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; otherwise 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 * During the first few packets of the autokey dance there will
329 * not (yet) be a keyid, but in this case FLAG_SKEY is set.
330 * So the NAK is invalid if either there's no peer, or
331 * if the keyid is 0 and FLAG_SKEY is not set.
333 if (!peer || (!peer->keyid && !(peer->flags & FLAG_SKEY))) {
338 * The ORIGIN must match, or this cannot be a valid NAK, either.
340 NTOHL_FP(&rpkt->org, &p_org);
346 if (L_ISZERO(&p_org) ||
348 !L_ISEQU(&p_org, myorg)) {
352 /* If we ever passed all that checks, we should be safe. Well,
353 * as safe as we can ever be with an unauthenticated crypto-nak.
360 * transmit - transmit procedure called by poll timeout
364 struct peer *peer /* peer structure pointer */
370 * The polling state machine. There are two kinds of machines,
371 * those that never expect a reply (broadcast and manycast
372 * server modes) and those that do (all other modes). The dance
378 * If we haven't received anything (even if unsync) since last
381 if (peer->outdate > peer->timelastrec && !peer->reach)
382 peer->ppoll = peer->maxpoll;
385 * In broadcast mode the poll interval is never changed from
388 if (peer->cast_flags & (MDF_BCAST | MDF_MCAST)) {
389 peer->outdate = current_time;
390 if (sys_leap != LEAP_NOTINSYNC)
392 poll_update(peer, hpoll);
397 * In manycast mode we start with unity ttl. The ttl is
398 * increased by one for each poll until either sys_maxclock
399 * servers have been found or the maximum ttl is reached. When
400 * sys_maxclock servers are found we stop polling until one or
401 * more servers have timed out or until less than sys_minclock
402 * associations turn up. In this case additional better servers
403 * are dragged in and preempt the existing ones. Once every
404 * sys_beacon seconds we are to transmit unconditionally, but
405 * this code is not quite right -- peer->unreach counts polls
406 * and is being compared with sys_beacon, so the beacons happen
407 * every sys_beacon polls.
409 if (peer->cast_flags & MDF_ACAST) {
410 peer->outdate = current_time;
411 if (peer->unreach > sys_beacon) {
415 } else if ( sys_survivors < sys_minclock
416 || peer_associations < sys_maxclock) {
417 if (peer->ttl < sys_ttlmax)
422 poll_update(peer, hpoll);
427 * Pool associations transmit unicast solicitations when there
428 * are less than a hard limit of 2 * sys_maxclock associations,
429 * and either less than sys_minclock survivors or less than
430 * sys_maxclock associations. The hard limit prevents unbounded
431 * growth in associations if the system clock or network quality
432 * result in survivor count dipping below sys_minclock often.
433 * This was observed testing with pool, where sys_maxclock == 12
434 * resulted in 60 associations without the hard limit. A
435 * similar hard limit on manycastclient ephemeral associations
436 * may be appropriate.
438 if (peer->cast_flags & MDF_POOL) {
439 peer->outdate = current_time;
440 if ( (peer_associations <= 2 * sys_maxclock)
441 && ( peer_associations < sys_maxclock
442 || sys_survivors < sys_minclock))
444 poll_update(peer, hpoll);
449 * In unicast modes the dance is much more intricate. It is
450 * designed to back off whenever possible to minimize network
453 if (peer->burst == 0) {
457 * Update the reachability status. If not heard for
458 * three consecutive polls, stuff infinity in the clock
461 oreach = peer->reach;
462 peer->outdate = current_time;
468 * Here the peer is unreachable. If it was
469 * previously reachable raise a trap. Send a
472 clock_filter(peer, 0., 0., MAXDISPERSE);
475 report_event(PEVNT_UNREACH, peer, NULL);
477 if ( (peer->flags & FLAG_IBURST)
479 peer->retry = NTP_RETRY;
483 * Here the peer is reachable. Send a burst if
484 * enabled and the peer is fit. Reset unreach
485 * for persistent and ephemeral associations.
486 * Unreach is also reset for survivors in
490 if (!(peer->flags & FLAG_PREEMPT))
492 if ( (peer->flags & FLAG_BURST)
494 && !peer_unfit(peer))
495 peer->retry = NTP_RETRY;
499 * Watch for timeout. If ephemeral, toss the rascal;
500 * otherwise, bump the poll interval. Note the
501 * poll_update() routine will clamp it to maxpoll.
502 * If preemptible and we have more peers than maxclock,
503 * and this peer has the minimum score of preemptibles,
506 if (peer->unreach >= NTP_UNREACH) {
508 /* ephemeral: no FLAG_CONFIG nor FLAG_PREEMPT */
509 if (!(peer->flags & (FLAG_CONFIG | FLAG_PREEMPT))) {
510 report_event(PEVNT_RESTART, peer, "timeout");
511 peer_clear(peer, "TIME");
515 if ( (peer->flags & FLAG_PREEMPT)
516 && (peer_associations > sys_maxclock)
517 && score_all(peer)) {
518 report_event(PEVNT_RESTART, peer, "timeout");
519 peer_clear(peer, "TIME");
526 if (peer->burst == 0) {
529 * If ntpdate mode and the clock has not been
530 * set and all peers have completed the burst,
531 * we declare a successful failure.
535 if (peer_ntpdate == 0) {
537 "ntpd: no servers found");
540 "ntpd: no servers found\n");
550 * Do not transmit if in broadcast client mode.
552 if (peer->hmode != MODE_BCLIENT)
554 poll_update(peer, hpoll);
568 case AM_ERR: return "AM_ERR";
569 case AM_NOMATCH: return "AM_NOMATCH";
570 case AM_PROCPKT: return "AM_PROCPKT";
571 case AM_BCST: return "AM_BCST";
572 case AM_FXMIT: return "AM_FXMIT";
573 case AM_MANYCAST: return "AM_MANYCAST";
574 case AM_NEWPASS: return "AM_NEWPASS";
575 case AM_NEWBCL: return "AM_NEWBCL";
576 case AM_POSSBCL: return "AM_POSSBCL";
579 snprintf(bp, LIB_BUFLENGTH, "AM_#%d", am);
586 * receive - receive procedure called for each packet received
590 struct recvbuf *rbufp
593 register struct peer *peer; /* peer structure pointer */
594 register struct pkt *pkt; /* receive packet pointer */
595 u_char hisversion; /* packet version */
596 u_char hisleap; /* packet leap indicator */
597 u_char hismode; /* packet mode */
598 u_char hisstratum; /* packet stratum */
599 r4addr r4a; /* address restrictions */
600 u_short restrict_mask; /* restrict bits */
601 const char *hm_str; /* hismode string */
602 const char *am_str; /* association match string */
603 int kissCode = NOKISS; /* Kiss Code */
604 int has_mac; /* length of MAC field */
605 int authlen; /* offset of MAC field */
606 auth_code is_authentic = AUTH_UNKNOWN; /* Was AUTH_NONE */
607 nak_code crypto_nak_test; /* result of crypto-NAK check */
608 int retcode = AM_NOMATCH; /* match code */
609 keyid_t skeyid = 0; /* key IDs */
610 u_int32 opcode = 0; /* extension field opcode */
611 sockaddr_u *dstadr_sin; /* active runway */
612 struct peer *peer2; /* aux peer structure pointer */
613 endpt *match_ep; /* newpeer() local address */
614 l_fp p_org; /* origin timestamp */
615 l_fp p_rec; /* receive timestamp */
616 l_fp p_xmt; /* transmit timestamp */
618 char hostname[NTP_MAXSTRLEN + 1];
619 char *groupname = NULL;
620 struct autokey *ap; /* autokey structure pointer */
621 int rval; /* cookie snatcher */
622 keyid_t pkeyid = 0, tkeyid = 0; /* key IDs */
624 #ifdef HAVE_NTP_SIGND
625 static unsigned char zero_key[16];
626 #endif /* HAVE_NTP_SIGND */
629 * Note that there are many places we do not call record_raw_stats().
631 * We only want to call it *after* we've sent a response, or perhaps
632 * when we've decided to drop a packet.
636 * Monitor the packet and get restrictions. Note that the packet
637 * length for control and private mode packets must be checked
638 * by the service routines. Some restrictions have to be handled
639 * later in order to generate a kiss-o'-death packet.
642 * Bogus port check is before anything, since it probably
643 * reveals a clogging attack.
646 if (0 == SRCPORT(&rbufp->recv_srcadr)) {
648 return; /* bogus port */
650 restrictions(&rbufp->recv_srcadr, &r4a);
651 restrict_mask = r4a.rflags;
653 pkt = &rbufp->recv_pkt;
654 hisversion = PKT_VERSION(pkt->li_vn_mode);
655 hisleap = PKT_LEAP(pkt->li_vn_mode);
656 hismode = (int)PKT_MODE(pkt->li_vn_mode);
657 hisstratum = PKT_TO_STRATUM(pkt->stratum);
658 DPRINTF(1, ("receive: at %ld %s<-%s ippeerlimit %d mode %d iflags %s restrict %s org %#010x.%08x xmt %#010x.%08x\n",
659 current_time, stoa(&rbufp->dstadr->sin),
660 stoa(&rbufp->recv_srcadr), r4a.ippeerlimit, hismode,
661 build_iflags(rbufp->dstadr->flags),
662 build_rflags(restrict_mask),
663 ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf),
664 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf)));
666 /* See basic mode and broadcast checks, below */
667 INSIST(0 != hisstratum);
669 if (restrict_mask & RES_IGNORE) {
670 DPRINTF(2, ("receive: drop: RES_IGNORE\n"));
672 return; /* ignore everything */
674 if (hismode == MODE_PRIVATE) {
675 if (!ntp_mode7 || (restrict_mask & RES_NOQUERY)) {
676 DPRINTF(2, ("receive: drop: RES_NOQUERY\n"));
678 return; /* no query private */
680 process_private(rbufp, ((restrict_mask &
681 RES_NOMODIFY) == 0));
684 if (hismode == MODE_CONTROL) {
685 if (restrict_mask & RES_NOQUERY) {
686 DPRINTF(2, ("receive: drop: RES_NOQUERY\n"));
688 return; /* no query control */
690 process_control(rbufp, restrict_mask);
693 if (restrict_mask & RES_DONTSERVE) {
694 DPRINTF(2, ("receive: drop: RES_DONTSERVE\n"));
696 return; /* no time serve */
700 * This is for testing. If restricted drop ten percent of
703 if (restrict_mask & RES_FLAKE) {
704 if ((double)ntp_random() / 0x7fffffff < .1) {
705 DPRINTF(2, ("receive: drop: RES_FLAKE\n"));
707 return; /* no flakeway */
712 ** Format Layer Checks
714 ** Validate the packet format. The packet size, packet header,
715 ** and any extension field lengths are checked. We identify
716 ** the beginning of the MAC, to identify the upper limit of
717 ** of the hash computation.
719 ** In case of a format layer check violation, the packet is
720 ** discarded with no further processing.
724 * Version check must be after the query packets, since they
725 * intentionally use an early version.
727 if (hisversion == NTP_VERSION) {
728 sys_newversion++; /* new version */
729 } else if ( !(restrict_mask & RES_VERSION)
730 && hisversion >= NTP_OLDVERSION) {
731 sys_oldversion++; /* previous version */
733 DPRINTF(2, ("receive: drop: RES_VERSION\n"));
735 return; /* old version */
739 * Figure out his mode and validate the packet. This has some
740 * legacy raunch that probably should be removed. In very early
741 * NTP versions mode 0 was equivalent to what later versions
742 * would interpret as client mode.
744 if (hismode == MODE_UNSPEC) {
745 if (hisversion == NTP_OLDVERSION) {
746 hismode = MODE_CLIENT;
748 DPRINTF(2, ("receive: drop: MODE_UNSPEC\n"));
750 return; /* invalid mode */
755 * Parse the extension field if present. We figure out whether
756 * an extension field is present by measuring the MAC size. If
757 * the number of words following the packet header is 0, no MAC
758 * is present and the packet is not authenticated. If 1, the
759 * packet is a crypto-NAK; if 3, the packet is authenticated
760 * with DES; if 5, the packet is authenticated with MD5; if 6,
761 * the packet is authenticated with SHA. If 2 or * 4, the packet
762 * is a runt and discarded forthwith. If greater than 6, an
763 * extension field is present, so we subtract the length of the
764 * field and go around again.
766 * Note the above description is lame. We should/could also check
767 * the two bytes that make up the EF type and subtype, and then
768 * check the two bytes that tell us the EF length. A legacy MAC
769 * has a 4 byte keyID, and for conforming symmetric keys its value
770 * must be <= 64k, meaning the top two bytes will always be zero.
771 * Since the EF Type of 0 is reserved/unused, there's no way a
772 * conforming legacy MAC could ever be misinterpreted as an EF.
774 * There is more, but this isn't the place to document it.
777 authlen = LEN_PKT_NOMAC;
778 has_mac = rbufp->recv_length - authlen;
779 while (has_mac > 0) {
786 if (has_mac % 4 != 0 || has_mac < (int)MIN_MAC_LEN) {
787 DPRINTF(2, ("receive: drop: bad post-packet length\n"));
789 return; /* bad length */
792 * This next test is clearly wrong - it needlessly
793 * prohibits short EFs (which don't yet exist)
795 if (has_mac <= (int)MAX_MAC_LEN) {
796 skeyid = ntohl(((u_int32 *)pkt)[authlen / 4]);
800 opcode = ntohl(((u_int32 *)pkt)[authlen / 4]);
801 len = opcode & 0xffff;
804 || (int)len + authlen > rbufp->recv_length) {
805 DPRINTF(2, ("receive: drop: bad EF length\n"));
807 return; /* bad length */
811 * Extract calling group name for later. If
812 * sys_groupname is non-NULL, there must be
813 * a group name provided to elicit a response.
815 if ( (opcode & 0x3fff0000) == CRYPTO_ASSOC
816 && sys_groupname != NULL) {
817 ep = (struct exten *)&((u_int32 *)pkt)[authlen / 4];
818 hostlen = ntohl(ep->vallen);
819 if ( hostlen >= sizeof(hostname)
821 offsetof(struct exten, pkt)) {
822 DPRINTF(2, ("receive: drop: bad autokey hostname length\n"));
824 return; /* bad length */
826 memcpy(hostname, &ep->pkt, hostlen);
827 hostname[hostlen] = '\0';
828 groupname = strchr(hostname, '@');
829 if (groupname == NULL) {
830 DPRINTF(2, ("receive: drop: empty autokey groupname\n"));
843 * If has_mac is < 0 we had a malformed packet.
846 DPRINTF(2, ("receive: drop: post-packet under-read\n"));
848 return; /* bad length */
852 ** Packet Data Verification Layer
854 ** This layer verifies the packet data content. If
855 ** authentication is required, a MAC must be present.
856 ** If a MAC is present, it must validate.
857 ** Crypto-NAK? Look - a shiny thing!
859 ** If authentication fails, we're done.
863 * If authentication is explicitly required, a MAC must be present.
865 if (restrict_mask & RES_DONTTRUST && has_mac == 0) {
866 DPRINTF(2, ("receive: drop: RES_DONTTRUST\n"));
868 return; /* access denied */
872 * Update the MRU list and finger the cloggers. It can be a
873 * little expensive, so turn it off for production use.
874 * RES_LIMITED and RES_KOD will be cleared in the returned
875 * restrict_mask unless one or both actions are warranted.
877 restrict_mask = ntp_monitor(rbufp, restrict_mask);
878 if (restrict_mask & RES_LIMITED) {
880 if ( !(restrict_mask & RES_KOD)
881 || MODE_BROADCAST == hismode
882 || MODE_SERVER == hismode) {
883 if (MODE_SERVER == hismode) {
884 DPRINTF(1, ("Possibly self-induced rate limiting of MODE_SERVER from %s\n",
885 stoa(&rbufp->recv_srcadr)));
887 DPRINTF(2, ("receive: drop: RES_KOD\n"));
889 return; /* rate exceeded */
891 if (hismode == MODE_CLIENT)
892 fast_xmit(rbufp, MODE_SERVER, skeyid,
895 fast_xmit(rbufp, MODE_ACTIVE, skeyid,
897 return; /* rate exceeded */
899 restrict_mask &= ~RES_KOD;
902 * We have tossed out as many buggy packets as possible early in
903 * the game to reduce the exposure to a clogging attack. Now we
904 * have to burn some cycles to find the association and
905 * authenticate the packet if required. Note that we burn only
906 * digest cycles, again to reduce exposure. There may be no
907 * matching association and that's okay.
909 * More on the autokey mambo. Normally the local interface is
910 * found when the association was mobilized with respect to a
911 * designated remote address. We assume packets arriving from
912 * the remote address arrive via this interface and the local
913 * address used to construct the autokey is the unicast address
914 * of the interface. However, if the sender is a broadcaster,
915 * the interface broadcast address is used instead.
916 * Notwithstanding this technobabble, if the sender is a
917 * multicaster, the broadcast address is null, so we use the
918 * unicast address anyway. Don't ask.
921 peer = findpeer(rbufp, hismode, &retcode);
922 dstadr_sin = &rbufp->dstadr->sin;
923 NTOHL_FP(&pkt->org, &p_org);
924 NTOHL_FP(&pkt->rec, &p_rec);
925 NTOHL_FP(&pkt->xmt, &p_xmt);
926 hm_str = modetoa(hismode);
927 am_str = amtoa(retcode);
930 * Authentication is conditioned by three switches:
932 * NOPEER (RES_NOPEER) do not mobilize an association unless
934 * NOTRUST (RES_DONTTRUST) do not allow access unless
935 * authenticated (implies NOPEER)
936 * enable (sys_authenticate) master NOPEER switch, by default
939 * The NOPEER and NOTRUST can be specified on a per-client basis
940 * using the restrict command. The enable switch if on implies
941 * NOPEER for all clients. There are four outcomes:
943 * NONE The packet has no MAC.
944 * OK the packet has a MAC and authentication succeeds
945 * ERROR the packet has a MAC and authentication fails
946 * CRYPTO crypto-NAK. The MAC has four octets only.
948 * Note: The AUTH(x, y) macro is used to filter outcomes. If x
949 * is zero, acceptable outcomes of y are NONE and OK. If x is
950 * one, the only acceptable outcome of y is OK.
952 crypto_nak_test = valid_NAK(peer, rbufp, hismode);
955 * Drop any invalid crypto-NAKs
957 if (crypto_nak_test == INVALIDNAK) {
958 report_event(PEVNT_AUTH, peer, "Invalid_NAK");
962 msyslog(LOG_ERR, "Invalid-NAK error at %ld %s<-%s",
963 current_time, stoa(dstadr_sin), stoa(&rbufp->recv_srcadr));
968 restrict_mask &= ~RES_MSSNTP;
969 is_authentic = AUTH_NONE; /* not required */
970 DPRINTF(1, ("receive: at %ld %s<-%s mode %d/%s:%s len %d org %#010x.%08x xmt %#010x.%08x NOMAC\n",
971 current_time, stoa(dstadr_sin),
972 stoa(&rbufp->recv_srcadr), hismode, hm_str, am_str,
974 ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf),
975 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf)));
976 } else if (crypto_nak_test == VALIDNAK) {
977 restrict_mask &= ~RES_MSSNTP;
978 is_authentic = AUTH_CRYPTO; /* crypto-NAK */
979 DPRINTF(1, ("receive: at %ld %s<-%s mode %d/%s:%s keyid %08x len %d auth %d org %#010x.%08x xmt %#010x.%08x CRYPTONAK\n",
980 current_time, stoa(dstadr_sin),
981 stoa(&rbufp->recv_srcadr), hismode, hm_str, am_str,
982 skeyid, authlen + has_mac, is_authentic,
983 ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf),
984 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf)));
986 #ifdef HAVE_NTP_SIGND
988 * If the signature is 20 bytes long, the last 16 of
989 * which are zero, then this is a Microsoft client
990 * wanting AD-style authentication of the server's
993 * This is described in Microsoft's WSPP docs, in MS-SNTP:
994 * http://msdn.microsoft.com/en-us/library/cc212930.aspx
996 } else if ( has_mac == MAX_MD5_LEN
997 && (restrict_mask & RES_MSSNTP)
998 && (retcode == AM_FXMIT || retcode == AM_NEWPASS)
999 && (memcmp(zero_key, (char *)pkt + authlen + 4,
1000 MAX_MD5_LEN - 4) == 0)) {
1001 is_authentic = AUTH_NONE;
1002 DPRINTF(1, ("receive: at %ld %s<-%s mode %d/%s:%s len %d org %#010x.%08x xmt %#010x.%08x SIGND\n",
1003 current_time, stoa(dstadr_sin),
1004 stoa(&rbufp->recv_srcadr), hismode, hm_str, am_str,
1006 ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf),
1007 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf)));
1008 #endif /* HAVE_NTP_SIGND */
1014 * Not an MS-SNTP SIGND packet
1016 * So there is a MAC here.
1019 restrict_mask &= ~RES_MSSNTP;
1022 * For autokey modes, generate the session key
1023 * and install in the key cache. Use the socket
1024 * broadcast or unicast address as appropriate.
1026 if (crypto_flags && skeyid > NTP_MAXKEY) {
1029 * More on the autokey dance (AKD). A cookie is
1030 * constructed from public and private values.
1031 * For broadcast packets, the cookie is public
1032 * (zero). For packets that match no
1033 * association, the cookie is hashed from the
1034 * addresses and private value. For server
1035 * packets, the cookie was previously obtained
1036 * from the server. For symmetric modes, the
1037 * cookie was previously constructed using an
1038 * agreement protocol; however, should PKI be
1039 * unavailable, we construct a fake agreement as
1040 * the EXOR of the peer and host cookies.
1042 * hismode ephemeral persistent
1043 * =======================================
1045 * passive 0% cookie#
1046 * client sys cookie 0%
1047 * server 0% sys cookie
1053 if (has_mac < (int)MAX_MD5_LEN) {
1054 DPRINTF(2, ("receive: drop: MD5 digest too short\n"));
1058 if (hismode == MODE_BROADCAST) {
1061 * For broadcaster, use the interface
1062 * broadcast address when available;
1063 * otherwise, use the unicast address
1064 * found when the association was
1065 * mobilized. However, if this is from
1066 * the wildcard interface, game over.
1070 ANY_INTERFACE_CHOOSE(&rbufp->recv_srcadr)) {
1071 DPRINTF(2, ("receive: drop: BCAST from wildcard\n"));
1073 return; /* no wildcard */
1076 if (!SOCK_UNSPEC(&rbufp->dstadr->bcast))
1078 &rbufp->dstadr->bcast;
1079 } else if (peer == NULL) {
1080 pkeyid = session_key(
1081 &rbufp->recv_srcadr, dstadr_sin, 0,
1084 pkeyid = peer->pcookie;
1088 * The session key includes both the public
1089 * values and cookie. In case of an extension
1090 * field, the cookie used for authentication
1091 * purposes is zero. Note the hash is saved for
1092 * use later in the autokey mambo.
1094 if (authlen > (int)LEN_PKT_NOMAC && pkeyid != 0) {
1095 session_key(&rbufp->recv_srcadr,
1096 dstadr_sin, skeyid, 0, 2);
1097 tkeyid = session_key(
1098 &rbufp->recv_srcadr, dstadr_sin,
1101 tkeyid = session_key(
1102 &rbufp->recv_srcadr, dstadr_sin,
1107 #endif /* AUTOKEY */
1110 * Compute the cryptosum. Note a clogging attack may
1111 * succeed in bloating the key cache. If an autokey,
1112 * purge it immediately, since we won't be needing it
1113 * again. If the packet is authentic, it can mobilize an
1114 * association. Note that there is no key zero.
1116 if (!authdecrypt(skeyid, (u_int32 *)pkt, authlen,
1118 is_authentic = AUTH_ERROR;
1120 is_authentic = AUTH_OK;
1122 if (crypto_flags && skeyid > NTP_MAXKEY)
1123 authtrust(skeyid, 0);
1124 #endif /* AUTOKEY */
1125 DPRINTF(1, ("receive: at %ld %s<-%s mode %d/%s:%s keyid %08x len %d auth %d org %#010x.%08x xmt %#010x.%08x MAC\n",
1126 current_time, stoa(dstadr_sin),
1127 stoa(&rbufp->recv_srcadr), hismode, hm_str, am_str,
1128 skeyid, authlen + has_mac, is_authentic,
1129 ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf),
1130 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf)));
1137 * Now come at this from a different perspective:
1138 * - If we expect a MAC and it's not there, we drop it.
1139 * - If we expect one keyID and get another, we drop it.
1140 * - If we have a MAC ahd it hasn't been validated yet, try.
1141 * - if the provided MAC doesn't validate, we drop it.
1143 * There might be more to this.
1145 if (0 != peer && 0 != peer->keyid) {
1146 /* Should we msyslog() any of these? */
1149 * This should catch:
1150 * - no keyID where one is expected,
1151 * - different keyID than what we expect.
1153 if (peer->keyid != skeyid) {
1154 DPRINTF(2, ("receive: drop: Wanted keyID %d, got %d from %s\n",
1155 peer->keyid, skeyid,
1156 stoa(&rbufp->recv_srcadr)));
1158 return; /* drop: access denied */
1162 * if has_mac != 0 ...
1163 * - If it has not yet been validated, do so.
1164 * (under what circumstances might that happen?)
1165 * - if missing or bad MAC, log and drop.
1168 if (is_authentic == AUTH_UNKNOWN) {
1169 /* How can this happen? */
1170 DPRINTF(2, ("receive: 3454 check: AUTH_UNKNOWN from %s\n",
1171 stoa(&rbufp->recv_srcadr)));
1172 if (!authdecrypt(skeyid, (u_int32 *)pkt, authlen,
1174 /* MAC invalid or not found */
1175 is_authentic = AUTH_ERROR;
1177 is_authentic = AUTH_OK;
1180 if (is_authentic != AUTH_OK) {
1181 DPRINTF(2, ("receive: drop: missing or bad MAC from %s\n",
1182 stoa(&rbufp->recv_srcadr)));
1184 return; /* drop: access denied */
1191 ** On-Wire Protocol Layer
1193 ** Verify protocol operations consistent with the on-wire protocol.
1194 ** The protocol discards bogus and duplicate packets as well as
1195 ** minimizes disruptions doe to protocol restarts and dropped
1196 ** packets. The operations are controlled by two timestamps:
1197 ** the transmit timestamp saved in the client state variables,
1198 ** and the origin timestamp in the server packet header. The
1199 ** comparison of these two timestamps is called the loopback test.
1200 ** The transmit timestamp functions as a nonce to verify that the
1201 ** response corresponds to the original request. The transmit
1202 ** timestamp also serves to discard replays of the most recent
1203 ** packet. Upon failure of either test, the packet is discarded
1204 ** with no further action.
1208 * The association matching rules are implemented by a set of
1209 * routines and an association table. A packet matching an
1210 * association is processed by the peer process for that
1211 * association. If there are no errors, an ephemeral association
1212 * is mobilized: a broadcast packet mobilizes a broadcast client
1213 * aassociation; a manycast server packet mobilizes a manycast
1214 * client association; a symmetric active packet mobilizes a
1215 * symmetric passive association.
1217 DPRINTF(1, ("receive: MATCH_ASSOC dispatch: mode %d/%s:%s \n",
1218 hismode, hm_str, am_str));
1222 * This is a client mode packet not matching any association. If
1223 * an ordinary client, simply toss a server mode packet back
1224 * over the fence. If a manycast client, we have to work a
1227 * There are cases here where we do not call record_raw_stats().
1232 * If authentication OK, send a server reply; otherwise,
1233 * send a crypto-NAK.
1235 if (!(rbufp->dstadr->flags & INT_MCASTOPEN)) {
1236 /* HMS: would be nice to log FAST_XMIT|BADAUTH|RESTRICTED */
1237 record_raw_stats(&rbufp->recv_srcadr,
1238 &rbufp->dstadr->sin,
1239 &p_org, &p_rec, &p_xmt, &rbufp->recv_time,
1240 PKT_LEAP(pkt->li_vn_mode),
1241 PKT_VERSION(pkt->li_vn_mode),
1242 PKT_MODE(pkt->li_vn_mode),
1243 PKT_TO_STRATUM(pkt->stratum),
1246 FPTOD(NTOHS_FP(pkt->rootdelay)),
1247 FPTOD(NTOHS_FP(pkt->rootdisp)),
1249 rbufp->recv_length - MIN_V4_PKT_LEN, (u_char *)&pkt->exten);
1251 if (AUTH(restrict_mask & RES_DONTTRUST,
1253 fast_xmit(rbufp, MODE_SERVER, skeyid,
1255 } else if (is_authentic == AUTH_ERROR) {
1256 fast_xmit(rbufp, MODE_SERVER, 0,
1260 DPRINTF(2, ("receive: AM_FXMIT drop: !mcast restricted\n"));
1264 return; /* hooray */
1268 * This must be manycast. Do not respond if not
1269 * configured as a manycast server.
1271 if (!sys_manycastserver) {
1272 DPRINTF(2, ("receive: AM_FXMIT drop: Not manycastserver\n"));
1274 return; /* not enabled */
1279 * Do not respond if not the same group.
1281 if (group_test(groupname, NULL)) {
1282 DPRINTF(2, ("receive: AM_FXMIT drop: empty groupname\n"));
1286 #endif /* AUTOKEY */
1289 * Do not respond if we are not synchronized or our
1290 * stratum is greater than the manycaster or the
1291 * manycaster has already synchronized to us.
1293 if ( sys_leap == LEAP_NOTINSYNC
1294 || sys_stratum >= hisstratum
1295 || (!sys_cohort && sys_stratum == hisstratum + 1)
1296 || rbufp->dstadr->addr_refid == pkt->refid) {
1297 DPRINTF(2, ("receive: AM_FXMIT drop: LEAP_NOTINSYNC || stratum || loop\n"));
1299 return; /* no help */
1303 * Respond only if authentication succeeds. Don't do a
1304 * crypto-NAK, as that would not be useful.
1306 if (AUTH(restrict_mask & RES_DONTTRUST, is_authentic)) {
1307 record_raw_stats(&rbufp->recv_srcadr,
1308 &rbufp->dstadr->sin,
1309 &p_org, &p_rec, &p_xmt, &rbufp->recv_time,
1310 PKT_LEAP(pkt->li_vn_mode),
1311 PKT_VERSION(pkt->li_vn_mode),
1312 PKT_MODE(pkt->li_vn_mode),
1313 PKT_TO_STRATUM(pkt->stratum),
1316 FPTOD(NTOHS_FP(pkt->rootdelay)),
1317 FPTOD(NTOHS_FP(pkt->rootdisp)),
1319 rbufp->recv_length - MIN_V4_PKT_LEN, (u_char *)&pkt->exten);
1321 fast_xmit(rbufp, MODE_SERVER, skeyid,
1324 return; /* hooray */
1327 * This is a server mode packet returned in response to a client
1328 * mode packet sent to a multicast group address (for
1329 * manycastclient) or to a unicast address (for pool). The
1330 * origin timestamp is a good nonce to reliably associate the
1331 * reply with what was sent. If there is no match, that's
1332 * curious and could be an intruder attempting to clog, so we
1335 * If the packet is authentic and the manycastclient or pool
1336 * association is found, we mobilize a client association and
1337 * copy pertinent variables from the manycastclient or pool
1338 * association to the new client association. If not, just
1339 * ignore the packet.
1341 * There is an implosion hazard at the manycast client, since
1342 * the manycast servers send the server packet immediately. If
1343 * the guy is already here, don't fire up a duplicate.
1345 * There are cases here where we do not call record_raw_stats().
1351 * Do not respond if not the same group.
1353 if (group_test(groupname, NULL)) {
1354 DPRINTF(2, ("receive: AM_MANYCAST drop: empty groupname\n"));
1358 #endif /* AUTOKEY */
1359 if ((peer2 = findmanycastpeer(rbufp)) == NULL) {
1360 DPRINTF(2, ("receive: AM_MANYCAST drop: No manycast peer\n"));
1362 return; /* not enabled */
1364 if (!AUTH( (!(peer2->cast_flags & MDF_POOL)
1365 && sys_authenticate)
1366 || (restrict_mask & (RES_NOPEER |
1367 RES_DONTTRUST)), is_authentic)
1368 /* MC: RES_NOEPEER? */
1370 DPRINTF(2, ("receive: AM_MANYCAST drop: bad auth || (NOPEER|DONTTRUST)\n"));
1372 return; /* access denied */
1376 * Do not respond if unsynchronized or stratum is below
1377 * the floor or at or above the ceiling.
1379 if ( hisleap == LEAP_NOTINSYNC
1380 || hisstratum < sys_floor
1381 || hisstratum >= sys_ceiling) {
1382 DPRINTF(2, ("receive: AM_MANYCAST drop: unsync/stratum\n"));
1384 return; /* no help */
1386 peer = newpeer(&rbufp->recv_srcadr, NULL, rbufp->dstadr,
1387 r4a.ippeerlimit, MODE_CLIENT, hisversion,
1388 peer2->minpoll, peer2->maxpoll,
1389 FLAG_PREEMPT | (FLAG_IBURST & peer2->flags),
1390 MDF_UCAST | MDF_UCLNT, 0, skeyid, sys_ident);
1392 DPRINTF(2, ("receive: AM_MANYCAST drop: duplicate\n"));
1394 return; /* ignore duplicate */
1398 * After each ephemeral pool association is spun,
1399 * accelerate the next poll for the pool solicitor so
1400 * the pool will fill promptly.
1402 if (peer2->cast_flags & MDF_POOL)
1403 peer2->nextdate = current_time + 1;
1406 * Further processing of the solicitation response would
1407 * simply detect its origin timestamp as bogus for the
1408 * brand-new association (it matches the prototype
1409 * association) and tinker with peer->nextdate delaying
1412 return; /* solicitation response handled */
1415 * This is the first packet received from a broadcast server. If
1416 * the packet is authentic and we are enabled as broadcast
1417 * client, mobilize a broadcast client association. We don't
1418 * kiss any frogs here.
1420 * There are cases here where we do not call record_raw_stats().
1426 * Do not respond if not the same group.
1428 if (group_test(groupname, sys_ident)) {
1429 DPRINTF(2, ("receive: AM_NEWBCL drop: groupname mismatch\n"));
1433 #endif /* AUTOKEY */
1434 if (sys_bclient == 0) {
1435 DPRINTF(2, ("receive: AM_NEWBCL drop: not a bclient\n"));
1437 return; /* not enabled */
1439 if (!AUTH(sys_authenticate | (restrict_mask &
1440 (RES_NOPEER | RES_DONTTRUST)), is_authentic)
1441 /* NEWBCL: RES_NOEPEER? */
1443 DPRINTF(2, ("receive: AM_NEWBCL drop: AUTH failed\n"));
1445 return; /* access denied */
1449 * Do not respond if unsynchronized or stratum is below
1450 * the floor or at or above the ceiling.
1452 if ( hisleap == LEAP_NOTINSYNC
1453 || hisstratum < sys_floor
1454 || hisstratum >= sys_ceiling) {
1455 DPRINTF(2, ("receive: AM_NEWBCL drop: Unsync or bad stratum\n"));
1457 return; /* no help */
1462 * Do not respond if Autokey and the opcode is not a
1463 * CRYPTO_ASSOC response with association ID.
1465 if ( crypto_flags && skeyid > NTP_MAXKEY
1466 && (opcode & 0xffff0000) != (CRYPTO_ASSOC | CRYPTO_RESP)) {
1467 DPRINTF(2, ("receive: AM_NEWBCL drop: Autokey but not CRYPTO_ASSOC\n"));
1469 return; /* protocol error */
1471 #endif /* AUTOKEY */
1474 * Broadcasts received via a multicast address may
1475 * arrive after a unicast volley has begun
1476 * with the same remote address. newpeer() will not
1477 * find duplicate associations on other local endpoints
1478 * if a non-NULL endpoint is supplied. multicastclient
1479 * ephemeral associations are unique across all local
1482 if (!(INT_MCASTOPEN & rbufp->dstadr->flags))
1483 match_ep = rbufp->dstadr;
1488 * Determine whether to execute the initial volley.
1490 if (sys_bdelay > 0.0) {
1493 * If a two-way exchange is not possible,
1494 * neither is Autokey.
1496 if (crypto_flags && skeyid > NTP_MAXKEY) {
1498 DPRINTF(2, ("receive: AM_NEWBCL drop: Autokey but not 2-way\n"));
1499 return; /* no autokey */
1501 #endif /* AUTOKEY */
1504 * Do not execute the volley. Start out in
1505 * broadcast client mode.
1507 peer = newpeer(&rbufp->recv_srcadr, NULL, match_ep,
1508 r4a.ippeerlimit, MODE_BCLIENT, hisversion,
1509 pkt->ppoll, pkt->ppoll,
1510 FLAG_PREEMPT, MDF_BCLNT, 0, skeyid, sys_ident);
1512 DPRINTF(2, ("receive: AM_NEWBCL drop: duplicate\n"));
1514 return; /* ignore duplicate */
1517 peer->delay = sys_bdelay;
1524 * Execute the initial volley in order to calibrate the
1525 * propagation delay and run the Autokey protocol.
1527 * Note that the minpoll is taken from the broadcast
1528 * packet, normally 6 (64 s) and that the poll interval
1529 * is fixed at this value.
1531 peer = newpeer(&rbufp->recv_srcadr, NULL, match_ep,
1532 r4a.ippeerlimit, MODE_CLIENT, hisversion,
1533 pkt->ppoll, pkt->ppoll,
1534 FLAG_BC_VOL | FLAG_IBURST | FLAG_PREEMPT, MDF_BCLNT,
1535 0, skeyid, sys_ident);
1537 DPRINTF(2, ("receive: AM_NEWBCL drop: empty newpeer() failed\n"));
1539 return; /* ignore duplicate */
1543 if (skeyid > NTP_MAXKEY)
1544 crypto_recv(peer, rbufp);
1545 #endif /* AUTOKEY */
1547 return; /* hooray */
1550 * This is the first packet received from a potential ephemeral
1551 * symmetric active peer. First, deal with broken Windows clients.
1552 * Then, if NOEPEER is enabled, drop it. If the packet meets our
1553 * authenticty requirements and is the first he sent, mobilize
1554 * a passive association.
1555 * Otherwise, kiss the frog.
1557 * There are cases here where we do not call record_raw_stats().
1561 DEBUG_REQUIRE(MODE_ACTIVE == hismode);
1565 * Do not respond if not the same group.
1567 if (group_test(groupname, sys_ident)) {
1568 DPRINTF(2, ("receive: AM_NEWPASS drop: Autokey group mismatch\n"));
1572 #endif /* AUTOKEY */
1573 if (!AUTH(sys_authenticate | (restrict_mask &
1574 (RES_NOPEER | RES_DONTTRUST)), is_authentic)
1577 * If authenticated but cannot mobilize an
1578 * association, send a symmetric passive
1579 * response without mobilizing an association.
1580 * This is for drat broken Windows clients. See
1581 * Microsoft KB 875424 for preferred workaround.
1583 if (AUTH(restrict_mask & RES_DONTTRUST,
1585 fast_xmit(rbufp, MODE_PASSIVE, skeyid,
1587 return; /* hooray */
1589 /* HMS: Why is this next set of lines a feature? */
1590 if (is_authentic == AUTH_ERROR) {
1591 fast_xmit(rbufp, MODE_PASSIVE, 0,
1597 if (restrict_mask & RES_NOEPEER) {
1598 DPRINTF(2, ("receive: AM_NEWPASS drop: NOEPEER\n"));
1604 * If we got here, the packet isn't part of an
1605 * existing association, either isn't correctly
1606 * authenticated or it is but we are refusing
1607 * ephemeral peer requests, and it didn't meet
1608 * either of the previous two special cases so we
1609 * should just drop it on the floor. For example,
1610 * crypto-NAKs (is_authentic == AUTH_CRYPTO)
1611 * will make it this far. This is just
1612 * debug-printed and not logged to avoid log
1615 DPRINTF(2, ("receive: at %ld refusing to mobilize passive association"
1616 " with unknown peer %s mode %d/%s:%s keyid %08x len %d auth %d\n",
1617 current_time, stoa(&rbufp->recv_srcadr),
1618 hismode, hm_str, am_str, skeyid,
1619 (authlen + has_mac), is_authentic));
1624 if (restrict_mask & RES_NOEPEER) {
1625 DPRINTF(2, ("receive: AM_NEWPASS drop: NOEPEER\n"));
1631 * Do not respond if synchronized and if stratum is
1632 * below the floor or at or above the ceiling. Note,
1633 * this allows an unsynchronized peer to synchronize to
1634 * us. It would be very strange if he did and then was
1635 * nipped, but that could only happen if we were
1636 * operating at the top end of the range. It also means
1637 * we will spin an ephemeral association in response to
1638 * MODE_ACTIVE KoDs, which will time out eventually.
1640 if ( hisleap != LEAP_NOTINSYNC
1641 && (hisstratum < sys_floor || hisstratum >= sys_ceiling)) {
1642 DPRINTF(2, ("receive: AM_NEWPASS drop: Autokey group mismatch\n"));
1644 return; /* no help */
1648 * The message is correctly authenticated and allowed.
1649 * Mobilize a symmetric passive association, if we won't
1650 * exceed the ippeerlimit.
1652 if ((peer = newpeer(&rbufp->recv_srcadr, NULL, rbufp->dstadr,
1653 r4a.ippeerlimit, MODE_PASSIVE, hisversion,
1654 pkt->ppoll, NTP_MAXDPOLL, 0, MDF_UCAST, 0,
1655 skeyid, sys_ident)) == NULL) {
1656 DPRINTF(2, ("receive: AM_NEWPASS drop: newpeer() failed\n"));
1658 return; /* ignore duplicate */
1664 * Process regular packet. Nothing special.
1666 * There are cases here where we do not call record_raw_stats().
1672 * Do not respond if not the same group.
1674 if (group_test(groupname, peer->ident)) {
1675 DPRINTF(2, ("receive: AM_PROCPKT drop: Autokey group mismatch\n"));
1679 #endif /* AUTOKEY */
1681 if (MODE_BROADCAST == hismode) {
1686 DPRINTF(2, ("receive: PROCPKT/BROADCAST: prev pkt %ld seconds ago, ppoll: %d, %d secs\n",
1687 (current_time - peer->timelastrec),
1688 peer->ppoll, (1 << peer->ppoll)
1690 /* Things we can check:
1692 * Did the poll interval change?
1693 * Is the poll interval in the packet in-range?
1694 * Did this packet arrive too soon?
1695 * Is the timestamp in this packet monotonic
1696 * with respect to the previous packet?
1699 /* This is noteworthy, not error-worthy */
1700 if (pkt->ppoll != peer->ppoll) {
1701 msyslog(LOG_INFO, "receive: broadcast poll from %s changed from %u to %u",
1702 stoa(&rbufp->recv_srcadr),
1703 peer->ppoll, pkt->ppoll);
1706 /* This is error-worthy */
1707 if ( pkt->ppoll < peer->minpoll
1708 || pkt->ppoll > peer->maxpoll) {
1709 msyslog(LOG_INFO, "receive: broadcast poll of %u from %s is out-of-range (%d to %d)!",
1710 pkt->ppoll, stoa(&rbufp->recv_srcadr),
1711 peer->minpoll, peer->maxpoll);
1715 /* too early? worth an error, too!
1717 * [Bug 3113] Ensure that at least one poll
1718 * interval has elapsed since the last **clean**
1719 * packet was received. We limit the check to
1720 * **clean** packets to prevent replayed packets
1721 * and incorrectly authenticated packets, which
1722 * we'll discard, from being used to create a
1723 * denial of service condition.
1725 deadband = (1u << pkt->ppoll);
1726 if (FLAG_BC_VOL & peer->flags)
1727 deadband -= 3; /* allow greater fuzz after volley */
1728 if ((current_time - peer->timereceived) < deadband) {
1729 msyslog(LOG_INFO, "receive: broadcast packet from %s arrived after %lu, not %lu seconds!",
1730 stoa(&rbufp->recv_srcadr),
1731 (current_time - peer->timereceived),
1736 /* Alert if time from the server is non-monotonic.
1738 * [Bug 3114] is about Broadcast mode replay DoS.
1740 * Broadcast mode *assumes* a trusted network.
1741 * Even so, it's nice to be robust in the face
1744 * If we get an authenticated broadcast packet
1745 * with an "earlier" timestamp, it means one of
1748 * - the broadcast server had a backward step.
1750 * - somebody is trying a replay attack.
1752 * deadband: By default, we assume the broadcast
1753 * network is trustable, so we take our accepted
1754 * broadcast packets as we receive them. But
1755 * some folks might want to take additional poll
1756 * delays before believing a backward step.
1758 if (sys_bcpollbstep) {
1759 /* pkt->ppoll or peer->ppoll ? */
1760 deadband = (1u << pkt->ppoll)
1761 * sys_bcpollbstep + 2;
1766 if (L_ISZERO(&peer->bxmt)) {
1767 tdiff.l_ui = tdiff.l_uf = 0;
1770 L_SUB(&tdiff, &peer->bxmt);
1773 && (current_time - peer->timereceived) < deadband)
1775 msyslog(LOG_INFO, "receive: broadcast packet from %s contains non-monotonic timestamp: %#010x.%08x -> %#010x.%08x",
1776 stoa(&rbufp->recv_srcadr),
1777 peer->bxmt.l_ui, peer->bxmt.l_uf,
1778 p_xmt.l_ui, p_xmt.l_uf
1784 DPRINTF(2, ("receive: AM_PROCPKT drop: bail\n"));
1785 peer->timelastrec = current_time;
1794 * A passive packet matches a passive association. This is
1795 * usually the result of reconfiguring a client on the fly. As
1796 * this association might be legitimate and this packet an
1797 * attempt to deny service, just ignore it.
1800 DPRINTF(2, ("receive: AM_ERR drop.\n"));
1805 * For everything else there is the bit bucket.
1808 DPRINTF(2, ("receive: default drop.\n"));
1815 * If the association is configured for Autokey, the packet must
1816 * have a public key ID; if not, the packet must have a
1819 if ( is_authentic != AUTH_CRYPTO
1820 && ( ((peer->flags & FLAG_SKEY) && skeyid <= NTP_MAXKEY)
1821 || (!(peer->flags & FLAG_SKEY) && skeyid > NTP_MAXKEY))) {
1822 DPRINTF(2, ("receive: drop: Autokey but wrong/bad auth\n"));
1826 #endif /* AUTOKEY */
1829 peer->flash &= ~PKT_TEST_MASK;
1830 if (peer->flags & FLAG_XBOGUS) {
1831 peer->flags &= ~FLAG_XBOGUS;
1832 peer->flash |= TEST3;
1836 * Next comes a rigorous schedule of timestamp checking. If the
1837 * transmit timestamp is zero, the server has not initialized in
1838 * interleaved modes or is horribly broken.
1840 * A KoD packet we pay attention to cannot have a 0 transmit
1844 kissCode = kiss_code_check(hisleap, hisstratum, hismode, pkt->refid);
1846 if (L_ISZERO(&p_xmt)) {
1847 peer->flash |= TEST3; /* unsynch */
1848 if (kissCode != NOKISS) { /* KoD packet */
1849 peer->bogusorg++; /* for TEST2 or TEST3 */
1851 "receive: Unexpected zero transmit timestamp in KoD from %s",
1852 ntoa(&peer->srcadr));
1857 * If the transmit timestamp duplicates our previous one, the
1858 * packet is a replay. This prevents the bad guys from replaying
1859 * the most recent packet, authenticated or not.
1861 } else if (L_ISEQU(&peer->xmt, &p_xmt)) {
1862 DPRINTF(2, ("receive: drop: Duplicate xmit\n"));
1863 peer->flash |= TEST1; /* duplicate */
1868 * If this is a broadcast mode packet, make sure hisstratum
1869 * is appropriate. Don't do anything else here - we wait to
1870 * see if this is an interleave broadcast packet until after
1871 * we've validated the MAC that SHOULD be provided.
1873 * hisstratum cannot be 0 - see assertion above.
1874 * If hisstratum is 15, then we'll advertise as UNSPEC but
1875 * at least we'll be able to sync with the broadcast server.
1877 } else if (hismode == MODE_BROADCAST) {
1878 /* 0 is unexpected too, and impossible */
1879 if (STRATUM_UNSPEC <= hisstratum) {
1880 /* Is this a ++sys_declined or ??? */
1882 "receive: Unexpected stratum (%d) in broadcast from %s",
1883 hisstratum, ntoa(&peer->srcadr));
1888 * Basic KoD validation checking:
1890 * KoD packets are a mixed-blessing. Forged KoD packets
1891 * are DoS attacks. There are rare situations where we might
1892 * get a valid KoD response, though. Since KoD packets are
1893 * a special case that complicate the checks we do next, we
1894 * handle the basic KoD checks here.
1896 * Note that we expect the incoming KoD packet to have its
1897 * (nonzero) org, rec, and xmt timestamps set to the xmt timestamp
1898 * that we have previously sent out. Watch interleave mode.
1900 } else if (kissCode != NOKISS) {
1901 DEBUG_INSIST(!L_ISZERO(&p_xmt));
1902 if ( L_ISZERO(&p_org) /* We checked p_xmt above */
1903 || L_ISZERO(&p_rec)) {
1906 "receive: KoD packet from %s has a zero org or rec timestamp. Ignoring.",
1907 ntoa(&peer->srcadr));
1911 if ( !L_ISEQU(&p_xmt, &p_org)
1912 || !L_ISEQU(&p_xmt, &p_rec)) {
1915 "receive: KoD packet from %s has inconsistent xmt/org/rec timestamps. Ignoring.",
1916 ntoa(&peer->srcadr));
1920 /* Be conservative */
1921 if (peer->flip == 0 && !L_ISEQU(&p_org, &peer->aorg)) {
1924 "receive: flip 0 KoD origin timestamp %#010x.%08x from %s does not match %#010x.%08x - ignoring.",
1925 p_org.l_ui, p_org.l_uf,
1926 ntoa(&peer->srcadr),
1927 peer->aorg.l_ui, peer->aorg.l_uf);
1929 } else if (peer->flip == 1 && !L_ISEQU(&p_org, &peer->borg)) {
1932 "receive: flip 1 KoD origin timestamp %#010x.%08x from %s does not match interleave %#010x.%08x - ignoring.",
1933 p_org.l_ui, p_org.l_uf,
1934 ntoa(&peer->srcadr),
1935 peer->borg.l_ui, peer->borg.l_uf);
1940 * Basic mode checks:
1942 * If there is no origin timestamp, it's either an initial packet
1943 * or we've already received a response to our query. Of course,
1944 * should 'aorg' be all-zero because this really was the original
1945 * transmit timestamp, we'll ignore this reply. There is a window
1946 * of one nanosecond once every 136 years' time where this is
1947 * possible. We currently ignore this situation, as a completely
1948 * zero timestamp is (quietly?) disallowed.
1950 * Otherwise, check for bogus packet in basic mode.
1951 * If it is bogus, switch to interleaved mode and resynchronize,
1952 * but only after confirming the packet is not bogus in
1953 * symmetric interleaved mode.
1955 * This could also mean somebody is forging packets claiming to
1956 * be from us, attempting to cause our server to KoD us.
1958 * We have earlier asserted that hisstratum cannot be 0.
1959 * If hisstratum is STRATUM_UNSPEC, it means he's not sync'd.
1961 } else if (peer->flip == 0) {
1963 } else if (L_ISZERO(&p_org)) {
1968 "receive: BUG 3361: Clearing peer->aorg ");
1973 /* We allow 0org for: */
1977 /* We disallow 0org for: */
1983 case MODE_BROADCAST:
1986 peer->flash |= TEST2; /* bogus */
1989 action = ""; /* for cranky compilers / MSVC */
1990 INSIST(!"receive(): impossible hismode");
1995 "receive: %s 0 origin timestamp from %s@%s xmt %#010x.%08x",
1996 action, hm_str, ntoa(&peer->srcadr),
1997 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf));
1998 } else if (!L_ISEQU(&p_org, &peer->aorg)) {
1999 /* are there cases here where we should bail? */
2000 /* Should we set TEST2 if we decide to try xleave? */
2002 peer->flash |= TEST2; /* bogus */
2004 "receive: Unexpected origin timestamp %#010x.%08x does not match aorg %#010x.%08x from %s@%s xmt %#010x.%08x",
2005 ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf),
2006 peer->aorg.l_ui, peer->aorg.l_uf,
2007 hm_str, ntoa(&peer->srcadr),
2008 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf));
2009 if ( !L_ISZERO(&peer->dst)
2010 && L_ISEQU(&p_org, &peer->dst)) {
2011 /* Might be the start of an interleave */
2012 if (dynamic_interleave) {
2014 report_event(PEVNT_XLEAVE, peer, NULL);
2017 "receive: Dynamic interleave from %s@%s denied",
2018 hm_str, ntoa(&peer->srcadr));
2026 * Check for valid nonzero timestamp fields.
2028 } else if ( L_ISZERO(&p_org)
2030 || L_ISZERO(&peer->dst)) {
2031 peer->flash |= TEST3; /* unsynch */
2034 * Check for bogus packet in interleaved symmetric mode. This
2035 * can happen if a packet is lost, duplicated or crossed. If
2036 * found, flip and resynchronize.
2038 } else if ( !L_ISZERO(&peer->dst)
2039 && !L_ISEQU(&p_org, &peer->dst)) {
2040 DPRINTF(2, ("receive: drop: Bogus packet in interleaved symmetric mode\n"));
2042 peer->flags |= FLAG_XBOGUS;
2043 peer->flash |= TEST2; /* bogus */
2045 return; /* Bogus packet, we are done */
2052 * If this is a crypto_NAK, the server cannot authenticate a
2053 * client packet. The server might have just changed keys. Clear
2054 * the association and restart the protocol.
2056 if (crypto_nak_test == VALIDNAK) {
2057 report_event(PEVNT_AUTH, peer, "crypto_NAK");
2058 peer->flash |= TEST5; /* bad auth */
2060 if (peer->flags & FLAG_PREEMPT) {
2061 if (unpeer_crypto_nak_early) {
2064 DPRINTF(2, ("receive: drop: PREEMPT crypto_NAK\n"));
2069 peer_clear(peer, "AUTH");
2071 #endif /* AUTOKEY */
2072 DPRINTF(2, ("receive: drop: crypto_NAK\n"));
2076 * If the digest fails or it's missing for authenticated
2077 * associations, the client cannot authenticate a server
2078 * reply to a client packet previously sent. The loopback check
2079 * is designed to avoid a bait-and-switch attack, which was
2080 * possible in past versions. If symmetric modes, return a
2081 * crypto-NAK. The peer should restart the protocol.
2083 } else if (!AUTH(peer->keyid || has_mac ||
2084 (restrict_mask & RES_DONTTRUST), is_authentic)) {
2086 if (peer->flash & PKT_TEST_MASK) {
2088 "receive: Bad auth in packet with bad timestamps from %s denied - spoof?",
2089 ntoa(&peer->srcadr));
2093 report_event(PEVNT_AUTH, peer, "digest");
2094 peer->flash |= TEST5; /* bad auth */
2097 && ( hismode == MODE_ACTIVE
2098 || hismode == MODE_PASSIVE))
2099 fast_xmit(rbufp, MODE_ACTIVE, 0, restrict_mask);
2100 if (peer->flags & FLAG_PREEMPT) {
2101 if (unpeer_digest_early) {
2106 else if (peer_clear_digest_early && peer->crypto) {
2107 peer_clear(peer, "AUTH");
2109 #endif /* AUTOKEY */
2110 DPRINTF(2, ("receive: drop: Bad or missing AUTH\n"));
2115 * For broadcast packets:
2117 * HMS: This next line never made much sense to me, even
2118 * when it was up higher:
2119 * If an initial volley, bail out now and let the
2120 * client do its stuff.
2122 * If the packet has not failed authentication, then
2123 * - if the origin timestamp is nonzero this is an
2124 * interleaved broadcast, so restart the protocol.
2125 * - else, this is not an interleaved broadcast packet.
2127 if (hismode == MODE_BROADCAST) {
2128 if ( is_authentic == AUTH_OK
2129 || is_authentic == AUTH_NONE) {
2130 if (!L_ISZERO(&p_org)) {
2131 if (!(peer->flags & FLAG_XB)) {
2133 "receive: Broadcast server at %s is in interleave mode",
2134 ntoa(&peer->srcadr));
2135 peer->flags |= FLAG_XB;
2137 peer->borg = rbufp->recv_time;
2138 report_event(PEVNT_XLEAVE, peer, NULL);
2141 } else if (peer->flags & FLAG_XB) {
2143 "receive: Broadcast server at %s is no longer in interleave mode",
2144 ntoa(&peer->srcadr));
2145 peer->flags &= ~FLAG_XB;
2149 "receive: Bad broadcast auth (%d) from %s",
2150 is_authentic, ntoa(&peer->srcadr));
2154 * Now that we know the packet is correctly authenticated,
2155 * update peer->bxmt.
2162 ** Update the state variables.
2164 if (peer->flip == 0) {
2165 if (hismode != MODE_BROADCAST)
2167 peer->dst = rbufp->recv_time;
2172 * Set the peer ppoll to the maximum of the packet ppoll and the
2173 * peer minpoll. If a kiss-o'-death, set the peer minpoll to
2174 * this maximum and advance the headway to give the sender some
2175 * headroom. Very intricate.
2179 * Check for any kiss codes. Note this is only used when a server
2180 * responds to a packet request.
2184 * Check to see if this is a RATE Kiss Code
2185 * Currently this kiss code will accept whatever poll
2186 * rate that the server sends
2188 peer->ppoll = max(peer->minpoll, pkt->ppoll);
2189 if (kissCode == RATEKISS) {
2190 peer->selbroken++; /* Increment the KoD count */
2191 report_event(PEVNT_RATE, peer, NULL);
2192 if (pkt->ppoll > peer->minpoll)
2193 peer->minpoll = peer->ppoll;
2194 peer->burst = peer->retry = 0;
2195 peer->throttle = (NTP_SHIFT + 1) * (1 << peer->minpoll);
2196 poll_update(peer, pkt->ppoll);
2197 return; /* kiss-o'-death */
2199 if (kissCode != NOKISS) {
2200 peer->selbroken++; /* Increment the KoD count */
2201 return; /* Drop any other kiss code packets */
2212 * - this is a *cast (uni-, broad-, or m-) server packet
2213 * - and it's symmetric-key authenticated
2214 * then see if the sender's IP is trusted for this keyid.
2215 * If it is, great - nothing special to do here.
2216 * Otherwise, we should report and bail.
2218 * Autokey-authenticated packets are accepted.
2222 case MODE_SERVER: /* server mode */
2223 case MODE_BROADCAST: /* broadcast mode */
2224 case MODE_ACTIVE: /* symmetric active mode */
2225 case MODE_PASSIVE: /* symmetric passive mode */
2226 if ( is_authentic == AUTH_OK
2228 && skeyid <= NTP_MAXKEY
2229 && !authistrustedip(skeyid, &peer->srcadr)) {
2230 report_event(PEVNT_AUTH, peer, "authIP");
2236 case MODE_CLIENT: /* client mode */
2237 #if 0 /* At this point, MODE_CONTROL is overloaded by MODE_BCLIENT */
2238 case MODE_CONTROL: /* control mode */
2240 case MODE_PRIVATE: /* private mode */
2241 case MODE_BCLIENT: /* broadcast client mode */
2244 case MODE_UNSPEC: /* unspecified (old version) */
2247 "receive: Unexpected mode (%d) in packet from %s",
2248 hismode, ntoa(&peer->srcadr));
2254 * That was hard and I am sweaty, but the packet is squeaky
2255 * clean. Get on with real work.
2257 peer->timereceived = current_time;
2258 peer->timelastrec = current_time;
2259 if (is_authentic == AUTH_OK)
2260 peer->flags |= FLAG_AUTHENTIC;
2262 peer->flags &= ~FLAG_AUTHENTIC;
2266 * More autokey dance. The rules of the cha-cha are as follows:
2268 * 1. If there is no key or the key is not auto, do nothing.
2270 * 2. If this packet is in response to the one just previously
2271 * sent or from a broadcast server, do the extension fields.
2272 * Otherwise, assume bogosity and bail out.
2274 * 3. If an extension field contains a verified signature, it is
2275 * self-authenticated and we sit the dance.
2277 * 4. If this is a server reply, check only to see that the
2278 * transmitted key ID matches the received key ID.
2280 * 5. Check to see that one or more hashes of the current key ID
2281 * matches the previous key ID or ultimate original key ID
2282 * obtained from the broadcaster or symmetric peer. If no
2283 * match, sit the dance and call for new autokey values.
2285 * In case of crypto error, fire the orchestra, stop dancing and
2286 * restart the protocol.
2288 if (peer->flags & FLAG_SKEY) {
2290 * Decrement remaining autokey hashes. This isn't
2291 * perfect if a packet is lost, but results in no harm.
2293 ap = (struct autokey *)peer->recval.ptr;
2298 peer->flash |= TEST8;
2299 rval = crypto_recv(peer, rbufp);
2300 if (rval == XEVNT_OK) {
2303 if (rval == XEVNT_ERR) {
2304 report_event(PEVNT_RESTART, peer,
2306 peer_clear(peer, "CRYP");
2307 peer->flash |= TEST9; /* bad crypt */
2308 if (peer->flags & FLAG_PREEMPT) {
2309 if (unpeer_crypto_early) {
2318 * If server mode, verify the receive key ID matches
2319 * the transmit key ID.
2321 if (hismode == MODE_SERVER) {
2322 if (skeyid == peer->keyid)
2323 peer->flash &= ~TEST8;
2326 * If an extension field is present, verify only that it
2327 * has been correctly signed. We don't need a sequence
2328 * check here, but the sequence continues.
2330 } else if (!(peer->flash & TEST8)) {
2331 peer->pkeyid = skeyid;
2334 * Now the fun part. Here, skeyid is the current ID in
2335 * the packet, pkeyid is the ID in the last packet and
2336 * tkeyid is the hash of skeyid. If the autokey values
2337 * have not been received, this is an automatic error.
2338 * If so, check that the tkeyid matches pkeyid. If not,
2339 * hash tkeyid and try again. If the number of hashes
2340 * exceeds the number remaining in the sequence, declare
2341 * a successful failure and refresh the autokey values.
2343 } else if (ap != NULL) {
2346 for (i = 0; ; i++) {
2347 if ( tkeyid == peer->pkeyid
2348 || tkeyid == ap->key) {
2349 peer->flash &= ~TEST8;
2350 peer->pkeyid = skeyid;
2359 tkeyid = session_key(
2360 &rbufp->recv_srcadr, dstadr_sin,
2363 if (peer->flash & TEST8)
2364 report_event(PEVNT_AUTH, peer, "keylist");
2366 if (!(peer->crypto & CRYPTO_FLAG_PROV)) /* test 9 */
2367 peer->flash |= TEST8; /* bad autokey */
2370 * The maximum lifetime of the protocol is about one
2371 * week before restarting the Autokey protocol to
2372 * refresh certificates and leapseconds values.
2374 if (current_time > peer->refresh) {
2375 report_event(PEVNT_RESTART, peer,
2377 peer_clear(peer, "TIME");
2381 #endif /* AUTOKEY */
2384 * The dance is complete and the flash bits have been lit. Toss
2385 * the packet over the fence for processing, which may light up
2388 process_packet(peer, pkt, rbufp->recv_length);
2391 * In interleaved mode update the state variables. Also adjust the
2392 * transmit phase to avoid crossover.
2394 if (peer->flip != 0) {
2396 peer->dst = rbufp->recv_time;
2397 if (peer->nextdate - current_time < (1U << min(peer->ppoll,
2407 * process_packet - Packet Procedure, a la Section 3.4.4 of RFC-1305
2408 * Or almost, at least. If we're in here we have a reasonable
2409 * expectation that we will be having a long term
2410 * relationship with this host.
2414 register struct peer *peer,
2415 register struct pkt *pkt,
2420 double p_offset, p_del, p_disp;
2421 l_fp p_rec, p_xmt, p_org, p_reftime, ci;
2422 u_char pmode, pleap, pversion, pstratum;
2423 char statstr[NTP_MAXSTRLEN];
2426 double etemp, ftemp, td;
2433 p_del = FPTOD(NTOHS_FP(pkt->rootdelay));
2435 p_disp = FPTOD(NTOHS_FP(pkt->rootdisp));
2436 NTOHL_FP(&pkt->reftime, &p_reftime);
2437 NTOHL_FP(&pkt->org, &p_org);
2438 NTOHL_FP(&pkt->rec, &p_rec);
2439 NTOHL_FP(&pkt->xmt, &p_xmt);
2440 pmode = PKT_MODE(pkt->li_vn_mode);
2441 pleap = PKT_LEAP(pkt->li_vn_mode);
2442 pversion = PKT_VERSION(pkt->li_vn_mode);
2443 pstratum = PKT_TO_STRATUM(pkt->stratum);
2450 * Verify the server is synchronized; that is, the leap bits,
2451 * stratum and root distance are valid.
2453 if ( pleap == LEAP_NOTINSYNC /* test 6 */
2454 || pstratum < sys_floor || pstratum >= sys_ceiling)
2455 peer->flash |= TEST6; /* bad synch or strat */
2456 if (p_del / 2 + p_disp >= MAXDISPERSE) /* test 7 */
2457 peer->flash |= TEST7; /* bad header */
2460 * If any tests fail at this point, the packet is discarded.
2461 * Note that some flashers may have already been set in the
2462 * receive() routine.
2464 if (peer->flash & PKT_TEST_MASK) {
2465 peer->seldisptoolarge++;
2466 DPRINTF(1, ("packet: flash header %04x\n",
2468 poll_update(peer, peer->hpoll); /* ppoll updated? */
2480 * Capture the header values in the client/peer association..
2482 record_raw_stats(&peer->srcadr,
2483 peer->dstadr ? &peer->dstadr->sin : NULL,
2484 &p_org, &p_rec, &p_xmt, &peer->dst,
2485 pleap, pversion, pmode, pstratum, pkt->ppoll, pkt->precision,
2486 p_del, p_disp, pkt->refid,
2487 len - MIN_V4_PKT_LEN, (u_char *)&pkt->exten);
2489 peer->stratum = min(pstratum, STRATUM_UNSPEC);
2490 peer->pmode = pmode;
2491 peer->precision = pkt->precision;
2492 peer->rootdelay = p_del;
2493 peer->rootdisp = p_disp;
2494 peer->refid = pkt->refid; /* network byte order */
2495 peer->reftime = p_reftime;
2498 * First, if either burst mode is armed, enable the burst.
2499 * Compute the headway for the next packet and delay if
2500 * necessary to avoid exceeding the threshold.
2502 if (peer->retry > 0) {
2505 peer->burst = min(1 << (peer->hpoll -
2506 peer->minpoll), NTP_SHIFT) - 1;
2508 peer->burst = NTP_IBURST - 1;
2509 if (peer->burst > 0)
2510 peer->nextdate = current_time;
2512 poll_update(peer, peer->hpoll);
2517 * If the peer was previously unreachable, raise a trap. In any
2518 * case, mark it reachable.
2521 report_event(PEVNT_REACH, peer, NULL);
2522 peer->timereachable = current_time;
2527 * For a client/server association, calculate the clock offset,
2528 * roundtrip delay and dispersion. The equations are reordered
2529 * from the spec for more efficient use of temporaries. For a
2530 * broadcast association, offset the last measurement by the
2531 * computed delay during the client/server volley. Note the
2532 * computation of dispersion includes the system precision plus
2533 * that due to the frequency error since the origin time.
2535 * It is very important to respect the hazards of overflow. The
2536 * only permitted operation on raw timestamps is subtraction,
2537 * where the result is a signed quantity spanning from 68 years
2538 * in the past to 68 years in the future. To avoid loss of
2539 * precision, these calculations are done using 64-bit integer
2540 * arithmetic. However, the offset and delay calculations are
2541 * sums and differences of these first-order differences, which
2542 * if done using 64-bit integer arithmetic, would be valid over
2543 * only half that span. Since the typical first-order
2544 * differences are usually very small, they are converted to 64-
2545 * bit doubles and all remaining calculations done in floating-
2546 * double arithmetic. This preserves the accuracy while
2547 * retaining the 68-year span.
2549 * There are three interleaving schemes, basic, interleaved
2550 * symmetric and interleaved broadcast. The timestamps are
2551 * idioscyncratically different. See the onwire briefing/white
2552 * paper at www.eecis.udel.edu/~mills for details.
2554 * Interleaved symmetric mode
2555 * t1 = peer->aorg/borg, t2 = peer->rec, t3 = p_xmt,
2558 if (peer->flip != 0) {
2559 ci = p_xmt; /* t3 - t4 */
2560 L_SUB(&ci, &peer->dst);
2562 ci = p_rec; /* t2 - t1 */
2564 L_SUB(&ci, &peer->borg);
2566 L_SUB(&ci, &peer->aorg);
2569 p_offset = (t21 + t34) / 2.;
2570 if (p_del < 0 || p_del > 1.) {
2571 snprintf(statstr, sizeof(statstr),
2572 "t21 %.6f t34 %.6f", t21, t34);
2573 report_event(PEVNT_XERR, peer, statstr);
2580 } else if (peer->pmode == MODE_BROADCAST) {
2583 * Interleaved broadcast mode. Use interleaved timestamps.
2584 * t1 = peer->borg, t2 = p_org, t3 = p_org, t4 = aorg
2586 if (peer->flags & FLAG_XB) {
2587 ci = p_org; /* delay */
2588 L_SUB(&ci, &peer->aorg);
2590 ci = p_org; /* t2 - t1 */
2591 L_SUB(&ci, &peer->borg);
2594 peer->borg = peer->dst;
2595 if (t34 < 0 || t34 > 1.) {
2596 /* drop all if in the initial volley */
2597 if (FLAG_BC_VOL & peer->flags)
2598 goto bcc_init_volley_fail;
2599 snprintf(statstr, sizeof(statstr),
2600 "offset %.6f delay %.6f", t21, t34);
2601 report_event(PEVNT_XERR, peer, statstr);
2608 * Basic broadcast - use direct timestamps.
2609 * t3 = p_xmt, t4 = peer->dst
2612 ci = p_xmt; /* t3 - t4 */
2613 L_SUB(&ci, &peer->dst);
2619 * When calibration is complete and the clock is
2620 * synchronized, the bias is calculated as the difference
2621 * between the unicast timestamp and the broadcast
2622 * timestamp. This works for both basic and interleaved
2624 * [Bug 3031] Don't keep this peer when the delay
2625 * calculation gives reason to suspect clock steps.
2626 * This is assumed for delays > 50ms.
2628 if (FLAG_BC_VOL & peer->flags) {
2629 peer->flags &= ~FLAG_BC_VOL;
2630 peer->delay = fabs(peer->offset - p_offset) * 2;
2631 DPRINTF(2, ("broadcast volley: initial delay=%.6f\n",
2633 if (peer->delay > fabs(sys_bdelay)) {
2634 bcc_init_volley_fail:
2635 DPRINTF(2, ("%s", "broadcast volley: initial delay exceeds limit\n"));
2640 peer->nextdate = current_time + (1u << peer->ppoll) - 2u;
2641 p_del = peer->delay;
2642 p_offset += p_del / 2;
2646 * Basic mode, otherwise known as the old fashioned way.
2648 * t1 = p_org, t2 = p_rec, t3 = p_xmt, t4 = peer->dst
2651 ci = p_xmt; /* t3 - t4 */
2652 L_SUB(&ci, &peer->dst);
2654 ci = p_rec; /* t2 - t1 */
2657 p_del = fabs(t21 - t34);
2658 p_offset = (t21 + t34) / 2.;
2660 p_del = max(p_del, LOGTOD(sys_precision));
2661 p_disp = LOGTOD(sys_precision) + LOGTOD(peer->precision) +
2666 * This code calculates the outbound and inbound data rates by
2667 * measuring the differences between timestamps at different
2668 * packet lengths. This is helpful in cases of large asymmetric
2669 * delays commonly experienced on deep space communication
2672 if (peer->t21_last > 0 && peer->t34_bytes > 0) {
2673 itemp = peer->t21_bytes - peer->t21_last;
2675 etemp = t21 - peer->t21;
2676 if (fabs(etemp) > 1e-6) {
2677 ftemp = itemp / etemp;
2682 itemp = len - peer->t34_bytes;
2684 etemp = -t34 - peer->t34;
2685 if (fabs(etemp) > 1e-6) {
2686 ftemp = itemp / etemp;
2694 * The following section compensates for different data rates on
2695 * the outbound (d21) and inbound (t34) directions. To do this,
2696 * it finds t such that r21 * t - r34 * (d - t) = 0, where d is
2697 * the roundtrip delay. Then it calculates the correction as a
2701 peer->t21_last = peer->t21_bytes;
2703 peer->t34_bytes = len;
2704 DPRINTF(2, ("packet: t21 %.9lf %d t34 %.9lf %d\n", peer->t21,
2705 peer->t21_bytes, peer->t34, peer->t34_bytes));
2706 if (peer->r21 > 0 && peer->r34 > 0 && p_del > 0) {
2707 if (peer->pmode != MODE_BROADCAST)
2708 td = (peer->r34 / (peer->r21 + peer->r34) -
2714 * Unfortunately, in many cases the errors are
2715 * unacceptable, so for the present the rates are not
2716 * used. In future, we might find conditions where the
2717 * calculations are useful, so this should be considered
2718 * a work in progress.
2722 DPRINTF(2, ("packet: del %.6lf r21 %.1lf r34 %.1lf %.6lf\n",
2723 p_del, peer->r21 / 1e3, peer->r34 / 1e3,
2729 * That was awesome. Now hand off to the clock filter.
2731 clock_filter(peer, p_offset + peer->bias, p_del, p_disp);
2734 * If we are in broadcast calibrate mode, return to broadcast
2735 * client mode when the client is fit and the autokey dance is
2738 if ( (FLAG_BC_VOL & peer->flags)
2739 && MODE_CLIENT == peer->hmode
2740 && !(TEST11 & peer_unfit(peer))) { /* distance exceeded */
2742 if (peer->flags & FLAG_SKEY) {
2743 if (!(~peer->crypto & CRYPTO_FLAG_ALL))
2744 peer->hmode = MODE_BCLIENT;
2746 peer->hmode = MODE_BCLIENT;
2748 #else /* !AUTOKEY follows */
2749 peer->hmode = MODE_BCLIENT;
2750 #endif /* !AUTOKEY */
2756 * clock_update - Called at system process update intervals.
2760 struct peer *peer /* peer structure pointer */
2765 #ifdef HAVE_LIBSCF_H
2767 #endif /* HAVE_LIBSCF_H */
2770 * Update the system state variables. We do this very carefully,
2771 * as the poll interval might need to be clamped differently.
2774 sys_epoch = peer->epoch;
2775 if (sys_poll < peer->minpoll)
2776 sys_poll = peer->minpoll;
2777 if (sys_poll > peer->maxpoll)
2778 sys_poll = peer->maxpoll;
2779 poll_update(peer, sys_poll);
2780 sys_stratum = min(peer->stratum + 1, STRATUM_UNSPEC);
2781 if ( peer->stratum == STRATUM_REFCLOCK
2782 || peer->stratum == STRATUM_UNSPEC)
2783 sys_refid = peer->refid;
2785 sys_refid = addr2refid(&peer->srcadr);
2787 * Root Dispersion (E) is defined (in RFC 5905) as:
2789 * E = p.epsilon_r + p.epsilon + p.psi + PHI*(s.t - p.t) + |THETA|
2792 * p.epsilon_r is the PollProc's root dispersion
2793 * p.epsilon is the PollProc's dispersion
2794 * p.psi is the PollProc's jitter
2795 * THETA is the combined offset
2797 * NB: Think Hard about where these numbers come from and
2798 * what they mean. When did peer->update happen? Has anything
2799 * interesting happened since then? What values are the most
2802 * DLM thinks this equation is probably the best of all worse choices.
2804 dtemp = peer->rootdisp
2807 + clock_phi * (current_time - peer->update)
2810 if (dtemp > sys_mindisp)
2811 sys_rootdisp = dtemp;
2813 sys_rootdisp = sys_mindisp;
2814 sys_rootdelay = peer->delay + peer->rootdelay;
2815 sys_reftime = peer->dst;
2817 DPRINTF(1, ("clock_update: at %lu sample %lu associd %d\n",
2818 current_time, peer->epoch, peer->associd));
2821 * Comes now the moment of truth. Crank the clock discipline and
2822 * see what comes out.
2824 switch (local_clock(peer, sys_offset)) {
2827 * Clock exceeds panic threshold. Life as we know it ends.
2830 #ifdef HAVE_LIBSCF_H
2832 * For Solaris enter the maintenance mode.
2834 if ((fmri = getenv("SMF_FMRI")) != NULL) {
2835 if (smf_maintain_instance(fmri, 0) < 0) {
2836 printf("smf_maintain_instance: %s\n",
2837 scf_strerror(scf_error()));
2841 * Sleep until SMF kills us.
2846 #endif /* HAVE_LIBSCF_H */
2851 * Clock was stepped. Flush all time values of all peers.
2855 set_sys_leap(LEAP_NOTINSYNC);
2856 sys_stratum = STRATUM_UNSPEC;
2857 memcpy(&sys_refid, "STEP", 4);
2860 L_CLR(&sys_reftime);
2861 sys_jitter = LOGTOD(sys_precision);
2862 leapsec_reset_frame();
2866 * Clock was slewed. Handle the leapsecond stuff.
2871 * If this is the first time the clock is set, reset the
2872 * leap bits. If crypto, the timer will goose the setup
2875 if (sys_leap == LEAP_NOTINSYNC) {
2876 set_sys_leap(LEAP_NOWARNING);
2880 #endif /* AUTOKEY */
2882 * If our parent process is waiting for the
2883 * first clock sync, send them home satisfied.
2885 #ifdef HAVE_WORKING_FORK
2886 if (waitsync_fd_to_close != -1) {
2887 close(waitsync_fd_to_close);
2888 waitsync_fd_to_close = -1;
2889 DPRINTF(1, ("notified parent --wait-sync is done\n"));
2891 #endif /* HAVE_WORKING_FORK */
2896 * If there is no leap second pending and the number of
2897 * survivor leap bits is greater than half the number of
2898 * survivors, try to schedule a leap for the end of the
2899 * current month. (This only works if no leap second for
2900 * that range is in the table, so doing this more than
2901 * once is mostly harmless.)
2903 if (leapsec == LSPROX_NOWARN) {
2904 if ( leap_vote_ins > leap_vote_del
2905 && leap_vote_ins > sys_survivors / 2) {
2907 leapsec_add_dyn(TRUE, now.l_ui, NULL);
2909 if ( leap_vote_del > leap_vote_ins
2910 && leap_vote_del > sys_survivors / 2) {
2912 leapsec_add_dyn(FALSE, now.l_ui, NULL);
2918 * Popcorn spike or step threshold exceeded. Pretend it never
2928 * poll_update - update peer poll interval
2932 struct peer *peer, /* peer structure pointer */
2940 * This routine figures out when the next poll should be sent.
2941 * That turns out to be wickedly complicated. One problem is
2942 * that sometimes the time for the next poll is in the past when
2943 * the poll interval is reduced. We watch out for races here
2944 * between the receive process and the poll process.
2946 * Clamp the poll interval between minpoll and maxpoll.
2948 hpoll = max(min(peer->maxpoll, mpoll), peer->minpoll);
2952 * If during the crypto protocol the poll interval has changed,
2953 * the lifetimes in the key list are probably bogus. Purge the
2954 * the key list and regenerate it later.
2956 if ((peer->flags & FLAG_SKEY) && hpoll != peer->hpoll)
2958 #endif /* AUTOKEY */
2959 peer->hpoll = hpoll;
2962 * There are three variables important for poll scheduling, the
2963 * current time (current_time), next scheduled time (nextdate)
2964 * and the earliest time (utemp). The earliest time is 2 s
2965 * seconds, but could be more due to rate management. When
2966 * sending in a burst, use the earliest time. When not in a
2967 * burst but with a reply pending, send at the earliest time
2968 * unless the next scheduled time has not advanced. This can
2969 * only happen if multiple replies are pending in the same
2970 * response interval. Otherwise, send at the later of the next
2971 * scheduled time and the earliest time.
2973 * Now we figure out if there is an override. If a burst is in
2974 * progress and we get called from the receive process, just
2975 * slink away. If called from the poll process, delay 1 s for a
2976 * reference clock, otherwise 2 s.
2978 utemp = current_time + max(peer->throttle - (NTP_SHIFT - 1) *
2979 (1 << peer->minpoll), ntp_minpkt);
2980 if (peer->burst > 0) {
2981 if (peer->nextdate > current_time)
2984 else if (peer->flags & FLAG_REFCLOCK)
2985 peer->nextdate = current_time + RESP_DELAY;
2986 #endif /* REFCLOCK */
2988 peer->nextdate = utemp;
2992 * If a burst is not in progress and a crypto response message
2993 * is pending, delay 2 s, but only if this is a new interval.
2995 } else if (peer->cmmd != NULL) {
2996 if (peer->nextdate > current_time) {
2997 if (peer->nextdate + ntp_minpkt != utemp)
2998 peer->nextdate = utemp;
3000 peer->nextdate = utemp;
3002 #endif /* AUTOKEY */
3005 * The ordinary case. If a retry, use minpoll; if unreachable,
3006 * use host poll; otherwise, use the minimum of host and peer
3007 * polls; In other words, oversampling is okay but
3008 * understampling is evil. Use the maximum of this value and the
3009 * headway. If the average headway is greater than the headway
3010 * threshold, increase the headway by the minimum interval.
3013 if (peer->retry > 0)
3014 hpoll = peer->minpoll;
3016 hpoll = min(peer->ppoll, peer->hpoll);
3018 if (peer->flags & FLAG_REFCLOCK)
3021 #endif /* REFCLOCK */
3022 next = ((0x1000UL | (ntp_random() & 0x0ff)) <<
3024 next += peer->outdate;
3026 peer->nextdate = next;
3028 peer->nextdate = utemp;
3029 if (peer->throttle > (1 << peer->minpoll))
3030 peer->nextdate += ntp_minpkt;
3032 DPRINTF(2, ("poll_update: at %lu %s poll %d burst %d retry %d head %d early %lu next %lu\n",
3033 current_time, ntoa(&peer->srcadr), peer->hpoll,
3034 peer->burst, peer->retry, peer->throttle,
3035 utemp - current_time, peer->nextdate -
3041 * peer_clear - clear peer filter registers. See Section 3.4.8 of the
3046 struct peer *peer, /* peer structure */
3047 const char *ident /* tally lights */
3051 l_fp bxmt = peer->bxmt; /* bcast clients retain this! */
3055 * If cryptographic credentials have been acquired, toss them to
3056 * Valhalla. Note that autokeys are ephemeral, in that they are
3057 * tossed immediately upon use. Therefore, the keylist can be
3058 * purged anytime without needing to preserve random keys. Note
3059 * that, if the peer is purged, the cryptographic variables are
3060 * purged, too. This makes it much harder to sneak in some
3061 * unauthenticated data in the clock filter.
3064 if (peer->iffval != NULL)
3065 BN_free(peer->iffval);
3066 value_free(&peer->cookval);
3067 value_free(&peer->recval);
3068 value_free(&peer->encrypt);
3069 value_free(&peer->sndval);
3070 if (peer->cmmd != NULL)
3072 if (peer->subject != NULL)
3073 free(peer->subject);
3074 if (peer->issuer != NULL)
3076 #endif /* AUTOKEY */
3079 * Clear all values, including the optional crypto values above.
3081 memset(CLEAR_TO_ZERO(peer), 0, LEN_CLEAR_TO_ZERO(peer));
3082 peer->ppoll = peer->maxpoll;
3083 peer->hpoll = peer->minpoll;
3084 peer->disp = MAXDISPERSE;
3085 peer->flash = peer_unfit(peer);
3086 peer->jitter = LOGTOD(sys_precision);
3088 /* Don't throw away our broadcast replay protection */
3089 if (peer->hmode == MODE_BCLIENT)
3093 * If interleave mode, initialize the alternate origin switch.
3095 if (peer->flags & FLAG_XLEAVE)
3097 for (u = 0; u < NTP_SHIFT; u++) {
3098 peer->filter_order[u] = u;
3099 peer->filter_disp[u] = MAXDISPERSE;
3102 if (!(peer->flags & FLAG_REFCLOCK)) {
3104 peer->leap = LEAP_NOTINSYNC;
3105 peer->stratum = STRATUM_UNSPEC;
3106 memcpy(&peer->refid, ident, 4);
3109 /* Clear refclock sample filter */
3110 peer->procptr->codeproc = 0;
3111 peer->procptr->coderecv = 0;
3116 * During initialization use the association count to spread out
3117 * the polls at one-second intervals. Passive associations'
3118 * first poll is delayed by the "discard minimum" to avoid rate
3119 * limiting. Other post-startup new or cleared associations
3120 * randomize the first poll over the minimum poll interval to
3123 peer->nextdate = peer->update = peer->outdate = current_time;
3125 peer->nextdate += peer_associations;
3126 } else if (MODE_PASSIVE == peer->hmode) {
3127 peer->nextdate += ntp_minpkt;
3129 peer->nextdate += ntp_random() % peer->minpoll;
3132 peer->refresh = current_time + (1 << NTP_REFRESH);
3133 #endif /* AUTOKEY */
3134 DPRINTF(1, ("peer_clear: at %ld next %ld associd %d refid %s\n",
3135 current_time, peer->nextdate, peer->associd,
3141 * clock_filter - add incoming clock sample to filter register and run
3142 * the filter procedure to find the best sample.
3146 struct peer *peer, /* peer structure pointer */
3147 double sample_offset, /* clock offset */
3148 double sample_delay, /* roundtrip delay */
3149 double sample_disp /* dispersion */
3152 double dst[NTP_SHIFT]; /* distance vector */
3153 int ord[NTP_SHIFT]; /* index vector */
3155 double dtemp, etemp;
3159 * A sample consists of the offset, delay, dispersion and epoch
3160 * of arrival. The offset and delay are determined by the on-
3161 * wire protocol. The dispersion grows from the last outbound
3162 * packet to the arrival of this one increased by the sum of the
3163 * peer precision and the system precision as required by the
3164 * error budget. First, shift the new arrival into the shift
3165 * register discarding the oldest one.
3167 j = peer->filter_nextpt;
3168 peer->filter_offset[j] = sample_offset;
3169 peer->filter_delay[j] = sample_delay;
3170 peer->filter_disp[j] = sample_disp;
3171 peer->filter_epoch[j] = current_time;
3172 j = (j + 1) % NTP_SHIFT;
3173 peer->filter_nextpt = j;
3176 * Update dispersions since the last update and at the same
3177 * time initialize the distance and index lists. Since samples
3178 * become increasingly uncorrelated beyond the Allan intercept,
3179 * only under exceptional cases will an older sample be used.
3180 * Therefore, the distance list uses a compound metric. If the
3181 * dispersion is greater than the maximum dispersion, clamp the
3182 * distance at that value. If the time since the last update is
3183 * less than the Allan intercept use the delay; otherwise, use
3184 * the sum of the delay and dispersion.
3186 dtemp = clock_phi * (current_time - peer->update);
3187 peer->update = current_time;
3188 for (i = NTP_SHIFT - 1; i >= 0; i--) {
3190 peer->filter_disp[j] += dtemp;
3191 if (peer->filter_disp[j] >= MAXDISPERSE) {
3192 peer->filter_disp[j] = MAXDISPERSE;
3193 dst[i] = MAXDISPERSE;
3194 } else if (peer->update - peer->filter_epoch[j] >
3195 (u_long)ULOGTOD(allan_xpt)) {
3196 dst[i] = peer->filter_delay[j] +
3197 peer->filter_disp[j];
3199 dst[i] = peer->filter_delay[j];
3202 j = (j + 1) % NTP_SHIFT;
3206 * If the clock has stabilized, sort the samples by distance.
3208 if (freq_cnt == 0) {
3209 for (i = 1; i < NTP_SHIFT; i++) {
3210 for (j = 0; j < i; j++) {
3211 if (dst[j] > dst[i]) {
3224 * Copy the index list to the association structure so ntpq
3225 * can see it later. Prune the distance list to leave only
3226 * samples less than the maximum dispersion, which disfavors
3227 * uncorrelated samples older than the Allan intercept. To
3228 * further improve the jitter estimate, of the remainder leave
3229 * only samples less than the maximum distance, but keep at
3230 * least two samples for jitter calculation.
3233 for (i = 0; i < NTP_SHIFT; i++) {
3234 peer->filter_order[i] = (u_char) ord[i];
3235 if ( dst[i] >= MAXDISPERSE
3236 || (m >= 2 && dst[i] >= sys_maxdist))
3242 * Compute the dispersion and jitter. The dispersion is weighted
3243 * exponentially by NTP_FWEIGHT (0.5) so it is normalized close
3244 * to 1.0. The jitter is the RMS differences relative to the
3245 * lowest delay sample.
3247 peer->disp = peer->jitter = 0;
3249 for (i = NTP_SHIFT - 1; i >= 0; i--) {
3251 peer->disp = NTP_FWEIGHT * (peer->disp +
3252 peer->filter_disp[j]);
3254 peer->jitter += DIFF(peer->filter_offset[j],
3255 peer->filter_offset[k]);
3259 * If no acceptable samples remain in the shift register,
3260 * quietly tiptoe home leaving only the dispersion. Otherwise,
3261 * save the offset, delay and jitter. Note the jitter must not
3262 * be less than the precision.
3268 etemp = fabs(peer->offset - peer->filter_offset[k]);
3269 peer->offset = peer->filter_offset[k];
3270 peer->delay = peer->filter_delay[k];
3272 peer->jitter /= m - 1;
3273 peer->jitter = max(SQRT(peer->jitter), LOGTOD(sys_precision));
3276 * If the the new sample and the current sample are both valid
3277 * and the difference between their offsets exceeds CLOCK_SGATE
3278 * (3) times the jitter and the interval between them is less
3279 * than twice the host poll interval, consider the new sample
3280 * a popcorn spike and ignore it.
3282 if ( peer->disp < sys_maxdist
3283 && peer->filter_disp[k] < sys_maxdist
3284 && etemp > CLOCK_SGATE * peer->jitter
3285 && peer->filter_epoch[k] - peer->epoch
3286 < 2. * ULOGTOD(peer->hpoll)) {
3287 snprintf(tbuf, sizeof(tbuf), "%.6f s", etemp);
3288 report_event(PEVNT_POPCORN, peer, tbuf);
3293 * A new minimum sample is useful only if it is later than the
3294 * last one used. In this design the maximum lifetime of any
3295 * sample is not greater than eight times the poll interval, so
3296 * the maximum interval between minimum samples is eight
3299 if (peer->filter_epoch[k] <= peer->epoch) {
3300 DPRINTF(2, ("clock_filter: old sample %lu\n", current_time -
3301 peer->filter_epoch[k]));
3304 peer->epoch = peer->filter_epoch[k];
3307 * The mitigated sample statistics are saved for later
3308 * processing. If not synchronized or not in a burst, tickle the
3309 * clock select algorithm.
3311 record_peer_stats(&peer->srcadr, ctlpeerstatus(peer),
3312 peer->offset, peer->delay, peer->disp, peer->jitter);
3313 DPRINTF(1, ("clock_filter: n %d off %.6f del %.6f dsp %.6f jit %.6f\n",
3314 m, peer->offset, peer->delay, peer->disp,
3316 if (peer->burst == 0 || sys_leap == LEAP_NOTINSYNC)
3322 * clock_select - find the pick-of-the-litter clock
3324 * LOCKCLOCK: (1) If the local clock is the prefer peer, it will always
3325 * be enabled, even if declared falseticker, (2) only the prefer peer
3326 * can be selected as the system peer, (3) if the external source is
3327 * down, the system leap bits are set to 11 and the stratum set to
3341 double orphmet = 2.0 * U_INT32_MAX; /* 2x is greater than */
3342 struct endpoint endp;
3343 struct peer *osys_peer;
3344 struct peer *sys_prefer = NULL; /* prefer peer */
3345 struct peer *typesystem = NULL;
3346 struct peer *typeorphan = NULL;
3348 struct peer *typeacts = NULL;
3349 struct peer *typelocal = NULL;
3350 struct peer *typepps = NULL;
3351 #endif /* REFCLOCK */
3352 static struct endpoint *endpoint = NULL;
3353 static int *indx = NULL;
3354 static peer_select *peers = NULL;
3355 static u_int endpoint_size = 0;
3356 static u_int peers_size = 0;
3357 static u_int indx_size = 0;
3361 * Initialize and create endpoint, index and peer lists big
3362 * enough to handle all associations.
3364 osys_peer = sys_peer;
3367 set_sys_leap(LEAP_NOTINSYNC);
3368 sys_stratum = STRATUM_UNSPEC;
3369 memcpy(&sys_refid, "DOWN", 4);
3370 #endif /* LOCKCLOCK */
3373 * Allocate dynamic space depending on the number of
3377 for (peer = peer_list; peer != NULL; peer = peer->p_link)
3379 endpoint_size = ALIGNED_SIZE(nlist * 2 * sizeof(*endpoint));
3380 peers_size = ALIGNED_SIZE(nlist * sizeof(*peers));
3381 indx_size = ALIGNED_SIZE(nlist * 2 * sizeof(*indx));
3382 octets = endpoint_size + peers_size + indx_size;
3383 endpoint = erealloc(endpoint, octets);
3384 peers = INC_ALIGNED_PTR(endpoint, endpoint_size);
3385 indx = INC_ALIGNED_PTR(peers, peers_size);
3388 * Initially, we populate the island with all the rifraff peers
3389 * that happen to be lying around. Those with seriously
3390 * defective clocks are immediately booted off the island. Then,
3391 * the falsetickers are culled and put to sea. The truechimers
3392 * remaining are subject to repeated rounds where the most
3393 * unpopular at each round is kicked off. When the population
3394 * has dwindled to sys_minclock, the survivors split a million
3395 * bucks and collectively crank the chimes.
3397 nlist = nl2 = 0; /* none yet */
3398 for (peer = peer_list; peer != NULL; peer = peer->p_link) {
3399 peer->new_status = CTL_PST_SEL_REJECT;
3402 * Leave the island immediately if the peer is
3403 * unfit to synchronize.
3405 if (peer_unfit(peer)) {
3410 * If this peer is an orphan parent, elect the
3411 * one with the lowest metric defined as the
3412 * IPv4 address or the first 64 bits of the
3413 * hashed IPv6 address. To ensure convergence
3414 * on the same selected orphan, consider as
3415 * well that this system may have the lowest
3416 * metric and be the orphan parent. If this
3417 * system wins, sys_peer will be NULL to trigger
3418 * orphan mode in timer().
3420 if (peer->stratum == sys_orphan) {
3424 if (peer->dstadr != NULL)
3425 localmet = ntohl(peer->dstadr->addr_refid);
3427 localmet = U_INT32_MAX;
3428 peermet = ntohl(addr2refid(&peer->srcadr));
3429 if (peermet < localmet && peermet < orphmet) {
3437 * If this peer could have the orphan parent
3438 * as a synchronization ancestor, exclude it
3439 * from selection to avoid forming a
3440 * synchronization loop within the orphan mesh,
3441 * triggering stratum climb to infinity
3442 * instability. Peers at stratum higher than
3443 * the orphan stratum could have the orphan
3444 * parent in ancestry so are excluded.
3445 * See http://bugs.ntp.org/2050
3447 if (peer->stratum > sys_orphan) {
3452 * The following are special cases. We deal
3455 if (!(peer->flags & FLAG_PREFER)) {
3456 switch (peer->refclktype) {
3457 case REFCLK_LOCALCLOCK:
3458 if ( current_time > orphwait
3459 && typelocal == NULL)
3464 if ( current_time > orphwait
3465 && typeacts == NULL)
3470 #endif /* REFCLOCK */
3473 * If we get this far, the peer can stay on the
3474 * island, but does not yet have the immunity
3477 peer->new_status = CTL_PST_SEL_SANE;
3478 f = root_distance(peer);
3479 peers[nlist].peer = peer;
3480 peers[nlist].error = peer->jitter;
3481 peers[nlist].synch = f;
3485 * Insert each interval endpoint on the unsorted
3489 endpoint[nl2].type = -1; /* lower end */
3490 endpoint[nl2].val = e - f;
3492 endpoint[nl2].type = 1; /* upper end */
3493 endpoint[nl2].val = e + f;
3497 * Construct sorted indx[] of endpoint[] indexes ordered by
3500 for (i = 0; i < nl2; i++)
3502 for (i = 0; i < nl2; i++) {
3503 endp = endpoint[indx[i]];
3506 for (j = i + 1; j < nl2; j++) {
3507 endp = endpoint[indx[j]];
3519 for (i = 0; i < nl2; i++)
3520 DPRINTF(3, ("select: endpoint %2d %.6f\n",
3521 endpoint[indx[i]].type, endpoint[indx[i]].val));
3524 * This is the actual algorithm that cleaves the truechimers
3525 * from the falsetickers. The original algorithm was described
3526 * in Keith Marzullo's dissertation, but has been modified for
3529 * Briefly put, we first assume there are no falsetickers, then
3530 * scan the candidate list first from the low end upwards and
3531 * then from the high end downwards. The scans stop when the
3532 * number of intersections equals the number of candidates less
3533 * the number of falsetickers. If this doesn't happen for a
3534 * given number of falsetickers, we bump the number of
3535 * falsetickers and try again. If the number of falsetickers
3536 * becomes equal to or greater than half the number of
3537 * candidates, the Albanians have won the Byzantine wars and
3538 * correct synchronization is not possible.
3540 * Here, nlist is the number of candidates and allow is the
3541 * number of falsetickers. Upon exit, the truechimers are the
3542 * survivors with offsets not less than low and not greater than
3543 * high. There may be none of them.
3547 for (allow = 0; 2 * allow < nlist; allow++) {
3550 * Bound the interval (low, high) as the smallest
3551 * interval containing points from the most sources.
3554 for (i = 0; i < nl2; i++) {
3555 low = endpoint[indx[i]].val;
3556 n -= endpoint[indx[i]].type;
3557 if (n >= nlist - allow)
3561 for (j = nl2 - 1; j >= 0; j--) {
3562 high = endpoint[indx[j]].val;
3563 n += endpoint[indx[j]].type;
3564 if (n >= nlist - allow)
3569 * If an interval containing truechimers is found, stop.
3570 * If not, increase the number of falsetickers and go
3578 * Clustering algorithm. Whittle candidate list of falsetickers,
3579 * who leave the island immediately. The TRUE peer is always a
3580 * truechimer. We must leave at least one peer to collect the
3583 * We assert the correct time is contained in the interval, but
3584 * the best offset estimate for the interval might not be
3585 * contained in the interval. For this purpose, a truechimer is
3586 * defined as the midpoint of an interval that overlaps the
3587 * intersection interval.
3590 for (i = 0; i < nlist; i++) {
3593 peer = peers[i].peer;
3596 || peer->offset + h < low
3597 || peer->offset - h > high
3598 ) && !(peer->flags & FLAG_TRUE))
3603 * Eligible PPS peers must survive the intersection
3604 * algorithm. Use the first one found, but don't
3605 * include any of them in the cluster population.
3607 if (peer->flags & FLAG_PPS) {
3608 if (typepps == NULL)
3610 if (!(peer->flags & FLAG_TSTAMP_PPS))
3613 #endif /* REFCLOCK */
3616 peers[j] = peers[i];
3622 * If no survivors remain at this point, check if the modem
3623 * driver, local driver or orphan parent in that order. If so,
3624 * nominate the first one found as the only survivor.
3625 * Otherwise, give up and leave the island to the rats.
3629 peers[0].synch = sys_mindisp;
3631 if (typeacts != NULL) {
3632 peers[0].peer = typeacts;
3634 } else if (typelocal != NULL) {
3635 peers[0].peer = typelocal;
3638 #endif /* REFCLOCK */
3639 if (typeorphan != NULL) {
3640 peers[0].peer = typeorphan;
3646 * Mark the candidates at this point as truechimers.
3648 for (i = 0; i < nlist; i++) {
3649 peers[i].peer->new_status = CTL_PST_SEL_SELCAND;
3650 DPRINTF(2, ("select: survivor %s %f\n",
3651 stoa(&peers[i].peer->srcadr), peers[i].synch));
3655 * Now, vote outliers off the island by select jitter weighted
3656 * by root distance. Continue voting as long as there are more
3657 * than sys_minclock survivors and the select jitter of the peer
3658 * with the worst metric is greater than the minimum peer
3659 * jitter. Stop if we are about to discard a TRUE or PREFER
3660 * peer, who of course have the immunity idol.
3667 for (i = 0; i < nlist; i++) {
3668 if (peers[i].error < d)
3670 peers[i].seljit = 0;
3673 for (j = 0; j < nlist; j++)
3674 f += DIFF(peers[j].peer->offset,
3675 peers[i].peer->offset);
3676 peers[i].seljit = SQRT(f / (nlist - 1));
3678 if (peers[i].seljit * peers[i].synch > e) {
3679 g = peers[i].seljit;
3680 e = peers[i].seljit * peers[i].synch;
3684 g = max(g, LOGTOD(sys_precision));
3685 if ( nlist <= max(1, sys_minclock)
3687 || ((FLAG_TRUE | FLAG_PREFER) & peers[k].peer->flags))
3690 DPRINTF(3, ("select: drop %s seljit %.6f jit %.6f\n",
3691 ntoa(&peers[k].peer->srcadr), g, d));
3692 if (nlist > sys_maxclock)
3693 peers[k].peer->new_status = CTL_PST_SEL_EXCESS;
3694 for (j = k + 1; j < nlist; j++)
3695 peers[j - 1] = peers[j];
3700 * What remains is a list usually not greater than sys_minclock
3701 * peers. Note that unsynchronized peers cannot survive this
3702 * far. Count and mark these survivors.
3704 * While at it, count the number of leap warning bits found.
3705 * This will be used later to vote the system leap warning bit.
3706 * If a leap warning bit is found on a reference clock, the vote
3709 * Choose the system peer using a hybrid metric composed of the
3710 * selection jitter scaled by the root distance augmented by
3711 * stratum scaled by sys_mindisp (.001 by default). The goal of
3712 * the small stratum factor is to avoid clockhop between a
3713 * reference clock and a network peer which has a refclock and
3714 * is using an older ntpd, which does not floor sys_rootdisp at
3717 * In contrast, ntpd 4.2.6 and earlier used stratum primarily
3718 * in selecting the system peer, using a weight of 1 second of
3719 * additional root distance per stratum. This heavy bias is no
3720 * longer appropriate, as the scaled root distance provides a
3721 * more rational metric carrying the cumulative error budget.
3727 for (i = 0; i < nlist; i++) {
3728 peer = peers[i].peer;
3730 peer->new_status = CTL_PST_SEL_SYNCCAND;
3732 if (peer->leap == LEAP_ADDSECOND) {
3733 if (peer->flags & FLAG_REFCLOCK)
3734 leap_vote_ins = nlist;
3735 else if (leap_vote_ins < nlist)
3738 if (peer->leap == LEAP_DELSECOND) {
3739 if (peer->flags & FLAG_REFCLOCK)
3740 leap_vote_del = nlist;
3741 else if (leap_vote_del < nlist)
3744 if (peer->flags & FLAG_PREFER)
3746 speermet = peers[i].seljit * peers[i].synch +
3747 peer->stratum * sys_mindisp;
3755 * Unless there are at least sys_misane survivors, leave the
3756 * building dark. Otherwise, do a clockhop dance. Ordinarily,
3757 * use the selected survivor speer. However, if the current
3758 * system peer is not speer, stay with the current system peer
3759 * as long as it doesn't get too old or too ugly.
3761 if (nlist > 0 && nlist >= sys_minsane) {
3764 typesystem = peers[speer].peer;
3765 if (osys_peer == NULL || osys_peer == typesystem) {
3767 } else if ((x = fabs(typesystem->offset -
3768 osys_peer->offset)) < sys_mindisp) {
3769 if (sys_clockhop == 0)
3770 sys_clockhop = sys_mindisp;
3773 DPRINTF(1, ("select: clockhop %d %.6f %.6f\n",
3774 j, x, sys_clockhop));
3775 if (fabs(x) < sys_clockhop)
3776 typesystem = osys_peer;
3785 * Mitigation rules of the game. We have the pick of the
3786 * litter in typesystem if any survivors are left. If
3787 * there is a prefer peer, use its offset and jitter.
3788 * Otherwise, use the combined offset and jitter of all kitters.
3790 if (typesystem != NULL) {
3791 if (sys_prefer == NULL) {
3792 typesystem->new_status = CTL_PST_SEL_SYSPEER;
3793 clock_combine(peers, sys_survivors, speer);
3795 typesystem = sys_prefer;
3797 typesystem->new_status = CTL_PST_SEL_SYSPEER;
3798 sys_offset = typesystem->offset;
3799 sys_jitter = typesystem->jitter;
3801 DPRINTF(1, ("select: combine offset %.9f jitter %.9f\n",
3802 sys_offset, sys_jitter));
3806 * If a PPS driver is lit and the combined offset is less than
3807 * 0.4 s, select the driver as the PPS peer and use its offset
3808 * and jitter. However, if this is the atom driver, use it only
3809 * if there is a prefer peer or there are no survivors and none
3812 if ( typepps != NULL
3813 && fabs(sys_offset) < 0.4
3814 && ( typepps->refclktype != REFCLK_ATOM_PPS
3815 || ( typepps->refclktype == REFCLK_ATOM_PPS
3816 && ( sys_prefer != NULL
3817 || (typesystem == NULL && sys_minsane == 0))))) {
3818 typesystem = typepps;
3820 typesystem->new_status = CTL_PST_SEL_PPS;
3821 sys_offset = typesystem->offset;
3822 sys_jitter = typesystem->jitter;
3823 DPRINTF(1, ("select: pps offset %.9f jitter %.9f\n",
3824 sys_offset, sys_jitter));
3826 #endif /* REFCLOCK */
3829 * If there are no survivors at this point, there is no
3830 * system peer. If so and this is an old update, keep the
3831 * current statistics, but do not update the clock.
3833 if (typesystem == NULL) {
3834 if (osys_peer != NULL) {
3835 if (sys_orphwait > 0)
3836 orphwait = current_time + sys_orphwait;
3837 report_event(EVNT_NOPEER, NULL, NULL);
3840 for (peer = peer_list; peer != NULL; peer = peer->p_link)
3841 peer->status = peer->new_status;
3846 * Do not use old data, as this may mess up the clock discipline
3849 if (typesystem->epoch <= sys_epoch)
3853 * We have found the alpha male. Wind the clock.
3855 if (osys_peer != typesystem)
3856 report_event(PEVNT_NEWPEER, typesystem, NULL);
3857 for (peer = peer_list; peer != NULL; peer = peer->p_link)
3858 peer->status = peer->new_status;
3859 clock_update(typesystem);
3865 peer_select * peers, /* survivor list */
3866 int npeers, /* number of survivors */
3867 int syspeer /* index of sys.peer */
3874 for (i = 0; i < npeers; i++) {
3875 x = 1. / peers[i].synch;
3877 z += x * peers[i].peer->offset;
3878 w += x * DIFF(peers[i].peer->offset,
3879 peers[syspeer].peer->offset);
3882 sys_jitter = SQRT(w / y + SQUARE(peers[syspeer].seljit));
3887 * root_distance - compute synchronization distance from peer to root
3891 struct peer *peer /* peer structure pointer */
3897 * Root Distance (LAMBDA) is defined as:
3898 * (delta + DELTA)/2 + epsilon + EPSILON + D
3901 * delta is the round-trip delay
3902 * DELTA is the root delay
3903 * epsilon is the peer dispersion
3904 * + (15 usec each second)
3905 * EPSILON is the root dispersion
3908 * NB: Think hard about why we are using these values, and what
3909 * the alternatives are, and the various pros/cons.
3911 * DLM thinks these are probably the best choices from any of the
3912 * other worse choices.
3914 dtemp = (peer->delay + peer->rootdelay) / 2
3916 + clock_phi * (current_time - peer->update)
3920 * Careful squeak here. The value returned must be greater than
3921 * the minimum root dispersion in order to avoid clockhop with
3922 * highly precise reference clocks. Note that the root distance
3923 * cannot exceed the sys_maxdist, as this is the cutoff by the
3924 * selection algorithm.
3926 if (dtemp < sys_mindisp)
3927 dtemp = sys_mindisp;
3933 * peer_xmit - send packet for persistent association.
3937 struct peer *peer /* peer structure pointer */
3940 struct pkt xpkt; /* transmit packet */
3941 size_t sendlen, authlen;
3942 keyid_t xkeyid = 0; /* transmit key ID */
3943 l_fp xmt_tx, xmt_ty;
3945 if (!peer->dstadr) /* drop peers without interface */
3948 xpkt.li_vn_mode = PKT_LI_VN_MODE(sys_leap, peer->version,
3950 xpkt.stratum = STRATUM_TO_PKT(sys_stratum);
3951 xpkt.ppoll = peer->hpoll;
3952 xpkt.precision = sys_precision;
3953 xpkt.refid = sys_refid;
3954 xpkt.rootdelay = HTONS_FP(DTOFP(sys_rootdelay));
3955 xpkt.rootdisp = HTONS_FP(DTOUFP(sys_rootdisp));
3956 HTONL_FP(&sys_reftime, &xpkt.reftime);
3957 HTONL_FP(&peer->rec, &xpkt.org);
3958 HTONL_FP(&peer->dst, &xpkt.rec);
3961 * If the received packet contains a MAC, the transmitted packet
3962 * is authenticated and contains a MAC. If not, the transmitted
3963 * packet is not authenticated.
3965 * It is most important when autokey is in use that the local
3966 * interface IP address be known before the first packet is
3967 * sent. Otherwise, it is not possible to compute a correct MAC
3968 * the recipient will accept. Thus, the I/O semantics have to do
3969 * a little more work. In particular, the wildcard interface
3970 * might not be usable.
3972 sendlen = LEN_PKT_NOMAC;
3975 !(peer->flags & FLAG_SKEY) &&
3976 #endif /* !AUTOKEY */
3980 * Transmit a-priori timestamps
3982 get_systime(&xmt_tx);
3983 if (peer->flip == 0) { /* basic mode */
3984 peer->aorg = xmt_tx;
3985 HTONL_FP(&xmt_tx, &xpkt.xmt);
3986 } else { /* interleaved modes */
3987 if (peer->hmode == MODE_BROADCAST) { /* bcst */
3988 HTONL_FP(&xmt_tx, &xpkt.xmt);
3990 HTONL_FP(&peer->borg,
3993 HTONL_FP(&peer->aorg,
3995 } else { /* symmetric */
3997 HTONL_FP(&peer->borg,
4000 HTONL_FP(&peer->aorg,
4004 peer->t21_bytes = sendlen;
4005 sendpkt(&peer->srcadr, peer->dstadr,
4006 sys_ttl[(peer->ttl >= sys_ttlmax) ? sys_ttlmax : peer->ttl],
4009 peer->throttle += (1 << peer->minpoll) - 2;
4012 * Capture a-posteriori timestamps
4014 get_systime(&xmt_ty);
4015 if (peer->flip != 0) { /* interleaved modes */
4017 peer->aorg = xmt_ty;
4019 peer->borg = xmt_ty;
4020 peer->flip = -peer->flip;
4022 L_SUB(&xmt_ty, &xmt_tx);
4023 LFPTOD(&xmt_ty, peer->xleave);
4024 DPRINTF(1, ("peer_xmit: at %ld %s->%s mode %d len %zu xmt %#010x.%08x\n",
4026 peer->dstadr ? stoa(&peer->dstadr->sin) : "-",
4027 stoa(&peer->srcadr), peer->hmode, sendlen,
4028 xmt_tx.l_ui, xmt_tx.l_uf));
4033 * Authentication is enabled, so the transmitted packet must be
4034 * authenticated. If autokey is enabled, fuss with the various
4035 * modes; otherwise, symmetric key cryptography is used.
4038 if (peer->flags & FLAG_SKEY) {
4039 struct exten *exten; /* extension field */
4042 * The Public Key Dance (PKD): Cryptographic credentials
4043 * are contained in extension fields, each including a
4044 * 4-octet length/code word followed by a 4-octet
4045 * association ID and optional additional data. Optional
4046 * data includes a 4-octet data length field followed by
4047 * the data itself. Request messages are sent from a
4048 * configured association; response messages can be sent
4049 * from a configured association or can take the fast
4050 * path without ever matching an association. Response
4051 * messages have the same code as the request, but have
4052 * a response bit and possibly an error bit set. In this
4053 * implementation, a message may contain no more than
4054 * one command and one or more responses.
4056 * Cryptographic session keys include both a public and
4057 * a private componet. Request and response messages
4058 * using extension fields are always sent with the
4059 * private component set to zero. Packets without
4060 * extension fields indlude the private component when
4061 * the session key is generated.
4066 * Allocate and initialize a keylist if not
4067 * already done. Then, use the list in inverse
4068 * order, discarding keys once used. Keep the
4069 * latest key around until the next one, so
4070 * clients can use client/server packets to
4071 * compute propagation delay.
4073 * Note that once a key is used from the list,
4074 * it is retained in the key cache until the
4075 * next key is used. This is to allow a client
4076 * to retrieve the encrypted session key
4077 * identifier to verify authenticity.
4079 * If for some reason a key is no longer in the
4080 * key cache, a birthday has happened or the key
4081 * has expired, so the pseudo-random sequence is
4082 * broken. In that case, purge the keylist and
4085 if (peer->keynumber == 0)
4086 make_keylist(peer, peer->dstadr);
4089 xkeyid = peer->keylist[peer->keynumber];
4090 if (authistrusted(xkeyid))
4095 peer->keyid = xkeyid;
4097 switch (peer->hmode) {
4100 * In broadcast server mode the autokey values are
4101 * required by the broadcast clients. Push them when a
4102 * new keylist is generated; otherwise, push the
4103 * association message so the client can request them at
4106 case MODE_BROADCAST:
4107 if (peer->flags & FLAG_ASSOC)
4108 exten = crypto_args(peer, CRYPTO_AUTO |
4109 CRYPTO_RESP, peer->associd, NULL);
4111 exten = crypto_args(peer, CRYPTO_ASSOC |
4112 CRYPTO_RESP, peer->associd, NULL);
4116 * In symmetric modes the parameter, certificate,
4117 * identity, cookie and autokey exchanges are
4118 * required. The leapsecond exchange is optional. But, a
4119 * peer will not believe the other peer until the other
4120 * peer has synchronized, so the certificate exchange
4121 * might loop until then. If a peer finds a broken
4122 * autokey sequence, it uses the autokey exchange to
4123 * retrieve the autokey values. In any case, if a new
4124 * keylist is generated, the autokey values are pushed.
4130 * Parameter, certificate and identity.
4133 exten = crypto_args(peer, CRYPTO_ASSOC,
4134 peer->associd, hostval.ptr);
4135 else if (!(peer->crypto & CRYPTO_FLAG_CERT))
4136 exten = crypto_args(peer, CRYPTO_CERT,
4137 peer->associd, peer->issuer);
4138 else if (!(peer->crypto & CRYPTO_FLAG_VRFY))
4139 exten = crypto_args(peer,
4140 crypto_ident(peer), peer->associd,
4144 * Cookie and autokey. We request the cookie
4145 * only when the this peer and the other peer
4146 * are synchronized. But, this peer needs the
4147 * autokey values when the cookie is zero. Any
4148 * time we regenerate the key list, we offer the
4149 * autokey values without being asked. If for
4150 * some reason either peer finds a broken
4151 * autokey sequence, the autokey exchange is
4152 * used to retrieve the autokey values.
4154 else if ( sys_leap != LEAP_NOTINSYNC
4155 && peer->leap != LEAP_NOTINSYNC
4156 && !(peer->crypto & CRYPTO_FLAG_COOK))
4157 exten = crypto_args(peer, CRYPTO_COOK,
4158 peer->associd, NULL);
4159 else if (!(peer->crypto & CRYPTO_FLAG_AUTO))
4160 exten = crypto_args(peer, CRYPTO_AUTO,
4161 peer->associd, NULL);
4162 else if ( peer->flags & FLAG_ASSOC
4163 && peer->crypto & CRYPTO_FLAG_SIGN)
4164 exten = crypto_args(peer, CRYPTO_AUTO |
4165 CRYPTO_RESP, peer->assoc, NULL);
4168 * Wait for clock sync, then sign the
4169 * certificate and retrieve the leapsecond
4172 else if (sys_leap == LEAP_NOTINSYNC)
4175 else if (!(peer->crypto & CRYPTO_FLAG_SIGN))
4176 exten = crypto_args(peer, CRYPTO_SIGN,
4177 peer->associd, hostval.ptr);
4178 else if (!(peer->crypto & CRYPTO_FLAG_LEAP))
4179 exten = crypto_args(peer, CRYPTO_LEAP,
4180 peer->associd, NULL);
4184 * In client mode the parameter, certificate, identity,
4185 * cookie and sign exchanges are required. The
4186 * leapsecond exchange is optional. If broadcast client
4187 * mode the same exchanges are required, except that the
4188 * autokey exchange is substitutes for the cookie
4189 * exchange, since the cookie is always zero. If the
4190 * broadcast client finds a broken autokey sequence, it
4191 * uses the autokey exchange to retrieve the autokey
4197 * Parameter, certificate and identity.
4200 exten = crypto_args(peer, CRYPTO_ASSOC,
4201 peer->associd, hostval.ptr);
4202 else if (!(peer->crypto & CRYPTO_FLAG_CERT))
4203 exten = crypto_args(peer, CRYPTO_CERT,
4204 peer->associd, peer->issuer);
4205 else if (!(peer->crypto & CRYPTO_FLAG_VRFY))
4206 exten = crypto_args(peer,
4207 crypto_ident(peer), peer->associd,
4211 * Cookie and autokey. These are requests, but
4212 * we use the peer association ID with autokey
4213 * rather than our own.
4215 else if (!(peer->crypto & CRYPTO_FLAG_COOK))
4216 exten = crypto_args(peer, CRYPTO_COOK,
4217 peer->associd, NULL);
4218 else if (!(peer->crypto & CRYPTO_FLAG_AUTO))
4219 exten = crypto_args(peer, CRYPTO_AUTO,
4223 * Wait for clock sync, then sign the
4224 * certificate and retrieve the leapsecond
4227 else if (sys_leap == LEAP_NOTINSYNC)
4230 else if (!(peer->crypto & CRYPTO_FLAG_SIGN))
4231 exten = crypto_args(peer, CRYPTO_SIGN,
4232 peer->associd, hostval.ptr);
4233 else if (!(peer->crypto & CRYPTO_FLAG_LEAP))
4234 exten = crypto_args(peer, CRYPTO_LEAP,
4235 peer->associd, NULL);
4240 * Add a queued extension field if present. This is
4241 * always a request message, so the reply ID is already
4242 * in the message. If an error occurs, the error bit is
4243 * lit in the response.
4245 if (peer->cmmd != NULL) {
4248 temp32 = CRYPTO_RESP;
4249 peer->cmmd->opcode |= htonl(temp32);
4250 sendlen += crypto_xmit(peer, &xpkt, NULL,
4251 sendlen, peer->cmmd, 0);
4257 * Add an extension field created above. All but the
4258 * autokey response message are request messages.
4260 if (exten != NULL) {
4261 if (exten->opcode != 0)
4262 sendlen += crypto_xmit(peer, &xpkt,
4263 NULL, sendlen, exten, 0);
4268 * Calculate the next session key. Since extension
4269 * fields are present, the cookie value is zero.
4271 if (sendlen > (int)LEN_PKT_NOMAC) {
4272 session_key(&peer->dstadr->sin, &peer->srcadr,
4276 #endif /* AUTOKEY */
4279 * Transmit a-priori timestamps
4281 get_systime(&xmt_tx);
4282 if (peer->flip == 0) { /* basic mode */
4283 peer->aorg = xmt_tx;
4284 HTONL_FP(&xmt_tx, &xpkt.xmt);
4285 } else { /* interleaved modes */
4286 if (peer->hmode == MODE_BROADCAST) { /* bcst */
4287 HTONL_FP(&xmt_tx, &xpkt.xmt);
4289 HTONL_FP(&peer->borg, &xpkt.org);
4291 HTONL_FP(&peer->aorg, &xpkt.org);
4292 } else { /* symmetric */
4294 HTONL_FP(&peer->borg, &xpkt.xmt);
4296 HTONL_FP(&peer->aorg, &xpkt.xmt);
4299 xkeyid = peer->keyid;
4300 authlen = authencrypt(xkeyid, (u_int32 *)&xpkt, sendlen);
4302 report_event(PEVNT_AUTH, peer, "no key");
4303 peer->flash |= TEST5; /* auth error */
4309 if (xkeyid > NTP_MAXKEY)
4310 authtrust(xkeyid, 0);
4311 #endif /* AUTOKEY */
4312 if (sendlen > sizeof(xpkt)) {
4313 msyslog(LOG_ERR, "peer_xmit: buffer overflow %zu", sendlen);
4316 peer->t21_bytes = sendlen;
4317 sendpkt(&peer->srcadr, peer->dstadr,
4318 sys_ttl[(peer->ttl >= sys_ttlmax) ? sys_ttlmax : peer->ttl],
4321 peer->throttle += (1 << peer->minpoll) - 2;
4324 * Capture a-posteriori timestamps
4326 get_systime(&xmt_ty);
4327 if (peer->flip != 0) { /* interleaved modes */
4329 peer->aorg = xmt_ty;
4331 peer->borg = xmt_ty;
4332 peer->flip = -peer->flip;
4334 L_SUB(&xmt_ty, &xmt_tx);
4335 LFPTOD(&xmt_ty, peer->xleave);
4337 DPRINTF(1, ("peer_xmit: at %ld %s->%s mode %d keyid %08x len %zu index %d\n",
4338 current_time, latoa(peer->dstadr),
4339 ntoa(&peer->srcadr), peer->hmode, xkeyid, sendlen,
4341 #else /* !AUTOKEY follows */
4342 DPRINTF(1, ("peer_xmit: at %ld %s->%s mode %d keyid %08x len %zu\n",
4343 current_time, peer->dstadr ?
4344 ntoa(&peer->dstadr->sin) : "-",
4345 ntoa(&peer->srcadr), peer->hmode, xkeyid, sendlen));
4346 #endif /* !AUTOKEY */
4355 leap_smear_add_offs(
4361 L_ADD(t, &leap_smear.offset);
4364 ** XXX: Should the smear be added to the root dispersion?
4370 #endif /* LEAP_SMEAR */
4374 * fast_xmit - Send packet for nonpersistent association. Note that
4375 * neither the source or destination can be a broadcast address.
4379 struct recvbuf *rbufp, /* receive packet pointer */
4380 int xmode, /* receive mode */
4381 keyid_t xkeyid, /* transmit key ID */
4382 int flags /* restrict mask */
4385 struct pkt xpkt; /* transmit packet structure */
4386 struct pkt *rpkt; /* receive packet structure */
4387 l_fp xmt_tx, xmt_ty;
4394 * Initialize transmit packet header fields from the receive
4395 * buffer provided. We leave the fields intact as received, but
4396 * set the peer poll at the maximum of the receive peer poll and
4397 * the system minimum poll (ntp_minpoll). This is for KoD rate
4398 * control and not strictly specification compliant, but doesn't
4401 * If the gazinta was from a multicast address, the gazoutta
4402 * must go out another way.
4404 rpkt = &rbufp->recv_pkt;
4405 if (rbufp->dstadr->flags & INT_MCASTOPEN)
4406 rbufp->dstadr = findinterface(&rbufp->recv_srcadr);
4409 * If this is a kiss-o'-death (KoD) packet, show leap
4410 * unsynchronized, stratum zero, reference ID the four-character
4411 * kiss code and system root delay. Note we don't reveal the
4412 * local time, so these packets can't be used for
4415 if (flags & RES_KOD) {
4417 xpkt.li_vn_mode = PKT_LI_VN_MODE(LEAP_NOTINSYNC,
4418 PKT_VERSION(rpkt->li_vn_mode), xmode);
4419 xpkt.stratum = STRATUM_PKT_UNSPEC;
4420 xpkt.ppoll = max(rpkt->ppoll, ntp_minpoll);
4421 xpkt.precision = rpkt->precision;
4422 memcpy(&xpkt.refid, "RATE", 4);
4423 xpkt.rootdelay = rpkt->rootdelay;
4424 xpkt.rootdisp = rpkt->rootdisp;
4425 xpkt.reftime = rpkt->reftime;
4426 xpkt.org = rpkt->xmt;
4427 xpkt.rec = rpkt->xmt;
4428 xpkt.xmt = rpkt->xmt;
4431 * This is a normal packet. Use the system variables.
4436 * Make copies of the variables which can be affected by smearing.
4439 l_fp this_recv_time;
4443 * If we are inside the leap smear interval we add the current smear offset to
4444 * the packet receive time, to the packet transmit time, and eventually to the
4445 * reftime to make sure the reftime isn't later than the transmit/receive times.
4447 xpkt.li_vn_mode = PKT_LI_VN_MODE(xmt_leap,
4448 PKT_VERSION(rpkt->li_vn_mode), xmode);
4450 xpkt.stratum = STRATUM_TO_PKT(sys_stratum);
4451 xpkt.ppoll = max(rpkt->ppoll, ntp_minpoll);
4452 xpkt.precision = sys_precision;
4453 xpkt.refid = sys_refid;
4454 xpkt.rootdelay = HTONS_FP(DTOFP(sys_rootdelay));
4455 xpkt.rootdisp = HTONS_FP(DTOUFP(sys_rootdisp));
4458 this_ref_time = sys_reftime;
4459 if (leap_smear.in_progress) {
4460 leap_smear_add_offs(&this_ref_time, NULL);
4461 xpkt.refid = convertLFPToRefID(leap_smear.offset);
4462 DPRINTF(2, ("fast_xmit: leap_smear.in_progress: refid %8x, smear %s\n",
4464 lfptoa(&leap_smear.offset, 8)
4467 HTONL_FP(&this_ref_time, &xpkt.reftime);
4469 HTONL_FP(&sys_reftime, &xpkt.reftime);
4472 xpkt.org = rpkt->xmt;
4475 this_recv_time = rbufp->recv_time;
4476 if (leap_smear.in_progress)
4477 leap_smear_add_offs(&this_recv_time, NULL);
4478 HTONL_FP(&this_recv_time, &xpkt.rec);
4480 HTONL_FP(&rbufp->recv_time, &xpkt.rec);
4483 get_systime(&xmt_tx);
4485 if (leap_smear.in_progress)
4486 leap_smear_add_offs(&xmt_tx, &this_recv_time);
4488 HTONL_FP(&xmt_tx, &xpkt.xmt);
4491 #ifdef HAVE_NTP_SIGND
4492 if (flags & RES_MSSNTP) {
4493 send_via_ntp_signd(rbufp, xmode, xkeyid, flags, &xpkt);
4496 #endif /* HAVE_NTP_SIGND */
4499 * If the received packet contains a MAC, the transmitted packet
4500 * is authenticated and contains a MAC. If not, the transmitted
4501 * packet is not authenticated.
4503 sendlen = LEN_PKT_NOMAC;
4504 if (rbufp->recv_length == sendlen) {
4505 sendpkt(&rbufp->recv_srcadr, rbufp->dstadr, 0, &xpkt,
4507 DPRINTF(1, ("fast_xmit: at %ld %s->%s mode %d len %lu\n",
4508 current_time, stoa(&rbufp->dstadr->sin),
4509 stoa(&rbufp->recv_srcadr), xmode,
4515 * The received packet contains a MAC, so the transmitted packet
4516 * must be authenticated. For symmetric key cryptography, use
4517 * the predefined and trusted symmetric keys to generate the
4518 * cryptosum. For autokey cryptography, use the server private
4519 * value to generate the cookie, which is unique for every
4520 * source-destination-key ID combination.
4523 if (xkeyid > NTP_MAXKEY) {
4527 * The only way to get here is a reply to a legitimate
4528 * client request message, so the mode must be
4529 * MODE_SERVER. If an extension field is present, there
4530 * can be only one and that must be a command. Do what
4531 * needs, but with private value of zero so the poor
4532 * jerk can decode it. If no extension field is present,
4533 * use the cookie to generate the session key.
4535 cookie = session_key(&rbufp->recv_srcadr,
4536 &rbufp->dstadr->sin, 0, sys_private, 0);
4537 if ((size_t)rbufp->recv_length > sendlen + MAX_MAC_LEN) {
4538 session_key(&rbufp->dstadr->sin,
4539 &rbufp->recv_srcadr, xkeyid, 0, 2);
4540 temp32 = CRYPTO_RESP;
4541 rpkt->exten[0] |= htonl(temp32);
4542 sendlen += crypto_xmit(NULL, &xpkt, rbufp,
4543 sendlen, (struct exten *)rpkt->exten,
4546 session_key(&rbufp->dstadr->sin,
4547 &rbufp->recv_srcadr, xkeyid, cookie, 2);
4550 #endif /* AUTOKEY */
4551 get_systime(&xmt_tx);
4552 sendlen += authencrypt(xkeyid, (u_int32 *)&xpkt, sendlen);
4554 if (xkeyid > NTP_MAXKEY)
4555 authtrust(xkeyid, 0);
4556 #endif /* AUTOKEY */
4557 sendpkt(&rbufp->recv_srcadr, rbufp->dstadr, 0, &xpkt, sendlen);
4558 get_systime(&xmt_ty);
4559 L_SUB(&xmt_ty, &xmt_tx);
4560 sys_authdelay = xmt_ty;
4561 DPRINTF(1, ("fast_xmit: at %ld %s->%s mode %d keyid %08x len %lu\n",
4562 current_time, ntoa(&rbufp->dstadr->sin),
4563 ntoa(&rbufp->recv_srcadr), xmode, xkeyid,
4569 * pool_xmit - resolve hostname or send unicast solicitation for pool.
4573 struct peer *pool /* pool solicitor association */
4577 struct pkt xpkt; /* transmit packet structure */
4578 struct addrinfo hints;
4580 struct interface * lcladr;
4581 sockaddr_u * rmtadr;
4587 if (NULL == pool->ai) {
4588 if (pool->addrs != NULL) {
4589 /* free() is used with copy_addrinfo_list() */
4594 hints.ai_family = AF(&pool->srcadr);
4595 hints.ai_socktype = SOCK_DGRAM;
4596 hints.ai_protocol = IPPROTO_UDP;
4597 /* ignore getaddrinfo_sometime() errors, we will retry */
4598 rc = getaddrinfo_sometime(
4603 &pool_name_resolved,
4604 (void *)(intptr_t)pool->associd);
4606 DPRINTF(1, ("pool DNS lookup %s started\n",
4610 "unable to start pool DNS %s: %m",
4616 /* copy_addrinfo_list ai_addr points to a sockaddr_u */
4617 rmtadr = (sockaddr_u *)(void *)pool->ai->ai_addr;
4618 pool->ai = pool->ai->ai_next;
4619 p = findexistingpeer(rmtadr, NULL, NULL, MODE_CLIENT, 0, NULL);
4620 } while (p != NULL && pool->ai != NULL);
4622 return; /* out of addresses, re-query DNS next poll */
4623 restrictions(rmtadr, &r4a);
4624 restrict_mask = r4a.rflags;
4625 if (RES_FLAGS & restrict_mask)
4626 restrict_source(rmtadr, 0,
4627 current_time + POOL_SOLICIT_WINDOW + 1);
4628 lcladr = findinterface(rmtadr);
4629 memset(&xpkt, 0, sizeof(xpkt));
4630 xpkt.li_vn_mode = PKT_LI_VN_MODE(sys_leap, pool->version,
4632 xpkt.stratum = STRATUM_TO_PKT(sys_stratum);
4633 xpkt.ppoll = pool->hpoll;
4634 xpkt.precision = sys_precision;
4635 xpkt.refid = sys_refid;
4636 xpkt.rootdelay = HTONS_FP(DTOFP(sys_rootdelay));
4637 xpkt.rootdisp = HTONS_FP(DTOUFP(sys_rootdisp));
4638 HTONL_FP(&sys_reftime, &xpkt.reftime);
4639 get_systime(&xmt_tx);
4640 pool->aorg = xmt_tx;
4641 HTONL_FP(&xmt_tx, &xpkt.xmt);
4642 sendpkt(rmtadr, lcladr,
4643 sys_ttl[(pool->ttl >= sys_ttlmax) ? sys_ttlmax : pool->ttl],
4644 &xpkt, LEN_PKT_NOMAC);
4646 pool->throttle += (1 << pool->minpoll) - 2;
4647 DPRINTF(1, ("pool_xmit: at %ld %s->%s pool\n",
4648 current_time, latoa(lcladr), stoa(rmtadr)));
4649 msyslog(LOG_INFO, "Soliciting pool server %s", stoa(rmtadr));
4656 * group_test - test if this is the same group
4658 * host assoc return action
4659 * none none 0 mobilize *
4660 * none group 0 mobilize *
4661 * group none 0 mobilize *
4662 * group group 1 mobilize
4663 * group different 1 ignore
4664 * * ignore if notrust
4675 if (strcmp(grp, sys_groupname) == 0)
4681 if (strcmp(grp, ident) == 0)
4686 #endif /* AUTOKEY */
4696 const char * service,
4697 const struct addrinfo * hints,
4698 const struct addrinfo * res
4701 struct peer * pool; /* pool solicitor association */
4706 "error resolving pool %s: %s (%d)",
4707 name, gai_strerror(rescode), rescode);
4711 assoc = (associd_t)(intptr_t)context;
4712 pool = findpeerbyassoc(assoc);
4715 "Could not find assoc %u for pool DNS %s",
4719 DPRINTF(1, ("pool DNS %s completed\n", name));
4720 pool->addrs = copy_addrinfo_list(res);
4721 pool->ai = pool->addrs;
4730 * key_expire - purge the key list
4734 struct peer *peer /* peer structure pointer */
4739 if (peer->keylist != NULL) {
4740 for (i = 0; i <= peer->keynumber; i++)
4741 authtrust(peer->keylist[i], 0);
4742 free(peer->keylist);
4743 peer->keylist = NULL;
4745 value_free(&peer->sndval);
4746 peer->keynumber = 0;
4747 peer->flags &= ~FLAG_ASSOC;
4748 DPRINTF(1, ("key_expire: at %lu associd %d\n", current_time,
4751 #endif /* AUTOKEY */
4755 * local_refid(peer) - check peer refid to avoid selecting peers
4756 * currently synced to this ntpd.
4765 if (p->dstadr != NULL && !(INT_MCASTIF & p->dstadr->flags))
4766 unicast_ep = p->dstadr;
4768 unicast_ep = findinterface(&p->srcadr);
4770 if (unicast_ep != NULL && p->refid == unicast_ep->addr_refid)
4778 * Determine if the peer is unfit for synchronization
4780 * A peer is unfit for synchronization if
4781 * > TEST10 bad leap or stratum below floor or at or above ceiling
4782 * > TEST11 root distance exceeded for remote peer
4783 * > TEST12 a direct or indirect synchronization loop would form
4784 * > TEST13 unreachable or noselect
4786 int /* FALSE if fit, TRUE if unfit */
4788 struct peer *peer /* peer structure pointer */
4794 * A stratum error occurs if (1) the server has never been
4795 * synchronized, (2) the server stratum is below the floor or
4796 * greater than or equal to the ceiling.
4798 if ( peer->leap == LEAP_NOTINSYNC
4799 || peer->stratum < sys_floor
4800 || peer->stratum >= sys_ceiling) {
4801 rval |= TEST10; /* bad synch or stratum */
4805 * A distance error for a remote peer occurs if the root
4806 * distance is greater than or equal to the distance threshold
4807 * plus the increment due to one host poll interval.
4809 if ( !(peer->flags & FLAG_REFCLOCK)
4810 && root_distance(peer) >= sys_maxdist
4811 + clock_phi * ULOGTOD(peer->hpoll)) {
4812 rval |= TEST11; /* distance exceeded */
4816 * A loop error occurs if the remote peer is synchronized to the
4817 * local peer or if the remote peer is synchronized to the same
4818 * server as the local peer but only if the remote peer is
4819 * neither a reference clock nor an orphan.
4821 if (peer->stratum > 1 && local_refid(peer)) {
4822 rval |= TEST12; /* synchronization loop */
4826 * An unreachable error occurs if the server is unreachable or
4827 * the noselect bit is set.
4829 if (!peer->reach || (peer->flags & FLAG_NOSELECT)) {
4830 rval |= TEST13; /* unreachable */
4833 peer->flash &= ~PEER_TEST_MASK;
4834 peer->flash |= rval;
4840 * Find the precision of this particular machine
4842 #define MINSTEP 20e-9 /* minimum clock increment (s) */
4843 #define MAXSTEP 1 /* maximum clock increment (s) */
4844 #define MINCHANGES 12 /* minimum number of step samples */
4845 #define MAXLOOPS ((int)(1. / MINSTEP)) /* avoid infinite loop */
4848 * This routine measures the system precision defined as the minimum of
4849 * a sequence of differences between successive readings of the system
4850 * clock. However, if a difference is less than MINSTEP, the clock has
4851 * been read more than once during a clock tick and the difference is
4852 * ignored. We set MINSTEP greater than zero in case something happens
4853 * like a cache miss, and to tolerate underlying system clocks which
4854 * ensure each reading is strictly greater than prior readings while
4855 * using an underlying stepping (not interpolated) clock.
4857 * sys_tick and sys_precision represent the time to read the clock for
4858 * systems with high-precision clocks, and the tick interval or step
4859 * size for lower-precision stepping clocks.
4861 * This routine also measures the time to read the clock on stepping
4862 * system clocks by counting the number of readings between changes of
4863 * the underlying clock. With either type of clock, the minimum time
4864 * to read the clock is saved as sys_fuzz, and used to ensure the
4865 * get_systime() readings always increase and are fuzzed below sys_fuzz.
4868 measure_precision(void)
4871 * With sys_fuzz set to zero, get_systime() fuzzing of low bits
4872 * is effectively disabled. trunc_os_clock is FALSE to disable
4873 * get_ostime() simulation of a low-precision system clock.
4876 trunc_os_clock = FALSE;
4877 measured_tick = measure_tick_fuzz();
4878 set_sys_tick_precision(measured_tick);
4879 msyslog(LOG_INFO, "proto: precision = %.3f usec (%d)",
4880 sys_tick * 1e6, sys_precision);
4881 if (sys_fuzz < sys_tick) {
4882 msyslog(LOG_NOTICE, "proto: fuzz beneath %.3f usec",
4889 * measure_tick_fuzz()
4891 * measures the minimum time to read the clock (stored in sys_fuzz)
4892 * and returns the tick, the larger of the minimum increment observed
4893 * between successive clock readings and the time to read the clock.
4896 measure_tick_fuzz(void)
4898 l_fp minstep; /* MINSTEP as l_fp */
4899 l_fp val; /* current seconds fraction */
4900 l_fp last; /* last seconds fraction */
4901 l_fp ldiff; /* val - last */
4902 double tick; /* computed tick value */
4907 int i; /* log2 precision */
4913 DTOLFP(MINSTEP, &minstep);
4915 for (i = 0; i < MAXLOOPS && changes < MINCHANGES; i++) {
4918 L_SUB(&ldiff, &last);
4920 if (L_ISGT(&ldiff, &minstep)) {
4921 max_repeats = max(repeats, max_repeats);
4924 LFPTOD(&ldiff, diff);
4925 tick = min(diff, tick);
4930 if (changes < MINCHANGES) {
4931 msyslog(LOG_ERR, "Fatal error: precision could not be measured (MINSTEP too large?)");
4935 if (0 == max_repeats) {
4938 set_sys_fuzz(tick / max_repeats);
4946 set_sys_tick_precision(
4954 "unsupported tick %.3f > 1s ignored", tick);
4957 if (tick < measured_tick) {
4959 "proto: tick %.3f less than measured tick %.3f, ignored",
4960 tick, measured_tick);
4962 } else if (tick > measured_tick) {
4963 trunc_os_clock = TRUE;
4965 "proto: truncating system clock to multiples of %.9f",
4971 * Find the nearest power of two.
4973 for (i = 0; tick <= 1; i--)
4975 if (tick - 1 > 1 - tick / 2)
4978 sys_precision = (s_char)i;
4983 * init_proto - initialize the protocol module's data
4992 * Fill in the sys_* stuff. Default is don't listen to
4993 * broadcasting, require authentication.
4995 set_sys_leap(LEAP_NOTINSYNC);
4996 sys_stratum = STRATUM_UNSPEC;
4997 memcpy(&sys_refid, "INIT", 4);
5001 L_CLR(&sys_reftime);
5003 measure_precision();
5004 get_systime(&dummy);
5006 sys_manycastserver = 0;
5008 sys_bdelay = BDELAY_DEFAULT; /*[Bug 3031] delay cutoff */
5009 sys_authenticate = 1;
5010 sys_stattime = current_time;
5011 orphwait = current_time + sys_orphwait;
5013 for (i = 0; i < MAX_TTL; ++i)
5014 sys_ttl[i] = (u_char)((i * 256) / MAX_TTL);
5015 sys_ttlmax = (MAX_TTL - 1);
5022 * proto_config - configure the protocol module
5033 * Figure out what he wants to change, then do it
5035 DPRINTF(2, ("proto_config: code %d value %lu dvalue %lf\n",
5036 item, value, dvalue));
5041 * enable and disable commands - arguments are Boolean.
5043 case PROTO_AUTHENTICATE: /* authentication (auth) */
5044 sys_authenticate = value;
5047 case PROTO_BROADCLIENT: /* broadcast client (bclient) */
5048 sys_bclient = (int)value;
5049 if (sys_bclient == 0)
5056 case PROTO_CAL: /* refclock calibrate (calibrate) */
5059 #endif /* REFCLOCK */
5061 case PROTO_KERNEL: /* kernel discipline (kernel) */
5065 case PROTO_MONITOR: /* monitoring (monitor) */
5071 msyslog(LOG_WARNING,
5072 "restrict: 'monitor' cannot be disabled while 'limited' is enabled");
5076 case PROTO_NTP: /* NTP discipline (ntp) */
5080 case PROTO_MODE7: /* mode7 management (ntpdc) */
5084 case PROTO_PPS: /* PPS discipline (pps) */
5085 hardpps_enable = value;
5088 case PROTO_FILEGEN: /* statistics (stats) */
5089 stats_control = value;
5093 * tos command - arguments are double, sometimes cast to int
5096 case PROTO_BCPOLLBSTEP: /* Broadcast Poll Backstep gate (bcpollbstep) */
5097 sys_bcpollbstep = (u_char)dvalue;
5100 case PROTO_BEACON: /* manycast beacon (beacon) */
5101 sys_beacon = (int)dvalue;
5104 case PROTO_BROADDELAY: /* default broadcast delay (bdelay) */
5105 sys_bdelay = (dvalue ? dvalue : BDELAY_DEFAULT);
5108 case PROTO_CEILING: /* stratum ceiling (ceiling) */
5109 sys_ceiling = (int)dvalue;
5112 case PROTO_COHORT: /* cohort switch (cohort) */
5113 sys_cohort = (int)dvalue;
5116 case PROTO_FLOOR: /* stratum floor (floor) */
5117 sys_floor = (int)dvalue;
5120 case PROTO_MAXCLOCK: /* maximum candidates (maxclock) */
5121 sys_maxclock = (int)dvalue;
5124 case PROTO_MAXDIST: /* select threshold (maxdist) */
5125 sys_maxdist = dvalue;
5128 case PROTO_CALLDELAY: /* modem call delay (mdelay) */
5129 break; /* NOT USED */
5131 case PROTO_MINCLOCK: /* minimum candidates (minclock) */
5132 sys_minclock = (int)dvalue;
5135 case PROTO_MINDISP: /* minimum distance (mindist) */
5136 sys_mindisp = dvalue;
5139 case PROTO_MINSANE: /* minimum survivors (minsane) */
5140 sys_minsane = (int)dvalue;
5143 case PROTO_ORPHAN: /* orphan stratum (orphan) */
5144 sys_orphan = (int)dvalue;
5147 case PROTO_ORPHWAIT: /* orphan wait (orphwait) */
5148 orphwait -= sys_orphwait;
5149 sys_orphwait = (int)dvalue;
5150 orphwait += sys_orphwait;
5154 * Miscellaneous commands
5156 case PROTO_MULTICAST_ADD: /* add group address */
5158 io_multicast_add(svalue);
5162 case PROTO_MULTICAST_DEL: /* delete group address */
5164 io_multicast_del(svalue);
5168 * Peer_clear Early policy choices
5171 case PROTO_PCEDIGEST: /* Digest */
5172 peer_clear_digest_early = value;
5176 * Unpeer Early policy choices
5179 case PROTO_UECRYPTO: /* Crypto */
5180 unpeer_crypto_early = value;
5183 case PROTO_UECRYPTONAK: /* Crypto_NAK */
5184 unpeer_crypto_nak_early = value;
5187 case PROTO_UEDIGEST: /* Digest */
5188 unpeer_digest_early = value;
5193 "proto: unsupported option %d", item);
5199 * proto_clr_stats - clear protocol stat counters
5202 proto_clr_stats(void)
5204 sys_stattime = current_time;
5213 sys_limitrejected = 0;
projects / FreeBSD / stable / 10.git / blob