES_DONTTRUST, is_authentic)) {
1289 record_raw_stats(&rbufp->recv_srcadr,
1290 &rbufp->dstadr->sin,
1291 &p_org, &p_rec, &p_xmt, &rbufp->recv_time,
1292 PKT_LEAP(pkt->li_vn_mode),
1293 PKT_VERSION(pkt->li_vn_mode),
1294 PKT_MODE(pkt->li_vn_mode),
1295 PKT_TO_STRATUM(pkt->stratum),
1298 FPTOD(NTOHS_FP(pkt->rootdelay)),
1299 FPTOD(NTOHS_FP(pkt->rootdisp)),
1301 rbufp->recv_length - MIN_V4_PKT_LEN, (u_char *)&pkt->exten);
1303 fast_xmit(rbufp, MODE_SERVER, skeyid,
1306 return; /* hooray */
1309 * This is a server mode packet returned in response to a client
1310 * mode packet sent to a multicast group address (for
1311 * manycastclient) or to a unicast address (for pool). The
1312 * origin timestamp is a good nonce to reliably associate the
1313 * reply with what was sent. If there is no match, that's
1314 * curious and could be an intruder attempting to clog, so we
1317 * If the packet is authentic and the manycastclient or pool
1318 * association is found, we mobilize a client association and
1319 * copy pertinent variables from the manycastclient or pool
1320 * association to the new client association. If not, just
1321 * ignore the packet.
1323 * There is an implosion hazard at the manycast client, since
1324 * the manycast servers send the server packet immediately. If
1325 * the guy is already here, don't fire up a duplicate.
1327 * There are cases here where we do not call record_raw_stats().
1333 * Do not respond if not the same group.
1335 if (group_test(groupname, NULL)) {
1336 DPRINTF(2, ("receive: AM_MANYCAST drop: empty groupname\n"));
1340 #endif /* AUTOKEY */
1341 if ((peer2 = findmanycastpeer(rbufp)) == NULL) {
1342 DPRINTF(2, ("receive: AM_MANYCAST drop: No manycast peer\n"));
1344 return; /* not enabled */
1346 if (!AUTH( (!(peer2->cast_flags & MDF_POOL)
1347 && sys_authenticate)
1348 || (restrict_mask & (RES_NOPEER |
1349 RES_DONTTRUST)), is_authentic)
1350 /* MC: RES_NOEPEER? */
1352 DPRINTF(2, ("receive: AM_MANYCAST drop: bad auth || (NOPEER|DONTTRUST)\n"));
1354 return; /* access denied */
1358 * Do not respond if unsynchronized or stratum is below
1359 * the floor or at or above the ceiling.
1361 if ( hisleap == LEAP_NOTINSYNC
1362 || hisstratum < sys_floor
1363 || hisstratum >= sys_ceiling) {
1364 DPRINTF(2, ("receive: AM_MANYCAST drop: unsync/stratum\n"));
1366 return; /* no help */
1368 peer = newpeer(&rbufp->recv_srcadr, NULL, rbufp->dstadr,
1369 r4a.ippeerlimit, MODE_CLIENT, hisversion,
1370 peer2->minpoll, peer2->maxpoll,
1371 FLAG_PREEMPT | (FLAG_IBURST & peer2->flags),
1372 MDF_UCAST | MDF_UCLNT, 0, skeyid, sys_ident);
1374 DPRINTF(2, ("receive: AM_MANYCAST drop: duplicate\n"));
1376 return; /* ignore duplicate */
1380 * After each ephemeral pool association is spun,
1381 * accelerate the next poll for the pool solicitor so
1382 * the pool will fill promptly.
1384 if (peer2->cast_flags & MDF_POOL)
1385 peer2->nextdate = current_time + 1;
1388 * Further processing of the solicitation response would
1389 * simply detect its origin timestamp as bogus for the
1390 * brand-new association (it matches the prototype
1391 * association) and tinker with peer->nextdate delaying
1394 return; /* solicitation response handled */
1397 * This is the first packet received from a broadcast server. If
1398 * the packet is authentic and we are enabled as broadcast
1399 * client, mobilize a broadcast client association. We don't
1400 * kiss any frogs here.
1402 * There are cases here where we do not call record_raw_stats().
1408 * Do not respond if not the same group.
1410 if (group_test(groupname, sys_ident)) {
1411 DPRINTF(2, ("receive: AM_NEWBCL drop: groupname mismatch\n"));
1415 #endif /* AUTOKEY */
1416 if (sys_bclient == 0) {
1417 DPRINTF(2, ("receive: AM_NEWBCL drop: not a bclient\n"));
1419 return; /* not enabled */
1421 if (!AUTH(sys_authenticate | (restrict_mask &
1422 (RES_NOPEER | RES_DONTTRUST)), is_authentic)
1423 /* NEWBCL: RES_NOEPEER? */
1425 DPRINTF(2, ("receive: AM_NEWBCL drop: AUTH failed\n"));
1427 return; /* access denied */
1431 * Do not respond if unsynchronized or stratum is below
1432 * the floor or at or above the ceiling.
1434 if ( hisleap == LEAP_NOTINSYNC
1435 || hisstratum < sys_floor
1436 || hisstratum >= sys_ceiling) {
1437 DPRINTF(2, ("receive: AM_NEWBCL drop: Unsync or bad stratum\n"));
1439 return; /* no help */
1444 * Do not respond if Autokey and the opcode is not a
1445 * CRYPTO_ASSOC response with association ID.
1447 if ( crypto_flags && skeyid > NTP_MAXKEY
1448 && (opcode & 0xffff0000) != (CRYPTO_ASSOC | CRYPTO_RESP)) {
1449 DPRINTF(2, ("receive: AM_NEWBCL drop: Autokey but not CRYPTO_ASSOC\n"));
1451 return; /* protocol error */
1453 #endif /* AUTOKEY */
1456 * Broadcasts received via a multicast address may
1457 * arrive after a unicast volley has begun
1458 * with the same remote address. newpeer() will not
1459 * find duplicate associations on other local endpoints
1460 * if a non-NULL endpoint is supplied. multicastclient
1461 * ephemeral associations are unique across all local
1464 if (!(INT_MCASTOPEN & rbufp->dstadr->flags))
1465 match_ep = rbufp->dstadr;
1470 * Determine whether to execute the initial volley.
1472 if (sys_bdelay > 0.0) {
1475 * If a two-way exchange is not possible,
1476 * neither is Autokey.
1478 if (crypto_flags && skeyid > NTP_MAXKEY) {
1480 DPRINTF(2, ("receive: AM_NEWBCL drop: Autokey but not 2-way\n"));
1481 return; /* no autokey */
1483 #endif /* AUTOKEY */
1486 * Do not execute the volley. Start out in
1487 * broadcast client mode.
1489 peer = newpeer(&rbufp->recv_srcadr, NULL, match_ep,
1490 r4a.ippeerlimit, MODE_BCLIENT, hisversion,
1491 pkt->ppoll, pkt->ppoll,
1492 FLAG_PREEMPT, MDF_BCLNT, 0, skeyid, sys_ident);
1494 DPRINTF(2, ("receive: AM_NEWBCL drop: duplicate\n"));
1496 return; /* ignore duplicate */
1499 peer->delay = sys_bdelay;
1506 * Execute the initial volley in order to calibrate the
1507 * propagation delay and run the Autokey protocol.
1509 * Note that the minpoll is taken from the broadcast
1510 * packet, normally 6 (64 s) and that the poll interval
1511 * is fixed at this value.
1513 peer = newpeer(&rbufp->recv_srcadr, NULL, match_ep,
1514 r4a.ippeerlimit, MODE_CLIENT, hisversion,
1515 pkt->ppoll, pkt->ppoll,
1516 FLAG_BC_VOL | FLAG_IBURST | FLAG_PREEMPT, MDF_BCLNT,
1517 0, skeyid, sys_ident);
1519 DPRINTF(2, ("receive: AM_NEWBCL drop: empty newpeer() failed\n"));
1521 return; /* ignore duplicate */
1525 if (skeyid > NTP_MAXKEY)
1526 crypto_recv(peer, rbufp);
1527 #endif /* AUTOKEY */
1529 return; /* hooray */
1532 * This is the first packet received from a symmetric active
1533 * peer. If the packet is authentic, the first he sent, and
1534 * RES_NOEPEER is not enabled, mobilize a passive association
1535 * If not, kiss the frog.
1537 * There are cases here where we do not call record_raw_stats().
1543 * Do not respond if not the same group.
1545 if (group_test(groupname, sys_ident)) {
1546 DPRINTF(2, ("receive: AM_NEWPASS drop: Autokey group mismatch\n"));
1550 #endif /* AUTOKEY */
1551 if (!AUTH(sys_authenticate | (restrict_mask &
1552 (RES_NOPEER | RES_DONTTRUST)), is_authentic)
1554 if (0 == (restrict_mask & RES_NOEPEER)) {
1556 * If authenticated but cannot mobilize an
1557 * association, send a symmetric passive
1558 * response without mobilizing an association.
1559 * This is for drat broken Windows clients. See
1560 * Microsoft KB 875424 for preferred workaround.
1562 if (AUTH(restrict_mask & RES_DONTTRUST,
1564 fast_xmit(rbufp, MODE_PASSIVE, skeyid,
1566 return; /* hooray */
1568 if (is_authentic == AUTH_ERROR) {
1569 fast_xmit(rbufp, MODE_ACTIVE, 0,
1576 * If we got here, the packet isn't part of an
1577 * existing association, either isn't correctly
1578 * authenticated or it is but we are refusing
1579 * ephemeral peer requests, and it didn't meet
1580 * either of the previous two special cases so we
1581 * should just drop it on the floor. For example,
1582 * crypto-NAKs (is_authentic == AUTH_CRYPTO)
1583 * will make it this far. This is just
1584 * debug-printed and not logged to avoid log
1587 DPRINTF(2, ("receive: at %ld refusing to mobilize passive association"
1588 " with unknown peer %s mode %d/%s:%s keyid %08x len %d auth %d\n",
1589 current_time, stoa(&rbufp->recv_srcadr),
1590 hismode, hm_str, am_str, skeyid,
1591 (authlen + has_mac), is_authentic));
1597 * Do not respond if synchronized and if stratum is
1598 * below the floor or at or above the ceiling. Note,
1599 * this allows an unsynchronized peer to synchronize to
1600 * us. It would be very strange if he did and then was
1601 * nipped, but that could only happen if we were
1602 * operating at the top end of the range. It also means
1603 * we will spin an ephemeral association in response to
1604 * MODE_ACTIVE KoDs, which will time out eventually.
1606 if ( hisleap != LEAP_NOTINSYNC
1607 && (hisstratum < sys_floor || hisstratum >= sys_ceiling)) {
1608 DPRINTF(2, ("receive: AM_NEWPASS drop: Autokey group mismatch\n"));
1610 return; /* no help */
1614 * The message is correctly authenticated and allowed.
1615 * Mobilize a symmetric passive association, if we won't
1616 * exceed the ippeerlimit.
1618 if ((peer = newpeer(&rbufp->recv_srcadr, NULL, rbufp->dstadr,
1619 r4a.ippeerlimit, MODE_PASSIVE, hisversion,
1620 pkt->ppoll, NTP_MAXDPOLL, 0, MDF_UCAST, 0,
1621 skeyid, sys_ident)) == NULL) {
1622 DPRINTF(2, ("receive: AM_NEWPASS drop: newpeer() failed\n"));
1624 return; /* ignore duplicate */
1630 * Process regular packet. Nothing special.
1632 * There are cases here where we do not call record_raw_stats().
1638 * Do not respond if not the same group.
1640 if (group_test(groupname, peer->ident)) {
1641 DPRINTF(2, ("receive: AM_PROCPKT drop: Autokey group mismatch\n"));
1645 #endif /* AUTOKEY */
1647 if (MODE_BROADCAST == hismode) {
1652 DPRINTF(2, ("receive: PROCPKT/BROADCAST: prev pkt %ld seconds ago, ppoll: %d, %d secs\n",
1653 (current_time - peer->timelastrec),
1654 peer->ppoll, (1 << peer->ppoll)
1656 /* Things we can check:
1658 * Did the poll interval change?
1659 * Is the poll interval in the packet in-range?
1660 * Did this packet arrive too soon?
1661 * Is the timestamp in this packet monotonic
1662 * with respect to the previous packet?
1665 /* This is noteworthy, not error-worthy */
1666 if (pkt->ppoll != peer->ppoll) {
1667 msyslog(LOG_INFO, "receive: broadcast poll from %s changed from %u to %u",
1668 stoa(&rbufp->recv_srcadr),
1669 peer->ppoll, pkt->ppoll);
1672 /* This is error-worthy */
1673 if (pkt->ppoll < peer->minpoll ||
1674 pkt->ppoll > peer->maxpoll ) {
1675 msyslog(LOG_INFO, "receive: broadcast poll of %u from %s is out-of-range (%d to %d)!",
1676 pkt->ppoll, stoa(&rbufp->recv_srcadr),
1677 peer->minpoll, peer->maxpoll);
1681 /* too early? worth an error, too!
1683 * [Bug 3113] Ensure that at least one poll
1684 * interval has elapsed since the last **clean**
1685 * packet was received. We limit the check to
1686 * **clean** packets to prevent replayed packets
1687 * and incorrectly authenticated packets, which
1688 * we'll discard, from being used to create a
1689 * denial of service condition.
1691 deadband = (1u << pkt->ppoll);
1692 if (FLAG_BC_VOL & peer->flags)
1693 deadband -= 3; /* allow greater fuzz after volley */
1694 if ((current_time - peer->timereceived) < deadband) {
1695 msyslog(LOG_INFO, "receive: broadcast packet from %s arrived after %lu, not %lu seconds!",
1696 stoa(&rbufp->recv_srcadr),
1697 (current_time - peer->timereceived),
1702 /* Alert if time from the server is non-monotonic.
1704 * [Bug 3114] is about Broadcast mode replay DoS.
1706 * Broadcast mode *assumes* a trusted network.
1707 * Even so, it's nice to be robust in the face
1710 * If we get an authenticated broadcast packet
1711 * with an "earlier" timestamp, it means one of
1714 * - the broadcast server had a backward step.
1716 * - somebody is trying a replay attack.
1718 * deadband: By default, we assume the broadcast
1719 * network is trustable, so we take our accepted
1720 * broadcast packets as we receive them. But
1721 * some folks might want to take additional poll
1722 * delays before believing a backward step.
1724 if (sys_bcpollbstep) {
1725 /* pkt->ppoll or peer->ppoll ? */
1726 deadband = (1u << pkt->ppoll)
1727 * sys_bcpollbstep + 2;
1732 if (L_ISZERO(&peer->bxmt)) {
1733 tdiff.l_ui = tdiff.l_uf = 0;
1736 L_SUB(&tdiff, &peer->bxmt);
1738 if (tdiff.l_i < 0 &&
1739 (current_time - peer->timereceived) < deadband)
1741 msyslog(LOG_INFO, "receive: broadcast packet from %s contains non-monotonic timestamp: %#010x.%08x -> %#010x.%08x",
1742 stoa(&rbufp->recv_srcadr),
1743 peer->bxmt.l_ui, peer->bxmt.l_uf,
1744 p_xmt.l_ui, p_xmt.l_uf
1750 DPRINTF(2, ("receive: AM_PROCPKT drop: bail\n"));
1751 peer->timelastrec = current_time;
1760 * A passive packet matches a passive association. This is
1761 * usually the result of reconfiguring a client on the fly. As
1762 * this association might be legitimate and this packet an
1763 * attempt to deny service, just ignore it.
1766 DPRINTF(2, ("receive: AM_ERR drop.\n"));
1771 * For everything else there is the bit bucket.
1774 DPRINTF(2, ("receive: default drop.\n"));
1781 * If the association is configured for Autokey, the packet must
1782 * have a public key ID; if not, the packet must have a
1785 if ( is_authentic != AUTH_CRYPTO
1786 && ( ((peer->flags & FLAG_SKEY) && skeyid <= NTP_MAXKEY)
1787 || (!(peer->flags & FLAG_SKEY) && skeyid > NTP_MAXKEY))) {
1788 DPRINTF(2, ("receive: drop: Autokey but wrong/bad auth\n"));
1792 #endif /* AUTOKEY */
1795 peer->flash &= ~PKT_TEST_MASK;
1796 if (peer->flags & FLAG_XBOGUS) {
1797 peer->flags &= ~FLAG_XBOGUS;
1798 peer->flash |= TEST3;
1802 * Next comes a rigorous schedule of timestamp checking. If the
1803 * transmit timestamp is zero, the server has not initialized in
1804 * interleaved modes or is horribly broken.
1806 * A KoD packet we pay attention to cannot have a 0 transmit
1810 kissCode = kiss_code_check(hisleap, hisstratum, hismode, pkt->refid);
1812 if (L_ISZERO(&p_xmt)) {
1813 peer->flash |= TEST3; /* unsynch */
1814 if (kissCode != NOKISS) { /* KoD packet */
1815 peer->bogusorg++; /* for TEST2 or TEST3 */
1817 "receive: Unexpected zero transmit timestamp in KoD from %s",
1818 ntoa(&peer->srcadr));
1823 * If the transmit timestamp duplicates our previous one, the
1824 * packet is a replay. This prevents the bad guys from replaying
1825 * the most recent packet, authenticated or not.
1827 } else if (L_ISEQU(&peer->xmt, &p_xmt)) {
1828 DPRINTF(2, ("receive: drop: Duplicate xmit\n"));
1829 peer->flash |= TEST1; /* duplicate */
1834 * If this is a broadcast mode packet, make sure hisstratum
1835 * is appropriate. Don't do anything else here - we wait to
1836 * see if this is an interleave broadcast packet until after
1837 * we've validated the MAC that SHOULD be provided.
1839 * hisstratum cannot be 0 - see assertion above.
1840 * If hisstratum is 15, then we'll advertise as UNSPEC but
1841 * at least we'll be able to sync with the broadcast server.
1843 } else if (hismode == MODE_BROADCAST) {
1844 /* 0 is unexpected too, and impossible */
1845 if (STRATUM_UNSPEC <= hisstratum) {
1846 /* Is this a ++sys_declined or ??? */
1848 "receive: Unexpected stratum (%d) in broadcast from %s",
1849 hisstratum, ntoa(&peer->srcadr));
1854 * Basic KoD validation checking:
1856 * KoD packets are a mixed-blessing. Forged KoD packets
1857 * are DoS attacks. There are rare situations where we might
1858 * get a valid KoD response, though. Since KoD packets are
1859 * a special case that complicate the checks we do next, we
1860 * handle the basic KoD checks here.
1862 * Note that we expect the incoming KoD packet to have its
1863 * (nonzero) org, rec, and xmt timestamps set to the xmt timestamp
1864 * that we have previously sent out. Watch interleave mode.
1866 } else if (kissCode != NOKISS) {
1867 DEBUG_INSIST(!L_ISZERO(&p_xmt));
1868 if ( L_ISZERO(&p_org) /* We checked p_xmt above */
1869 || L_ISZERO(&p_rec)) {
1872 "receive: KoD packet from %s has a zero org or rec timestamp. Ignoring.",
1873 ntoa(&peer->srcadr));
1877 if ( !L_ISEQU(&p_xmt, &p_org)
1878 || !L_ISEQU(&p_xmt, &p_rec)) {
1881 "receive: KoD packet from %s has inconsistent xmt/org/rec timestamps. Ignoring.",
1882 ntoa(&peer->srcadr));
1886 /* Be conservative */
1887 if (peer->flip == 0 && !L_ISEQU(&p_org, &peer->aorg)) {
1890 "receive: flip 0 KoD origin timestamp %#010x.%08x from %s does not match %#010x.%08x - ignoring.",
1891 p_org.l_ui, p_org.l_uf,
1892 ntoa(&peer->srcadr),
1893 peer->aorg.l_ui, peer->aorg.l_uf);
1895 } else if (peer->flip == 1 && !L_ISEQU(&p_org, &peer->borg)) {
1898 "receive: flip 1 KoD origin timestamp %#010x.%08x from %s does not match interleave %#010x.%08x - ignoring.",
1899 p_org.l_ui, p_org.l_uf,
1900 ntoa(&peer->srcadr),
1901 peer->borg.l_ui, peer->borg.l_uf);
1906 * Basic mode checks:
1908 * If there is no origin timestamp, it's either an initial packet
1909 * or we've already received a response to our query. Of course,
1910 * should 'aorg' be all-zero because this really was the original
1911 * transmit timestamp, we'll ignore this reply. There is a window
1912 * of one nanosecond once every 136 years' time where this is
1913 * possible. We currently ignore this situation, as a completely
1914 * zero timestamp is (quietly?) disallowed.
1916 * Otherwise, check for bogus packet in basic mode.
1917 * If it is bogus, switch to interleaved mode and resynchronize,
1918 * but only after confirming the packet is not bogus in
1919 * symmetric interleaved mode.
1921 * This could also mean somebody is forging packets claiming to
1922 * be from us, attempting to cause our server to KoD us.
1924 * We have earlier asserted that hisstratum cannot be 0.
1925 * If hisstratum is STRATUM_UNSPEC, it means he's not sync'd.
1927 } else if (peer->flip == 0) {
1929 } else if (L_ISZERO(&p_org)) {
1934 "receive: BUG 3361: Clearing peer->aorg ");
1939 /* We allow 0org for: */
1943 /* We disallow 0org for: */
1949 case MODE_BROADCAST:
1952 peer->flash |= TEST2; /* bogus */
1955 action = ""; /* for cranky compilers / MSVC */
1956 INSIST(!"receive(): impossible hismode");
1961 "receive: %s 0 origin timestamp from %s@%s xmt %#010x.%08x",
1962 action, hm_str, ntoa(&peer->srcadr),
1963 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf));
1964 } else if (!L_ISEQU(&p_org, &peer->aorg)) {
1965 /* are there cases here where we should bail? */
1966 /* Should we set TEST2 if we decide to try xleave? */
1968 peer->flash |= TEST2; /* bogus */
1970 "receive: Unexpected origin timestamp %#010x.%08x does not match aorg %#010x.%08x from %s@%s xmt %#010x.%08x",
1971 ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf),
1972 peer->aorg.l_ui, peer->aorg.l_uf,
1973 hm_str, ntoa(&peer->srcadr),
1974 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf));
1975 if ( !L_ISZERO(&peer->dst)
1976 && L_ISEQU(&p_org, &peer->dst)) {
1977 /* Might be the start of an interleave */
1978 if (dynamic_interleave) {
1980 report_event(PEVNT_XLEAVE, peer, NULL);
1983 "receive: Dynamic interleave from %s@%s denied",
1984 hm_str, ntoa(&peer->srcadr));
1992 * Check for valid nonzero timestamp fields.
1994 } else if ( L_ISZERO(&p_org)
1996 || L_ISZERO(&peer->dst)) {
1997 peer->flash |= TEST3; /* unsynch */
2000 * Check for bogus packet in interleaved symmetric mode. This
2001 * can happen if a packet is lost, duplicated or crossed. If
2002 * found, flip and resynchronize.
2004 } else if ( !L_ISZERO(&peer->dst)
2005 && !L_ISEQU(&p_org, &peer->dst)) {
2006 DPRINTF(2, ("receive: drop: Bogus packet in interleaved symmetric mode\n"));
2008 peer->flags |= FLAG_XBOGUS;
2009 peer->flash |= TEST2; /* bogus */
2011 return; /* Bogus packet, we are done */
2018 * If this is a crypto_NAK, the server cannot authenticate a
2019 * client packet. The server might have just changed keys. Clear
2020 * the association and restart the protocol.
2022 if (crypto_nak_test == VALIDNAK) {
2023 report_event(PEVNT_AUTH, peer, "crypto_NAK");
2024 peer->flash |= TEST5; /* bad auth */
2026 if (peer->flags & FLAG_PREEMPT) {
2027 if (unpeer_crypto_nak_early) {
2030 DPRINTF(2, ("receive: drop: PREEMPT crypto_NAK\n"));
2035 peer_clear(peer, "AUTH");
2037 #endif /* AUTOKEY */
2038 DPRINTF(2, ("receive: drop: crypto_NAK\n"));
2042 * If the digest fails or it's missing for authenticated
2043 * associations, the client cannot authenticate a server
2044 * reply to a client packet previously sent. The loopback check
2045 * is designed to avoid a bait-and-switch attack, which was
2046 * possible in past versions. If symmetric modes, return a
2047 * crypto-NAK. The peer should restart the protocol.
2049 } else if (!AUTH(peer->keyid || has_mac ||
2050 (restrict_mask & RES_DONTTRUST), is_authentic)) {
2052 if (peer->flash & PKT_TEST_MASK) {
2054 "receive: Bad auth in packet with bad timestamps from %s denied - spoof?",
2055 ntoa(&peer->srcadr));
2059 report_event(PEVNT_AUTH, peer, "digest");
2060 peer->flash |= TEST5; /* bad auth */
2063 && ( hismode == MODE_ACTIVE
2064 || hismode == MODE_PASSIVE))
2065 fast_xmit(rbufp, MODE_ACTIVE, 0, restrict_mask);
2066 if (peer->flags & FLAG_PREEMPT) {
2067 if (unpeer_digest_early) {
2072 else if (peer_clear_digest_early && peer->crypto) {
2073 peer_clear(peer, "AUTH");
2075 #endif /* AUTOKEY */
2076 DPRINTF(2, ("receive: drop: Bad or missing AUTH\n"));
2081 * For broadcast packets:
2083 * HMS: This next line never made much sense to me, even
2084 * when it was up higher:
2085 * If an initial volley, bail out now and let the
2086 * client do its stuff.
2088 * If the packet has not failed authentication, then
2089 * - if the origin timestamp is nonzero this is an
2090 * interleaved broadcast, so restart the protocol.
2091 * - else, this is not an interleaved broadcast packet.
2093 if (hismode == MODE_BROADCAST) {
2094 if ( is_authentic == AUTH_OK
2095 || is_authentic == AUTH_NONE) {
2096 if (!L_ISZERO(&p_org)) {
2097 if (!(peer->flags & FLAG_XB)) {
2099 "receive: Broadcast server at %s is in interleave mode",
2100 ntoa(&peer->srcadr));
2101 peer->flags |= FLAG_XB;
2103 peer->borg = rbufp->recv_time;
2104 report_event(PEVNT_XLEAVE, peer, NULL);
2107 } else if (peer->flags & FLAG_XB) {
2109 "receive: Broadcast server at %s is no longer in interleave mode",
2110 ntoa(&peer->srcadr));
2111 peer->flags &= ~FLAG_XB;
2115 "receive: Bad broadcast auth (%d) from %s",
2116 is_authentic, ntoa(&peer->srcadr));
2120 * Now that we know the packet is correctly authenticated,
2121 * update peer->bxmt.
2128 ** Update the state variables.
2130 if (peer->flip == 0) {
2131 if (hismode != MODE_BROADCAST)
2133 peer->dst = rbufp->recv_time;
2138 * Set the peer ppoll to the maximum of the packet ppoll and the
2139 * peer minpoll. If a kiss-o'-death, set the peer minpoll to
2140 * this maximum and advance the headway to give the sender some
2141 * headroom. Very intricate.
2145 * Check for any kiss codes. Note this is only used when a server
2146 * responds to a packet request.
2150 * Check to see if this is a RATE Kiss Code
2151 * Currently this kiss code will accept whatever poll
2152 * rate that the server sends
2154 peer->ppoll = max(peer->minpoll, pkt->ppoll);
2155 if (kissCode == RATEKISS) {
2156 peer->selbroken++; /* Increment the KoD count */
2157 report_event(PEVNT_RATE, peer, NULL);
2158 if (pkt->ppoll > peer->minpoll)
2159 peer->minpoll = peer->ppoll;
2160 peer->burst = peer->retry = 0;
2161 peer->throttle = (NTP_SHIFT + 1) * (1 << peer->minpoll);
2162 poll_update(peer, pkt->ppoll);
2163 return; /* kiss-o'-death */
2165 if (kissCode != NOKISS) {
2166 peer->selbroken++; /* Increment the KoD count */
2167 return; /* Drop any other kiss code packets */
2178 * - this is a *cast (uni-, broad-, or m-) server packet
2179 * - and it's symmetric-key authenticated
2180 * then see if the sender's IP is trusted for this keyid.
2181 * If it is, great - nothing special to do here.
2182 * Otherwise, we should report and bail.
2184 * Autokey-authenticated packets are accepted.
2188 case MODE_SERVER: /* server mode */
2189 case MODE_BROADCAST: /* broadcast mode */
2190 case MODE_ACTIVE: /* symmetric active mode */
2191 case MODE_PASSIVE: /* symmetric passive mode */
2192 if ( is_authentic == AUTH_OK
2194 && skeyid <= NTP_MAXKEY
2195 && !authistrustedip(skeyid, &peer->srcadr)) {
2196 report_event(PEVNT_AUTH, peer, "authIP");
2202 case MODE_CLIENT: /* client mode */
2203 #if 0 /* At this point, MODE_CONTROL is overloaded by MODE_BCLIENT */
2204 case MODE_CONTROL: /* control mode */
2206 case MODE_PRIVATE: /* private mode */
2207 case MODE_BCLIENT: /* broadcast client mode */
2210 case MODE_UNSPEC: /* unspecified (old version) */
2213 "receive: Unexpected mode (%d) in packet from %s",
2214 hismode, ntoa(&peer->srcadr));
2220 * That was hard and I am sweaty, but the packet is squeaky
2221 * clean. Get on with real work.
2223 peer->timereceived = current_time;
2224 peer->timelastrec = current_time;
2225 if (is_authentic == AUTH_OK)
2226 peer->flags |= FLAG_AUTHENTIC;
2228 peer->flags &= ~FLAG_AUTHENTIC;
2232 * More autokey dance. The rules of the cha-cha are as follows:
2234 * 1. If there is no key or the key is not auto, do nothing.
2236 * 2. If this packet is in response to the one just previously
2237 * sent or from a broadcast server, do the extension fields.
2238 * Otherwise, assume bogosity and bail out.
2240 * 3. If an extension field contains a verified signature, it is
2241 * self-authenticated and we sit the dance.
2243 * 4. If this is a server reply, check only to see that the
2244 * transmitted key ID matches the received key ID.
2246 * 5. Check to see that one or more hashes of the current key ID
2247 * matches the previous key ID or ultimate original key ID
2248 * obtained from the broadcaster or symmetric peer. If no
2249 * match, sit the dance and call for new autokey values.
2251 * In case of crypto error, fire the orchestra, stop dancing and
2252 * restart the protocol.
2254 if (peer->flags & FLAG_SKEY) {
2256 * Decrement remaining autokey hashes. This isn't
2257 * perfect if a packet is lost, but results in no harm.
2259 ap = (struct autokey *)peer->recval.ptr;
2264 peer->flash |= TEST8;
2265 rval = crypto_recv(peer, rbufp);
2266 if (rval == XEVNT_OK) {
2269 if (rval == XEVNT_ERR) {
2270 report_event(PEVNT_RESTART, peer,
2272 peer_clear(peer, "CRYP");
2273 peer->flash |= TEST9; /* bad crypt */
2274 if (peer->flags & FLAG_PREEMPT) {
2275 if (unpeer_crypto_early) {
2284 * If server mode, verify the receive key ID matches
2285 * the transmit key ID.
2287 if (hismode == MODE_SERVER) {
2288 if (skeyid == peer->keyid)
2289 peer->flash &= ~TEST8;
2292 * If an extension field is present, verify only that it
2293 * has been correctly signed. We don't need a sequence
2294 * check here, but the sequence continues.
2296 } else if (!(peer->flash & TEST8)) {
2297 peer->pkeyid = skeyid;
2300 * Now the fun part. Here, skeyid is the current ID in
2301 * the packet, pkeyid is the ID in the last packet and
2302 * tkeyid is the hash of skeyid. If the autokey values
2303 * have not been received, this is an automatic error.
2304 * If so, check that the tkeyid matches pkeyid. If not,
2305 * hash tkeyid and try again. If the number of hashes
2306 * exceeds the number remaining in the sequence, declare
2307 * a successful failure and refresh the autokey values.
2309 } else if (ap != NULL) {
2312 for (i = 0; ; i++) {
2313 if ( tkeyid == peer->pkeyid
2314 || tkeyid == ap->key) {
2315 peer->flash &= ~TEST8;
2316 peer->pkeyid = skeyid;
2325 tkeyid = session_key(
2326 &rbufp->recv_srcadr, dstadr_sin,
2329 if (peer->flash & TEST8)
2330 report_event(PEVNT_AUTH, peer, "keylist");
2332 if (!(peer->crypto & CRYPTO_FLAG_PROV)) /* test 9 */
2333 peer->flash |= TEST8; /* bad autokey */
2336 * The maximum lifetime of the protocol is about one
2337 * week before restarting the Autokey protocol to
2338 * refresh certificates and leapseconds values.
2340 if (current_time > peer->refresh) {
2341 report_event(PEVNT_RESTART, peer,
2343 peer_clear(peer, "TIME");
2347 #endif /* AUTOKEY */
2350 * The dance is complete and the flash bits have been lit. Toss
2351 * the packet over the fence for processing, which may light up
2354 process_packet(peer, pkt, rbufp->recv_length);
2357 * In interleaved mode update the state variables. Also adjust the
2358 * transmit phase to avoid crossover.
2360 if (peer->flip != 0) {
2362 peer->dst = rbufp->recv_time;
2363 if (peer->nextdate - current_time < (1U << min(peer->ppoll,
2373 * process_packet - Packet Procedure, a la Section 3.4.4 of RFC-1305
2374 * Or almost, at least. If we're in here we have a reasonable
2375 * expectation that we will be having a long term
2376 * relationship with this host.
2380 register struct peer *peer,
2381 register struct pkt *pkt,
2386 double p_offset, p_del, p_disp;
2387 l_fp p_rec, p_xmt, p_org, p_reftime, ci;
2388 u_char pmode, pleap, pversion, pstratum;
2389 char statstr[NTP_MAXSTRLEN];
2392 double etemp, ftemp, td;
2399 p_del = FPTOD(NTOHS_FP(pkt->rootdelay));
2401 p_disp = FPTOD(NTOHS_FP(pkt->rootdisp));
2402 NTOHL_FP(&pkt->reftime, &p_reftime);
2403 NTOHL_FP(&pkt->org, &p_org);
2404 NTOHL_FP(&pkt->rec, &p_rec);
2405 NTOHL_FP(&pkt->xmt, &p_xmt);
2406 pmode = PKT_MODE(pkt->li_vn_mode);
2407 pleap = PKT_LEAP(pkt->li_vn_mode);
2408 pversion = PKT_VERSION(pkt->li_vn_mode);
2409 pstratum = PKT_TO_STRATUM(pkt->stratum);
2416 * Verify the server is synchronized; that is, the leap bits,
2417 * stratum and root distance are valid.
2419 if ( pleap == LEAP_NOTINSYNC /* test 6 */
2420 || pstratum < sys_floor || pstratum >= sys_ceiling)
2421 peer->flash |= TEST6; /* bad synch or strat */
2422 if (p_del / 2 + p_disp >= MAXDISPERSE) /* test 7 */
2423 peer->flash |= TEST7; /* bad header */
2426 * If any tests fail at this point, the packet is discarded.
2427 * Note that some flashers may have already been set in the
2428 * receive() routine.
2430 if (peer->flash & PKT_TEST_MASK) {
2431 peer->seldisptoolarge++;
2432 DPRINTF(1, ("packet: flash header %04x\n",
2445 * Capture the header values in the client/peer association..
2447 record_raw_stats(&peer->srcadr,
2448 peer->dstadr ? &peer->dstadr->sin : NULL,
2449 &p_org, &p_rec, &p_xmt, &peer->dst,
2450 pleap, pversion, pmode, pstratum, pkt->ppoll, pkt->precision,
2451 p_del, p_disp, pkt->refid,
2452 len - MIN_V4_PKT_LEN, (u_char *)&pkt->exten);
2454 peer->stratum = min(pstratum, STRATUM_UNSPEC);
2455 peer->pmode = pmode;
2456 peer->precision = pkt->precision;
2457 peer->rootdelay = p_del;
2458 peer->rootdisp = p_disp;
2459 peer->refid = pkt->refid; /* network byte order */
2460 peer->reftime = p_reftime;
2463 * First, if either burst mode is armed, enable the burst.
2464 * Compute the headway for the next packet and delay if
2465 * necessary to avoid exceeding the threshold.
2467 if (peer->retry > 0) {
2470 peer->burst = min(1 << (peer->hpoll -
2471 peer->minpoll), NTP_SHIFT) - 1;
2473 peer->burst = NTP_IBURST - 1;
2474 if (peer->burst > 0)
2475 peer->nextdate = current_time;
2477 poll_update(peer, peer->hpoll);
2482 * If the peer was previously unreachable, raise a trap. In any
2483 * case, mark it reachable.
2486 report_event(PEVNT_REACH, peer, NULL);
2487 peer->timereachable = current_time;
2492 * For a client/server association, calculate the clock offset,
2493 * roundtrip delay and dispersion. The equations are reordered
2494 * from the spec for more efficient use of temporaries. For a
2495 * broadcast association, offset the last measurement by the
2496 * computed delay during the client/server volley. Note the
2497 * computation of dispersion includes the system precision plus
2498 * that due to the frequency error since the origin time.
2500 * It is very important to respect the hazards of overflow. The
2501 * only permitted operation on raw timestamps is subtraction,
2502 * where the result is a signed quantity spanning from 68 years
2503 * in the past to 68 years in the future. To avoid loss of
2504 * precision, these calculations are done using 64-bit integer
2505 * arithmetic. However, the offset and delay calculations are
2506 * sums and differences of these first-order differences, which
2507 * if done using 64-bit integer arithmetic, would be valid over
2508 * only half that span. Since the typical first-order
2509 * differences are usually very small, they are converted to 64-
2510 * bit doubles and all remaining calculations done in floating-
2511 * double arithmetic. This preserves the accuracy while
2512 * retaining the 68-year span.
2514 * There are three interleaving schemes, basic, interleaved
2515 * symmetric and interleaved broadcast. The timestamps are
2516 * idioscyncratically different. See the onwire briefing/white
2517 * paper at www.eecis.udel.edu/~mills for details.
2519 * Interleaved symmetric mode
2520 * t1 = peer->aorg/borg, t2 = peer->rec, t3 = p_xmt,
2523 if (peer->flip != 0) {
2524 ci = p_xmt; /* t3 - t4 */
2525 L_SUB(&ci, &peer->dst);
2527 ci = p_rec; /* t2 - t1 */
2529 L_SUB(&ci, &peer->borg);
2531 L_SUB(&ci, &peer->aorg);
2534 p_offset = (t21 + t34) / 2.;
2535 if (p_del < 0 || p_del > 1.) {
2536 snprintf(statstr, sizeof(statstr),
2537 "t21 %.6f t34 %.6f", t21, t34);
2538 report_event(PEVNT_XERR, peer, statstr);
2545 } else if (peer->pmode == MODE_BROADCAST) {
2548 * Interleaved broadcast mode. Use interleaved timestamps.
2549 * t1 = peer->borg, t2 = p_org, t3 = p_org, t4 = aorg
2551 if (peer->flags & FLAG_XB) {
2552 ci = p_org; /* delay */
2553 L_SUB(&ci, &peer->aorg);
2555 ci = p_org; /* t2 - t1 */
2556 L_SUB(&ci, &peer->borg);
2559 peer->borg = peer->dst;
2560 if (t34 < 0 || t34 > 1.) {
2561 /* drop all if in the initial volley */
2562 if (FLAG_BC_VOL & peer->flags)
2563 goto bcc_init_volley_fail;
2564 snprintf(statstr, sizeof(statstr),
2565 "offset %.6f delay %.6f", t21, t34);
2566 report_event(PEVNT_XERR, peer, statstr);
2573 * Basic broadcast - use direct timestamps.
2574 * t3 = p_xmt, t4 = peer->dst
2577 ci = p_xmt; /* t3 - t4 */
2578 L_SUB(&ci, &peer->dst);
2584 * When calibration is complete and the clock is
2585 * synchronized, the bias is calculated as the difference
2586 * between the unicast timestamp and the broadcast
2587 * timestamp. This works for both basic and interleaved
2589 * [Bug 3031] Don't keep this peer when the delay
2590 * calculation gives reason to suspect clock steps.
2591 * This is assumed for delays > 50ms.
2593 if (FLAG_BC_VOL & peer->flags) {
2594 peer->flags &= ~FLAG_BC_VOL;
2595 peer->delay = fabs(peer->offset - p_offset) * 2;
2596 DPRINTF(2, ("broadcast volley: initial delay=%.6f\n",
2598 if (peer->delay > fabs(sys_bdelay)) {
2599 bcc_init_volley_fail:
2600 DPRINTF(2, ("%s", "broadcast volley: initial delay exceeds limit\n"));
2605 peer->nextdate = current_time + (1u << peer->ppoll) - 2u;
2606 p_del = peer->delay;
2607 p_offset += p_del / 2;
2611 * Basic mode, otherwise known as the old fashioned way.
2613 * t1 = p_org, t2 = p_rec, t3 = p_xmt, t4 = peer->dst
2616 ci = p_xmt; /* t3 - t4 */
2617 L_SUB(&ci, &peer->dst);
2619 ci = p_rec; /* t2 - t1 */
2622 p_del = fabs(t21 - t34);
2623 p_offset = (t21 + t34) / 2.;
2625 p_del = max(p_del, LOGTOD(sys_precision));
2626 p_disp = LOGTOD(sys_precision) + LOGTOD(peer->precision) +
2631 * This code calculates the outbound and inbound data rates by
2632 * measuring the differences between timestamps at different
2633 * packet lengths. This is helpful in cases of large asymmetric
2634 * delays commonly experienced on deep space communication
2637 if (peer->t21_last > 0 && peer->t34_bytes > 0) {
2638 itemp = peer->t21_bytes - peer->t21_last;
2640 etemp = t21 - peer->t21;
2641 if (fabs(etemp) > 1e-6) {
2642 ftemp = itemp / etemp;
2647 itemp = len - peer->t34_bytes;
2649 etemp = -t34 - peer->t34;
2650 if (fabs(etemp) > 1e-6) {
2651 ftemp = itemp / etemp;
2659 * The following section compensates for different data rates on
2660 * the outbound (d21) and inbound (t34) directions. To do this,
2661 * it finds t such that r21 * t - r34 * (d - t) = 0, where d is
2662 * the roundtrip delay. Then it calculates the correction as a
2666 peer->t21_last = peer->t21_bytes;
2668 peer->t34_bytes = len;
2669 DPRINTF(2, ("packet: t21 %.9lf %d t34 %.9lf %d\n", peer->t21,
2670 peer->t21_bytes, peer->t34, peer->t34_bytes));
2671 if (peer->r21 > 0 && peer->r34 > 0 && p_del > 0) {
2672 if (peer->pmode != MODE_BROADCAST)
2673 td = (peer->r34 / (peer->r21 + peer->r34) -
2679 * Unfortunately, in many cases the errors are
2680 * unacceptable, so for the present the rates are not
2681 * used. In future, we might find conditions where the
2682 * calculations are useful, so this should be considered
2683 * a work in progress.
2687 DPRINTF(2, ("packet: del %.6lf r21 %.1lf r34 %.1lf %.6lf\n",
2688 p_del, peer->r21 / 1e3, peer->r34 / 1e3,
2694 * That was awesome. Now hand off to the clock filter.
2696 clock_filter(peer, p_offset + peer->bias, p_del, p_disp);
2699 * If we are in broadcast calibrate mode, return to broadcast
2700 * client mode when the client is fit and the autokey dance is
2703 if ( (FLAG_BC_VOL & peer->flags)
2704 && MODE_CLIENT == peer->hmode
2705 && !(TEST11 & peer_unfit(peer))) { /* distance exceeded */
2707 if (peer->flags & FLAG_SKEY) {
2708 if (!(~peer->crypto & CRYPTO_FLAG_ALL))
2709 peer->hmode = MODE_BCLIENT;
2711 peer->hmode = MODE_BCLIENT;
2713 #else /* !AUTOKEY follows */
2714 peer->hmode = MODE_BCLIENT;
2715 #endif /* !AUTOKEY */
2721 * clock_update - Called at system process update intervals.
2725 struct peer *peer /* peer structure pointer */
2730 #ifdef HAVE_LIBSCF_H
2732 #endif /* HAVE_LIBSCF_H */
2735 * Update the system state variables. We do this very carefully,
2736 * as the poll interval might need to be clamped differently.
2739 sys_epoch = peer->epoch;
2740 if (sys_poll < peer->minpoll)
2741 sys_poll = peer->minpoll;
2742 if (sys_poll > peer->maxpoll)
2743 sys_poll = peer->maxpoll;
2744 poll_update(peer, sys_poll);
2745 sys_stratum = min(peer->stratum + 1, STRATUM_UNSPEC);
2746 if ( peer->stratum == STRATUM_REFCLOCK
2747 || peer->stratum == STRATUM_UNSPEC)
2748 sys_refid = peer->refid;
2750 sys_refid = addr2refid(&peer->srcadr);
2752 * Root Dispersion (E) is defined (in RFC 5905) as:
2754 * E = p.epsilon_r + p.epsilon + p.psi + PHI*(s.t - p.t) + |THETA|
2757 * p.epsilon_r is the PollProc's root dispersion
2758 * p.epsilon is the PollProc's dispersion
2759 * p.psi is the PollProc's jitter
2760 * THETA is the combined offset
2762 * NB: Think Hard about where these numbers come from and
2763 * what they mean. When did peer->update happen? Has anything
2764 * interesting happened since then? What values are the most
2767 * DLM thinks this equation is probably the best of all worse choices.
2769 dtemp = peer->rootdisp
2772 + clock_phi * (current_time - peer->update)
2775 if (dtemp > sys_mindisp)
2776 sys_rootdisp = dtemp;
2778 sys_rootdisp = sys_mindisp;
2779 sys_rootdelay = peer->delay + peer->rootdelay;
2780 sys_reftime = peer->dst;
2782 DPRINTF(1, ("clock_update: at %lu sample %lu associd %d\n",
2783 current_time, peer->epoch, peer->associd));
2786 * Comes now the moment of truth. Crank the clock discipline and
2787 * see what comes out.
2789 switch (local_clock(peer, sys_offset)) {
2792 * Clock exceeds panic threshold. Life as we know it ends.
2795 #ifdef HAVE_LIBSCF_H
2797 * For Solaris enter the maintenance mode.
2799 if ((fmri = getenv("SMF_FMRI")) != NULL) {
2800 if (smf_maintain_instance(fmri, 0) < 0) {
2801 printf("smf_maintain_instance: %s\n",
2802 scf_strerror(scf_error()));
2806 * Sleep until SMF kills us.
2811 #endif /* HAVE_LIBSCF_H */
2816 * Clock was stepped. Flush all time values of all peers.
2820 set_sys_leap(LEAP_NOTINSYNC);
2821 sys_stratum = STRATUM_UNSPEC;
2822 memcpy(&sys_refid, "STEP", 4);
2825 L_CLR(&sys_reftime);
2826 sys_jitter = LOGTOD(sys_precision);
2827 leapsec_reset_frame();
2831 * Clock was slewed. Handle the leapsecond stuff.
2836 * If this is the first time the clock is set, reset the
2837 * leap bits. If crypto, the timer will goose the setup
2840 if (sys_leap == LEAP_NOTINSYNC) {
2841 set_sys_leap(LEAP_NOWARNING);
2845 #endif /* AUTOKEY */
2847 * If our parent process is waiting for the
2848 * first clock sync, send them home satisfied.
2850 #ifdef HAVE_WORKING_FORK
2851 if (waitsync_fd_to_close != -1) {
2852 close(waitsync_fd_to_close);
2853 waitsync_fd_to_close = -1;
2854 DPRINTF(1, ("notified parent --wait-sync is done\n"));
2856 #endif /* HAVE_WORKING_FORK */
2861 * If there is no leap second pending and the number of
2862 * survivor leap bits is greater than half the number of
2863 * survivors, try to schedule a leap for the end of the
2864 * current month. (This only works if no leap second for
2865 * that range is in the table, so doing this more than
2866 * once is mostly harmless.)
2868 if (leapsec == LSPROX_NOWARN) {
2869 if ( leap_vote_ins > leap_vote_del
2870 && leap_vote_ins > sys_survivors / 2) {
2872 leapsec_add_dyn(TRUE, now.l_ui, NULL);
2874 if ( leap_vote_del > leap_vote_ins
2875 && leap_vote_del > sys_survivors / 2) {
2877 leapsec_add_dyn(FALSE, now.l_ui, NULL);
2883 * Popcorn spike or step threshold exceeded. Pretend it never
2893 * poll_update - update peer poll interval
2897 struct peer *peer, /* peer structure pointer */
2905 * This routine figures out when the next poll should be sent.
2906 * That turns out to be wickedly complicated. One problem is
2907 * that sometimes the time for the next poll is in the past when
2908 * the poll interval is reduced. We watch out for races here
2909 * between the receive process and the poll process.
2911 * Clamp the poll interval between minpoll and maxpoll.
2913 hpoll = max(min(peer->maxpoll, mpoll), peer->minpoll);
2917 * If during the crypto protocol the poll interval has changed,
2918 * the lifetimes in the key list are probably bogus. Purge the
2919 * the key list and regenerate it later.
2921 if ((peer->flags & FLAG_SKEY) && hpoll != peer->hpoll)
2923 #endif /* AUTOKEY */
2924 peer->hpoll = hpoll;
2927 * There are three variables important for poll scheduling, the
2928 * current time (current_time), next scheduled time (nextdate)
2929 * and the earliest time (utemp). The earliest time is 2 s
2930 * seconds, but could be more due to rate management. When
2931 * sending in a burst, use the earliest time. When not in a
2932 * burst but with a reply pending, send at the earliest time
2933 * unless the next scheduled time has not advanced. This can
2934 * only happen if multiple replies are pending in the same
2935 * response interval. Otherwise, send at the later of the next
2936 * scheduled time and the earliest time.
2938 * Now we figure out if there is an override. If a burst is in
2939 * progress and we get called from the receive process, just
2940 * slink away. If called from the poll process, delay 1 s for a
2941 * reference clock, otherwise 2 s.
2943 utemp = current_time + max(peer->throttle - (NTP_SHIFT - 1) *
2944 (1 << peer->minpoll), ntp_minpkt);
2945 if (peer->burst > 0) {
2946 if (peer->nextdate > current_time)
2949 else if (peer->flags & FLAG_REFCLOCK)
2950 peer->nextdate = current_time + RESP_DELAY;
2951 #endif /* REFCLOCK */
2953 peer->nextdate = utemp;
2957 * If a burst is not in progress and a crypto response message
2958 * is pending, delay 2 s, but only if this is a new interval.
2960 } else if (peer->cmmd != NULL) {
2961 if (peer->nextdate > current_time) {
2962 if (peer->nextdate + ntp_minpkt != utemp)
2963 peer->nextdate = utemp;
2965 peer->nextdate = utemp;
2967 #endif /* AUTOKEY */
2970 * The ordinary case. If a retry, use minpoll; if unreachable,
2971 * use host poll; otherwise, use the minimum of host and peer
2972 * polls; In other words, oversampling is okay but
2973 * understampling is evil. Use the maximum of this value and the
2974 * headway. If the average headway is greater than the headway
2975 * threshold, increase the headway by the minimum interval.
2978 if (peer->retry > 0)
2979 hpoll = peer->minpoll;
2980 else if (!(peer->reach))
2981 hpoll = peer->hpoll;
2983 hpoll = min(peer->ppoll, peer->hpoll);
2985 if (peer->flags & FLAG_REFCLOCK)
2988 #endif /* REFCLOCK */
2989 next = ((0x1000UL | (ntp_random() & 0x0ff)) <<
2991 next += peer->outdate;
2993 peer->nextdate = next;
2995 peer->nextdate = utemp;
2996 if (peer->throttle > (1 << peer->minpoll))
2997 peer->nextdate += ntp_minpkt;
2999 DPRINTF(2, ("poll_update: at %lu %s poll %d burst %d retry %d head %d early %lu next %lu\n",
3000 current_time, ntoa(&peer->srcadr), peer->hpoll,
3001 peer->burst, peer->retry, peer->throttle,
3002 utemp - current_time, peer->nextdate -
3008 * peer_clear - clear peer filter registers. See Section 3.4.8 of the
3013 struct peer *peer, /* peer structure */
3014 const char *ident /* tally lights */
3018 l_fp bxmt = peer->bxmt; /* bcast clients retain this! */
3022 * If cryptographic credentials have been acquired, toss them to
3023 * Valhalla. Note that autokeys are ephemeral, in that they are
3024 * tossed immediately upon use. Therefore, the keylist can be
3025 * purged anytime without needing to preserve random keys. Note
3026 * that, if the peer is purged, the cryptographic variables are
3027 * purged, too. This makes it much harder to sneak in some
3028 * unauthenticated data in the clock filter.
3031 if (peer->iffval != NULL)
3032 BN_free(peer->iffval);
3033 value_free(&peer->cookval);
3034 value_free(&peer->recval);
3035 value_free(&peer->encrypt);
3036 value_free(&peer->sndval);
3037 if (peer->cmmd != NULL)
3039 if (peer->subject != NULL)
3040 free(peer->subject);
3041 if (peer->issuer != NULL)
3043 #endif /* AUTOKEY */
3046 * Clear all values, including the optional crypto values above.
3048 memset(CLEAR_TO_ZERO(peer), 0, LEN_CLEAR_TO_ZERO(peer));
3049 peer->ppoll = peer->maxpoll;
3050 peer->hpoll = peer->minpoll;
3051 peer->disp = MAXDISPERSE;
3052 peer->flash = peer_unfit(peer);
3053 peer->jitter = LOGTOD(sys_precision);
3055 /* Don't throw away our broadcast replay protection */
3056 if (peer->hmode == MODE_BCLIENT)
3060 * If interleave mode, initialize the alternate origin switch.
3062 if (peer->flags & FLAG_XLEAVE)
3064 for (u = 0; u < NTP_SHIFT; u++) {
3065 peer->filter_order[u] = u;
3066 peer->filter_disp[u] = MAXDISPERSE;
3069 if (!(peer->flags & FLAG_REFCLOCK)) {
3071 peer->leap = LEAP_NOTINSYNC;
3072 peer->stratum = STRATUM_UNSPEC;
3073 memcpy(&peer->refid, ident, 4);
3079 * During initialization use the association count to spread out
3080 * the polls at one-second intervals. Passive associations'
3081 * first poll is delayed by the "discard minimum" to avoid rate
3082 * limiting. Other post-startup new or cleared associations
3083 * randomize the first poll over the minimum poll interval to
3086 peer->nextdate = peer->update = peer->outdate = current_time;
3088 peer->nextdate += peer_associations;
3089 } else if (MODE_PASSIVE == peer->hmode) {
3090 peer->nextdate += ntp_minpkt;
3092 peer->nextdate += ntp_random() % peer->minpoll;
3095 peer->refresh = current_time + (1 << NTP_REFRESH);
3096 #endif /* AUTOKEY */
3097 DPRINTF(1, ("peer_clear: at %ld next %ld associd %d refid %s\n",
3098 current_time, peer->nextdate, peer->associd,
3104 * clock_filter - add incoming clock sample to filter register and run
3105 * the filter procedure to find the best sample.
3109 struct peer *peer, /* peer structure pointer */
3110 double sample_offset, /* clock offset */
3111 double sample_delay, /* roundtrip delay */
3112 double sample_disp /* dispersion */
3115 double dst[NTP_SHIFT]; /* distance vector */
3116 int ord[NTP_SHIFT]; /* index vector */
3118 double dtemp, etemp;
3122 * A sample consists of the offset, delay, dispersion and epoch
3123 * of arrival. The offset and delay are determined by the on-
3124 * wire protocol. The dispersion grows from the last outbound
3125 * packet to the arrival of this one increased by the sum of the
3126 * peer precision and the system precision as required by the
3127 * error budget. First, shift the new arrival into the shift
3128 * register discarding the oldest one.
3130 j = peer->filter_nextpt;
3131 peer->filter_offset[j] = sample_offset;
3132 peer->filter_delay[j] = sample_delay;
3133 peer->filter_disp[j] = sample_disp;
3134 peer->filter_epoch[j] = current_time;
3135 j = (j + 1) % NTP_SHIFT;
3136 peer->filter_nextpt = j;
3139 * Update dispersions since the last update and at the same
3140 * time initialize the distance and index lists. Since samples
3141 * become increasingly uncorrelated beyond the Allan intercept,
3142 * only under exceptional cases will an older sample be used.
3143 * Therefore, the distance list uses a compound metric. If the
3144 * dispersion is greater than the maximum dispersion, clamp the
3145 * distance at that value. If the time since the last update is
3146 * less than the Allan intercept use the delay; otherwise, use
3147 * the sum of the delay and dispersion.
3149 dtemp = clock_phi * (current_time - peer->update);
3150 peer->update = current_time;
3151 for (i = NTP_SHIFT - 1; i >= 0; i--) {
3153 peer->filter_disp[j] += dtemp;
3154 if (peer->filter_disp[j] >= MAXDISPERSE) {
3155 peer->filter_disp[j] = MAXDISPERSE;
3156 dst[i] = MAXDISPERSE;
3157 } else if (peer->update - peer->filter_epoch[j] >
3158 (u_long)ULOGTOD(allan_xpt)) {
3159 dst[i] = peer->filter_delay[j] +
3160 peer->filter_disp[j];
3162 dst[i] = peer->filter_delay[j];
3165 j = (j + 1) % NTP_SHIFT;
3169 * If the clock has stabilized, sort the samples by distance.
3171 if (freq_cnt == 0) {
3172 for (i = 1; i < NTP_SHIFT; i++) {
3173 for (j = 0; j < i; j++) {
3174 if (dst[j] > dst[i]) {
3187 * Copy the index list to the association structure so ntpq
3188 * can see it later. Prune the distance list to leave only
3189 * samples less than the maximum dispersion, which disfavors
3190 * uncorrelated samples older than the Allan intercept. To
3191 * further improve the jitter estimate, of the remainder leave
3192 * only samples less than the maximum distance, but keep at
3193 * least two samples for jitter calculation.
3196 for (i = 0; i < NTP_SHIFT; i++) {
3197 peer->filter_order[i] = (u_char) ord[i];
3198 if ( dst[i] >= MAXDISPERSE
3199 || (m >= 2 && dst[i] >= sys_maxdist))
3205 * Compute the dispersion and jitter. The dispersion is weighted
3206 * exponentially by NTP_FWEIGHT (0.5) so it is normalized close
3207 * to 1.0. The jitter is the RMS differences relative to the
3208 * lowest delay sample.
3210 peer->disp = peer->jitter = 0;
3212 for (i = NTP_SHIFT - 1; i >= 0; i--) {
3214 peer->disp = NTP_FWEIGHT * (peer->disp +
3215 peer->filter_disp[j]);
3217 peer->jitter += DIFF(peer->filter_offset[j],
3218 peer->filter_offset[k]);
3222 * If no acceptable samples remain in the shift register,
3223 * quietly tiptoe home leaving only the dispersion. Otherwise,
3224 * save the offset, delay and jitter. Note the jitter must not
3225 * be less than the precision.
3231 etemp = fabs(peer->offset - peer->filter_offset[k]);
3232 peer->offset = peer->filter_offset[k];
3233 peer->delay = peer->filter_delay[k];
3235 peer->jitter /= m - 1;
3236 peer->jitter = max(SQRT(peer->jitter), LOGTOD(sys_precision));
3239 * If the the new sample and the current sample are both valid
3240 * and the difference between their offsets exceeds CLOCK_SGATE
3241 * (3) times the jitter and the interval between them is less
3242 * than twice the host poll interval, consider the new sample
3243 * a popcorn spike and ignore it.
3245 if ( peer->disp < sys_maxdist
3246 && peer->filter_disp[k] < sys_maxdist
3247 && etemp > CLOCK_SGATE * peer->jitter
3248 && peer->filter_epoch[k] - peer->epoch
3249 < 2. * ULOGTOD(peer->hpoll)) {
3250 snprintf(tbuf, sizeof(tbuf), "%.6f s", etemp);
3251 report_event(PEVNT_POPCORN, peer, tbuf);
3256 * A new minimum sample is useful only if it is later than the
3257 * last one used. In this design the maximum lifetime of any
3258 * sample is not greater than eight times the poll interval, so
3259 * the maximum interval between minimum samples is eight
3262 if (peer->filter_epoch[k] <= peer->epoch) {
3263 DPRINTF(2, ("clock_filter: old sample %lu\n", current_time -
3264 peer->filter_epoch[k]));
3267 peer->epoch = peer->filter_epoch[k];
3270 * The mitigated sample statistics are saved for later
3271 * processing. If not synchronized or not in a burst, tickle the
3272 * clock select algorithm.
3274 record_peer_stats(&peer->srcadr, ctlpeerstatus(peer),
3275 peer->offset, peer->delay, peer->disp, peer->jitter);
3276 DPRINTF(1, ("clock_filter: n %d off %.6f del %.6f dsp %.6f jit %.6f\n",
3277 m, peer->offset, peer->delay, peer->disp,
3279 if (peer->burst == 0 || sys_leap == LEAP_NOTINSYNC)
3285 * clock_select - find the pick-of-the-litter clock
3287 * LOCKCLOCK: (1) If the local clock is the prefer peer, it will always
3288 * be enabled, even if declared falseticker, (2) only the prefer peer
3289 * can be selected as the system peer, (3) if the external source is
3290 * down, the system leap bits are set to 11 and the stratum set to
3304 double orphmet = 2.0 * U_INT32_MAX; /* 2x is greater than */
3305 struct endpoint endp;
3306 struct peer *osys_peer;
3307 struct peer *sys_prefer = NULL; /* prefer peer */
3308 struct peer *typesystem = NULL;
3309 struct peer *typeorphan = NULL;
3311 struct peer *typeacts = NULL;
3312 struct peer *typelocal = NULL;
3313 struct peer *typepps = NULL;
3314 #endif /* REFCLOCK */
3315 static struct endpoint *endpoint = NULL;
3316 static int *indx = NULL;
3317 static peer_select *peers = NULL;
3318 static u_int endpoint_size = 0;
3319 static u_int peers_size = 0;
3320 static u_int indx_size = 0;
3324 * Initialize and create endpoint, index and peer lists big
3325 * enough to handle all associations.
3327 osys_peer = sys_peer;
3330 set_sys_leap(LEAP_NOTINSYNC);
3331 sys_stratum = STRATUM_UNSPEC;
3332 memcpy(&sys_refid, "DOWN", 4);
3333 #endif /* LOCKCLOCK */
3336 * Allocate dynamic space depending on the number of
3340 for (peer = peer_list; peer != NULL; peer = peer->p_link)
3342 endpoint_size = ALIGNED_SIZE(nlist * 2 * sizeof(*endpoint));
3343 peers_size = ALIGNED_SIZE(nlist * sizeof(*peers));
3344 indx_size = ALIGNED_SIZE(nlist * 2 * sizeof(*indx));
3345 octets = endpoint_size + peers_size + indx_size;
3346 endpoint = erealloc(endpoint, octets);
3347 peers = INC_ALIGNED_PTR(endpoint, endpoint_size);
3348 indx = INC_ALIGNED_PTR(peers, peers_size);
3351 * Initially, we populate the island with all the rifraff peers
3352 * that happen to be lying around. Those with seriously
3353 * defective clocks are immediately booted off the island. Then,
3354 * the falsetickers are culled and put to sea. The truechimers
3355 * remaining are subject to repeated rounds where the most
3356 * unpopular at each round is kicked off. When the population
3357 * has dwindled to sys_minclock, the survivors split a million
3358 * bucks and collectively crank the chimes.
3360 nlist = nl2 = 0; /* none yet */
3361 for (peer = peer_list; peer != NULL; peer = peer->p_link) {
3362 peer->new_status = CTL_PST_SEL_REJECT;
3365 * Leave the island immediately if the peer is
3366 * unfit to synchronize.
3368 if (peer_unfit(peer)) {
3373 * If this peer is an orphan parent, elect the
3374 * one with the lowest metric defined as the
3375 * IPv4 address or the first 64 bits of the
3376 * hashed IPv6 address. To ensure convergence
3377 * on the same selected orphan, consider as
3378 * well that this system may have the lowest
3379 * metric and be the orphan parent. If this
3380 * system wins, sys_peer will be NULL to trigger
3381 * orphan mode in timer().
3383 if (peer->stratum == sys_orphan) {
3387 if (peer->dstadr != NULL)
3388 localmet = ntohl(peer->dstadr->addr_refid);
3390 localmet = U_INT32_MAX;
3391 peermet = ntohl(addr2refid(&peer->srcadr));
3392 if (peermet < localmet && peermet < orphmet) {
3400 * If this peer could have the orphan parent
3401 * as a synchronization ancestor, exclude it
3402 * from selection to avoid forming a
3403 * synchronization loop within the orphan mesh,
3404 * triggering stratum climb to infinity
3405 * instability. Peers at stratum higher than
3406 * the orphan stratum could have the orphan
3407 * parent in ancestry so are excluded.
3408 * See http://bugs.ntp.org/2050
3410 if (peer->stratum > sys_orphan) {
3415 * The following are special cases. We deal
3418 if (!(peer->flags & FLAG_PREFER)) {
3419 switch (peer->refclktype) {
3420 case REFCLK_LOCALCLOCK:
3421 if ( current_time > orphwait
3422 && typelocal == NULL)
3427 if ( current_time > orphwait
3428 && typeacts == NULL)
3433 #endif /* REFCLOCK */
3436 * If we get this far, the peer can stay on the
3437 * island, but does not yet have the immunity
3440 peer->new_status = CTL_PST_SEL_SANE;
3441 f = root_distance(peer);
3442 peers[nlist].peer = peer;
3443 peers[nlist].error = peer->jitter;
3444 peers[nlist].synch = f;
3448 * Insert each interval endpoint on the unsorted
3452 endpoint[nl2].type = -1; /* lower end */
3453 endpoint[nl2].val = e - f;
3455 endpoint[nl2].type = 1; /* upper end */
3456 endpoint[nl2].val = e + f;
3460 * Construct sorted indx[] of endpoint[] indexes ordered by
3463 for (i = 0; i < nl2; i++)
3465 for (i = 0; i < nl2; i++) {
3466 endp = endpoint[indx[i]];
3469 for (j = i + 1; j < nl2; j++) {
3470 endp = endpoint[indx[j]];
3482 for (i = 0; i < nl2; i++)
3483 DPRINTF(3, ("select: endpoint %2d %.6f\n",
3484 endpoint[indx[i]].type, endpoint[indx[i]].val));
3487 * This is the actual algorithm that cleaves the truechimers
3488 * from the falsetickers. The original algorithm was described
3489 * in Keith Marzullo's dissertation, but has been modified for
3492 * Briefly put, we first assume there are no falsetickers, then
3493 * scan the candidate list first from the low end upwards and
3494 * then from the high end downwards. The scans stop when the
3495 * number of intersections equals the number of candidates less
3496 * the number of falsetickers. If this doesn't happen for a
3497 * given number of falsetickers, we bump the number of
3498 * falsetickers and try again. If the number of falsetickers
3499 * becomes equal to or greater than half the number of
3500 * candidates, the Albanians have won the Byzantine wars and
3501 * correct synchronization is not possible.
3503 * Here, nlist is the number of candidates and allow is the
3504 * number of falsetickers. Upon exit, the truechimers are the
3505 * survivors with offsets not less than low and not greater than
3506 * high. There may be none of them.
3510 for (allow = 0; 2 * allow < nlist; allow++) {
3513 * Bound the interval (low, high) as the smallest
3514 * interval containing points from the most sources.
3517 for (i = 0; i < nl2; i++) {
3518 low = endpoint[indx[i]].val;
3519 n -= endpoint[indx[i]].type;
3520 if (n >= nlist - allow)
3524 for (j = nl2 - 1; j >= 0; j--) {
3525 high = endpoint[indx[j]].val;
3526 n += endpoint[indx[j]].type;
3527 if (n >= nlist - allow)
3532 * If an interval containing truechimers is found, stop.
3533 * If not, increase the number of falsetickers and go
3541 * Clustering algorithm. Whittle candidate list of falsetickers,
3542 * who leave the island immediately. The TRUE peer is always a
3543 * truechimer. We must leave at least one peer to collect the
3546 * We assert the correct time is contained in the interval, but
3547 * the best offset estimate for the interval might not be
3548 * contained in the interval. For this purpose, a truechimer is
3549 * defined as the midpoint of an interval that overlaps the
3550 * intersection interval.
3553 for (i = 0; i < nlist; i++) {
3556 peer = peers[i].peer;
3559 || peer->offset + h < low
3560 || peer->offset - h > high
3561 ) && !(peer->flags & FLAG_TRUE))
3566 * Eligible PPS peers must survive the intersection
3567 * algorithm. Use the first one found, but don't
3568 * include any of them in the cluster population.
3570 if (peer->flags & FLAG_PPS) {
3571 if (typepps == NULL)
3573 if (!(peer->flags & FLAG_TSTAMP_PPS))
3576 #endif /* REFCLOCK */
3579 peers[j] = peers[i];
3585 * If no survivors remain at this point, check if the modem
3586 * driver, local driver or orphan parent in that order. If so,
3587 * nominate the first one found as the only survivor.
3588 * Otherwise, give up and leave the island to the rats.
3592 peers[0].synch = sys_mindisp;
3594 if (typeacts != NULL) {
3595 peers[0].peer = typeacts;
3597 } else if (typelocal != NULL) {
3598 peers[0].peer = typelocal;
3601 #endif /* REFCLOCK */
3602 if (typeorphan != NULL) {
3603 peers[0].peer = typeorphan;
3609 * Mark the candidates at this point as truechimers.
3611 for (i = 0; i < nlist; i++) {
3612 peers[i].peer->new_status = CTL_PST_SEL_SELCAND;
3613 DPRINTF(2, ("select: survivor %s %f\n",
3614 stoa(&peers[i].peer->srcadr), peers[i].synch));
3618 * Now, vote outliers off the island by select jitter weighted
3619 * by root distance. Continue voting as long as there are more
3620 * than sys_minclock survivors and the select jitter of the peer
3621 * with the worst metric is greater than the minimum peer
3622 * jitter. Stop if we are about to discard a TRUE or PREFER
3623 * peer, who of course have the immunity idol.
3630 for (i = 0; i < nlist; i++) {
3631 if (peers[i].error < d)
3633 peers[i].seljit = 0;
3636 for (j = 0; j < nlist; j++)
3637 f += DIFF(peers[j].peer->offset,
3638 peers[i].peer->offset);
3639 peers[i].seljit = SQRT(f / (nlist - 1));
3641 if (peers[i].seljit * peers[i].synch > e) {
3642 g = peers[i].seljit;
3643 e = peers[i].seljit * peers[i].synch;
3647 g = max(g, LOGTOD(sys_precision));
3648 if ( nlist <= max(1, sys_minclock)
3650 || ((FLAG_TRUE | FLAG_PREFER) & peers[k].peer->flags))
3653 DPRINTF(3, ("select: drop %s seljit %.6f jit %.6f\n",
3654 ntoa(&peers[k].peer->srcadr), g, d));
3655 if (nlist > sys_maxclock)
3656 peers[k].peer->new_status = CTL_PST_SEL_EXCESS;
3657 for (j = k + 1; j < nlist; j++)
3658 peers[j - 1] = peers[j];
3663 * What remains is a list usually not greater than sys_minclock
3664 * peers. Note that unsynchronized peers cannot survive this
3665 * far. Count and mark these survivors.
3667 * While at it, count the number of leap warning bits found.
3668 * This will be used later to vote the system leap warning bit.
3669 * If a leap warning bit is found on a reference clock, the vote
3672 * Choose the system peer using a hybrid metric composed of the
3673 * selection jitter scaled by the root distance augmented by
3674 * stratum scaled by sys_mindisp (.001 by default). The goal of
3675 * the small stratum factor is to avoid clockhop between a
3676 * reference clock and a network peer which has a refclock and
3677 * is using an older ntpd, which does not floor sys_rootdisp at
3680 * In contrast, ntpd 4.2.6 and earlier used stratum primarily
3681 * in selecting the system peer, using a weight of 1 second of
3682 * additional root distance per stratum. This heavy bias is no
3683 * longer appropriate, as the scaled root distance provides a
3684 * more rational metric carrying the cumulative error budget.
3690 for (i = 0; i < nlist; i++) {
3691 peer = peers[i].peer;
3693 peer->new_status = CTL_PST_SEL_SYNCCAND;
3695 if (peer->leap == LEAP_ADDSECOND) {
3696 if (peer->flags & FLAG_REFCLOCK)
3697 leap_vote_ins = nlist;
3698 else if (leap_vote_ins < nlist)
3701 if (peer->leap == LEAP_DELSECOND) {
3702 if (peer->flags & FLAG_REFCLOCK)
3703 leap_vote_del = nlist;
3704 else if (leap_vote_del < nlist)
3707 if (peer->flags & FLAG_PREFER)
3709 speermet = peers[i].seljit * peers[i].synch +
3710 peer->stratum * sys_mindisp;
3718 * Unless there are at least sys_misane survivors, leave the
3719 * building dark. Otherwise, do a clockhop dance. Ordinarily,
3720 * use the selected survivor speer. However, if the current
3721 * system peer is not speer, stay with the current system peer
3722 * as long as it doesn't get too old or too ugly.
3724 if (nlist > 0 && nlist >= sys_minsane) {
3727 typesystem = peers[speer].peer;
3728 if (osys_peer == NULL || osys_peer == typesystem) {
3730 } else if ((x = fabs(typesystem->offset -
3731 osys_peer->offset)) < sys_mindisp) {
3732 if (sys_clockhop == 0)
3733 sys_clockhop = sys_mindisp;
3736 DPRINTF(1, ("select: clockhop %d %.6f %.6f\n",
3737 j, x, sys_clockhop));
3738 if (fabs(x) < sys_clockhop)
3739 typesystem = osys_peer;
3748 * Mitigation rules of the game. We have the pick of the
3749 * litter in typesystem if any survivors are left. If
3750 * there is a prefer peer, use its offset and jitter.
3751 * Otherwise, use the combined offset and jitter of all kitters.
3753 if (typesystem != NULL) {
3754 if (sys_prefer == NULL) {
3755 typesystem->new_status = CTL_PST_SEL_SYSPEER;
3756 clock_combine(peers, sys_survivors, speer);
3758 typesystem = sys_prefer;
3760 typesystem->new_status = CTL_PST_SEL_SYSPEER;
3761 sys_offset = typesystem->offset;
3762 sys_jitter = typesystem->jitter;
3764 DPRINTF(1, ("select: combine offset %.9f jitter %.9f\n",
3765 sys_offset, sys_jitter));
3769 * If a PPS driver is lit and the combined offset is less than
3770 * 0.4 s, select the driver as the PPS peer and use its offset
3771 * and jitter. However, if this is the atom driver, use it only
3772 * if there is a prefer peer or there are no survivors and none
3775 if ( typepps != NULL
3776 && fabs(sys_offset) < 0.4
3777 && ( typepps->refclktype != REFCLK_ATOM_PPS
3778 || ( typepps->refclktype == REFCLK_ATOM_PPS
3779 && ( sys_prefer != NULL
3780 || (typesystem == NULL && sys_minsane == 0))))) {
3781 typesystem = typepps;
3783 typesystem->new_status = CTL_PST_SEL_PPS;
3784 sys_offset = typesystem->offset;
3785 sys_jitter = typesystem->jitter;
3786 DPRINTF(1, ("select: pps offset %.9f jitter %.9f\n",
3787 sys_offset, sys_jitter));
3789 #endif /* REFCLOCK */
3792 * If there are no survivors at this point, there is no
3793 * system peer. If so and this is an old update, keep the
3794 * current statistics, but do not update the clock.
3796 if (typesystem == NULL) {
3797 if (osys_peer != NULL) {
3798 if (sys_orphwait > 0)
3799 orphwait = current_time + sys_orphwait;
3800 report_event(EVNT_NOPEER, NULL, NULL);
3803 for (peer = peer_list; peer != NULL; peer = peer->p_link)
3804 peer->status = peer->new_status;
3809 * Do not use old data, as this may mess up the clock discipline
3812 if (typesystem->epoch <= sys_epoch)
3816 * We have found the alpha male. Wind the clock.
3818 if (osys_peer != typesystem)
3819 report_event(PEVNT_NEWPEER, typesystem, NULL);
3820 for (peer = peer_list; peer != NULL; peer = peer->p_link)
3821 peer->status = peer->new_status;
3822 clock_update(typesystem);
3828 peer_select * peers, /* survivor list */
3829 int npeers, /* number of survivors */
3830 int syspeer /* index of sys.peer */
3837 for (i = 0; i < npeers; i++) {
3838 x = 1. / peers[i].synch;
3840 z += x * peers[i].peer->offset;
3841 w += x * DIFF(peers[i].peer->offset,
3842 peers[syspeer].peer->offset);
3845 sys_jitter = SQRT(w / y + SQUARE(peers[syspeer].seljit));
3850 * root_distance - compute synchronization distance from peer to root
3854 struct peer *peer /* peer structure pointer */
3860 * Root Distance (LAMBDA) is defined as:
3861 * (delta + DELTA)/2 + epsilon + EPSILON + D
3864 * delta is the round-trip delay
3865 * DELTA is the root delay
3866 * epsilon is the peer dispersion
3867 * + (15 usec each second)
3868 * EPSILON is the root dispersion
3871 * NB: Think hard about why we are using these values, and what
3872 * the alternatives are, and the various pros/cons.
3874 * DLM thinks these are probably the best choices from any of the
3875 * other worse choices.
3877 dtemp = (peer->delay + peer->rootdelay) / 2
3879 + clock_phi * (current_time - peer->update)
3883 * Careful squeak here. The value returned must be greater than
3884 * the minimum root dispersion in order to avoid clockhop with
3885 * highly precise reference clocks. Note that the root distance
3886 * cannot exceed the sys_maxdist, as this is the cutoff by the
3887 * selection algorithm.
3889 if (dtemp < sys_mindisp)
3890 dtemp = sys_mindisp;
3896 * peer_xmit - send packet for persistent association.
3900 struct peer *peer /* peer structure pointer */
3903 struct pkt xpkt; /* transmit packet */
3904 size_t sendlen, authlen;
3905 keyid_t xkeyid = 0; /* transmit key ID */
3906 l_fp xmt_tx, xmt_ty;
3908 if (!peer->dstadr) /* drop peers without interface */
3911 xpkt.li_vn_mode = PKT_LI_VN_MODE(sys_leap, peer->version,
3913 xpkt.stratum = STRATUM_TO_PKT(sys_stratum);
3914 xpkt.ppoll = peer->hpoll;
3915 xpkt.precision = sys_precision;
3916 xpkt.refid = sys_refid;
3917 xpkt.rootdelay = HTONS_FP(DTOFP(sys_rootdelay));
3918 xpkt.rootdisp = HTONS_FP(DTOUFP(sys_rootdisp));
3919 HTONL_FP(&sys_reftime, &xpkt.reftime);
3920 HTONL_FP(&peer->rec, &xpkt.org);
3921 HTONL_FP(&peer->dst, &xpkt.rec);
3924 * If the received packet contains a MAC, the transmitted packet
3925 * is authenticated and contains a MAC. If not, the transmitted
3926 * packet is not authenticated.
3928 * It is most important when autokey is in use that the local
3929 * interface IP address be known before the first packet is
3930 * sent. Otherwise, it is not possible to compute a correct MAC
3931 * the recipient will accept. Thus, the I/O semantics have to do
3932 * a little more work. In particular, the wildcard interface
3933 * might not be usable.
3935 sendlen = LEN_PKT_NOMAC;
3938 !(peer->flags & FLAG_SKEY) &&
3939 #endif /* !AUTOKEY */
3943 * Transmit a-priori timestamps
3945 get_systime(&xmt_tx);
3946 if (peer->flip == 0) { /* basic mode */
3947 peer->aorg = xmt_tx;
3948 HTONL_FP(&xmt_tx, &xpkt.xmt);
3949 } else { /* interleaved modes */
3950 if (peer->hmode == MODE_BROADCAST) { /* bcst */
3951 HTONL_FP(&xmt_tx, &xpkt.xmt);
3953 HTONL_FP(&peer->borg,
3956 HTONL_FP(&peer->aorg,
3958 } else { /* symmetric */
3960 HTONL_FP(&peer->borg,
3963 HTONL_FP(&peer->aorg,
3967 peer->t21_bytes = sendlen;
3968 sendpkt(&peer->srcadr, peer->dstadr,
3969 sys_ttl[(peer->ttl >= sys_ttlmax) ? sys_ttlmax : peer->ttl],
3972 peer->throttle += (1 << peer->minpoll) - 2;
3975 * Capture a-posteriori timestamps
3977 get_systime(&xmt_ty);
3978 if (peer->flip != 0) { /* interleaved modes */
3980 peer->aorg = xmt_ty;
3982 peer->borg = xmt_ty;
3983 peer->flip = -peer->flip;
3985 L_SUB(&xmt_ty, &xmt_tx);
3986 LFPTOD(&xmt_ty, peer->xleave);
3987 DPRINTF(1, ("peer_xmit: at %ld %s->%s mode %d len %zu xmt %#010x.%08x\n",
3989 peer->dstadr ? stoa(&peer->dstadr->sin) : "-",
3990 stoa(&peer->srcadr), peer->hmode, sendlen,
3991 xmt_tx.l_ui, xmt_tx.l_uf));
3996 * Authentication is enabled, so the transmitted packet must be
3997 * authenticated. If autokey is enabled, fuss with the various
3998 * modes; otherwise, symmetric key cryptography is used.
4001 if (peer->flags & FLAG_SKEY) {
4002 struct exten *exten; /* extension field */
4005 * The Public Key Dance (PKD): Cryptographic credentials
4006 * are contained in extension fields, each including a
4007 * 4-octet length/code word followed by a 4-octet
4008 * association ID and optional additional data. Optional
4009 * data includes a 4-octet data length field followed by
4010 * the data itself. Request messages are sent from a
4011 * configured association; response messages can be sent
4012 * from a configured association or can take the fast
4013 * path without ever matching an association. Response
4014 * messages have the same code as the request, but have
4015 * a response bit and possibly an error bit set. In this
4016 * implementation, a message may contain no more than
4017 * one command and one or more responses.
4019 * Cryptographic session keys include both a public and
4020 * a private componet. Request and response messages
4021 * using extension fields are always sent with the
4022 * private component set to zero. Packets without
4023 * extension fields indlude the private component when
4024 * the session key is generated.
4029 * Allocate and initialize a keylist if not
4030 * already done. Then, use the list in inverse
4031 * order, discarding keys once used. Keep the
4032 * latest key around until the next one, so
4033 * clients can use client/server packets to
4034 * compute propagation delay.
4036 * Note that once a key is used from the list,
4037 * it is retained in the key cache until the
4038 * next key is used. This is to allow a client
4039 * to retrieve the encrypted session key
4040 * identifier to verify authenticity.
4042 * If for some reason a key is no longer in the
4043 * key cache, a birthday has happened or the key
4044 * has expired, so the pseudo-random sequence is
4045 * broken. In that case, purge the keylist and
4048 if (peer->keynumber == 0)
4049 make_keylist(peer, peer->dstadr);
4052 xkeyid = peer->keylist[peer->keynumber];
4053 if (authistrusted(xkeyid))
4058 peer->keyid = xkeyid;
4060 switch (peer->hmode) {
4063 * In broadcast server mode the autokey values are
4064 * required by the broadcast clients. Push them when a
4065 * new keylist is generated; otherwise, push the
4066 * association message so the client can request them at
4069 case MODE_BROADCAST:
4070 if (peer->flags & FLAG_ASSOC)
4071 exten = crypto_args(peer, CRYPTO_AUTO |
4072 CRYPTO_RESP, peer->associd, NULL);
4074 exten = crypto_args(peer, CRYPTO_ASSOC |
4075 CRYPTO_RESP, peer->associd, NULL);
4079 * In symmetric modes the parameter, certificate,
4080 * identity, cookie and autokey exchanges are
4081 * required. The leapsecond exchange is optional. But, a
4082 * peer will not believe the other peer until the other
4083 * peer has synchronized, so the certificate exchange
4084 * might loop until then. If a peer finds a broken
4085 * autokey sequence, it uses the autokey exchange to
4086 * retrieve the autokey values. In any case, if a new
4087 * keylist is generated, the autokey values are pushed.
4093 * Parameter, certificate and identity.
4096 exten = crypto_args(peer, CRYPTO_ASSOC,
4097 peer->associd, hostval.ptr);
4098 else if (!(peer->crypto & CRYPTO_FLAG_CERT))
4099 exten = crypto_args(peer, CRYPTO_CERT,
4100 peer->associd, peer->issuer);
4101 else if (!(peer->crypto & CRYPTO_FLAG_VRFY))
4102 exten = crypto_args(peer,
4103 crypto_ident(peer), peer->associd,
4107 * Cookie and autokey. We request the cookie
4108 * only when the this peer and the other peer
4109 * are synchronized. But, this peer needs the
4110 * autokey values when the cookie is zero. Any
4111 * time we regenerate the key list, we offer the
4112 * autokey values without being asked. If for
4113 * some reason either peer finds a broken
4114 * autokey sequence, the autokey exchange is
4115 * used to retrieve the autokey values.
4117 else if ( sys_leap != LEAP_NOTINSYNC
4118 && peer->leap != LEAP_NOTINSYNC
4119 && !(peer->crypto & CRYPTO_FLAG_COOK))
4120 exten = crypto_args(peer, CRYPTO_COOK,
4121 peer->associd, NULL);
4122 else if (!(peer->crypto & CRYPTO_FLAG_AUTO))
4123 exten = crypto_args(peer, CRYPTO_AUTO,
4124 peer->associd, NULL);
4125 else if ( peer->flags & FLAG_ASSOC
4126 && peer->crypto & CRYPTO_FLAG_SIGN)
4127 exten = crypto_args(peer, CRYPTO_AUTO |
4128 CRYPTO_RESP, peer->assoc, NULL);
4131 * Wait for clock sync, then sign the
4132 * certificate and retrieve the leapsecond
4135 else if (sys_leap == LEAP_NOTINSYNC)
4138 else if (!(peer->crypto & CRYPTO_FLAG_SIGN))
4139 exten = crypto_args(peer, CRYPTO_SIGN,
4140 peer->associd, hostval.ptr);
4141 else if (!(peer->crypto & CRYPTO_FLAG_LEAP))
4142 exten = crypto_args(peer, CRYPTO_LEAP,
4143 peer->associd, NULL);
4147 * In client mode the parameter, certificate, identity,
4148 * cookie and sign exchanges are required. The
4149 * leapsecond exchange is optional. If broadcast client
4150 * mode the same exchanges are required, except that the
4151 * autokey exchange is substitutes for the cookie
4152 * exchange, since the cookie is always zero. If the
4153 * broadcast client finds a broken autokey sequence, it
4154 * uses the autokey exchange to retrieve the autokey
4160 * Parameter, certificate and identity.
4163 exten = crypto_args(peer, CRYPTO_ASSOC,
4164 peer->associd, hostval.ptr);
4165 else if (!(peer->crypto & CRYPTO_FLAG_CERT))
4166 exten = crypto_args(peer, CRYPTO_CERT,
4167 peer->associd, peer->issuer);
4168 else if (!(peer->crypto & CRYPTO_FLAG_VRFY))
4169 exten = crypto_args(peer,
4170 crypto_ident(peer), peer->associd,
4174 * Cookie and autokey. These are requests, but
4175 * we use the peer association ID with autokey
4176 * rather than our own.
4178 else if (!(peer->crypto & CRYPTO_FLAG_COOK))
4179 exten = crypto_args(peer, CRYPTO_COOK,
4180 peer->associd, NULL);
4181 else if (!(peer->crypto & CRYPTO_FLAG_AUTO))
4182 exten = crypto_args(peer, CRYPTO_AUTO,
4186 * Wait for clock sync, then sign the
4187 * certificate and retrieve the leapsecond
4190 else if (sys_leap == LEAP_NOTINSYNC)
4193 else if (!(peer->crypto & CRYPTO_FLAG_SIGN))
4194 exten = crypto_args(peer, CRYPTO_SIGN,
4195 peer->associd, hostval.ptr);
4196 else if (!(peer->crypto & CRYPTO_FLAG_LEAP))
4197 exten = crypto_args(peer, CRYPTO_LEAP,
4198 peer->associd, NULL);
4203 * Add a queued extension field if present. This is
4204 * always a request message, so the reply ID is already
4205 * in the message. If an error occurs, the error bit is
4206 * lit in the response.
4208 if (peer->cmmd != NULL) {
4211 temp32 = CRYPTO_RESP;
4212 peer->cmmd->opcode |= htonl(temp32);
4213 sendlen += crypto_xmit(peer, &xpkt, NULL,
4214 sendlen, peer->cmmd, 0);
4220 * Add an extension field created above. All but the
4221 * autokey response message are request messages.
4223 if (exten != NULL) {
4224 if (exten->opcode != 0)
4225 sendlen += crypto_xmit(peer, &xpkt,
4226 NULL, sendlen, exten, 0);
4231 * Calculate the next session key. Since extension
4232 * fields are present, the cookie value is zero.
4234 if (sendlen > (int)LEN_PKT_NOMAC) {
4235 session_key(&peer->dstadr->sin, &peer->srcadr,
4239 #endif /* AUTOKEY */
4242 * Transmit a-priori timestamps
4244 get_systime(&xmt_tx);
4245 if (peer->flip == 0) { /* basic mode */
4246 peer->aorg = xmt_tx;
4247 HTONL_FP(&xmt_tx, &xpkt.xmt);
4248 } else { /* interleaved modes */
4249 if (peer->hmode == MODE_BROADCAST) { /* bcst */
4250 HTONL_FP(&xmt_tx, &xpkt.xmt);
4252 HTONL_FP(&peer->borg, &xpkt.org);
4254 HTONL_FP(&peer->aorg, &xpkt.org);
4255 } else { /* symmetric */
4257 HTONL_FP(&peer->borg, &xpkt.xmt);
4259 HTONL_FP(&peer->aorg, &xpkt.xmt);
4262 xkeyid = peer->keyid;
4263 authlen = authencrypt(xkeyid, (u_int32 *)&xpkt, sendlen);
4265 report_event(PEVNT_AUTH, peer, "no key");
4266 peer->flash |= TEST5; /* auth error */
4272 if (xkeyid > NTP_MAXKEY)
4273 authtrust(xkeyid, 0);
4274 #endif /* AUTOKEY */
4275 if (sendlen > sizeof(xpkt)) {
4276 msyslog(LOG_ERR, "peer_xmit: buffer overflow %zu", sendlen);
4279 peer->t21_bytes = sendlen;
4280 sendpkt(&peer->srcadr, peer->dstadr,
4281 sys_ttl[(peer->ttl >= sys_ttlmax) ? sys_ttlmax : peer->ttl],
4284 peer->throttle += (1 << peer->minpoll) - 2;
4287 * Capture a-posteriori timestamps
4289 get_systime(&xmt_ty);
4290 if (peer->flip != 0) { /* interleaved modes */
4292 peer->aorg = xmt_ty;
4294 peer->borg = xmt_ty;
4295 peer->flip = -peer->flip;
4297 L_SUB(&xmt_ty, &xmt_tx);
4298 LFPTOD(&xmt_ty, peer->xleave);
4300 DPRINTF(1, ("peer_xmit: at %ld %s->%s mode %d keyid %08x len %zu index %d\n",
4301 current_time, latoa(peer->dstadr),
4302 ntoa(&peer->srcadr), peer->hmode, xkeyid, sendlen,
4304 #else /* !AUTOKEY follows */
4305 DPRINTF(1, ("peer_xmit: at %ld %s->%s mode %d keyid %08x len %zu\n",
4306 current_time, peer->dstadr ?
4307 ntoa(&peer->dstadr->sin) : "-",
4308 ntoa(&peer->srcadr), peer->hmode, xkeyid, sendlen));
4309 #endif /* !AUTOKEY */
4318 leap_smear_add_offs(
4324 L_ADD(t, &leap_smear.offset);
4327 ** XXX: Should the smear be added to the root dispersion?
4333 #endif /* LEAP_SMEAR */
4337 * fast_xmit - Send packet for nonpersistent association. Note that
4338 * neither the source or destination can be a broadcast address.
4342 struct recvbuf *rbufp, /* receive packet pointer */
4343 int xmode, /* receive mode */
4344 keyid_t xkeyid, /* transmit key ID */
4345 int flags /* restrict mask */
4348 struct pkt xpkt; /* transmit packet structure */
4349 struct pkt *rpkt; /* receive packet structure */
4350 l_fp xmt_tx, xmt_ty;
4357 * Initialize transmit packet header fields from the receive
4358 * buffer provided. We leave the fields intact as received, but
4359 * set the peer poll at the maximum of the receive peer poll and
4360 * the system minimum poll (ntp_minpoll). This is for KoD rate
4361 * control and not strictly specification compliant, but doesn't
4364 * If the gazinta was from a multicast address, the gazoutta
4365 * must go out another way.
4367 rpkt = &rbufp->recv_pkt;
4368 if (rbufp->dstadr->flags & INT_MCASTOPEN)
4369 rbufp->dstadr = findinterface(&rbufp->recv_srcadr);
4372 * If this is a kiss-o'-death (KoD) packet, show leap
4373 * unsynchronized, stratum zero, reference ID the four-character
4374 * kiss code and system root delay. Note we don't reveal the
4375 * local time, so these packets can't be used for
4378 if (flags & RES_KOD) {
4380 xpkt.li_vn_mode = PKT_LI_VN_MODE(LEAP_NOTINSYNC,
4381 PKT_VERSION(rpkt->li_vn_mode), xmode);
4382 xpkt.stratum = STRATUM_PKT_UNSPEC;
4383 xpkt.ppoll = max(rpkt->ppoll, ntp_minpoll);
4384 xpkt.precision = rpkt->precision;
4385 memcpy(&xpkt.refid, "RATE", 4);
4386 xpkt.rootdelay = rpkt->rootdelay;
4387 xpkt.rootdisp = rpkt->rootdisp;
4388 xpkt.reftime = rpkt->reftime;
4389 xpkt.org = rpkt->xmt;
4390 xpkt.rec = rpkt->xmt;
4391 xpkt.xmt = rpkt->xmt;
4394 * This is a normal packet. Use the system variables.
4399 * Make copies of the variables which can be affected by smearing.
4402 l_fp this_recv_time;
4406 * If we are inside the leap smear interval we add the current smear offset to
4407 * the packet receive time, to the packet transmit time, and eventually to the
4408 * reftime to make sure the reftime isn't later than the transmit/receive times.
4410 xpkt.li_vn_mode = PKT_LI_VN_MODE(xmt_leap,
4411 PKT_VERSION(rpkt->li_vn_mode), xmode);
4413 xpkt.stratum = STRATUM_TO_PKT(sys_stratum);
4414 xpkt.ppoll = max(rpkt->ppoll, ntp_minpoll);
4415 xpkt.precision = sys_precision;
4416 xpkt.refid = sys_refid;
4417 xpkt.rootdelay = HTONS_FP(DTOFP(sys_rootdelay));
4418 xpkt.rootdisp = HTONS_FP(DTOUFP(sys_rootdisp));
4421 this_ref_time = sys_reftime;
4422 if (leap_smear.in_progress) {
4423 leap_smear_add_offs(&this_ref_time, NULL);
4424 xpkt.refid = convertLFPToRefID(leap_smear.offset);
4425 DPRINTF(2, ("fast_xmit: leap_smear.in_progress: refid %8x, smear %s\n",
4427 lfptoa(&leap_smear.offset, 8)
4430 HTONL_FP(&this_ref_time, &xpkt.reftime);
4432 HTONL_FP(&sys_reftime, &xpkt.reftime);
4435 xpkt.org = rpkt->xmt;
4438 this_recv_time = rbufp->recv_time;
4439 if (leap_smear.in_progress)
4440 leap_smear_add_offs(&this_recv_time, NULL);
4441 HTONL_FP(&this_recv_time, &xpkt.rec);
4443 HTONL_FP(&rbufp->recv_time, &xpkt.rec);
4446 get_systime(&xmt_tx);
4448 if (leap_smear.in_progress)
4449 leap_smear_add_offs(&xmt_tx, &this_recv_time);
4451 HTONL_FP(&xmt_tx, &xpkt.xmt);
4454 #ifdef HAVE_NTP_SIGND
4455 if (flags & RES_MSSNTP) {
4456 send_via_ntp_signd(rbufp, xmode, xkeyid, flags, &xpkt);
4459 #endif /* HAVE_NTP_SIGND */
4462 * If the received packet contains a MAC, the transmitted packet
4463 * is authenticated and contains a MAC. If not, the transmitted
4464 * packet is not authenticated.
4466 sendlen = LEN_PKT_NOMAC;
4467 if (rbufp->recv_length == sendlen) {
4468 sendpkt(&rbufp->recv_srcadr, rbufp->dstadr, 0, &xpkt,
4470 DPRINTF(1, ("fast_xmit: at %ld %s->%s mode %d len %lu\n",
4471 current_time, stoa(&rbufp->dstadr->sin),
4472 stoa(&rbufp->recv_srcadr), xmode,
4478 * The received packet contains a MAC, so the transmitted packet
4479 * must be authenticated. For symmetric key cryptography, use
4480 * the predefined and trusted symmetric keys to generate the
4481 * cryptosum. For autokey cryptography, use the server private
4482 * value to generate the cookie, which is unique for every
4483 * source-destination-key ID combination.
4486 if (xkeyid > NTP_MAXKEY) {
4490 * The only way to get here is a reply to a legitimate
4491 * client request message, so the mode must be
4492 * MODE_SERVER. If an extension field is present, there
4493 * can be only one and that must be a command. Do what
4494 * needs, but with private value of zero so the poor
4495 * jerk can decode it. If no extension field is present,
4496 * use the cookie to generate the session key.
4498 cookie = session_key(&rbufp->recv_srcadr,
4499 &rbufp->dstadr->sin, 0, sys_private, 0);
4500 if ((size_t)rbufp->recv_length > sendlen + MAX_MAC_LEN) {
4501 session_key(&rbufp->dstadr->sin,
4502 &rbufp->recv_srcadr, xkeyid, 0, 2);
4503 temp32 = CRYPTO_RESP;
4504 rpkt->exten[0] |= htonl(temp32);
4505 sendlen += crypto_xmit(NULL, &xpkt, rbufp,
4506 sendlen, (struct exten *)rpkt->exten,
4509 session_key(&rbufp->dstadr->sin,
4510 &rbufp->recv_srcadr, xkeyid, cookie, 2);
4513 #endif /* AUTOKEY */
4514 get_systime(&xmt_tx);
4515 sendlen += authencrypt(xkeyid, (u_int32 *)&xpkt, sendlen);
4517 if (xkeyid > NTP_MAXKEY)
4518 authtrust(xkeyid, 0);
4519 #endif /* AUTOKEY */
4520 sendpkt(&rbufp->recv_srcadr, rbufp->dstadr, 0, &xpkt, sendlen);
4521 get_systime(&xmt_ty);
4522 L_SUB(&xmt_ty, &xmt_tx);
4523 sys_authdelay = xmt_ty;
4524 DPRINTF(1, ("fast_xmit: at %ld %s->%s mode %d keyid %08x len %lu\n",
4525 current_time, ntoa(&rbufp->dstadr->sin),
4526 ntoa(&rbufp->recv_srcadr), xmode, xkeyid,
4532 * pool_xmit - resolve hostname or send unicast solicitation for pool.
4536 struct peer *pool /* pool solicitor association */
4540 struct pkt xpkt; /* transmit packet structure */
4541 struct addrinfo hints;
4543 struct interface * lcladr;
4544 sockaddr_u * rmtadr;
4550 if (NULL == pool->ai) {
4551 if (pool->addrs != NULL) {
4552 /* free() is used with copy_addrinfo_list() */
4557 hints.ai_family = AF(&pool->srcadr);
4558 hints.ai_socktype = SOCK_DGRAM;
4559 hints.ai_protocol = IPPROTO_UDP;
4560 /* ignore getaddrinfo_sometime() errors, we will retry */
4561 rc = getaddrinfo_sometime(
4566 &pool_name_resolved,
4567 (void *)(intptr_t)pool->associd);
4569 DPRINTF(1, ("pool DNS lookup %s started\n",
4573 "unable to start pool DNS %s: %m",
4579 /* copy_addrinfo_list ai_addr points to a sockaddr_u */
4580 rmtadr = (sockaddr_u *)(void *)pool->ai->ai_addr;
4581 pool->ai = pool->ai->ai_next;
4582 p = findexistingpeer(rmtadr, NULL, NULL, MODE_CLIENT, 0, NULL);
4583 } while (p != NULL && pool->ai != NULL);
4585 return; /* out of addresses, re-query DNS next poll */
4586 restrictions(rmtadr, &r4a);
4587 restrict_mask = r4a.rflags;
4588 if (RES_FLAGS & restrict_mask)
4589 restrict_source(rmtadr, 0,
4590 current_time + POOL_SOLICIT_WINDOW + 1);
4591 lcladr = findinterface(rmtadr);
4592 memset(&xpkt, 0, sizeof(xpkt));
4593 xpkt.li_vn_mode = PKT_LI_VN_MODE(sys_leap, pool->version,
4595 xpkt.stratum = STRATUM_TO_PKT(sys_stratum);
4596 xpkt.ppoll = pool->hpoll;
4597 xpkt.precision = sys_precision;
4598 xpkt.refid = sys_refid;
4599 xpkt.rootdelay = HTONS_FP(DTOFP(sys_rootdelay));
4600 xpkt.rootdisp = HTONS_FP(DTOUFP(sys_rootdisp));
4601 HTONL_FP(&sys_reftime, &xpkt.reftime);
4602 get_systime(&xmt_tx);
4603 pool->aorg = xmt_tx;
4604 HTONL_FP(&xmt_tx, &xpkt.xmt);
4605 sendpkt(rmtadr, lcladr,
4606 sys_ttl[(pool->ttl >= sys_ttlmax) ? sys_ttlmax : pool->ttl],
4607 &xpkt, LEN_PKT_NOMAC);
4609 pool->throttle += (1 << pool->minpoll) - 2;
4610 DPRINTF(1, ("pool_xmit: at %ld %s->%s pool\n",
4611 current_time, latoa(lcladr), stoa(rmtadr)));
4612 msyslog(LOG_INFO, "Soliciting pool server %s", stoa(rmtadr));
4619 * group_test - test if this is the same group
4621 * host assoc return action
4622 * none none 0 mobilize *
4623 * none group 0 mobilize *
4624 * group none 0 mobilize *
4625 * group group 1 mobilize
4626 * group different 1 ignore
4627 * * ignore if notrust
4638 if (strcmp(grp, sys_groupname) == 0)
4644 if (strcmp(grp, ident) == 0)
4649 #endif /* AUTOKEY */
4659 const char * service,
4660 const struct addrinfo * hints,
4661 const struct addrinfo * res
4664 struct peer * pool; /* pool solicitor association */
4669 "error resolving pool %s: %s (%d)",
4670 name, gai_strerror(rescode), rescode);
4674 assoc = (associd_t)(intptr_t)context;
4675 pool = findpeerbyassoc(assoc);
4678 "Could not find assoc %u for pool DNS %s",
4682 DPRINTF(1, ("pool DNS %s completed\n", name));
4683 pool->addrs = copy_addrinfo_list(res);
4684 pool->ai = pool->addrs;
4693 * key_expire - purge the key list
4697 struct peer *peer /* peer structure pointer */
4702 if (peer->keylist != NULL) {
4703 for (i = 0; i <= peer->keynumber; i++)
4704 authtrust(peer->keylist[i], 0);
4705 free(peer->keylist);
4706 peer->keylist = NULL;
4708 value_free(&peer->sndval);
4709 peer->keynumber = 0;
4710 peer->flags &= ~FLAG_ASSOC;
4711 DPRINTF(1, ("key_expire: at %lu associd %d\n", current_time,
4714 #endif /* AUTOKEY */
4718 * local_refid(peer) - check peer refid to avoid selecting peers
4719 * currently synced to this ntpd.
4728 if (p->dstadr != NULL && !(INT_MCASTIF & p->dstadr->flags))
4729 unicast_ep = p->dstadr;
4731 unicast_ep = findinterface(&p->srcadr);
4733 if (unicast_ep != NULL && p->refid == unicast_ep->addr_refid)
4741 * Determine if the peer is unfit for synchronization
4743 * A peer is unfit for synchronization if
4744 * > TEST10 bad leap or stratum below floor or at or above ceiling
4745 * > TEST11 root distance exceeded for remote peer
4746 * > TEST12 a direct or indirect synchronization loop would form
4747 * > TEST13 unreachable or noselect
4749 int /* FALSE if fit, TRUE if unfit */
4751 struct peer *peer /* peer structure pointer */
4757 * A stratum error occurs if (1) the server has never been
4758 * synchronized, (2) the server stratum is below the floor or
4759 * greater than or equal to the ceiling.
4761 if ( peer->leap == LEAP_NOTINSYNC
4762 || peer->stratum < sys_floor
4763 || peer->stratum >= sys_ceiling) {
4764 rval |= TEST10; /* bad synch or stratum */
4768 * A distance error for a remote peer occurs if the root
4769 * distance is greater than or equal to the distance threshold
4770 * plus the increment due to one host poll interval.
4772 if ( !(peer->flags & FLAG_REFCLOCK)
4773 && root_distance(peer) >= sys_maxdist
4774 + clock_phi * ULOGTOD(peer->hpoll)) {
4775 rval |= TEST11; /* distance exceeded */
4779 * A loop error occurs if the remote peer is synchronized to the
4780 * local peer or if the remote peer is synchronized to the same
4781 * server as the local peer but only if the remote peer is
4782 * neither a reference clock nor an orphan.
4784 if (peer->stratum > 1 && local_refid(peer)) {
4785 rval |= TEST12; /* synchronization loop */
4789 * An unreachable error occurs if the server is unreachable or
4790 * the noselect bit is set.
4792 if (!peer->reach || (peer->flags & FLAG_NOSELECT)) {
4793 rval |= TEST13; /* unreachable */
4796 peer->flash &= ~PEER_TEST_MASK;
4797 peer->flash |= rval;
4803 * Find the precision of this particular machine
4805 #define MINSTEP 20e-9 /* minimum clock increment (s) */
4806 #define MAXSTEP 1 /* maximum clock increment (s) */
4807 #define MINCHANGES 12 /* minimum number of step samples */
4808 #define MAXLOOPS ((int)(1. / MINSTEP)) /* avoid infinite loop */
4811 * This routine measures the system precision defined as the minimum of
4812 * a sequence of differences between successive readings of the system
4813 * clock. However, if a difference is less than MINSTEP, the clock has
4814 * been read more than once during a clock tick and the difference is
4815 * ignored. We set MINSTEP greater than zero in case something happens
4816 * like a cache miss, and to tolerate underlying system clocks which
4817 * ensure each reading is strictly greater than prior readings while
4818 * using an underlying stepping (not interpolated) clock.
4820 * sys_tick and sys_precision represent the time to read the clock for
4821 * systems with high-precision clocks, and the tick interval or step
4822 * size for lower-precision stepping clocks.
4824 * This routine also measures the time to read the clock on stepping
4825 * system clocks by counting the number of readings between changes of
4826 * the underlying clock. With either type of clock, the minimum time
4827 * to read the clock is saved as sys_fuzz, and used to ensure the
4828 * get_systime() readings always increase and are fuzzed below sys_fuzz.
4831 measure_precision(void)
4834 * With sys_fuzz set to zero, get_systime() fuzzing of low bits
4835 * is effectively disabled. trunc_os_clock is FALSE to disable
4836 * get_ostime() simulation of a low-precision system clock.
4839 trunc_os_clock = FALSE;
4840 measured_tick = measure_tick_fuzz();
4841 set_sys_tick_precision(measured_tick);
4842 msyslog(LOG_INFO, "proto: precision = %.3f usec (%d)",
4843 sys_tick * 1e6, sys_precision);
4844 if (sys_fuzz < sys_tick) {
4845 msyslog(LOG_NOTICE, "proto: fuzz beneath %.3f usec",
4852 * measure_tick_fuzz()
4854 * measures the minimum time to read the clock (stored in sys_fuzz)
4855 * and returns the tick, the larger of the minimum increment observed
4856 * between successive clock readings and the time to read the clock.
4859 measure_tick_fuzz(void)
4861 l_fp minstep; /* MINSTEP as l_fp */
4862 l_fp val; /* current seconds fraction */
4863 l_fp last; /* last seconds fraction */
4864 l_fp ldiff; /* val - last */
4865 double tick; /* computed tick value */
4870 int i; /* log2 precision */
4876 DTOLFP(MINSTEP, &minstep);
4878 for (i = 0; i < MAXLOOPS && changes < MINCHANGES; i++) {
4881 L_SUB(&ldiff, &last);
4883 if (L_ISGT(&ldiff, &minstep)) {
4884 max_repeats = max(repeats, max_repeats);
4887 LFPTOD(&ldiff, diff);
4888 tick = min(diff, tick);
4893 if (changes < MINCHANGES) {
4894 msyslog(LOG_ERR, "Fatal error: precision could not be measured (MINSTEP too large?)");
4898 if (0 == max_repeats) {
4901 set_sys_fuzz(tick / max_repeats);
4909 set_sys_tick_precision(
4917 "unsupported tick %.3f > 1s ignored", tick);
4920 if (tick < measured_tick) {
4922 "proto: tick %.3f less than measured tick %.3f, ignored",
4923 tick, measured_tick);
4925 } else if (tick > measured_tick) {
4926 trunc_os_clock = TRUE;
4928 "proto: truncating system clock to multiples of %.9f",
4934 * Find the nearest power of two.
4936 for (i = 0; tick <= 1; i--)
4938 if (tick - 1 > 1 - tick / 2)
4941 sys_precision = (s_char)i;
4946 * init_proto - initialize the protocol module's data
4955 * Fill in the sys_* stuff. Default is don't listen to
4956 * broadcasting, require authentication.
4958 set_sys_leap(LEAP_NOTINSYNC);
4959 sys_stratum = STRATUM_UNSPEC;
4960 memcpy(&sys_refid, "INIT", 4);
4964 L_CLR(&sys_reftime);
4966 measure_precision();
4967 get_systime(&dummy);
4969 sys_manycastserver = 0;
4971 sys_bdelay = BDELAY_DEFAULT; /*[Bug 3031] delay cutoff */
4972 sys_authenticate = 1;
4973 sys_stattime = current_time;
4974 orphwait = current_time + sys_orphwait;
4976 for (i = 0; i < MAX_TTL; ++i)
4977 sys_ttl[i] = (u_char)((i * 256) / MAX_TTL);
4978 sys_ttlmax = (MAX_TTL - 1);
4985 * proto_config - configure the protocol module
4996 * Figure out what he wants to change, then do it
4998 DPRINTF(2, ("proto_config: code %d value %lu dvalue %lf\n",
4999 item, value, dvalue));
5004 * enable and disable commands - arguments are Boolean.
5006 case PROTO_AUTHENTICATE: /* authentication (auth) */
5007 sys_authenticate = value;
5010 case PROTO_BROADCLIENT: /* broadcast client (bclient) */
5011 sys_bclient = (int)value;
5012 if (sys_bclient == 0)
5019 case PROTO_CAL: /* refclock calibrate (calibrate) */
5022 #endif /* REFCLOCK */
5024 case PROTO_KERNEL: /* kernel discipline (kernel) */
5028 case PROTO_MONITOR: /* monitoring (monitor) */
5034 msyslog(LOG_WARNING,
5035 "restrict: 'monitor' cannot be disabled while 'limited' is enabled");
5039 case PROTO_NTP: /* NTP discipline (ntp) */
5043 case PROTO_MODE7: /* mode7 management (ntpdc) */
5047 case PROTO_PPS: /* PPS discipline (pps) */
5048 hardpps_enable = value;
5051 case PROTO_FILEGEN: /* statistics (stats) */
5052 stats_control = value;
5056 * tos command - arguments are double, sometimes cast to int
5059 case PROTO_BCPOLLBSTEP: /* Broadcast Poll Backstep gate (bcpollbstep) */
5060 sys_bcpollbstep = (u_char)dvalue;
5063 case PROTO_BEACON: /* manycast beacon (beacon) */
5064 sys_beacon = (int)dvalue;
5067 case PROTO_BROADDELAY: /* default broadcast delay (bdelay) */
5068 sys_bdelay = (dvalue ? dvalue : BDELAY_DEFAULT);
5071 case PROTO_CEILING: /* stratum ceiling (ceiling) */
5072 sys_ceiling = (int)dvalue;
5075 case PROTO_COHORT: /* cohort switch (cohort) */
5076 sys_cohort = (int)dvalue;
5079 case PROTO_FLOOR: /* stratum floor (floor) */
5080 sys_floor = (int)dvalue;
5083 case PROTO_MAXCLOCK: /* maximum candidates (maxclock) */
5084 sys_maxclock = (int)dvalue;
5087 case PROTO_MAXDIST: /* select threshold (maxdist) */
5088 sys_maxdist = dvalue;
5091 case PROTO_CALLDELAY: /* modem call delay (mdelay) */
5092 break; /* NOT USED */
5094 case PROTO_MINCLOCK: /* minimum candidates (minclock) */
5095 sys_minclock = (int)dvalue;
5098 case PROTO_MINDISP: /* minimum distance (mindist) */
5099 sys_mindisp = dvalue;
5102 case PROTO_MINSANE: /* minimum survivors (minsane) */
5103 sys_minsane = (int)dvalue;
5106 case PROTO_ORPHAN: /* orphan stratum (orphan) */
5107 sys_orphan = (int)dvalue;
5110 case PROTO_ORPHWAIT: /* orphan wait (orphwait) */
5111 orphwait -= sys_orphwait;
5112 sys_orphwait = (int)dvalue;
5113 orphwait += sys_orphwait;
5117 * Miscellaneous commands
5119 case PROTO_MULTICAST_ADD: /* add group address */
5121 io_multicast_add(svalue);
5125 case PROTO_MULTICAST_DEL: /* delete group address */
5127 io_multicast_del(svalue);
5131 * Peer_clear Early policy choices
5134 case PROTO_PCEDIGEST: /* Digest */
5135 peer_clear_digest_early = value;
5139 * Unpeer Early policy choices
5142 case PROTO_UECRYPTO: /* Crypto */
5143 unpeer_crypto_early = value;
5146 case PROTO_UECRYPTONAK: /* Crypto_NAK */
5147 unpeer_crypto_nak_early = value;
5150 case PROTO_UEDIGEST: /* Digest */
5151 unpeer_digest_early = value;
5156 "proto: unsupported option %d", item);
5162 * proto_clr_stats - clear protocol stat counters
5165 proto_clr_stats(void)
5167 sys_stattime = current_time;
5176 sys_limitrejected = 0;