1 /* $NetBSD: ntp_proto.c,v 1.19 2022/10/09 21:41:03 christos Exp $ */
2
3 /*
4 * ntp_proto.c - NTP version 4 protocol machinery
5 *
6 * ATTENTION: Get approval from Harlan on all changes to this file!
7 * (Harlan will be discussing these changes with Dave Mills.)
8 *
9 */
10 #ifdef HAVE_CONFIG_H
11 #include <config.h>
12 #endif
13
14 #include "ntpd.h"
15 #include "ntp_stdlib.h"
16 #include "ntp_unixtime.h"
17 #include "ntp_control.h"
18 #include "ntp_string.h"
19 #include "ntp_leapsec.h"
20 #include "ntp_psl.h"
21 #include "refidsmear.h"
22 #include "lib_strbuf.h"
23
24 #include <stdio.h>
25 #ifdef HAVE_LIBSCF_H
26 #include <libscf.h>
27 #endif
28 #ifdef HAVE_UNISTD_H
29 #include <unistd.h>
30 #endif
31
32 /* [Bug 3031] define automatic broadcastdelay cutoff preset */
33 #ifndef BDELAY_DEFAULT
34 # define BDELAY_DEFAULT (-0.050)
35 #endif
36
37 #define SRVFUZ_SHIFT 6 /* 64 seconds */
38 #define SRVRSP_FUZZ(x) \
39 do { \
40 x.l_uf &= 0; \
41 x.l_ui &= ~((1 << SRVFUZ_SHIFT) - 1U); \
42 } while(0)
43
44 /*
45 * This macro defines the authentication state. If x is 1 authentication
46 * is required; otherwise it is optional.
47 */
48 #define AUTH(x, y) ((x) ? (y) == AUTH_OK \
49 : (y) == AUTH_OK || (y) == AUTH_NONE)
50
51 typedef enum
52 auth_state {
53 AUTH_UNKNOWN = -1, /* Unknown */
54 AUTH_NONE, /* authentication not required */
55 AUTH_OK, /* authentication OK */
56 AUTH_ERROR, /* authentication error */
57 AUTH_CRYPTO /* crypto_NAK */
58 } auth_code;
59
60 /*
61 * Set up Kiss Code values
62 */
63
64 typedef enum
65 kiss_codes {
66 NOKISS, /* No Kiss Code */
67 RATEKISS, /* Rate limit Kiss Code */
68 DENYKISS, /* Deny Kiss */
69 RSTRKISS, /* Restricted Kiss */
70 XKISS /* Experimental Kiss */
71 } kiss_code;
72
73 typedef enum
74 nak_error_codes {
75 NONAK, /* No NAK seen */
76 INVALIDNAK, /* NAK cannot be used */
77 VALIDNAK /* NAK is valid */
78 } nak_code;
79
80 /*
81 * traffic shaping parameters
82 */
83 #define NTP_IBURST 6 /* packets in iburst */
84 #define RESP_DELAY 1 /* refclock burst delay (s) */
85
86 /*
87 * pool soliciting restriction duration (s)
88 */
89 #define POOL_SOLICIT_WINDOW 8
90
91 /*
92 * flag bits propagated from pool to individual peers
93 */
94 #define POOL_FLAG_PMASK (FLAG_IBURST | FLAG_NOSELECT)
95
96 /*
97 * peer_select groups statistics for a peer used by clock_select() and
98 * clock_cluster().
99 */
100 typedef struct peer_select_tag {
101 struct peer * peer;
102 double synch; /* sync distance */
103 double error; /* jitter */
104 double seljit; /* selection jitter */
105 } peer_select;
106
107 /*
108 * System variables are declared here. Unless specified otherwise, all
109 * times are in seconds.
110 */
111 u_char sys_leap; /* system leap indicator, use set_sys_leap() to change this */
112 u_char xmt_leap; /* leap indicator sent in client requests, set up by set_sys_leap() */
113 u_char sys_stratum; /* system stratum */
114 s_char sys_precision; /* local clock precision (log2 s) */
115 double sys_rootdelay; /* roundtrip delay to root (primary source) */
116 double sys_rootdisp; /* dispersion to root (primary source) */
117 double prev_rootdisp; /* previous root dispersion */
118 double p2_rootdisp; /* previous previous root dispersion */
119 u_int32 sys_refid; /* reference id (network byte order) */
120 l_fp sys_reftime; /* last update time */
121 l_fp prev_reftime; /* previous sys_reftime */
122 l_fp p2_reftime; /* previous previous sys_reftime */
123 u_long prev_time; /* "current_time" when saved prev_time */
124 u_long p2_time; /* previous prev_time */
125 struct peer *sys_peer; /* current peer */
126
127 #ifdef LEAP_SMEAR
128 struct leap_smear_info leap_smear;
129 #endif
130 int leap_sec_in_progress;
131
132 /*
133 * Rate controls. Leaky buckets are used to throttle the packet
134 * transmission rates in order to protect busy servers such as at NIST
135 * and USNO. There is a counter for each association and another for KoD
136 * packets. The association counter decrements each second, but not
137 * below zero. Each time a packet is sent the counter is incremented by
138 * a configurable value representing the average interval between
139 * packets. A packet is delayed as long as the counter is greater than
140 * zero. Note this does not affect the time value computations.
141 */
142 /*
143 * Nonspecified system state variables
144 */
145 int sys_bclient; /* broadcast client enable */
146 double sys_bdelay; /* broadcast client default delay */
147 int sys_authenticate; /* requre authentication for config */
148 l_fp sys_authdelay; /* authentication delay */
149 double sys_offset; /* current local clock offset */
150 double sys_mindisp = MINDISPERSE; /* minimum distance (s) */
151 double sys_maxdist = MAXDISTANCE; /* selection threshold */
152 double sys_jitter; /* system jitter */
153 u_long sys_epoch; /* last clock update time */
154 static double sys_clockhop; /* clockhop threshold */
155 static int leap_vote_ins; /* leap consensus for insert */
156 static int leap_vote_del; /* leap consensus for delete */
157 keyid_t sys_private; /* private value for session seed */
158 int sys_manycastserver; /* respond to manycast client pkts */
159 int ntp_mode7; /* respond to ntpdc (mode7) */
160 int peer_ntpdate; /* active peers in ntpdate mode */
161 int sys_survivors; /* truest of the truechimers */
162 char *sys_ident = NULL; /* identity scheme */
163
164 /*
165 * TOS and multicast mapping stuff
166 */
167 int sys_floor = 0; /* cluster stratum floor */
168 u_char sys_bcpollbstep = 0; /* Broadcast Poll backstep gate */
169 int sys_ceiling = STRATUM_UNSPEC - 1; /* cluster stratum ceiling */
170 int sys_minsane = 1; /* minimum candidates */
171 int sys_minclock = NTP_MINCLOCK; /* minimum candidates */
172 int sys_maxclock = NTP_MAXCLOCK; /* maximum candidates */
173 int sys_cohort = 0; /* cohort switch */
174 int sys_orphan = STRATUM_UNSPEC + 1; /* orphan stratum */
175 int sys_orphwait = NTP_ORPHWAIT; /* orphan wait */
176 int sys_beacon = BEACON; /* manycast beacon interval */
177 u_int sys_ttlmax; /* max ttl mapping vector index */
178 u_char sys_ttl[MAX_TTL]; /* ttl mapping vector */
179
180 /*
181 * Statistics counters - first the good, then the bad
182 */
183 u_long sys_stattime; /* elapsed time */
184 u_long sys_received; /* packets received */
185 u_long sys_processed; /* packets for this host */
186 u_long sys_newversion; /* current version */
187 u_long sys_oldversion; /* old version */
188 u_long sys_restricted; /* access denied */
189 u_long sys_badlength; /* bad length or format */
190 u_long sys_badauth; /* bad authentication */
191 u_long sys_declined; /* declined */
192 u_long sys_limitrejected; /* rate exceeded */
193 u_long sys_kodsent; /* KoD sent */
194
195 /*
196 * Mechanism knobs: how soon do we peer_clear() or unpeer()?
197 *
198 * The default way is "on-receipt". If this was a packet from a
199 * well-behaved source, on-receipt will offer the fastest recovery.
200 * If this was from a DoS attack, the default way makes it easier
201 * for a bad-guy to DoS us. So look and see what bites you harder
202 * and choose according to your environment.
203 */
204 int peer_clear_digest_early = 1; /* bad digest (TEST5) and Autokey */
205 int unpeer_crypto_early = 1; /* bad crypto (TEST9) */
206 int unpeer_crypto_nak_early = 1; /* crypto_NAK (TEST5) */
207 int unpeer_digest_early = 1; /* bad digest (TEST5) */
208
209 int dynamic_interleave = DYNAMIC_INTERLEAVE; /* Bug 2978 mitigation */
210
211 int kiss_code_check(u_char hisleap, u_char hisstratum, u_char hismode, u_int32 refid);
212 nak_code valid_NAK (struct peer *peer, struct recvbuf *rbufp, u_char hismode);
213 static double root_distance (struct peer *);
214 static void clock_combine (peer_select *, int, int);
215 static void peer_xmit (struct peer *);
216 static void fast_xmit (struct recvbuf *, int, keyid_t, int);
217 static void pool_xmit (struct peer *);
218 static void clock_update (struct peer *);
219 static void measure_precision(void);
220 static double measure_tick_fuzz(void);
221 static int local_refid (struct peer *);
222 static int peer_unfit (struct peer *);
223 #ifdef AUTOKEY
224 static int group_test (char *, char *);
225 #endif /* AUTOKEY */
226 #ifdef WORKER
227 void pool_name_resolved (int, int, void *, const char *,
228 const char *, const struct addrinfo *,
229 const struct addrinfo *);
230 #endif /* WORKER */
231
232 const char * amtoa (int am);
233
234
235 void
set_sys_leap(u_char new_sys_leap)236 set_sys_leap(
237 u_char new_sys_leap
238 )
239 {
240 sys_leap = new_sys_leap;
241 xmt_leap = sys_leap;
242
243 /*
244 * Under certain conditions we send faked leap bits to clients, so
245 * eventually change xmt_leap below, but never change LEAP_NOTINSYNC.
246 */
247 if (xmt_leap != LEAP_NOTINSYNC) {
248 if (leap_sec_in_progress) {
249 /* always send "not sync" */
250 xmt_leap = LEAP_NOTINSYNC;
251 }
252 #ifdef LEAP_SMEAR
253 else {
254 /*
255 * If leap smear is enabled in general we must
256 * never send a leap second warning to clients,
257 * so make sure we only send "in sync".
258 */
259 if (leap_smear.enabled)
260 xmt_leap = LEAP_NOWARNING;
261 }
262 #endif /* LEAP_SMEAR */
263 }
264 }
265
266
267 /*
268 * Kiss Code check
269 */
270 int
kiss_code_check(u_char hisleap,u_char hisstratum,u_char hismode,u_int32 refid)271 kiss_code_check(
272 u_char hisleap,
273 u_char hisstratum,
274 u_char hismode,
275 u_int32 refid
276 )
277 {
278
279 if ( hismode == MODE_SERVER
280 && hisleap == LEAP_NOTINSYNC
281 && hisstratum == STRATUM_UNSPEC) {
282 if(memcmp(&refid,"RATE", 4) == 0) {
283 return (RATEKISS);
284 } else if(memcmp(&refid,"DENY", 4) == 0) {
285 return (DENYKISS);
286 } else if(memcmp(&refid,"RSTR", 4) == 0) {
287 return (RSTRKISS);
288 } else if(memcmp(&refid,"X", 1) == 0) {
289 return (XKISS);
290 }
291 }
292 return (NOKISS);
293 }
294
295
296 /*
297 * Check that NAK is valid
298 */
299 nak_code
valid_NAK(struct peer * peer,struct recvbuf * rbufp,u_char hismode)300 valid_NAK(
301 struct peer *peer,
302 struct recvbuf *rbufp,
303 u_char hismode
304 )
305 {
306 int base_packet_length = MIN_V4_PKT_LEN;
307 int remainder_size;
308 struct pkt * rpkt;
309 int keyid;
310 l_fp p_org; /* origin timestamp */
311 const l_fp * myorg; /* selected peer origin */
312
313 /*
314 * Check to see if there is something beyond the basic packet
315 */
316 if (rbufp->recv_length == base_packet_length) {
317 return NONAK;
318 }
319
320 remainder_size = rbufp->recv_length - base_packet_length;
321 /*
322 * Is this a potential NAK?
323 */
324 if (remainder_size != 4) {
325 return NONAK;
326 }
327
328 /*
329 * Only server responses can contain NAK's
330 */
331
332 if (hismode != MODE_SERVER &&
333 hismode != MODE_ACTIVE &&
334 hismode != MODE_PASSIVE
335 ) {
336 return INVALIDNAK;
337 }
338
339 /*
340 * Make sure that the extra field in the packet is all zeros
341 */
342 rpkt = &rbufp->recv_pkt;
343 keyid = ntohl(((u_int32 *)rpkt)[base_packet_length / 4]);
344 if (keyid != 0) {
345 return INVALIDNAK;
346 }
347
348 /*
349 * During the first few packets of the autokey dance there will
350 * not (yet) be a keyid, but in this case FLAG_SKEY is set.
351 * So the NAK is invalid if either there's no peer, or
352 * if the keyid is 0 and FLAG_SKEY is not set.
353 */
354 if (!peer || (!peer->keyid && !(peer->flags & FLAG_SKEY))) {
355 return INVALIDNAK;
356 }
357
358 /*
359 * The ORIGIN must match, or this cannot be a valid NAK, either.
360 */
361
362 if (FLAG_LOOPNONCE & peer->flags) {
363 myorg = &peer->nonce;
364 } else {
365 if (peer->flip > 0) {
366 myorg = &peer->borg;
367 } else {
368 myorg = &peer->aorg;
369 }
370 }
371
372 NTOHL_FP(&rpkt->org, &p_org);
373
374 if (L_ISZERO(&p_org) ||
375 L_ISZERO( myorg) ||
376 !L_ISEQU(&p_org, myorg)) {
377 return INVALIDNAK;
378 }
379
380 /* If we ever passed all that checks, we should be safe. Well,
381 * as safe as we can ever be with an unauthenticated crypto-nak.
382 */
383 return VALIDNAK;
384 }
385
386
387 /*
388 * transmit - transmit procedure called by poll timeout
389 */
390 void
transmit(struct peer * peer)391 transmit(
392 struct peer *peer /* peer structure pointer */
393 )
394 {
395 u_char hpoll;
396
397 /*
398 * The polling state machine. There are two kinds of machines,
399 * those that never expect a reply (broadcast and manycast
400 * server modes) and those that do (all other modes). The dance
401 * is intricate...
402 */
403 hpoll = peer->hpoll;
404
405 /*
406 * If we haven't received anything (even if unsync) since last
407 * send, reset ppoll.
408 */
409 if (peer->outdate > peer->timelastrec && !peer->reach)
410 peer->ppoll = peer->maxpoll;
411
412 /*
413 * In broadcast mode the poll interval is never changed from
414 * minpoll.
415 */
416 if (peer->cast_flags & (MDF_BCAST | MDF_MCAST)) {
417 peer->outdate = current_time;
418 poll_update(peer, hpoll, 0);
419 if (sys_leap != LEAP_NOTINSYNC)
420 peer_xmit(peer);
421 return;
422 }
423
424 /*
425 * In manycast mode we start with unity ttl. The ttl is
426 * increased by one for each poll until either sys_maxclock
427 * servers have been found or the maximum ttl is reached. When
428 * sys_maxclock servers are found we stop polling until one or
429 * more servers have timed out or until less than sys_minclock
430 * associations turn up. In this case additional better servers
431 * are dragged in and preempt the existing ones. Once every
432 * sys_beacon seconds we are to transmit unconditionally, but
433 * this code is not quite right -- peer->unreach counts polls
434 * and is being compared with sys_beacon, so the beacons happen
435 * every sys_beacon polls.
436 */
437 if (peer->cast_flags & MDF_ACAST) {
438 peer->outdate = current_time;
439 poll_update(peer, hpoll, 0);
440 if (peer->unreach > sys_beacon) {
441 peer->unreach = 0;
442 peer->ttl = 0;
443 peer_xmit(peer);
444 } else if ( sys_survivors < sys_minclock
445 || peer_associations < sys_maxclock) {
446 if (peer->ttl < sys_ttlmax)
447 peer->ttl++;
448 peer_xmit(peer);
449 }
450 peer->unreach++;
451 return;
452 }
453
454 /*
455 * Pool associations transmit unicast solicitations when there
456 * are less than a hard limit of 2 * sys_maxclock associations,
457 * and either less than sys_minclock survivors or less than
458 * sys_maxclock associations. The hard limit prevents unbounded
459 * growth in associations if the system clock or network quality
460 * result in survivor count dipping below sys_minclock often.
461 * This was observed testing with pool, where sys_maxclock == 12
462 * resulted in 60 associations without the hard limit. A
463 * similar hard limit on manycastclient ephemeral associations
464 * may be appropriate.
465 */
466 if (peer->cast_flags & MDF_POOL) {
467 peer->outdate = current_time;
468 poll_update(peer, hpoll, 0);
469 if ( (peer_associations <= 2 * sys_maxclock)
470 && ( peer_associations < sys_maxclock
471 || sys_survivors < sys_minclock))
472 pool_xmit(peer);
473 return;
474 }
475
476 /*
477 * In unicast modes the dance is much more intricate. It is
478 * designed to back off whenever possible to minimize network
479 * traffic.
480 */
481 if (peer->burst == 0) {
482 u_char oreach;
483
484 /*
485 * Update the reachability status. If not heard for
486 * three consecutive polls, stuff infinity in the clock
487 * filter.
488 */
489 oreach = peer->reach;
490 peer->outdate = current_time;
491 peer->unreach++;
492 peer->reach <<= 1;
493 if (!peer->reach) {
494
495 /*
496 * Here the peer is unreachable. If it was
497 * previously reachable raise a trap. Send a
498 * burst if enabled.
499 */
500 clock_filter(peer, 0., 0., MAXDISPERSE);
501 if (oreach) {
502 peer_unfit(peer);
503 report_event(PEVNT_UNREACH, peer, NULL);
504 }
505 if ( (peer->flags & FLAG_IBURST)
506 && peer->retry == 0)
507 peer->retry = NTP_RETRY;
508 } else {
509
510 /*
511 * Here the peer is reachable. Send a burst if
512 * enabled and the peer is fit. Reset unreach
513 * for persistent and ephemeral associations.
514 * Unreach is also reset for survivors in
515 * clock_select().
516 */
517 hpoll = sys_poll;
518 if (!(peer->flags & FLAG_PREEMPT))
519 peer->unreach = 0;
520 if ( (peer->flags & FLAG_BURST)
521 && peer->retry == 0
522 && !peer_unfit(peer))
523 peer->retry = NTP_RETRY;
524 }
525
526 /*
527 * Watch for timeout. If ephemeral, toss the rascal;
528 * otherwise, bump the poll interval. Note the
529 * poll_update() routine will clamp it to maxpoll.
530 * If preemptible and we have more peers than maxclock,
531 * and this peer has the minimum score of preemptibles,
532 * demobilize.
533 */
534 if (peer->unreach >= NTP_UNREACH) {
535 hpoll++;
536 /* ephemeral: no FLAG_CONFIG nor FLAG_PREEMPT */
537 if (!(peer->flags & (FLAG_CONFIG | FLAG_PREEMPT))) {
538 report_event(PEVNT_RESTART, peer, "timeout");
539 peer_clear(peer, "TIME");
540 unpeer(peer);
541 return;
542 }
543 if ( (peer->flags & FLAG_PREEMPT)
544 && (peer_associations > sys_maxclock)
545 && score_all(peer)) {
546 report_event(PEVNT_RESTART, peer, "timeout");
547 peer_clear(peer, "TIME");
548 unpeer(peer);
549 return;
550 }
551 }
552 } else {
553 peer->burst--;
554 if (peer->burst == 0) {
555
556 /*
557 * If ntpdate mode and the clock has not been
558 * set and all peers have completed the burst,
559 * we declare a successful failure.
560 */
561 if (mode_ntpdate) {
562 peer_ntpdate--;
563 if (peer_ntpdate == 0) {
564 msyslog(LOG_NOTICE,
565 "ntpd: no servers found");
566 if (!msyslog_term)
567 printf(
568 "ntpd: no servers found\n");
569 exit (0);
570 }
571 }
572 }
573 }
574 if (peer->retry > 0)
575 peer->retry--;
576
577 /*
578 * Do not transmit if in broadcast client mode.
579 */
580 poll_update(peer, hpoll, (peer->hmode == MODE_CLIENT));
581 if (peer->hmode != MODE_BCLIENT)
582 peer_xmit(peer);
583
584 return;
585 }
586
587
588 const char *
amtoa(int am)589 amtoa(
590 int am
591 )
592 {
593 char *bp;
594
595 switch(am) {
596 case AM_ERR: return "AM_ERR";
597 case AM_NOMATCH: return "AM_NOMATCH";
598 case AM_PROCPKT: return "AM_PROCPKT";
599 case AM_BCST: return "AM_BCST";
600 case AM_FXMIT: return "AM_FXMIT";
601 case AM_MANYCAST: return "AM_MANYCAST";
602 case AM_NEWPASS: return "AM_NEWPASS";
603 case AM_NEWBCL: return "AM_NEWBCL";
604 case AM_POSSBCL: return "AM_POSSBCL";
605 default:
606 LIB_GETBUF(bp);
607 snprintf(bp, LIB_BUFLENGTH, "AM_#%d", am);
608 return bp;
609 }
610 }
611
612
613 /*
614 * receive - receive procedure called for each packet received
615 */
616 void
receive(struct recvbuf * rbufp)617 receive(
618 struct recvbuf *rbufp
619 )
620 {
621 register struct peer *peer; /* peer structure pointer */
622 register struct pkt *pkt; /* receive packet pointer */
623 u_char hisversion; /* packet version */
624 u_char hisleap; /* packet leap indicator */
625 u_char hismode; /* packet mode */
626 u_char hisstratum; /* packet stratum */
627 r4addr r4a; /* address restrictions */
628 u_short restrict_mask; /* restrict bits */
629 const char *hm_str; /* hismode string */
630 const char *am_str; /* association match string */
631 int kissCode = NOKISS; /* Kiss Code */
632 int has_mac; /* length of MAC field */
633 int authlen; /* offset of MAC field */
634 auth_code is_authentic = AUTH_UNKNOWN; /* Was AUTH_NONE */
635 nak_code crypto_nak_test; /* result of crypto-NAK check */
636 int retcode = AM_NOMATCH; /* match code */
637 keyid_t skeyid = 0; /* key IDs */
638 u_int32 opcode = 0; /* extension field opcode */
639 sockaddr_u *dstadr_sin; /* active runway */
640 struct peer *peer2; /* aux peer structure pointer */
641 endpt *match_ep; /* newpeer() local address */
642 l_fp p_org; /* origin timestamp */
643 l_fp p_rec; /* receive timestamp */
644 l_fp p_xmt; /* transmit timestamp */
645 #ifdef AUTOKEY
646 char hostname[NTP_MAXSTRLEN + 1];
647 char *groupname = NULL;
648 struct autokey *ap; /* autokey structure pointer */
649 int rval; /* cookie snatcher */
650 keyid_t pkeyid = 0, tkeyid = 0; /* key IDs */
651 #endif /* AUTOKEY */
652 #ifdef HAVE_NTP_SIGND
653 static unsigned char zero_key[16];
654 #endif /* HAVE_NTP_SIGND */
655
656 /*
657 * Note that there are many places we do not call record_raw_stats().
658 *
659 * We only want to call it *after* we've sent a response, or perhaps
660 * when we've decided to drop a packet.
661 */
662
663 /*
664 * Monitor the packet and get restrictions. Note that the packet
665 * length for control and private mode packets must be checked
666 * by the service routines. Some restrictions have to be handled
667 * later in order to generate a kiss-o'-death packet.
668 */
669 /*
670 * Bogus port check is before anything, since it probably
671 * reveals a clogging attack. Likewise the mimimum packet size
672 * of 2 bytes (for mode 6/7) must be checked first.
673 */
674 sys_received++;
675 if (0 == SRCPORT(&rbufp->recv_srcadr) || rbufp->recv_length < 2) {
676 sys_badlength++;
677 return; /* bogus port / length */
678 }
679 restrictions(&rbufp->recv_srcadr, &r4a);
680 restrict_mask = r4a.rflags;
681
682 pkt = &rbufp->recv_pkt;
683 hisversion = PKT_VERSION(pkt->li_vn_mode);
684 hismode = (int)PKT_MODE(pkt->li_vn_mode);
685
686 if (restrict_mask & RES_IGNORE) {
687 DPRINTF(2, ("receive: drop: RES_IGNORE\n"));
688 sys_restricted++;
689 return; /* ignore everything */
690 }
691 if (hismode == MODE_PRIVATE) {
692 if (!ntp_mode7 || (restrict_mask & RES_NOQUERY)) {
693 DPRINTF(2, ("receive: drop: RES_NOQUERY\n"));
694 sys_restricted++;
695 return; /* no query private */
696 }
697 process_private(rbufp, ((restrict_mask &
698 RES_NOMODIFY) == 0));
699 return;
700 }
701 if (hismode == MODE_CONTROL) {
702 if (restrict_mask & RES_NOQUERY) {
703 DPRINTF(2, ("receive: drop: RES_NOQUERY\n"));
704 sys_restricted++;
705 return; /* no query control */
706 }
707 process_control(rbufp, restrict_mask);
708 return;
709 }
710 if (restrict_mask & RES_DONTSERVE) {
711 DPRINTF(2, ("receive: drop: RES_DONTSERVE\n"));
712 sys_restricted++;
713 return; /* no time serve */
714 }
715
716
717 /* If we arrive here, we should have a standard NTP packet. We
718 * check that the minimum size is available and fetch some more
719 * items from the packet once we can be sure they are indeed
720 * there.
721 */
722 if ((size_t)rbufp->recv_length < LEN_PKT_NOMAC) {
723 sys_badlength++;
724 return; /* bogus length */
725 }
726
727 hisleap = PKT_LEAP(pkt->li_vn_mode);
728 hisstratum = PKT_TO_STRATUM(pkt->stratum);
729 INSIST(0 != hisstratum); /* paranoia check PKT_TO_STRATUM result */
730
731 DPRINTF(1, ("receive: at %ld %s<-%s ippeerlimit %d mode %d iflags %s "
732 "restrict %s org %#010x.%08x xmt %#010x.%08x\n",
733 current_time, stoa(&rbufp->dstadr->sin),
734 stoa(&rbufp->recv_srcadr), r4a.ippeerlimit, hismode,
735 build_iflags(rbufp->dstadr->flags),
736 build_rflags(restrict_mask),
737 ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf),
738 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf)));
739
740 /*
741 * This is for testing. If restricted drop ten percent of
742 * surviving packets.
743 */
744 if (restrict_mask & RES_FLAKE) {
745 if ((double)ntp_random() / 0x7fffffff < .1) {
746 DPRINTF(2, ("receive: drop: RES_FLAKE\n"));
747 sys_restricted++;
748 return; /* no flakeway */
749 }
750 }
751
752 /*
753 ** Format Layer Checks
754 **
755 ** Validate the packet format. The packet size, packet header,
756 ** and any extension field lengths are checked. We identify
757 ** the beginning of the MAC, to identify the upper limit of
758 ** of the hash computation.
759 **
760 ** In case of a format layer check violation, the packet is
761 ** discarded with no further processing.
762 */
763
764 /*
765 * Version check must be after the query packets, since they
766 * intentionally use an early version.
767 */
768 if (hisversion == NTP_VERSION) {
769 sys_newversion++; /* new version */
770 } else if ( !(restrict_mask & RES_VERSION)
771 && hisversion >= NTP_OLDVERSION) {
772 sys_oldversion++; /* previous version */
773 } else {
774 DPRINTF(2, ("receive: drop: RES_VERSION\n"));
775 sys_badlength++;
776 return; /* old version */
777 }
778
779 /*
780 * Figure out his mode and validate the packet. This has some
781 * legacy raunch that probably should be removed. In very early
782 * NTP versions mode 0 was equivalent to what later versions
783 * would interpret as client mode.
784 */
785 if (hismode == MODE_UNSPEC) {
786 if (hisversion == NTP_OLDVERSION) {
787 hismode = MODE_CLIENT;
788 } else {
789 DPRINTF(2, ("receive: drop: MODE_UNSPEC\n"));
790 sys_badlength++;
791 return; /* invalid mode */
792 }
793 }
794
795 /*
796 * Parse the extension field if present. We figure out whether
797 * an extension field is present by measuring the MAC size. If
798 * the number of words following the packet header is 0, no MAC
799 * is present and the packet is not authenticated. If 1, the
800 * packet is a crypto-NAK; if 3, the packet is authenticated
801 * with DES; if 5, the packet is authenticated with MD5; if 6,
802 * the packet is authenticated with SHA. If 2 or * 4, the packet
803 * is a runt and discarded forthwith. If greater than 6, an
804 * extension field is present, so we subtract the length of the
805 * field and go around again.
806 *
807 * Note the above description is lame. We should/could also check
808 * the two bytes that make up the EF type and subtype, and then
809 * check the two bytes that tell us the EF length. A legacy MAC
810 * has a 4 byte keyID, and for conforming symmetric keys its value
811 * must be <= 64k, meaning the top two bytes will always be zero.
812 * Since the EF Type of 0 is reserved/unused, there's no way a
813 * conforming legacy MAC could ever be misinterpreted as an EF.
814 *
815 * There is more, but this isn't the place to document it.
816 */
817
818 authlen = LEN_PKT_NOMAC;
819 has_mac = rbufp->recv_length - authlen;
820 while (has_mac > 0) {
821 u_int32 len;
822 #ifdef AUTOKEY
823 u_int32 hostlen;
824 struct exten *ep;
825 #endif /*AUTOKEY */
826
827 if (has_mac % 4 != 0 || has_mac < (int)MIN_MAC_LEN) {
828 DPRINTF(2, ("receive: drop: bad post-packet length\n"));
829 sys_badlength++;
830 return; /* bad length */
831 }
832 /*
833 * This next test is clearly wrong - it needlessly
834 * prohibits short EFs (which don't yet exist)
835 */
836 if (has_mac <= (int)MAX_MAC_LEN) {
837 skeyid = ntohl(((u_int32 *)pkt)[authlen / 4]);
838 break;
839
840 } else {
841 opcode = ntohl(((u_int32 *)pkt)[authlen / 4]);
842 len = opcode & 0xffff;
843 if ( len % 4 != 0
844 || len < 4
845 || (int)len + authlen > rbufp->recv_length) {
846 DPRINTF(2, ("receive: drop: bad EF length\n"));
847 sys_badlength++;
848 return; /* bad length */
849 }
850 #ifdef AUTOKEY
851 /*
852 * Extract calling group name for later. If
853 * sys_groupname is non-NULL, there must be
854 * a group name provided to elicit a response.
855 */
856 if ( (opcode & 0x3fff0000) == CRYPTO_ASSOC
857 && sys_groupname != NULL) {
858 ep = (struct exten *)&((u_int32 *)pkt)[authlen / 4];
859 hostlen = ntohl(ep->vallen);
860 if ( hostlen >= sizeof(hostname)
861 || hostlen > len -
862 offsetof(struct exten, pkt)) {
863 DPRINTF(2, ("receive: drop: bad autokey hostname length\n"));
864 sys_badlength++;
865 return; /* bad length */
866 }
867 memcpy(hostname, &ep->pkt, hostlen);
868 hostname[hostlen] = '\0';
869 groupname = strchr(hostname, '@');
870 if (groupname == NULL) {
871 DPRINTF(2, ("receive: drop: empty autokey groupname\n"));
872 sys_declined++;
873 return;
874 }
875 groupname++;
876 }
877 #endif /* AUTOKEY */
878 authlen += len;
879 has_mac -= len;
880 }
881 }
882
883 /*
884 * If has_mac is < 0 we had a malformed packet.
885 */
886 if (has_mac < 0) {
887 DPRINTF(2, ("receive: drop: post-packet under-read\n"));
888 sys_badlength++;
889 return; /* bad length */
890 }
891
892 /*
893 ** Packet Data Verification Layer
894 **
895 ** This layer verifies the packet data content. If
896 ** authentication is required, a MAC must be present.
897 ** If a MAC is present, it must validate.
898 ** Crypto-NAK? Look - a shiny thing!
899 **
900 ** If authentication fails, we're done.
901 */
902
903 /*
904 * If authentication is explicitly required, a MAC must be present.
905 */
906 if (restrict_mask & RES_DONTTRUST && has_mac == 0) {
907 DPRINTF(2, ("receive: drop: RES_DONTTRUST\n"));
908 sys_restricted++;
909 return; /* access denied */
910 }
911
912 /*
913 * Update the MRU list and finger the cloggers. It can be a
914 * little expensive, so turn it off for production use.
915 * RES_LIMITED and RES_KOD will be cleared in the returned
916 * restrict_mask unless one or both actions are warranted.
917 */
918 restrict_mask = ntp_monitor(rbufp, restrict_mask);
919 if (restrict_mask & RES_LIMITED) {
920 sys_limitrejected++;
921 if ( !(restrict_mask & RES_KOD)
922 || MODE_BROADCAST == hismode
923 || MODE_SERVER == hismode) {
924 if (MODE_SERVER == hismode) {
925 DPRINTF(1, ("Possibly self-induced rate limiting of MODE_SERVER from %s\n",
926 stoa(&rbufp->recv_srcadr)));
927 } else {
928 DPRINTF(2, ("receive: drop: RES_KOD\n"));
929 }
930 return; /* rate exceeded */
931 }
932 if (hismode == MODE_CLIENT) {
933 fast_xmit(rbufp, MODE_SERVER, skeyid,
934 restrict_mask);
935 } else {
936 fast_xmit(rbufp, MODE_ACTIVE, skeyid,
937 restrict_mask);
938 }
939 return; /* rate exceeded */
940 }
941 restrict_mask &= ~RES_KOD;
942
943 /*
944 * We have tossed out as many buggy packets as possible early in
945 * the game to reduce the exposure to a clogging attack. Now we
946 * have to burn some cycles to find the association and
947 * authenticate the packet if required. Note that we burn only
948 * digest cycles, again to reduce exposure. There may be no
949 * matching association and that's okay.
950 *
951 * More on the autokey mambo. Normally the local interface is
952 * found when the association was mobilized with respect to a
953 * designated remote address. We assume packets arriving from
954 * the remote address arrive via this interface and the local
955 * address used to construct the autokey is the unicast address
956 * of the interface. However, if the sender is a broadcaster,
957 * the interface broadcast address is used instead.
958 * Notwithstanding this technobabble, if the sender is a
959 * multicaster, the broadcast address is null, so we use the
960 * unicast address anyway. Don't ask.
961 */
962
963 peer = findpeer(rbufp, hismode, &retcode);
964 dstadr_sin = &rbufp->dstadr->sin;
965 NTOHL_FP(&pkt->org, &p_org);
966 NTOHL_FP(&pkt->rec, &p_rec);
967 NTOHL_FP(&pkt->xmt, &p_xmt);
968 hm_str = modetoa(hismode);
969 am_str = amtoa(retcode);
970
971 /*
972 * Authentication is conditioned by three switches:
973 *
974 * NOPEER (RES_NOPEER) do not mobilize an association unless
975 * authenticated
976 * NOTRUST (RES_DONTTRUST) do not allow access unless
977 * authenticated (implies NOPEER)
978 * enable (sys_authenticate) master NOPEER switch, by default
979 * on
980 *
981 * The NOPEER and NOTRUST can be specified on a per-client basis
982 * using the restrict command. The enable switch if on implies
983 * NOPEER for all clients. There are four outcomes:
984 *
985 * NONE The packet has no MAC.
986 * OK the packet has a MAC and authentication succeeds
987 * ERROR the packet has a MAC and authentication fails
988 * CRYPTO crypto-NAK. The MAC has four octets only.
989 *
990 * Note: The AUTH(x, y) macro is used to filter outcomes. If x
991 * is zero, acceptable outcomes of y are NONE and OK. If x is
992 * one, the only acceptable outcome of y is OK.
993 */
994 crypto_nak_test = valid_NAK(peer, rbufp, hismode);
995
996 /*
997 * Drop any invalid crypto-NAKs
998 */
999 if (crypto_nak_test == INVALIDNAK) {
1000 report_event(PEVNT_AUTH, peer, "Invalid_NAK");
1001 if (0 != peer) {
1002 peer->badNAK++;
1003 }
1004 msyslog(LOG_ERR, "Invalid-NAK error at %ld %s<-%s",
1005 current_time, stoa(dstadr_sin), stoa(&rbufp->recv_srcadr));
1006 return;
1007 }
1008
1009 if (has_mac == 0) {
1010 restrict_mask &= ~RES_MSSNTP;
1011 is_authentic = AUTH_NONE; /* not required */
1012 DPRINTF(1, ("receive: at %ld %s<-%s mode %d/%s:%s len %d org %#010x.%08x xmt %#010x.%08x NOMAC\n",
1013 current_time, stoa(dstadr_sin),
1014 stoa(&rbufp->recv_srcadr), hismode, hm_str, am_str,
1015 authlen,
1016 ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf),
1017 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf)));
1018 } else if (crypto_nak_test == VALIDNAK) {
1019 restrict_mask &= ~RES_MSSNTP;
1020 is_authentic = AUTH_CRYPTO; /* crypto-NAK */
1021 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",
1022 current_time, stoa(dstadr_sin),
1023 stoa(&rbufp->recv_srcadr), hismode, hm_str, am_str,
1024 skeyid, authlen + has_mac, is_authentic,
1025 ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf),
1026 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf)));
1027
1028 #ifdef HAVE_NTP_SIGND
1029 /*
1030 * If the signature is 20 bytes long, the last 16 of
1031 * which are zero, then this is a Microsoft client
1032 * wanting AD-style authentication of the server's
1033 * reply.
1034 *
1035 * This is described in Microsoft's WSPP docs, in MS-SNTP:
1036 * http://msdn.microsoft.com/en-us/library/cc212930.aspx
1037 */
1038 } else if ( has_mac == MAX_MD5_LEN
1039 && (restrict_mask & RES_MSSNTP)
1040 && (retcode == AM_FXMIT || retcode == AM_NEWPASS)
1041 && (memcmp(zero_key, (char *)pkt + authlen + 4,
1042 MAX_MD5_LEN - 4) == 0)) {
1043 is_authentic = AUTH_NONE;
1044 DPRINTF(1, ("receive: at %ld %s<-%s mode %d/%s:%s len %d org %#010x.%08x xmt %#010x.%08x SIGND\n",
1045 current_time, stoa(dstadr_sin),
1046 stoa(&rbufp->recv_srcadr), hismode, hm_str, am_str,
1047 authlen,
1048 ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf),
1049 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf)));
1050 #endif /* HAVE_NTP_SIGND */
1051
1052 } else {
1053 /*
1054 * has_mac is not 0
1055 * Not a VALID_NAK
1056 * Not an MS-SNTP SIGND packet
1057 *
1058 * So there is a MAC here.
1059 */
1060
1061 restrict_mask &= ~RES_MSSNTP;
1062 #ifdef AUTOKEY
1063 /*
1064 * For autokey modes, generate the session key
1065 * and install in the key cache. Use the socket
1066 * broadcast or unicast address as appropriate.
1067 */
1068 if (crypto_flags && skeyid > NTP_MAXKEY) {
1069
1070 /*
1071 * More on the autokey dance (AKD). A cookie is
1072 * constructed from public and private values.
1073 * For broadcast packets, the cookie is public
1074 * (zero). For packets that match no
1075 * association, the cookie is hashed from the
1076 * addresses and private value. For server
1077 * packets, the cookie was previously obtained
1078 * from the server. For symmetric modes, the
1079 * cookie was previously constructed using an
1080 * agreement protocol; however, should PKI be
1081 * unavailable, we construct a fake agreement as
1082 * the EXOR of the peer and host cookies.
1083 *
1084 * hismode ephemeral persistent
1085 * =======================================
1086 * active 0 cookie#
1087 * passive 0% cookie#
1088 * client sys cookie 0%
1089 * server 0% sys cookie
1090 * broadcast 0 0
1091 *
1092 * # if unsync, 0
1093 * % can't happen
1094 */
1095 if (has_mac < (int)MAX_MD5_LEN) {
1096 DPRINTF(2, ("receive: drop: MD5 digest too short\n"));
1097 sys_badauth++;
1098 return;
1099 }
1100 if (hismode == MODE_BROADCAST) {
1101
1102 /*
1103 * For broadcaster, use the interface
1104 * broadcast address when available;
1105 * otherwise, use the unicast address
1106 * found when the association was
1107 * mobilized. However, if this is from
1108 * the wildcard interface, game over.
1109 */
1110 if ( crypto_flags
1111 && rbufp->dstadr ==
1112 ANY_INTERFACE_CHOOSE(&rbufp->recv_srcadr)) {
1113 DPRINTF(2, ("receive: drop: BCAST from wildcard\n"));
1114 sys_restricted++;
1115 return; /* no wildcard */
1116 }
1117 pkeyid = 0;
1118 if (!SOCK_UNSPEC(&rbufp->dstadr->bcast))
1119 dstadr_sin =
1120 &rbufp->dstadr->bcast;
1121 } else if (peer == NULL) {
1122 pkeyid = session_key(
1123 &rbufp->recv_srcadr, dstadr_sin, 0,
1124 sys_private, 0);
1125 } else {
1126 pkeyid = peer->pcookie;
1127 }
1128
1129 /*
1130 * The session key includes both the public
1131 * values and cookie. In case of an extension
1132 * field, the cookie used for authentication
1133 * purposes is zero. Note the hash is saved for
1134 * use later in the autokey mambo.
1135 */
1136 if (authlen > (int)LEN_PKT_NOMAC && pkeyid != 0) {
1137 session_key(&rbufp->recv_srcadr,
1138 dstadr_sin, skeyid, 0, 2);
1139 tkeyid = session_key(
1140 &rbufp->recv_srcadr, dstadr_sin,
1141 skeyid, pkeyid, 0);
1142 } else {
1143 tkeyid = session_key(
1144 &rbufp->recv_srcadr, dstadr_sin,
1145 skeyid, pkeyid, 2);
1146 }
1147
1148 }
1149 #endif /* AUTOKEY */
1150
1151 /*
1152 * Compute the cryptosum. Note a clogging attack may
1153 * succeed in bloating the key cache. If an autokey,
1154 * purge it immediately, since we won't be needing it
1155 * again. If the packet is authentic, it can mobilize an
1156 * association. Note that there is no key zero.
1157 */
1158 if (!authdecrypt(skeyid, (u_int32 *)pkt, authlen,
1159 has_mac))
1160 is_authentic = AUTH_ERROR;
1161 else
1162 is_authentic = AUTH_OK;
1163 #ifdef AUTOKEY
1164 if (crypto_flags && skeyid > NTP_MAXKEY)
1165 authtrust(skeyid, 0);
1166 #endif /* AUTOKEY */
1167 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",
1168 current_time, stoa(dstadr_sin),
1169 stoa(&rbufp->recv_srcadr), hismode, hm_str, am_str,
1170 skeyid, authlen + has_mac, is_authentic,
1171 ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf),
1172 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf)));
1173 }
1174
1175
1176 /*
1177 * Bug 3454:
1178 *
1179 * Now come at this from a different perspective:
1180 * - If we expect a MAC and it's not there, we drop it.
1181 * - If we expect one keyID and get another, we drop it.
1182 * - If we have a MAC ahd it hasn't been validated yet, try.
1183 * - if the provided MAC doesn't validate, we drop it.
1184 *
1185 * There might be more to this.
1186 */
1187 if (0 != peer && 0 != peer->keyid) {
1188 /* Should we msyslog() any of these? */
1189
1190 /*
1191 * This should catch:
1192 * - no keyID where one is expected,
1193 * - different keyID than what we expect.
1194 */
1195 if (peer->keyid != skeyid) {
1196 DPRINTF(2, ("receive: drop: Wanted keyID %d, got %d from %s\n",
1197 peer->keyid, skeyid,
1198 stoa(&rbufp->recv_srcadr)));
1199 sys_restricted++;
1200 return; /* drop: access denied */
1201 }
1202
1203 /*
1204 * if has_mac != 0 ...
1205 * - If it has not yet been validated, do so.
1206 * (under what circumstances might that happen?)
1207 * - if missing or bad MAC, log and drop.
1208 */
1209 if (0 != has_mac) {
1210 if (is_authentic == AUTH_UNKNOWN) {
1211 /* How can this happen? */
1212 DPRINTF(2, ("receive: 3454 check: AUTH_UNKNOWN from %s\n",
1213 stoa(&rbufp->recv_srcadr)));
1214 if (!authdecrypt(skeyid, (u_int32 *)pkt, authlen,
1215 has_mac)) {
1216 /* MAC invalid or not found */
1217 is_authentic = AUTH_ERROR;
1218 } else {
1219 is_authentic = AUTH_OK;
1220 }
1221 }
1222 if (is_authentic != AUTH_OK) {
1223 DPRINTF(2, ("receive: drop: missing or bad MAC from %s\n",
1224 stoa(&rbufp->recv_srcadr)));
1225 sys_restricted++;
1226 return; /* drop: access denied */
1227 }
1228 }
1229 }
1230 /**/
1231
1232 /*
1233 ** On-Wire Protocol Layer
1234 **
1235 ** Verify protocol operations consistent with the on-wire protocol.
1236 ** The protocol discards bogus and duplicate packets as well as
1237 ** minimizes disruptions doe to protocol restarts and dropped
1238 ** packets. The operations are controlled by two timestamps:
1239 ** the transmit timestamp saved in the client state variables,
1240 ** and the origin timestamp in the server packet header. The
1241 ** comparison of these two timestamps is called the loopback test.
1242 ** The transmit timestamp functions as a nonce to verify that the
1243 ** response corresponds to the original request. The transmit
1244 ** timestamp also serves to discard replays of the most recent
1245 ** packet. Upon failure of either test, the packet is discarded
1246 ** with no further action.
1247 */
1248
1249 /*
1250 * The association matching rules are implemented by a set of
1251 * routines and an association table. A packet matching an
1252 * association is processed by the peer process for that
1253 * association. If there are no errors, an ephemeral association
1254 * is mobilized: a broadcast packet mobilizes a broadcast client
1255 * aassociation; a manycast server packet mobilizes a manycast
1256 * client association; a symmetric active packet mobilizes a
1257 * symmetric passive association.
1258 */
1259 DPRINTF(1, ("receive: MATCH_ASSOC dispatch: mode %d/%s:%s \n",
1260 hismode, hm_str, am_str));
1261 switch (retcode) {
1262
1263 /*
1264 * This is a client mode packet not matching any association. If
1265 * an ordinary client, simply toss a server mode packet back
1266 * over the fence. If a manycast client, we have to work a
1267 * little harder.
1268 *
1269 * There are cases here where we do not call record_raw_stats().
1270 */
1271 case AM_FXMIT:
1272
1273 /*
1274 * If authentication OK, send a server reply; otherwise,
1275 * send a crypto-NAK.
1276 */
1277 if (!(rbufp->dstadr->flags & INT_MCASTOPEN)) {
1278 /* HMS: would be nice to log FAST_XMIT|BADAUTH|RESTRICTED */
1279 record_raw_stats(&rbufp->recv_srcadr,
1280 &rbufp->dstadr->sin,
1281 &p_org, &p_rec, &p_xmt, &rbufp->recv_time,
1282 PKT_LEAP(pkt->li_vn_mode),
1283 PKT_VERSION(pkt->li_vn_mode),
1284 PKT_MODE(pkt->li_vn_mode),
1285 PKT_TO_STRATUM(pkt->stratum),
1286 pkt->ppoll,
1287 pkt->precision,
1288 FPTOD(NTOHS_FP(pkt->rootdelay)),
1289 FPTOD(NTOHS_FP(pkt->rootdisp)),
1290 pkt->refid,
1291 rbufp->recv_length - MIN_V4_PKT_LEN, (u_char *)&pkt->exten);
1292
1293 if (AUTH(restrict_mask & RES_DONTTRUST,
1294 is_authentic)) {
1295 /* Bug 3596: Do we want to fuzz the reftime? */
1296 fast_xmit(rbufp, MODE_SERVER, skeyid,
1297 restrict_mask);
1298 } else if (is_authentic == AUTH_ERROR) {
1299 /* Bug 3596: Do we want to fuzz the reftime? */
1300 fast_xmit(rbufp, MODE_SERVER, 0,
1301 restrict_mask);
1302 sys_badauth++;
1303 } else {
1304 DPRINTF(2, ("receive: AM_FXMIT drop: !mcast restricted\n"));
1305 sys_restricted++;
1306 }
1307
1308 return; /* hooray */
1309 }
1310
1311 /*
1312 * This must be manycast. Do not respond if not
1313 * configured as a manycast server.
1314 */
1315 if (!sys_manycastserver) {
1316 DPRINTF(2, ("receive: AM_FXMIT drop: Not manycastserver\n"));
1317 sys_restricted++;
1318 return; /* not enabled */
1319 }
1320
1321 #ifdef AUTOKEY
1322 /*
1323 * Do not respond if not the same group.
1324 */
1325 if (group_test(groupname, NULL)) {
1326 DPRINTF(2, ("receive: AM_FXMIT drop: empty groupname\n"));
1327 sys_declined++;
1328 return;
1329 }
1330 #endif /* AUTOKEY */
1331
1332 /*
1333 * Do not respond if we are not synchronized or our
1334 * stratum is greater than the manycaster or the
1335 * manycaster has already synchronized to us.
1336 */
1337 if ( sys_leap == LEAP_NOTINSYNC
1338 || sys_stratum > hisstratum + 1
1339 || (!sys_cohort && sys_stratum == hisstratum + 1)
1340 || rbufp->dstadr->addr_refid == pkt->refid) {
1341 DPRINTF(2, ("receive: sys leap: %0x, sys_stratum %d > hisstratum+1 %d, !sys_cohort %d && sys_stratum == hisstratum+1, loop refid %#x == pkt refid %#x\n", sys_leap, sys_stratum, hisstratum + 1, !sys_cohort, rbufp->dstadr->addr_refid, pkt->refid));
1342 DPRINTF(2, ("receive: AM_FXMIT drop: LEAP_NOTINSYNC || stratum || loop\n"));
1343 sys_declined++;
1344 return; /* no help */
1345 }
1346
1347 /*
1348 * Respond only if authentication succeeds. Don't do a
1349 * crypto-NAK, as that would not be useful.
1350 */
1351 if (AUTH(restrict_mask & RES_DONTTRUST, is_authentic)) {
1352 record_raw_stats(&rbufp->recv_srcadr,
1353 &rbufp->dstadr->sin,
1354 &p_org, &p_rec, &p_xmt, &rbufp->recv_time,
1355 PKT_LEAP(pkt->li_vn_mode),
1356 PKT_VERSION(pkt->li_vn_mode),
1357 PKT_MODE(pkt->li_vn_mode),
1358 PKT_TO_STRATUM(pkt->stratum),
1359 pkt->ppoll,
1360 pkt->precision,
1361 FPTOD(NTOHS_FP(pkt->rootdelay)),
1362 FPTOD(NTOHS_FP(pkt->rootdisp)),
1363 pkt->refid,
1364 rbufp->recv_length - MIN_V4_PKT_LEN, (u_char *)&pkt->exten);
1365
1366 /* Bug 3596: Do we want to fuzz the reftime? */
1367 fast_xmit(rbufp, MODE_SERVER, skeyid,
1368 restrict_mask);
1369 }
1370 return; /* hooray */
1371
1372 /*
1373 * This is a server mode packet returned in response to a client
1374 * mode packet sent to a multicast group address (for
1375 * manycastclient) or to a unicast address (for pool). The
1376 * origin timestamp is a good nonce to reliably associate the
1377 * reply with what was sent. If there is no match, that's
1378 * curious and could be an intruder attempting to clog, so we
1379 * just ignore it.
1380 *
1381 * If the packet is authentic and the manycastclient or pool
1382 * association is found, we mobilize a client association and
1383 * copy pertinent variables from the manycastclient or pool
1384 * association to the new client association. If not, just
1385 * ignore the packet.
1386 *
1387 * There is an implosion hazard at the manycast client, since
1388 * the manycast servers send the server packet immediately. If
1389 * the guy is already here, don't fire up a duplicate.
1390 *
1391 * There are cases here where we do not call record_raw_stats().
1392 */
1393 case AM_MANYCAST:
1394
1395 #ifdef AUTOKEY
1396 /*
1397 * Do not respond if not the same group.
1398 */
1399 if (group_test(groupname, NULL)) {
1400 DPRINTF(2, ("receive: AM_MANYCAST drop: empty groupname\n"));
1401 sys_declined++;
1402 return;
1403 }
1404 #endif /* AUTOKEY */
1405 if ((peer2 = findmanycastpeer(rbufp)) == NULL) {
1406 DPRINTF(2, ("receive: AM_MANYCAST drop: No manycast peer\n"));
1407 sys_restricted++;
1408 return; /* not enabled */
1409 }
1410 if (!AUTH( (!(peer2->cast_flags & MDF_POOL)
1411 && sys_authenticate)
1412 || (restrict_mask & (RES_NOPEER |
1413 RES_DONTTRUST)), is_authentic)
1414 /* MC: RES_NOEPEER? */
1415 ) {
1416 DPRINTF(2, ("receive: AM_MANYCAST drop: bad auth || (NOPEER|DONTTRUST)\n"));
1417 sys_restricted++;
1418 return; /* access denied */
1419 }
1420
1421 /*
1422 * Do not respond if unsynchronized or stratum is below
1423 * the floor or at or above the ceiling.
1424 */
1425 if ( hisleap == LEAP_NOTINSYNC
1426 || hisstratum < sys_floor
1427 || hisstratum >= sys_ceiling) {
1428 DPRINTF(2, ("receive: AM_MANYCAST drop: unsync/stratum\n"));
1429 sys_declined++;
1430 return; /* no help */
1431 }
1432 peer = newpeer(&rbufp->recv_srcadr, NULL, rbufp->dstadr,
1433 r4a.ippeerlimit, MODE_CLIENT, hisversion,
1434 peer2->minpoll, peer2->maxpoll,
1435 (FLAG_PREEMPT | (POOL_FLAG_PMASK & peer2->flags)),
1436 (MDF_UCAST | MDF_UCLNT), 0, skeyid, sys_ident);
1437 if (NULL == peer) {
1438 DPRINTF(2, ("receive: AM_MANYCAST drop: duplicate\n"));
1439 sys_declined++;
1440 return; /* ignore duplicate */
1441 }
1442
1443 /*
1444 * After each ephemeral pool association is spun,
1445 * accelerate the next poll for the pool solicitor so
1446 * the pool will fill promptly.
1447 */
1448 if (peer2->cast_flags & MDF_POOL)
1449 peer2->nextdate = current_time + 1;
1450
1451 /*
1452 * Further processing of the solicitation response would
1453 * simply detect its origin timestamp as bogus for the
1454 * brand-new association (it matches the prototype
1455 * association) and tinker with peer->nextdate delaying
1456 * first sync.
1457 */
1458 return; /* solicitation response handled */
1459
1460 /*
1461 * This is the first packet received from a broadcast server. If
1462 * the packet is authentic and we are enabled as broadcast
1463 * client, mobilize a broadcast client association. We don't
1464 * kiss any frogs here.
1465 *
1466 * There are cases here where we do not call record_raw_stats().
1467 */
1468 case AM_NEWBCL:
1469
1470 #ifdef AUTOKEY
1471 /*
1472 * Do not respond if not the same group.
1473 */
1474 if (group_test(groupname, sys_ident)) {
1475 DPRINTF(2, ("receive: AM_NEWBCL drop: groupname mismatch\n"));
1476 sys_declined++;
1477 return;
1478 }
1479 #endif /* AUTOKEY */
1480 if (sys_bclient == 0) {
1481 DPRINTF(2, ("receive: AM_NEWBCL drop: not a bclient\n"));
1482 sys_restricted++;
1483 return; /* not enabled */
1484 }
1485 if (!AUTH(sys_authenticate | (restrict_mask &
1486 (RES_NOPEER | RES_DONTTRUST)), is_authentic)
1487 /* NEWBCL: RES_NOEPEER? */
1488 ) {
1489 DPRINTF(2, ("receive: AM_NEWBCL drop: AUTH failed\n"));
1490 sys_restricted++;
1491 return; /* access denied */
1492 }
1493
1494 /*
1495 * Do not respond if unsynchronized or stratum is below
1496 * the floor or at or above the ceiling.
1497 */
1498 if ( hisleap == LEAP_NOTINSYNC
1499 || hisstratum < sys_floor
1500 || hisstratum >= sys_ceiling) {
1501 DPRINTF(2, ("receive: AM_NEWBCL drop: Unsync or bad stratum\n"));
1502 sys_declined++;
1503 return; /* no help */
1504 }
1505
1506 #ifdef AUTOKEY
1507 /*
1508 * Do not respond if Autokey and the opcode is not a
1509 * CRYPTO_ASSOC response with association ID.
1510 */
1511 if ( crypto_flags && skeyid > NTP_MAXKEY
1512 && (opcode & 0xffff0000) != (CRYPTO_ASSOC | CRYPTO_RESP)) {
1513 DPRINTF(2, ("receive: AM_NEWBCL drop: Autokey but not CRYPTO_ASSOC\n"));
1514 sys_declined++;
1515 return; /* protocol error */
1516 }
1517 #endif /* AUTOKEY */
1518
1519 /*
1520 * Broadcasts received via a multicast address may
1521 * arrive after a unicast volley has begun
1522 * with the same remote address. newpeer() will not
1523 * find duplicate associations on other local endpoints
1524 * if a non-NULL endpoint is supplied. multicastclient
1525 * ephemeral associations are unique across all local
1526 * endpoints.
1527 */
1528 if (!(INT_MCASTOPEN & rbufp->dstadr->flags))
1529 match_ep = rbufp->dstadr;
1530 else
1531 match_ep = NULL;
1532
1533 /*
1534 * Determine whether to execute the initial volley.
1535 */
1536 if (sys_bdelay > 0.0) {
1537 #ifdef AUTOKEY
1538 /*
1539 * If a two-way exchange is not possible,
1540 * neither is Autokey.
1541 */
1542 if (crypto_flags && skeyid > NTP_MAXKEY) {
1543 sys_restricted++;
1544 DPRINTF(2, ("receive: AM_NEWBCL drop: Autokey but not 2-way\n"));
1545 return; /* no autokey */
1546 }
1547 #endif /* AUTOKEY */
1548
1549 /*
1550 * Do not execute the volley. Start out in
1551 * broadcast client mode.
1552 */
1553 peer = newpeer(&rbufp->recv_srcadr, NULL, match_ep,
1554 r4a.ippeerlimit, MODE_BCLIENT, hisversion,
1555 pkt->ppoll, pkt->ppoll,
1556 FLAG_PREEMPT, MDF_BCLNT, 0, skeyid, sys_ident);
1557 if (NULL == peer) {
1558 DPRINTF(2, ("receive: AM_NEWBCL drop: duplicate\n"));
1559 sys_restricted++;
1560 return; /* ignore duplicate */
1561
1562 } else {
1563 peer->delay = sys_bdelay;
1564 peer->bxmt = p_xmt;
1565 }
1566 break;
1567 }
1568
1569 /*
1570 * Execute the initial volley in order to calibrate the
1571 * propagation delay and run the Autokey protocol.
1572 *
1573 * Note that the minpoll is taken from the broadcast
1574 * packet, normally 6 (64 s) and that the poll interval
1575 * is fixed at this value.
1576 */
1577 peer = newpeer(&rbufp->recv_srcadr, NULL, match_ep,
1578 r4a.ippeerlimit, MODE_CLIENT, hisversion,
1579 pkt->ppoll, pkt->ppoll,
1580 FLAG_BC_VOL | FLAG_IBURST | FLAG_PREEMPT, MDF_BCLNT,
1581 0, skeyid, sys_ident);
1582 if (NULL == peer) {
1583 DPRINTF(2, ("receive: AM_NEWBCL drop: empty newpeer() failed\n"));
1584 sys_restricted++;
1585 return; /* ignore duplicate */
1586 }
1587 peer->bxmt = p_xmt;
1588 #ifdef AUTOKEY
1589 if (skeyid > NTP_MAXKEY)
1590 crypto_recv(peer, rbufp);
1591 #endif /* AUTOKEY */
1592
1593 return; /* hooray */
1594
1595 /*
1596 * This is the first packet received from a potential ephemeral
1597 * symmetric active peer. First, deal with broken Windows clients.
1598 * Then, if NOEPEER is enabled, drop it. If the packet meets our
1599 * authenticty requirements and is the first he sent, mobilize
1600 * a passive association.
1601 * Otherwise, kiss the frog.
1602 *
1603 * There are cases here where we do not call record_raw_stats().
1604 */
1605 case AM_NEWPASS:
1606
1607 DEBUG_REQUIRE(MODE_ACTIVE == hismode);
1608
1609 #ifdef AUTOKEY
1610 /*
1611 * Do not respond if not the same group.
1612 */
1613 if (group_test(groupname, sys_ident)) {
1614 DPRINTF(2, ("receive: AM_NEWPASS drop: Autokey group mismatch\n"));
1615 sys_declined++;
1616 return;
1617 }
1618 #endif /* AUTOKEY */
1619 if (!AUTH(sys_authenticate | (restrict_mask &
1620 (RES_NOPEER | RES_DONTTRUST)), is_authentic)
1621 ) {
1622 /*
1623 * If authenticated but cannot mobilize an
1624 * association, send a symmetric passive
1625 * response without mobilizing an association.
1626 * This is for drat broken Windows clients. See
1627 * Microsoft KB 875424 for preferred workaround.
1628 */
1629 if (AUTH(restrict_mask & RES_DONTTRUST,
1630 is_authentic)) {
1631 fast_xmit(rbufp, MODE_PASSIVE, skeyid,
1632 restrict_mask);
1633 return; /* hooray */
1634 }
1635 /* HMS: Why is this next set of lines a feature? */
1636 if (is_authentic == AUTH_ERROR) {
1637 fast_xmit(rbufp, MODE_PASSIVE, 0,
1638 restrict_mask);
1639 sys_restricted++;
1640 return;
1641 }
1642
1643 if (restrict_mask & RES_NOEPEER) {
1644 DPRINTF(2, ("receive: AM_NEWPASS drop: NOEPEER\n"));
1645 sys_declined++;
1646 return;
1647 }
1648
1649 /* [Bug 2941]
1650 * If we got here, the packet isn't part of an
1651 * existing association, either isn't correctly
1652 * authenticated or it is but we are refusing
1653 * ephemeral peer requests, and it didn't meet
1654 * either of the previous two special cases so we
1655 * should just drop it on the floor. For example,
1656 * crypto-NAKs (is_authentic == AUTH_CRYPTO)
1657 * will make it this far. This is just
1658 * debug-printed and not logged to avoid log
1659 * flooding.
1660 */
1661 DPRINTF(2, ("receive: at %ld refusing to mobilize passive association"
1662 " with unknown peer %s mode %d/%s:%s keyid %08x len %d auth %d\n",
1663 current_time, stoa(&rbufp->recv_srcadr),
1664 hismode, hm_str, am_str, skeyid,
1665 (authlen + has_mac), is_authentic));
1666 sys_declined++;
1667 return;
1668 }
1669
1670 if (restrict_mask & RES_NOEPEER) {
1671 DPRINTF(2, ("receive: AM_NEWPASS drop: NOEPEER\n"));
1672 sys_declined++;
1673 return;
1674 }
1675
1676 /*
1677 * Do not respond if synchronized and if stratum is
1678 * below the floor or at or above the ceiling. Note,
1679 * this allows an unsynchronized peer to synchronize to
1680 * us. It would be very strange if he did and then was
1681 * nipped, but that could only happen if we were
1682 * operating at the top end of the range. It also means
1683 * we will spin an ephemeral association in response to
1684 * MODE_ACTIVE KoDs, which will time out eventually.
1685 */
1686 if ( hisleap != LEAP_NOTINSYNC
1687 && (hisstratum < sys_floor || hisstratum >= sys_ceiling)) {
1688 DPRINTF(2, ("receive: AM_NEWPASS drop: Remote stratum (%d) out of range\n",
1689 hisstratum));
1690 sys_declined++;
1691 return; /* no help */
1692 }
1693
1694 /*
1695 * The message is correctly authenticated and allowed.
1696 * Mobilize a symmetric passive association, if we won't
1697 * exceed the ippeerlimit.
1698 */
1699 if ((peer = newpeer(&rbufp->recv_srcadr, NULL, rbufp->dstadr,
1700 r4a.ippeerlimit, MODE_PASSIVE, hisversion,
1701 pkt->ppoll, NTP_MAXDPOLL, 0, MDF_UCAST, 0,
1702 skeyid, sys_ident)) == NULL) {
1703 DPRINTF(2, ("receive: AM_NEWPASS drop: newpeer() failed\n"));
1704 sys_declined++;
1705 return; /* ignore duplicate */
1706 }
1707 break;
1708
1709
1710 /*
1711 * Process regular packet. Nothing special.
1712 *
1713 * There are cases here where we do not call record_raw_stats().
1714 */
1715 case AM_PROCPKT:
1716
1717 #ifdef AUTOKEY
1718 /*
1719 * Do not respond if not the same group.
1720 */
1721 if (group_test(groupname, peer->ident)) {
1722 DPRINTF(2, ("receive: AM_PROCPKT drop: Autokey group mismatch\n"));
1723 sys_declined++;
1724 return;
1725 }
1726 #endif /* AUTOKEY */
1727
1728 if (MODE_BROADCAST == hismode) {
1729 int bail = 0;
1730 l_fp tdiff;
1731 u_long deadband;
1732
1733 DPRINTF(2, ("receive: PROCPKT/BROADCAST: prev pkt %ld seconds ago, ppoll: %d, %d secs\n",
1734 (current_time - peer->timelastrec),
1735 peer->ppoll, (1 << peer->ppoll)
1736 ));
1737 /* Things we can check:
1738 *
1739 * Did the poll interval change?
1740 * Is the poll interval in the packet in-range?
1741 * Did this packet arrive too soon?
1742 * Is the timestamp in this packet monotonic
1743 * with respect to the previous packet?
1744 */
1745
1746 /* This is noteworthy, not error-worthy */
1747 if (pkt->ppoll != peer->ppoll) {
1748 msyslog(LOG_INFO, "receive: broadcast poll from %s changed from %u to %u",
1749 stoa(&rbufp->recv_srcadr),
1750 peer->ppoll, pkt->ppoll);
1751 }
1752
1753 /* This is error-worthy */
1754 if ( pkt->ppoll < peer->minpoll
1755 || pkt->ppoll > peer->maxpoll) {
1756 msyslog(LOG_INFO, "receive: broadcast poll of %u from %s is out-of-range (%d to %d)!",
1757 pkt->ppoll, stoa(&rbufp->recv_srcadr),
1758 peer->minpoll, peer->maxpoll);
1759 ++bail;
1760 }
1761
1762 /* too early? worth an error, too!
1763 *
1764 * [Bug 3113] Ensure that at least one poll
1765 * interval has elapsed since the last **clean**
1766 * packet was received. We limit the check to
1767 * **clean** packets to prevent replayed packets
1768 * and incorrectly authenticated packets, which
1769 * we'll discard, from being used to create a
1770 * denial of service condition.
1771 */
1772 deadband = (1u << pkt->ppoll);
1773 if (FLAG_BC_VOL & peer->flags)
1774 deadband -= 3; /* allow greater fuzz after volley */
1775 if ((current_time - peer->timereceived) < deadband) {
1776 msyslog(LOG_INFO, "receive: broadcast packet from %s arrived after %lu, not %lu seconds!",
1777 stoa(&rbufp->recv_srcadr),
1778 (current_time - peer->timereceived),
1779 deadband);
1780 ++bail;
1781 }
1782
1783 /* Alert if time from the server is non-monotonic.
1784 *
1785 * [Bug 3114] is about Broadcast mode replay DoS.
1786 *
1787 * Broadcast mode *assumes* a trusted network.
1788 * Even so, it's nice to be robust in the face
1789 * of attacks.
1790 *
1791 * If we get an authenticated broadcast packet
1792 * with an "earlier" timestamp, it means one of
1793 * two things:
1794 *
1795 * - the broadcast server had a backward step.
1796 *
1797 * - somebody is trying a replay attack.
1798 *
1799 * deadband: By default, we assume the broadcast
1800 * network is trustable, so we take our accepted
1801 * broadcast packets as we receive them. But
1802 * some folks might want to take additional poll
1803 * delays before believing a backward step.
1804 */
1805 if (sys_bcpollbstep) {
1806 /* pkt->ppoll or peer->ppoll ? */
1807 deadband = (1u << pkt->ppoll)
1808 * sys_bcpollbstep + 2;
1809 } else {
1810 deadband = 0;
1811 }
1812
1813 if (L_ISZERO(&peer->bxmt)) {
1814 tdiff.l_ui = tdiff.l_uf = 0;
1815 } else {
1816 tdiff = p_xmt;
1817 L_SUB(&tdiff, &peer->bxmt);
1818 }
1819 if ( tdiff.l_i < 0
1820 && (current_time - peer->timereceived) < deadband)
1821 {
1822 msyslog(LOG_INFO, "receive: broadcast packet from %s contains non-monotonic timestamp: %#010x.%08x -> %#010x.%08x",
1823 stoa(&rbufp->recv_srcadr),
1824 peer->bxmt.l_ui, peer->bxmt.l_uf,
1825 p_xmt.l_ui, p_xmt.l_uf
1826 );
1827 ++bail;
1828 }
1829
1830 if (bail) {
1831 DPRINTF(2, ("receive: AM_PROCPKT drop: bail\n"));
1832 peer->timelastrec = current_time;
1833 sys_declined++;
1834 return;
1835 }
1836 }
1837
1838 break;
1839
1840 /*
1841 * A passive packet matches a passive association. This is
1842 * usually the result of reconfiguring a client on the fly. As
1843 * this association might be legitimate and this packet an
1844 * attempt to deny service, just ignore it.
1845 */
1846 case AM_ERR:
1847 DPRINTF(2, ("receive: AM_ERR drop.\n"));
1848 sys_declined++;
1849 return;
1850
1851 /*
1852 * For everything else there is the bit bucket.
1853 */
1854 default:
1855 DPRINTF(2, ("receive: default drop.\n"));
1856 sys_declined++;
1857 return;
1858 }
1859
1860 #ifdef AUTOKEY
1861 /*
1862 * If the association is configured for Autokey, the packet must
1863 * have a public key ID; if not, the packet must have a
1864 * symmetric key ID.
1865 */
1866 if ( is_authentic != AUTH_CRYPTO
1867 && ( ((peer->flags & FLAG_SKEY) && skeyid <= NTP_MAXKEY)
1868 || (!(peer->flags & FLAG_SKEY) && skeyid > NTP_MAXKEY))) {
1869 DPRINTF(2, ("receive: drop: Autokey but wrong/bad auth\n"));
1870 sys_badauth++;
1871 return;
1872 }
1873 #endif /* AUTOKEY */
1874
1875 peer->received++;
1876 peer->flash &= ~PKT_TEST_MASK;
1877 if (peer->flags & FLAG_XBOGUS) {
1878 peer->flags &= ~FLAG_XBOGUS;
1879 peer->flash |= TEST3;
1880 }
1881
1882 /*
1883 * Next comes a rigorous schedule of timestamp checking. If the
1884 * transmit timestamp is zero, the server has not initialized in
1885 * interleaved modes or is horribly broken.
1886 *
1887 * A KoD packet we pay attention to cannot have a 0 transmit
1888 * timestamp.
1889 */
1890
1891 kissCode = kiss_code_check(hisleap, hisstratum, hismode, pkt->refid);
1892
1893 if (L_ISZERO(&p_xmt)) {
1894 peer->flash |= TEST3; /* unsynch */
1895 if (kissCode != NOKISS) { /* KoD packet */
1896 peer->bogusorg++; /* for TEST2 or TEST3 */
1897 msyslog(LOG_INFO,
1898 "receive: Unexpected zero transmit timestamp in KoD from %s",
1899 ntoa(&peer->srcadr));
1900 return;
1901 }
1902
1903 /*
1904 * If the transmit timestamp duplicates our previous one, the
1905 * packet is a replay. This prevents the bad guys from replaying
1906 * the most recent packet, authenticated or not.
1907 */
1908 } else if ( ((FLAG_LOOPNONCE & peer->flags) && L_ISEQU(&peer->nonce, &p_xmt))
1909 || (!(FLAG_LOOPNONCE & peer->flags) && L_ISEQU(&peer->xmt, &p_xmt))
1910 ) {
1911 DPRINTF(2, ("receive: drop: Duplicate xmit\n"));
1912 peer->flash |= TEST1; /* duplicate */
1913 peer->oldpkt++;
1914 return;
1915
1916 /*
1917 * If this is a broadcast mode packet, make sure hisstratum
1918 * is appropriate. Don't do anything else here - we wait to
1919 * see if this is an interleave broadcast packet until after
1920 * we've validated the MAC that SHOULD be provided.
1921 *
1922 * hisstratum cannot be 0 - see assertion above.
1923 * If hisstratum is 15, then we'll advertise as UNSPEC but
1924 * at least we'll be able to sync with the broadcast server.
1925 */
1926 } else if (hismode == MODE_BROADCAST) {
1927 /* 0 is unexpected too, and impossible */
1928 if (STRATUM_UNSPEC <= hisstratum) {
1929 /* Is this a ++sys_declined or ??? */
1930 msyslog(LOG_INFO,
1931 "receive: Unexpected stratum (%d) in broadcast from %s",
1932 hisstratum, ntoa(&peer->srcadr));
1933 return;
1934 }
1935
1936 /*
1937 * Basic KoD validation checking:
1938 *
1939 * KoD packets are a mixed-blessing. Forged KoD packets
1940 * are DoS attacks. There are rare situations where we might
1941 * get a valid KoD response, though. Since KoD packets are
1942 * a special case that complicate the checks we do next, we
1943 * handle the basic KoD checks here.
1944 *
1945 * Note that we expect the incoming KoD packet to have its
1946 * (nonzero) org, rec, and xmt timestamps set to the xmt timestamp
1947 * that we have previously sent out. Watch interleave mode.
1948 */
1949 } else if (kissCode != NOKISS) {
1950 DEBUG_INSIST(!L_ISZERO(&p_xmt));
1951 if ( L_ISZERO(&p_org) /* We checked p_xmt above */
1952 || L_ISZERO(&p_rec)) {
1953 peer->bogusorg++;
1954 msyslog(LOG_INFO,
1955 "receive: KoD packet from %s has a zero org or rec timestamp. Ignoring.",
1956 ntoa(&peer->srcadr));
1957 return;
1958 }
1959
1960 if ( !L_ISEQU(&p_xmt, &p_org)
1961 || !L_ISEQU(&p_xmt, &p_rec)) {
1962 peer->bogusorg++;
1963 msyslog(LOG_INFO,
1964 "receive: KoD packet from %s has inconsistent xmt/org/rec timestamps. Ignoring.",
1965 ntoa(&peer->srcadr));
1966 return;
1967 }
1968
1969 /* Be conservative */
1970 if (peer->flip == 0 && !L_ISEQU(&p_org, &peer->aorg)) {
1971 peer->bogusorg++;
1972 msyslog(LOG_INFO,
1973 "receive: flip 0 KoD origin timestamp %#010x.%08x from %s does not match %#010x.%08x - ignoring.",
1974 p_org.l_ui, p_org.l_uf,
1975 ntoa(&peer->srcadr),
1976 peer->aorg.l_ui, peer->aorg.l_uf);
1977 return;
1978 } else if (peer->flip == 1 && !L_ISEQU(&p_org, &peer->borg)) {
1979 peer->bogusorg++;
1980 msyslog(LOG_INFO,
1981 "receive: flip 1 KoD origin timestamp %#010x.%08x from %s does not match interleave %#010x.%08x - ignoring.",
1982 p_org.l_ui, p_org.l_uf,
1983 ntoa(&peer->srcadr),
1984 peer->borg.l_ui, peer->borg.l_uf);
1985 return;
1986 }
1987
1988 /*
1989 * Basic mode checks:
1990 *
1991 * If there is no origin timestamp, it's either an initial packet
1992 * or we've already received a response to our query. Of course,
1993 * should 'aorg' be all-zero because this really was the original
1994 * transmit timestamp, we'll ignore this reply. There is a window
1995 * of one nanosecond once every 136 years' time where this is
1996 * possible. We currently ignore this situation, as a completely
1997 * zero timestamp is (quietly?) disallowed.
1998 *
1999 * Otherwise, check for bogus packet in basic mode.
2000 * If it is bogus, switch to interleaved mode and resynchronize,
2001 * but only after confirming the packet is not bogus in
2002 * symmetric interleaved mode.
2003 *
2004 * This could also mean somebody is forging packets claiming to
2005 * be from us, attempting to cause our server to KoD us.
2006 *
2007 * We have earlier asserted that hisstratum cannot be 0.
2008 * If hisstratum is STRATUM_UNSPEC, it means he's not sync'd.
2009 */
2010
2011 /* XXX: FLAG_LOOPNONCE */
2012 DEBUG_INSIST(0 == (FLAG_LOOPNONCE & peer->flags));
2013
2014 } else if (peer->flip == 0) {
2015 if (0) {
2016 } else if (L_ISZERO(&p_org)) {
2017 const char *action;
2018
2019 #ifdef BUG3361
2020 msyslog(LOG_INFO,
2021 "receive: BUG 3361: Clearing peer->aorg ");
2022 L_CLR(&peer->aorg);
2023 /* Clear peer->nonce, too? */
2024 #endif
2025 /**/
2026 switch (hismode) {
2027 /* We allow 0org for: */
2028 case UCHAR_MAX:
2029 action = "Allow";
2030 break;
2031 /* We disallow 0org for: */
2032 case MODE_UNSPEC:
2033 case MODE_ACTIVE:
2034 case MODE_PASSIVE:
2035 case MODE_CLIENT:
2036 case MODE_SERVER:
2037 case MODE_BROADCAST:
2038 action = "Drop";
2039 peer->bogusorg++;
2040 peer->flash |= TEST2; /* bogus */
2041 break;
2042 default:
2043 action = ""; /* for cranky compilers / MSVC */
2044 INSIST(!"receive(): impossible hismode");
2045 break;
2046 }
2047 /**/
2048 msyslog(LOG_INFO,
2049 "receive: %s 0 origin timestamp from %s@%s xmt %#010x.%08x",
2050 action, hm_str, ntoa(&peer->srcadr),
2051 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf));
2052 } else if (!L_ISEQU(&p_org, &peer->aorg)) {
2053 /* are there cases here where we should bail? */
2054 /* Should we set TEST2 if we decide to try xleave? */
2055 peer->bogusorg++;
2056 peer->flash |= TEST2; /* bogus */
2057 msyslog(LOG_INFO,
2058 "receive: Unexpected origin timestamp %#010x.%08x does not match aorg %#010x.%08x from %s@%s xmt %#010x.%08x",
2059 ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf),
2060 peer->aorg.l_ui, peer->aorg.l_uf,
2061 hm_str, ntoa(&peer->srcadr),
2062 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf));
2063 if ( !L_ISZERO(&peer->dst)
2064 && L_ISEQU(&p_org, &peer->dst)) {
2065 /* Might be the start of an interleave */
2066 if (dynamic_interleave) {
2067 peer->flip = 1;
2068 report_event(PEVNT_XLEAVE, peer, NULL);
2069 } else {
2070 msyslog(LOG_INFO,
2071 "receive: Dynamic interleave from %s@%s denied",
2072 hm_str, ntoa(&peer->srcadr));
2073 }
2074 }
2075 } else {
2076 L_CLR(&peer->aorg);
2077 /* XXX: FLAG_LOOPNONCE */
2078 }
2079
2080 /*
2081 * Check for valid nonzero timestamp fields.
2082 */
2083 } else if ( L_ISZERO(&p_org)
2084 || L_ISZERO(&p_rec)
2085 || L_ISZERO(&peer->dst)) {
2086 peer->flash |= TEST3; /* unsynch */
2087
2088 /*
2089 * Check for bogus packet in interleaved symmetric mode. This
2090 * can happen if a packet is lost, duplicated or crossed. If
2091 * found, flip and resynchronize.
2092 */
2093 } else if ( !L_ISZERO(&peer->dst)
2094 && !L_ISEQU(&p_org, &peer->dst)) {
2095 DPRINTF(2, ("receive: drop: Bogus packet in interleaved symmetric mode\n"));
2096 peer->bogusorg++;
2097 peer->flags |= FLAG_XBOGUS;
2098 peer->flash |= TEST2; /* bogus */
2099 #ifdef BUG3453
2100 return; /* Bogus packet, we are done */
2101 #endif
2102 }
2103
2104 /**/
2105
2106 /*
2107 * If this is a crypto_NAK, the server cannot authenticate a
2108 * client packet. The server might have just changed keys. Clear
2109 * the association and restart the protocol.
2110 */
2111 if (crypto_nak_test == VALIDNAK) {
2112 report_event(PEVNT_AUTH, peer, "crypto_NAK");
2113 peer->flash |= TEST5; /* bad auth */
2114 peer->badauth++;
2115 if (peer->flags & FLAG_PREEMPT) {
2116 if (unpeer_crypto_nak_early) {
2117 unpeer(peer);
2118 }
2119 DPRINTF(2, ("receive: drop: PREEMPT crypto_NAK\n"));
2120 return;
2121 }
2122 #ifdef AUTOKEY
2123 if (peer->crypto) {
2124 peer_clear(peer, "AUTH");
2125 }
2126 #endif /* AUTOKEY */
2127 DPRINTF(2, ("receive: drop: crypto_NAK\n"));
2128 return;
2129
2130 /*
2131 * If the digest fails or it's missing for authenticated
2132 * associations, the client cannot authenticate a server
2133 * reply to a client packet previously sent. The loopback check
2134 * is designed to avoid a bait-and-switch attack, which was
2135 * possible in past versions. If symmetric modes, return a
2136 * crypto-NAK. The peer should restart the protocol.
2137 */
2138 } else if (!AUTH(peer->keyid || has_mac ||
2139 (restrict_mask & RES_DONTTRUST), is_authentic)) {
2140
2141 if (peer->flash & PKT_TEST_MASK) {
2142 msyslog(LOG_INFO,
2143 "receive: Bad auth in packet with bad timestamps from %s denied - spoof?",
2144 ntoa(&peer->srcadr));
2145 return;
2146 }
2147
2148 report_event(PEVNT_AUTH, peer, "digest");
2149 peer->flash |= TEST5; /* bad auth */
2150 peer->badauth++;
2151 if ( has_mac
2152 && ( hismode == MODE_ACTIVE
2153 || hismode == MODE_PASSIVE))
2154 fast_xmit(rbufp, MODE_ACTIVE, 0, restrict_mask);
2155 if (peer->flags & FLAG_PREEMPT) {
2156 if (unpeer_digest_early) {
2157 unpeer(peer);
2158 }
2159 }
2160 #ifdef AUTOKEY
2161 else if (peer_clear_digest_early && peer->crypto) {
2162 peer_clear(peer, "AUTH");
2163 }
2164 #endif /* AUTOKEY */
2165 DPRINTF(2, ("receive: drop: Bad or missing AUTH\n"));
2166 return;
2167 }
2168
2169 /*
2170 * For broadcast packets:
2171 *
2172 * HMS: This next line never made much sense to me, even
2173 * when it was up higher:
2174 * If an initial volley, bail out now and let the
2175 * client do its stuff.
2176 *
2177 * If the packet has not failed authentication, then
2178 * - if the origin timestamp is nonzero this is an
2179 * interleaved broadcast, so restart the protocol.
2180 * - else, this is not an interleaved broadcast packet.
2181 */
2182 if (hismode == MODE_BROADCAST) {
2183 if ( is_authentic == AUTH_OK
2184 || is_authentic == AUTH_NONE) {
2185 if (!L_ISZERO(&p_org)) {
2186 if (!(peer->flags & FLAG_XB)) {
2187 msyslog(LOG_INFO,
2188 "receive: Broadcast server at %s is in interleave mode",
2189 ntoa(&peer->srcadr));
2190 peer->flags |= FLAG_XB;
2191 peer->aorg = p_xmt;
2192 peer->borg = rbufp->recv_time;
2193 report_event(PEVNT_XLEAVE, peer, NULL);
2194 return;
2195 }
2196 } else if (peer->flags & FLAG_XB) {
2197 msyslog(LOG_INFO,
2198 "receive: Broadcast server at %s is no longer in interleave mode",
2199 ntoa(&peer->srcadr));
2200 peer->flags &= ~FLAG_XB;
2201 }
2202 } else {
2203 msyslog(LOG_INFO,
2204 "receive: Bad broadcast auth (%d) from %s",
2205 is_authentic, ntoa(&peer->srcadr));
2206 }
2207
2208 /*
2209 * Now that we know the packet is correctly authenticated,
2210 * update peer->bxmt.
2211 */
2212 peer->bxmt = p_xmt;
2213 }
2214
2215
2216 /*
2217 ** Update the state variables.
2218 */
2219 if (peer->flip == 0) {
2220 if (hismode != MODE_BROADCAST)
2221 peer->rec = p_xmt;
2222 peer->dst = rbufp->recv_time;
2223 }
2224 peer->xmt = p_xmt;
2225
2226 /*
2227 * Set the peer ppoll to the maximum of the packet ppoll and the
2228 * peer minpoll. If a kiss-o'-death, set the peer minpoll to
2229 * this maximum and advance the headway to give the sender some
2230 * headroom. Very intricate.
2231 */
2232
2233 /*
2234 * Check for any kiss codes. Note this is only used when a server
2235 * responds to a packet request.
2236 */
2237
2238 /*
2239 * Check to see if this is a RATE Kiss Code
2240 * Currently this kiss code will accept whatever poll
2241 * rate that the server sends
2242 */
2243 peer->ppoll = max(peer->minpoll, pkt->ppoll);
2244 if (kissCode == RATEKISS) {
2245 peer->selbroken++; /* Increment the KoD count */
2246 report_event(PEVNT_RATE, peer, NULL);
2247 if (pkt->ppoll > peer->minpoll)
2248 peer->minpoll = peer->ppoll;
2249 peer->burst = peer->retry = 0;
2250 peer->throttle = (NTP_SHIFT + 1) * (1 << peer->minpoll);
2251 poll_update(peer, pkt->ppoll, 0);
2252 return; /* kiss-o'-death */
2253 }
2254 if (kissCode != NOKISS) {
2255 peer->selbroken++; /* Increment the KoD count */
2256 return; /* Drop any other kiss code packets */
2257 }
2258
2259
2260 /*
2261 * XXX
2262 */
2263
2264
2265 /*
2266 * If:
2267 * - this is a *cast (uni-, broad-, or m-) server packet
2268 * - and it's symmetric-key authenticated
2269 * then see if the sender's IP is trusted for this keyid.
2270 * If it is, great - nothing special to do here.
2271 * Otherwise, we should report and bail.
2272 *
2273 * Autokey-authenticated packets are accepted.
2274 */
2275
2276 switch (hismode) {
2277 case MODE_SERVER: /* server mode */
2278 case MODE_BROADCAST: /* broadcast mode */
2279 case MODE_ACTIVE: /* symmetric active mode */
2280 case MODE_PASSIVE: /* symmetric passive mode */
2281 if ( is_authentic == AUTH_OK
2282 && skeyid
2283 && skeyid <= NTP_MAXKEY
2284 && !authistrustedip(skeyid, &peer->srcadr)) {
2285 report_event(PEVNT_AUTH, peer, "authIP");
2286 peer->badauth++;
2287 return;
2288 }
2289 break;
2290
2291 case MODE_CLIENT: /* client mode */
2292 #if 0 /* At this point, MODE_CONTROL is overloaded by MODE_BCLIENT */
2293 case MODE_CONTROL: /* control mode */
2294 #endif
2295 case MODE_PRIVATE: /* private mode */
2296 case MODE_BCLIENT: /* broadcast client mode */
2297 break;
2298
2299 case MODE_UNSPEC: /* unspecified (old version) */
2300 default:
2301 msyslog(LOG_INFO,
2302 "receive: Unexpected mode (%d) in packet from %s",
2303 hismode, ntoa(&peer->srcadr));
2304 break;
2305 }
2306
2307
2308 /*
2309 * That was hard and I am sweaty, but the packet is squeaky
2310 * clean. Get on with real work.
2311 */
2312 peer->timereceived = current_time;
2313 peer->timelastrec = current_time;
2314 if (is_authentic == AUTH_OK)
2315 peer->flags |= FLAG_AUTHENTIC;
2316 else
2317 peer->flags &= ~FLAG_AUTHENTIC;
2318
2319 #ifdef AUTOKEY
2320 /*
2321 * More autokey dance. The rules of the cha-cha are as follows:
2322 *
2323 * 1. If there is no key or the key is not auto, do nothing.
2324 *
2325 * 2. If this packet is in response to the one just previously
2326 * sent or from a broadcast server, do the extension fields.
2327 * Otherwise, assume bogosity and bail out.
2328 *
2329 * 3. If an extension field contains a verified signature, it is
2330 * self-authenticated and we sit the dance.
2331 *
2332 * 4. If this is a server reply, check only to see that the
2333 * transmitted key ID matches the received key ID.
2334 *
2335 * 5. Check to see that one or more hashes of the current key ID
2336 * matches the previous key ID or ultimate original key ID
2337 * obtained from the broadcaster or symmetric peer. If no
2338 * match, sit the dance and call for new autokey values.
2339 *
2340 * In case of crypto error, fire the orchestra, stop dancing and
2341 * restart the protocol.
2342 */
2343 if (peer->flags & FLAG_SKEY) {
2344 /*
2345 * Decrement remaining autokey hashes. This isn't
2346 * perfect if a packet is lost, but results in no harm.
2347 */
2348 ap = (struct autokey *)peer->recval.ptr;
2349 if (ap != NULL) {
2350 if (ap->seq > 0)
2351 ap->seq--;
2352 }
2353 peer->flash |= TEST8;
2354 rval = crypto_recv(peer, rbufp);
2355 if (rval == XEVNT_OK) {
2356 peer->unreach = 0;
2357 } else {
2358 if (rval == XEVNT_ERR) {
2359 report_event(PEVNT_RESTART, peer,
2360 "crypto error");
2361 peer_clear(peer, "CRYP");
2362 peer->flash |= TEST9; /* bad crypt */
2363 if (peer->flags & FLAG_PREEMPT) {
2364 if (unpeer_crypto_early) {
2365 unpeer(peer);
2366 }
2367 }
2368 }
2369 return;
2370 }
2371
2372 /*
2373 * If server mode, verify the receive key ID matches
2374 * the transmit key ID.
2375 */
2376 if (hismode == MODE_SERVER) {
2377 if (skeyid == peer->keyid)
2378 peer->flash &= ~TEST8;
2379
2380 /*
2381 * If an extension field is present, verify only that it
2382 * has been correctly signed. We don't need a sequence
2383 * check here, but the sequence continues.
2384 */
2385 } else if (!(peer->flash & TEST8)) {
2386 peer->pkeyid = skeyid;
2387
2388 /*
2389 * Now the fun part. Here, skeyid is the current ID in
2390 * the packet, pkeyid is the ID in the last packet and
2391 * tkeyid is the hash of skeyid. If the autokey values
2392 * have not been received, this is an automatic error.
2393 * If so, check that the tkeyid matches pkeyid. If not,
2394 * hash tkeyid and try again. If the number of hashes
2395 * exceeds the number remaining in the sequence, declare
2396 * a successful failure and refresh the autokey values.
2397 */
2398 } else if (ap != NULL) {
2399 int i;
2400
2401 for (i = 0; ; i++) {
2402 if ( tkeyid == peer->pkeyid
2403 || tkeyid == ap->key) {
2404 peer->flash &= ~TEST8;
2405 peer->pkeyid = skeyid;
2406 ap->seq -= i;
2407 break;
2408 }
2409 if (i > ap->seq) {
2410 peer->crypto &=
2411 ~CRYPTO_FLAG_AUTO;
2412 break;
2413 }
2414 tkeyid = session_key(
2415 &rbufp->recv_srcadr, dstadr_sin,
2416 tkeyid, pkeyid, 0);
2417 }
2418 if (peer->flash & TEST8)
2419 report_event(PEVNT_AUTH, peer, "keylist");
2420 }
2421 if (!(peer->crypto & CRYPTO_FLAG_PROV)) /* test 9 */
2422 peer->flash |= TEST8; /* bad autokey */
2423
2424 /*
2425 * The maximum lifetime of the protocol is about one
2426 * week before restarting the Autokey protocol to
2427 * refresh certificates and leapseconds values.
2428 */
2429 if (current_time > peer->refresh) {
2430 report_event(PEVNT_RESTART, peer,
2431 "crypto refresh");
2432 peer_clear(peer, "TIME");
2433 return;
2434 }
2435 }
2436 #endif /* AUTOKEY */
2437
2438 /*
2439 * The dance is complete and the flash bits have been lit. Toss
2440 * the packet over the fence for processing, which may light up
2441 * more flashers. Leave if the packet is not good.
2442 */
2443 process_packet(peer, pkt, rbufp->recv_length);
2444 if (peer->flash & PKT_TEST_MASK)
2445 return;
2446
2447 /* [bug 3592] Update poll. Ideally this should not happen in a
2448 * receive branch, but too much is going on here... at least we
2449 * do it only if the packet was good!
2450 */
2451 poll_update(peer, peer->hpoll, (peer->hmode == MODE_CLIENT));
2452
2453 /*
2454 * In interleaved mode update the state variables. Also adjust the
2455 * transmit phase to avoid crossover.
2456 */
2457 if (peer->flip != 0) {
2458 peer->rec = p_rec;
2459 peer->dst = rbufp->recv_time;
2460 if (peer->nextdate - current_time < (1U << min(peer->ppoll,
2461 peer->hpoll)) / 2)
2462 peer->nextdate++;
2463 else
2464 peer->nextdate--;
2465 }
2466 }
2467
2468
2469 /*
2470 * process_packet - Packet Procedure, a la Section 3.4.4 of RFC-1305
2471 * Or almost, at least. If we're in here we have a reasonable
2472 * expectation that we will be having a long term
2473 * relationship with this host.
2474 */
2475 void
process_packet(register struct peer * peer,register struct pkt * pkt,u_int len)2476 process_packet(
2477 register struct peer *peer,
2478 register struct pkt *pkt,
2479 u_int len
2480 )
2481 {
2482 double t34, t21;
2483 double p_offset, p_del, p_disp;
2484 l_fp p_rec, p_xmt, p_org, p_reftime, ci;
2485 u_char pmode, pleap, pversion, pstratum;
2486 char statstr[NTP_MAXSTRLEN];
2487 #ifdef ASSYM
2488 int itemp;
2489 double etemp, ftemp, td;
2490 #endif /* ASSYM */
2491
2492 p_del = FPTOD(NTOHS_FP(pkt->rootdelay));
2493 p_offset = 0;
2494 p_disp = FPTOD(NTOHS_FP(pkt->rootdisp));
2495 NTOHL_FP(&pkt->reftime, &p_reftime);
2496 NTOHL_FP(&pkt->org, &p_org);
2497 NTOHL_FP(&pkt->rec, &p_rec);
2498 NTOHL_FP(&pkt->xmt, &p_xmt);
2499 pmode = PKT_MODE(pkt->li_vn_mode);
2500 pleap = PKT_LEAP(pkt->li_vn_mode);
2501 pversion = PKT_VERSION(pkt->li_vn_mode);
2502 pstratum = PKT_TO_STRATUM(pkt->stratum);
2503
2504 /*
2505 * Verify the server is synchronized; that is, the leap bits,
2506 * stratum and root distance are valid.
2507 */
2508 if ( pleap == LEAP_NOTINSYNC /* test 6 */
2509 || pstratum < sys_floor || pstratum >= sys_ceiling)
2510 peer->flash |= TEST6; /* bad synch or strat */
2511 if (p_del / 2 + p_disp >= MAXDISPERSE) /* test 7 */
2512 peer->flash |= TEST7; /* bad header */
2513
2514 /*
2515 * If any tests fail at this point, the packet is discarded.
2516 * Note that some flashers may have already been set in the
2517 * receive() routine.
2518 */
2519 if (peer->flash & PKT_TEST_MASK) {
2520 peer->seldisptoolarge++;
2521 DPRINTF(1, ("packet: flash header %04x\n",
2522 peer->flash));
2523 /* [Bug 3592] do *not* update poll on bad packets! */
2524 return;
2525 }
2526
2527 /*
2528 * update stats, now that we really handle this packet:
2529 */
2530 sys_processed++;
2531 peer->processed++;
2532
2533 /*
2534 * Capture the header values in the client/peer association..
2535 */
2536 record_raw_stats(&peer->srcadr,
2537 peer->dstadr ? &peer->dstadr->sin : NULL,
2538 &p_org, &p_rec, &p_xmt, &peer->dst,
2539 pleap, pversion, pmode, pstratum, pkt->ppoll, pkt->precision,
2540 p_del, p_disp, pkt->refid,
2541 len - MIN_V4_PKT_LEN, (u_char *)&pkt->exten);
2542 peer->leap = pleap;
2543 peer->stratum = min(pstratum, STRATUM_UNSPEC);
2544 peer->pmode = pmode;
2545 peer->precision = pkt->precision;
2546 peer->rootdelay = p_del;
2547 peer->rootdisp = p_disp;
2548 peer->refid = pkt->refid; /* network byte order */
2549 peer->reftime = p_reftime;
2550
2551 /*
2552 * First, if either burst mode is armed, enable the burst.
2553 * Compute the headway for the next packet and delay if
2554 * necessary to avoid exceeding the threshold.
2555 */
2556 if (peer->retry > 0) {
2557 peer->retry = 0;
2558 if (peer->reach)
2559 peer->burst = min(1 << (peer->hpoll -
2560 peer->minpoll), NTP_SHIFT) - 1;
2561 else
2562 peer->burst = NTP_IBURST - 1;
2563 if (peer->burst > 0)
2564 peer->nextdate = current_time;
2565 }
2566
2567 /*
2568 * If the peer was previously unreachable, raise a trap. In any
2569 * case, mark it reachable.
2570 */
2571 if (!peer->reach) {
2572 report_event(PEVNT_REACH, peer, NULL);
2573 peer->timereachable = current_time;
2574 }
2575 peer->reach |= 1;
2576
2577 /*
2578 * For a client/server association, calculate the clock offset,
2579 * roundtrip delay and dispersion. The equations are reordered
2580 * from the spec for more efficient use of temporaries. For a
2581 * broadcast association, offset the last measurement by the
2582 * computed delay during the client/server volley. Note the
2583 * computation of dispersion includes the system precision plus
2584 * that due to the frequency error since the origin time.
2585 *
2586 * It is very important to respect the hazards of overflow. The
2587 * only permitted operation on raw timestamps is subtraction,
2588 * where the result is a signed quantity spanning from 68 years
2589 * in the past to 68 years in the future. To avoid loss of
2590 * precision, these calculations are done using 64-bit integer
2591 * arithmetic. However, the offset and delay calculations are
2592 * sums and differences of these first-order differences, which
2593 * if done using 64-bit integer arithmetic, would be valid over
2594 * only half that span. Since the typical first-order
2595 * differences are usually very small, they are converted to 64-
2596 * bit doubles and all remaining calculations done in floating-
2597 * double arithmetic. This preserves the accuracy while
2598 * retaining the 68-year span.
2599 *
2600 * There are three interleaving schemes, basic, interleaved
2601 * symmetric and interleaved broadcast. The timestamps are
2602 * idioscyncratically different. See the onwire briefing/white
2603 * paper at www.eecis.udel.edu/~mills for details.
2604 *
2605 * Interleaved symmetric mode
2606 * t1 = peer->aorg/borg, t2 = peer->rec, t3 = p_xmt,
2607 * t4 = peer->dst
2608 */
2609 if (peer->flip != 0) {
2610 ci = p_xmt; /* t3 - t4 */
2611 L_SUB(&ci, &peer->dst);
2612 LFPTOD(&ci, t34);
2613 ci = p_rec; /* t2 - t1 */
2614 if (peer->flip > 0)
2615 L_SUB(&ci, &peer->borg);
2616 else
2617 L_SUB(&ci, &peer->aorg);
2618 LFPTOD(&ci, t21);
2619 p_del = t21 - t34;
2620 p_offset = (t21 + t34) / 2.;
2621 if (p_del < 0 || p_del > 1.) {
2622 snprintf(statstr, sizeof(statstr),
2623 "t21 %.6f t34 %.6f", t21, t34);
2624 report_event(PEVNT_XERR, peer, statstr);
2625 return;
2626 }
2627
2628 /*
2629 * Broadcast modes
2630 */
2631 } else if (peer->pmode == MODE_BROADCAST) {
2632
2633 /*
2634 * Interleaved broadcast mode. Use interleaved timestamps.
2635 * t1 = peer->borg, t2 = p_org, t3 = p_org, t4 = aorg
2636 */
2637 if (peer->flags & FLAG_XB) {
2638 ci = p_org; /* delay */
2639 L_SUB(&ci, &peer->aorg);
2640 LFPTOD(&ci, t34);
2641 ci = p_org; /* t2 - t1 */
2642 L_SUB(&ci, &peer->borg);
2643 LFPTOD(&ci, t21);
2644 peer->aorg = p_xmt;
2645 peer->borg = peer->dst;
2646 if (t34 < 0 || t34 > 1.) {
2647 /* drop all if in the initial volley */
2648 if (FLAG_BC_VOL & peer->flags)
2649 goto bcc_init_volley_fail;
2650 snprintf(statstr, sizeof(statstr),
2651 "offset %.6f delay %.6f", t21, t34);
2652 report_event(PEVNT_XERR, peer, statstr);
2653 return;
2654 }
2655 p_offset = t21;
2656 peer->xleave = t34;
2657
2658 /*
2659 * Basic broadcast - use direct timestamps.
2660 * t3 = p_xmt, t4 = peer->dst
2661 */
2662 } else {
2663 ci = p_xmt; /* t3 - t4 */
2664 L_SUB(&ci, &peer->dst);
2665 LFPTOD(&ci, t34);
2666 p_offset = t34;
2667 }
2668
2669 /*
2670 * When calibration is complete and the clock is
2671 * synchronized, the bias is calculated as the difference
2672 * between the unicast timestamp and the broadcast
2673 * timestamp. This works for both basic and interleaved
2674 * modes.
2675 * [Bug 3031] Don't keep this peer when the delay
2676 * calculation gives reason to suspect clock steps.
2677 * This is assumed for delays > 50ms.
2678 */
2679 if (FLAG_BC_VOL & peer->flags) {
2680 peer->flags &= ~FLAG_BC_VOL;
2681 peer->delay = fabs(peer->offset - p_offset) * 2;
2682 DPRINTF(2, ("broadcast volley: initial delay=%.6f\n",
2683 peer->delay));
2684 if (peer->delay > fabs(sys_bdelay)) {
2685 bcc_init_volley_fail:
2686 DPRINTF(2, ("%s", "broadcast volley: initial delay exceeds limit\n"));
2687 unpeer(peer);
2688 return;
2689 }
2690 }
2691 peer->nextdate = current_time + (1u << peer->ppoll) - 2u;
2692 p_del = peer->delay;
2693 p_offset += p_del / 2;
2694
2695
2696 /*
2697 * Basic mode, otherwise known as the old fashioned way.
2698 *
2699 * t1 = p_org, t2 = p_rec, t3 = p_xmt, t4 = peer->dst
2700 */
2701 } else {
2702 ci = p_xmt; /* t3 - t4 */
2703 L_SUB(&ci, &peer->dst);
2704 LFPTOD(&ci, t34);
2705 ci = p_rec; /* t2 - t1 */
2706 L_SUB(&ci, &p_org);
2707 LFPTOD(&ci, t21);
2708 p_del = fabs(t21 - t34);
2709 p_offset = (t21 + t34) / 2.;
2710 }
2711 p_del = max(p_del, LOGTOD(sys_precision));
2712 p_disp = LOGTOD(sys_precision) + LOGTOD(peer->precision) +
2713 clock_phi * p_del;
2714
2715 #if ASSYM
2716 /*
2717 * This code calculates the outbound and inbound data rates by
2718 * measuring the differences between timestamps at different
2719 * packet lengths. This is helpful in cases of large asymmetric
2720 * delays commonly experienced on deep space communication
2721 * links.
2722 */
2723 if (peer->t21_last > 0 && peer->t34_bytes > 0) {
2724 itemp = peer->t21_bytes - peer->t21_last;
2725 if (itemp > 25) {
2726 etemp = t21 - peer->t21;
2727 if (fabs(etemp) > 1e-6) {
2728 ftemp = itemp / etemp;
2729 if (ftemp > 1000.)
2730 peer->r21 = ftemp;
2731 }
2732 }
2733 itemp = len - peer->t34_bytes;
2734 if (itemp > 25) {
2735 etemp = -t34 - peer->t34;
2736 if (fabs(etemp) > 1e-6) {
2737 ftemp = itemp / etemp;
2738 if (ftemp > 1000.)
2739 peer->r34 = ftemp;
2740 }
2741 }
2742 }
2743
2744 /*
2745 * The following section compensates for different data rates on
2746 * the outbound (d21) and inbound (t34) directions. To do this,
2747 * it finds t such that r21 * t - r34 * (d - t) = 0, where d is
2748 * the roundtrip delay. Then it calculates the correction as a
2749 * fraction of d.
2750 */
2751 peer->t21 = t21;
2752 peer->t21_last = peer->t21_bytes;
2753 peer->t34 = -t34;
2754 peer->t34_bytes = len;
2755 DPRINTF(2, ("packet: t21 %.9lf %d t34 %.9lf %d\n", peer->t21,
2756 peer->t21_bytes, peer->t34, peer->t34_bytes));
2757 if (peer->r21 > 0 && peer->r34 > 0 && p_del > 0) {
2758 if (peer->pmode != MODE_BROADCAST)
2759 td = (peer->r34 / (peer->r21 + peer->r34) -
2760 .5) * p_del;
2761 else
2762 td = 0;
2763
2764 /*
2765 * Unfortunately, in many cases the errors are
2766 * unacceptable, so for the present the rates are not
2767 * used. In future, we might find conditions where the
2768 * calculations are useful, so this should be considered
2769 * a work in progress.
2770 */
2771 t21 -= td;
2772 t34 -= td;
2773 DPRINTF(2, ("packet: del %.6lf r21 %.1lf r34 %.1lf %.6lf\n",
2774 p_del, peer->r21 / 1e3, peer->r34 / 1e3,
2775 td));
2776 }
2777 #endif /* ASSYM */
2778
2779 /*
2780 * That was awesome. Now hand off to the clock filter.
2781 */
2782 clock_filter(peer, p_offset + peer->bias, p_del, p_disp);
2783
2784 /*
2785 * If we are in broadcast calibrate mode, return to broadcast
2786 * client mode when the client is fit and the autokey dance is
2787 * complete.
2788 */
2789 if ( (FLAG_BC_VOL & peer->flags)
2790 && MODE_CLIENT == peer->hmode
2791 && !(TEST11 & peer_unfit(peer))) { /* distance exceeded */
2792 #ifdef AUTOKEY
2793 if (peer->flags & FLAG_SKEY) {
2794 if (!(~peer->crypto & CRYPTO_FLAG_ALL))
2795 peer->hmode = MODE_BCLIENT;
2796 } else {
2797 peer->hmode = MODE_BCLIENT;
2798 }
2799 #else /* !AUTOKEY follows */
2800 peer->hmode = MODE_BCLIENT;
2801 #endif /* !AUTOKEY */
2802 }
2803 }
2804
2805
2806 /*
2807 * clock_update - Called at system process update intervals.
2808 */
2809 static void
clock_update(struct peer * peer)2810 clock_update(
2811 struct peer *peer /* peer structure pointer */
2812 )
2813 {
2814 double dtemp;
2815 l_fp now;
2816 #ifdef HAVE_LIBSCF_H
2817 char *fmri;
2818 #endif /* HAVE_LIBSCF_H */
2819
2820 /*
2821 * Update the system state variables. We do this very carefully,
2822 * as the poll interval might need to be clamped differently.
2823 */
2824 sys_peer = peer;
2825 sys_epoch = peer->epoch;
2826 if (sys_poll < peer->minpoll)
2827 sys_poll = peer->minpoll;
2828 if (sys_poll > peer->maxpoll)
2829 sys_poll = peer->maxpoll;
2830 poll_update(peer, sys_poll, 0);
2831 sys_stratum = min(peer->stratum + 1, STRATUM_UNSPEC);
2832 if ( peer->stratum == STRATUM_REFCLOCK
2833 || peer->stratum == STRATUM_UNSPEC)
2834 sys_refid = peer->refid;
2835 else
2836 sys_refid = addr2refid(&peer->srcadr);
2837 /*
2838 * Root Dispersion (E) is defined (in RFC 5905) as:
2839 *
2840 * E = p.epsilon_r + p.epsilon + p.psi + PHI*(s.t - p.t) + |THETA|
2841 *
2842 * where:
2843 * p.epsilon_r is the PollProc's root dispersion
2844 * p.epsilon is the PollProc's dispersion
2845 * p.psi is the PollProc's jitter
2846 * THETA is the combined offset
2847 *
2848 * NB: Think Hard about where these numbers come from and
2849 * what they mean. When did peer->update happen? Has anything
2850 * interesting happened since then? What values are the most
2851 * defensible? Why?
2852 *
2853 * DLM thinks this equation is probably the best of all worse choices.
2854 */
2855 dtemp = peer->rootdisp
2856 + peer->disp
2857 + sys_jitter
2858 + clock_phi * (current_time - peer->update)
2859 + fabs(sys_offset);
2860
2861 p2_rootdisp = prev_rootdisp;
2862 prev_rootdisp = sys_rootdisp;
2863 if (dtemp > sys_mindisp)
2864 sys_rootdisp = dtemp;
2865 else
2866 sys_rootdisp = sys_mindisp;
2867
2868 sys_rootdelay = peer->delay + peer->rootdelay;
2869
2870 p2_reftime = prev_reftime;
2871 p2_time = prev_time;
2872
2873 prev_reftime = sys_reftime;
2874 prev_time = current_time + 64 + (rand() & 0x3f); /* 64-127 s */
2875
2876 sys_reftime = peer->dst;
2877
2878 DPRINTF(1, ("clock_update: at %lu sample %lu associd %d\n",
2879 current_time, peer->epoch, peer->associd));
2880
2881 /*
2882 * Comes now the moment of truth. Crank the clock discipline and
2883 * see what comes out.
2884 */
2885 switch (local_clock(peer, sys_offset)) {
2886
2887 /*
2888 * Clock exceeds panic threshold. Life as we know it ends.
2889 */
2890 case -1:
2891 #ifdef HAVE_LIBSCF_H
2892 /*
2893 * For Solaris enter the maintenance mode.
2894 */
2895 if ((fmri = getenv("SMF_FMRI")) != NULL) {
2896 if (smf_maintain_instance(fmri, 0) < 0) {
2897 printf("smf_maintain_instance: %s\n",
2898 scf_strerror(scf_error()));
2899 exit(1);
2900 }
2901 /*
2902 * Sleep until SMF kills us.
2903 */
2904 for (;;)
2905 pause();
2906 }
2907 #endif /* HAVE_LIBSCF_H */
2908 exit (-1);
2909 /* not reached */
2910
2911 /*
2912 * Clock was stepped. Flush all time values of all peers.
2913 */
2914 case 2:
2915 clear_all();
2916 set_sys_leap(LEAP_NOTINSYNC);
2917 sys_stratum = STRATUM_UNSPEC;
2918 memcpy(&sys_refid, "STEP", 4);
2919 sys_rootdelay = 0;
2920 p2_rootdisp = 0;
2921 prev_rootdisp = 0;
2922 sys_rootdisp = 0;
2923 L_CLR(&p2_reftime); /* Should we clear p2_reftime? */
2924 L_CLR(&prev_reftime); /* Should we clear prev_reftime? */
2925 L_CLR(&sys_reftime);
2926 sys_jitter = LOGTOD(sys_precision);
2927 leapsec_reset_frame();
2928 break;
2929
2930 /*
2931 * Clock was slewed. Handle the leapsecond stuff.
2932 */
2933 case 1:
2934
2935 /*
2936 * If this is the first time the clock is set, reset the
2937 * leap bits. If crypto, the timer will goose the setup
2938 * process.
2939 */
2940 if (sys_leap == LEAP_NOTINSYNC) {
2941 set_sys_leap(LEAP_NOWARNING);
2942 #ifdef AUTOKEY
2943 if (crypto_flags)
2944 crypto_update();
2945 #endif /* AUTOKEY */
2946 /*
2947 * If our parent process is waiting for the
2948 * first clock sync, send them home satisfied.
2949 */
2950 #ifdef HAVE_WORKING_FORK
2951 if (daemon_pipe[1] != -1) {
2952 write(daemon_pipe[1], "S\n", 2);
2953 close(daemon_pipe[1]);
2954 daemon_pipe[1] = -1;
2955 DPRINTF(1, ("notified parent --wait-sync is done\n"));
2956 }
2957 #endif /* HAVE_WORKING_FORK */
2958
2959 }
2960
2961 /*
2962 * If there is no leap second pending and the number of
2963 * survivor leap bits is greater than half the number of
2964 * survivors, try to schedule a leap for the end of the
2965 * current month. (This only works if no leap second for
2966 * that range is in the table, so doing this more than
2967 * once is mostly harmless.)
2968 */
2969 if (leapsec == LSPROX_NOWARN) {
2970 if ( leap_vote_ins > leap_vote_del
2971 && leap_vote_ins > sys_survivors / 2) {
2972 get_systime(&now);
2973 leapsec_add_dyn(TRUE, now.l_ui, NULL);
2974 }
2975 if ( leap_vote_del > leap_vote_ins
2976 && leap_vote_del > sys_survivors / 2) {
2977 get_systime(&now);
2978 leapsec_add_dyn(FALSE, now.l_ui, NULL);
2979 }
2980 }
2981 break;
2982
2983 /*
2984 * Popcorn spike or step threshold exceeded. Pretend it never
2985 * happened.
2986 */
2987 default:
2988 break;
2989 }
2990 }
2991
2992
2993 /*
2994 * poll_update - update peer poll interval
2995 */
2996 void
poll_update(struct peer * peer,u_char mpoll,u_char skewpoll)2997 poll_update(
2998 struct peer *peer, /* peer structure pointer */
2999 u_char mpoll,
3000 u_char skewpoll
3001 )
3002 {
3003 u_long next, utemp, limit;
3004 u_char hpoll;
3005
3006 /*
3007 * This routine figures out when the next poll should be sent.
3008 * That turns out to be wickedly complicated. One problem is
3009 * that sometimes the time for the next poll is in the past when
3010 * the poll interval is reduced. We watch out for races here
3011 * between the receive process and the poll process.
3012 *
3013 * Clamp the poll interval between minpoll and maxpoll.
3014 */
3015 hpoll = max(min(peer->maxpoll, mpoll), peer->minpoll);
3016
3017 #ifdef AUTOKEY
3018 /*
3019 * If during the crypto protocol the poll interval has changed,
3020 * the lifetimes in the key list are probably bogus. Purge the
3021 * the key list and regenerate it later.
3022 */
3023 if ((peer->flags & FLAG_SKEY) && hpoll != peer->hpoll)
3024 key_expire(peer);
3025 #endif /* AUTOKEY */
3026 peer->hpoll = hpoll;
3027
3028 /*
3029 * There are three variables important for poll scheduling, the
3030 * current time (current_time), next scheduled time (nextdate)
3031 * and the earliest time (utemp). The earliest time is 2 s
3032 * seconds, but could be more due to rate management. When
3033 * sending in a burst, use the earliest time. When not in a
3034 * burst but with a reply pending, send at the earliest time
3035 * unless the next scheduled time has not advanced. This can
3036 * only happen if multiple replies are pending in the same
3037 * response interval. Otherwise, send at the later of the next
3038 * scheduled time and the earliest time.
3039 *
3040 * Now we figure out if there is an override. If a burst is in
3041 * progress and we get called from the receive process, just
3042 * slink away. If called from the poll process, delay 1 s for a
3043 * reference clock, otherwise 2 s.
3044 */
3045 utemp = current_time + max(peer->throttle - (NTP_SHIFT - 1) *
3046 (1 << peer->minpoll), ntp_minpkt);
3047
3048 /*[Bug 3592] avoid unlimited postpone of next poll */
3049 limit = (2u << hpoll);
3050 if (limit > 64)
3051 limit -= (limit >> 2);
3052 limit += peer->outdate;
3053 if (limit < current_time)
3054 limit = current_time;
3055
3056 if (peer->burst > 0) {
3057 if (peer->nextdate > current_time)
3058 return;
3059 #ifdef REFCLOCK
3060 else if (peer->flags & FLAG_REFCLOCK)
3061 peer->nextdate = current_time + RESP_DELAY;
3062 #endif /* REFCLOCK */
3063 else
3064 peer->nextdate = utemp;
3065
3066 #ifdef AUTOKEY
3067 /*
3068 * If a burst is not in progress and a crypto response message
3069 * is pending, delay 2 s, but only if this is a new interval.
3070 */
3071 } else if (peer->cmmd != NULL) {
3072 if (peer->nextdate > current_time) {
3073 if (peer->nextdate + ntp_minpkt != utemp)
3074 peer->nextdate = utemp;
3075 } else {
3076 peer->nextdate = utemp;
3077 }
3078 #endif /* AUTOKEY */
3079
3080 /*
3081 * The ordinary case. If a retry, use minpoll; if unreachable,
3082 * use host poll; otherwise, use the minimum of host and peer
3083 * polls; In other words, oversampling is okay but
3084 * understampling is evil. Use the maximum of this value and the
3085 * headway. If the average headway is greater than the headway
3086 * threshold, increase the headway by the minimum interval.
3087 */
3088 } else {
3089 if (peer->retry > 0)
3090 hpoll = peer->minpoll;
3091 else
3092 hpoll = min(peer->ppoll, peer->hpoll);
3093 #ifdef REFCLOCK
3094 if (peer->flags & FLAG_REFCLOCK)
3095 next = 1 << hpoll;
3096 else
3097 #endif /* REFCLOCK */
3098 next = ((0x1000UL | (ntp_random() & 0x0ff)) <<
3099 hpoll) >> 12;
3100 next += peer->outdate;
3101 /* XXX: bug3596: Deal with poll skew list? */
3102 if (skewpoll) {
3103 psl_item psi;
3104
3105 if (0 == get_pollskew(hpoll, &psi)) {
3106 int sub = psi.sub;
3107 int qty = psi.qty;
3108 int msk = psi.msk;
3109 int val;
3110
3111 if ( 0 != sub
3112 || 0 != qty) {
3113 do {
3114 val = ntp_random() & msk;
3115 } while (val > qty);
3116
3117 next -= sub;
3118 next += val;
3119 }
3120 } else {
3121 /* get_pollskew() already logged this */
3122 }
3123 }
3124 if (next > utemp)
3125 peer->nextdate = next;
3126 else
3127 peer->nextdate = utemp;
3128 if (peer->throttle > (1 << peer->minpoll))
3129 peer->nextdate += ntp_minpkt;
3130 }
3131
3132 /*[Bug 3592] avoid unlimited postpone of next poll */
3133 if (peer->nextdate > limit) {
3134 DPRINTF(1, ("poll_update: clamp reached; limit %lu next %lu\n",
3135 limit, peer->nextdate));
3136 peer->nextdate = limit;
3137 }
3138 DPRINTF(2, ("poll_update: at %lu %s poll %d burst %d retry %d head %d early %lu next %lu\n",
3139 current_time, ntoa(&peer->srcadr), peer->hpoll,
3140 peer->burst, peer->retry, peer->throttle,
3141 utemp - current_time, peer->nextdate -
3142 current_time));
3143 }
3144
3145
3146 /*
3147 * peer_clear - clear peer filter registers. See Section 3.4.8 of the
3148 * spec.
3149 */
3150 void
peer_clear(struct peer * peer,const char * ident)3151 peer_clear(
3152 struct peer *peer, /* peer structure */
3153 const char *ident /* tally lights */
3154 )
3155 {
3156 u_char u;
3157 l_fp bxmt = peer->bxmt; /* bcast clients retain this! */
3158
3159 #ifdef AUTOKEY
3160 /*
3161 * If cryptographic credentials have been acquired, toss them to
3162 * Valhalla. Note that autokeys are ephemeral, in that they are
3163 * tossed immediately upon use. Therefore, the keylist can be
3164 * purged anytime without needing to preserve random keys. Note
3165 * that, if the peer is purged, the cryptographic variables are
3166 * purged, too. This makes it much harder to sneak in some
3167 * unauthenticated data in the clock filter.
3168 */
3169 key_expire(peer);
3170 if (peer->iffval != NULL)
3171 BN_free(peer->iffval);
3172 value_free(&peer->cookval);
3173 value_free(&peer->recval);
3174 value_free(&peer->encrypt);
3175 value_free(&peer->sndval);
3176 if (peer->cmmd != NULL)
3177 free(peer->cmmd);
3178 if (peer->subject != NULL)
3179 free(peer->subject);
3180 if (peer->issuer != NULL)
3181 free(peer->issuer);
3182 #endif /* AUTOKEY */
3183
3184 /*
3185 * Clear all values, including the optional crypto values above.
3186 */
3187 memset(CLEAR_TO_ZERO(peer), 0, LEN_CLEAR_TO_ZERO(peer));
3188 peer->ppoll = peer->maxpoll;
3189 peer->hpoll = peer->minpoll;
3190 peer->disp = MAXDISPERSE;
3191 peer->flash = peer_unfit(peer);
3192 peer->jitter = LOGTOD(sys_precision);
3193
3194 /* Don't throw away our broadcast replay protection */
3195 if (peer->hmode == MODE_BCLIENT)
3196 peer->bxmt = bxmt;
3197
3198 /*
3199 * If interleave mode, initialize the alternate origin switch.
3200 */
3201 if (peer->flags & FLAG_XLEAVE)
3202 peer->flip = 1;
3203 for (u = 0; u < NTP_SHIFT; u++) {
3204 peer->filter_order[u] = u;
3205 peer->filter_disp[u] = MAXDISPERSE;
3206 }
3207 #ifdef REFCLOCK
3208 if (!(peer->flags & FLAG_REFCLOCK)) {
3209 #endif
3210 peer->leap = LEAP_NOTINSYNC;
3211 peer->stratum = STRATUM_UNSPEC;
3212 memcpy(&peer->refid, ident, 4);
3213 #ifdef REFCLOCK
3214 } else {
3215 /* Clear refclock sample filter */
3216 peer->procptr->codeproc = 0;
3217 peer->procptr->coderecv = 0;
3218 }
3219 #endif
3220
3221 /*
3222 * During initialization use the association count to spread out
3223 * the polls at one-second intervals. Passive associations'
3224 * first poll is delayed by the "discard minimum" to avoid rate
3225 * limiting. Other post-startup new or cleared associations
3226 * randomize the first poll over the minimum poll interval to
3227 * avoid implosion.
3228 */
3229 peer->nextdate = peer->update = peer->outdate = current_time;
3230 if (initializing) {
3231 peer->nextdate += peer_associations;
3232 } else if (MODE_PASSIVE == peer->hmode) {
3233 peer->nextdate += ntp_minpkt;
3234 } else {
3235 peer->nextdate += ntp_random() % peer->minpoll;
3236 }
3237 #ifdef AUTOKEY
3238 peer->refresh = current_time + (1 << NTP_REFRESH);
3239 #endif /* AUTOKEY */
3240 DPRINTF(1, ("peer_clear: at %ld next %ld associd %d refid %s\n",
3241 current_time, peer->nextdate, peer->associd,
3242 ident));
3243 }
3244
3245
3246 /*
3247 * clock_filter - add incoming clock sample to filter register and run
3248 * the filter procedure to find the best sample.
3249 */
3250 void
clock_filter(struct peer * peer,double sample_offset,double sample_delay,double sample_disp)3251 clock_filter(
3252 struct peer *peer, /* peer structure pointer */
3253 double sample_offset, /* clock offset */
3254 double sample_delay, /* roundtrip delay */
3255 double sample_disp /* dispersion */
3256 )
3257 {
3258 double dst[NTP_SHIFT]; /* distance vector */
3259 int ord[NTP_SHIFT]; /* index vector */
3260 int i, j, k, m;
3261 double dtemp, etemp;
3262 char tbuf[80];
3263
3264 /*
3265 * A sample consists of the offset, delay, dispersion and epoch
3266 * of arrival. The offset and delay are determined by the on-
3267 * wire protocol. The dispersion grows from the last outbound
3268 * packet to the arrival of this one increased by the sum of the
3269 * peer precision and the system precision as required by the
3270 * error budget. First, shift the new arrival into the shift
3271 * register discarding the oldest one.
3272 */
3273 j = peer->filter_nextpt;
3274 peer->filter_offset[j] = sample_offset;
3275 peer->filter_delay[j] = sample_delay;
3276 peer->filter_disp[j] = sample_disp;
3277 peer->filter_epoch[j] = current_time;
3278 j = (j + 1) % NTP_SHIFT;
3279 peer->filter_nextpt = j;
3280
3281 /*
3282 * Update dispersions since the last update and at the same
3283 * time initialize the distance and index lists. Since samples
3284 * become increasingly uncorrelated beyond the Allan intercept,
3285 * only under exceptional cases will an older sample be used.
3286 * Therefore, the distance list uses a compound metric. If the
3287 * dispersion is greater than the maximum dispersion, clamp the
3288 * distance at that value. If the time since the last update is
3289 * less than the Allan intercept use the delay; otherwise, use
3290 * the sum of the delay and dispersion.
3291 */
3292 dtemp = clock_phi * (current_time - peer->update);
3293 peer->update = current_time;
3294 for (i = NTP_SHIFT - 1; i >= 0; i--) {
3295 if (i != 0)
3296 peer->filter_disp[j] += dtemp;
3297 if (peer->filter_disp[j] >= MAXDISPERSE) {
3298 peer->filter_disp[j] = MAXDISPERSE;
3299 dst[i] = MAXDISPERSE;
3300 } else if (peer->update - peer->filter_epoch[j] >
3301 (u_long)ULOGTOD(allan_xpt)) {
3302 dst[i] = peer->filter_delay[j] +
3303 peer->filter_disp[j];
3304 } else {
3305 dst[i] = peer->filter_delay[j];
3306 }
3307 ord[i] = j;
3308 j = (j + 1) % NTP_SHIFT;
3309 }
3310
3311 /*
3312 * If the clock has stabilized, sort the samples by distance.
3313 */
3314 if (freq_cnt == 0) {
3315 for (i = 1; i < NTP_SHIFT; i++) {
3316 for (j = 0; j < i; j++) {
3317 if (dst[j] > dst[i]) {
3318 k = ord[j];
3319 ord[j] = ord[i];
3320 ord[i] = k;
3321 etemp = dst[j];
3322 dst[j] = dst[i];
3323 dst[i] = etemp;
3324 }
3325 }
3326 }
3327 }
3328
3329 /*
3330 * Copy the index list to the association structure so ntpq
3331 * can see it later. Prune the distance list to leave only
3332 * samples less than the maximum dispersion, which disfavors
3333 * uncorrelated samples older than the Allan intercept. To
3334 * further improve the jitter estimate, of the remainder leave
3335 * only samples less than the maximum distance, but keep at
3336 * least two samples for jitter calculation.
3337 */
3338 m = 0;
3339 for (i = 0; i < NTP_SHIFT; i++) {
3340 peer->filter_order[i] = (u_char) ord[i];
3341 if ( dst[i] >= MAXDISPERSE
3342 || (m >= 2 && dst[i] >= sys_maxdist))
3343 continue;
3344 m++;
3345 }
3346
3347 /*
3348 * Compute the dispersion and jitter. The dispersion is weighted
3349 * exponentially by NTP_FWEIGHT (0.5) so it is normalized close
3350 * to 1.0. The jitter is the RMS differences relative to the
3351 * lowest delay sample.
3352 */
3353 peer->disp = peer->jitter = 0;
3354 k = ord[0];
3355 for (i = NTP_SHIFT - 1; i >= 0; i--) {
3356 j = ord[i];
3357 peer->disp = NTP_FWEIGHT * (peer->disp +
3358 peer->filter_disp[j]);
3359 if (i < m)
3360 peer->jitter += DIFF(peer->filter_offset[j],
3361 peer->filter_offset[k]);
3362 }
3363
3364 /*
3365 * If no acceptable samples remain in the shift register,
3366 * quietly tiptoe home leaving only the dispersion. Otherwise,
3367 * save the offset, delay and jitter. Note the jitter must not
3368 * be less than the precision.
3369 */
3370 if (m == 0) {
3371 clock_select();
3372 return;
3373 }
3374 etemp = fabs(peer->offset - peer->filter_offset[k]);
3375 peer->offset = peer->filter_offset[k];
3376 peer->delay = peer->filter_delay[k];
3377 if (m > 1)
3378 peer->jitter /= m - 1;
3379 peer->jitter = max(SQRT(peer->jitter), LOGTOD(sys_precision));
3380
3381 /*
3382 * If the the new sample and the current sample are both valid
3383 * and the difference between their offsets exceeds CLOCK_SGATE
3384 * (3) times the jitter and the interval between them is less
3385 * than twice the host poll interval, consider the new sample
3386 * a popcorn spike and ignore it.
3387 */
3388 if ( peer->disp < sys_maxdist
3389 && peer->filter_disp[k] < sys_maxdist
3390 && etemp > CLOCK_SGATE * peer->jitter
3391 && peer->filter_epoch[k] - peer->epoch
3392 < 2. * ULOGTOD(peer->hpoll)) {
3393 snprintf(tbuf, sizeof(tbuf), "%.6f s", etemp);
3394 report_event(PEVNT_POPCORN, peer, tbuf);
3395 return;
3396 }
3397
3398 /*
3399 * A new minimum sample is useful only if it is later than the
3400 * last one used. In this design the maximum lifetime of any
3401 * sample is not greater than eight times the poll interval, so
3402 * the maximum interval between minimum samples is eight
3403 * packets.
3404 */
3405 if (peer->filter_epoch[k] <= peer->epoch) {
3406 DPRINTF(2, ("clock_filter: old sample %lu\n", current_time -
3407 peer->filter_epoch[k]));
3408 return;
3409 }
3410 peer->epoch = peer->filter_epoch[k];
3411
3412 /*
3413 * The mitigated sample statistics are saved for later
3414 * processing. If not synchronized or not in a burst, tickle the
3415 * clock select algorithm.
3416 */
3417 record_peer_stats(&peer->srcadr, ctlpeerstatus(peer),
3418 peer->offset, peer->delay, peer->disp, peer->jitter);
3419 DPRINTF(1, ("clock_filter: n %d off %.6f del %.6f dsp %.6f jit %.6f\n",
3420 m, peer->offset, peer->delay, peer->disp,
3421 peer->jitter));
3422 if (peer->burst == 0 || sys_leap == LEAP_NOTINSYNC)
3423 clock_select();
3424 }
3425
3426
3427 /*
3428 * clock_select - find the pick-of-the-litter clock
3429 *
3430 * LOCKCLOCK: (1) If the local clock is the prefer peer, it will always
3431 * be enabled, even if declared falseticker, (2) only the prefer peer
3432 * can be selected as the system peer, (3) if the external source is
3433 * down, the system leap bits are set to 11 and the stratum set to
3434 * infinity.
3435 */
3436 void
clock_select(void)3437 clock_select(void)
3438 {
3439 struct peer *peer;
3440 int i, j, k, n;
3441 int nlist, nl2;
3442 int allow;
3443 int speer;
3444 double d, e, f, g;
3445 double high, low;
3446 double speermet;
3447 double lastresort_dist = MAXDISPERSE;
3448 double orphmet = 2.0 * U_INT32_MAX; /* 2x is greater than */
3449 struct endpoint endp;
3450 struct peer *osys_peer;
3451 struct peer *sys_prefer = NULL; /* prefer peer */
3452 struct peer *typesystem = NULL;
3453 struct peer *typelastresort = NULL;
3454 struct peer *typeorphan = NULL;
3455 #ifdef REFCLOCK
3456 struct peer *typeacts = NULL;
3457 struct peer *typelocal = NULL;
3458 struct peer *typepps = NULL;
3459 #endif /* REFCLOCK */
3460 static struct endpoint *endpoint = NULL;
3461 static int *indx = NULL;
3462 static peer_select *peers = NULL;
3463 static u_int endpoint_size = 0;
3464 static u_int peers_size = 0;
3465 static u_int indx_size = 0;
3466 size_t octets;
3467
3468 /*
3469 * Initialize and create endpoint, index and peer lists big
3470 * enough to handle all associations.
3471 */
3472 osys_peer = sys_peer;
3473 sys_survivors = 0;
3474 #ifdef LOCKCLOCK
3475 set_sys_leap(LEAP_NOTINSYNC);
3476 sys_stratum = STRATUM_UNSPEC;
3477 memcpy(&sys_refid, "DOWN", 4);
3478 #endif /* LOCKCLOCK */
3479
3480 /*
3481 * Allocate dynamic space depending on the number of
3482 * associations.
3483 */
3484 nlist = 1;
3485 for (peer = peer_list; peer != NULL; peer = peer->p_link)
3486 nlist++;
3487 endpoint_size = ALIGNED_SIZE(nlist * 2 * sizeof(*endpoint));
3488 peers_size = ALIGNED_SIZE(nlist * sizeof(*peers));
3489 indx_size = ALIGNED_SIZE(nlist * 2 * sizeof(*indx));
3490 octets = endpoint_size + peers_size + indx_size;
3491 endpoint = erealloc(endpoint, octets);
3492 peers = INC_ALIGNED_PTR(endpoint, endpoint_size);
3493 indx = INC_ALIGNED_PTR(peers, peers_size);
3494
3495 /*
3496 * Initially, we populate the island with all the rifraff peers
3497 * that happen to be lying around. Those with seriously
3498 * defective clocks are immediately booted off the island. Then,
3499 * the falsetickers are culled and put to sea. The truechimers
3500 * remaining are subject to repeated rounds where the most
3501 * unpopular at each round is kicked off. When the population
3502 * has dwindled to sys_minclock, the survivors split a million
3503 * bucks and collectively crank the chimes.
3504 */
3505 nlist = nl2 = 0; /* none yet */
3506 for (peer = peer_list; peer != NULL; peer = peer->p_link) {
3507 peer->new_status = CTL_PST_SEL_REJECT;
3508
3509 /*
3510 * Leave the island immediately if the peer is
3511 * unfit to synchronize.
3512 */
3513 if (peer_unfit(peer)) {
3514 continue;
3515 }
3516
3517 /*
3518 * If we have never been synchronised, look for any peer
3519 * which has ever been synchronised and pick the one which
3520 * has the lowest root distance. This can be used as a last
3521 * resort if all else fails. Once we get an initial sync
3522 * with this peer, sys_reftime gets set and so this
3523 * function becomes disabled.
3524 */
3525 if (L_ISZERO(&sys_reftime)) {
3526 d = root_distance(peer);
3527 if (!L_ISZERO(&peer->reftime) && d < lastresort_dist) {
3528 typelastresort = peer;
3529 lastresort_dist = d;
3530 }
3531 }
3532
3533 /*
3534 * If this peer is an orphan parent, elect the
3535 * one with the lowest metric defined as the
3536 * IPv4 address or the first 64 bits of the
3537 * hashed IPv6 address. To ensure convergence
3538 * on the same selected orphan, consider as
3539 * well that this system may have the lowest
3540 * metric and be the orphan parent. If this
3541 * system wins, sys_peer will be NULL to trigger
3542 * orphan mode in timer().
3543 */
3544 if (peer->stratum == sys_orphan) {
3545 u_int32 localmet;
3546 u_int32 peermet;
3547
3548 if (peer->dstadr != NULL)
3549 localmet = ntohl(peer->dstadr->addr_refid);
3550 else
3551 localmet = U_INT32_MAX;
3552 peermet = ntohl(addr2refid(&peer->srcadr));
3553 if (peermet < localmet && peermet < orphmet) {
3554 typeorphan = peer;
3555 orphmet = peermet;
3556 }
3557 continue;
3558 }
3559
3560 /*
3561 * If this peer could have the orphan parent
3562 * as a synchronization ancestor, exclude it
3563 * from selection to avoid forming a
3564 * synchronization loop within the orphan mesh,
3565 * triggering stratum climb to infinity
3566 * instability. Peers at stratum higher than
3567 * the orphan stratum could have the orphan
3568 * parent in ancestry so are excluded.
3569 * See http://bugs.ntp.org/2050
3570 */
3571 if (peer->stratum > sys_orphan) {
3572 continue;
3573 }
3574 #ifdef REFCLOCK
3575 /*
3576 * The following are special cases. We deal
3577 * with them later.
3578 */
3579 if (!(peer->flags & FLAG_PREFER)) {
3580 switch (peer->refclktype) {
3581 case REFCLK_LOCALCLOCK:
3582 if ( current_time > orphwait
3583 && typelocal == NULL)
3584 typelocal = peer;
3585 continue;
3586
3587 case REFCLK_ACTS:
3588 if ( current_time > orphwait
3589 && typeacts == NULL)
3590 typeacts = peer;
3591 continue;
3592 }
3593 }
3594 #endif /* REFCLOCK */
3595
3596 /*
3597 * If we get this far, the peer can stay on the
3598 * island, but does not yet have the immunity
3599 * idol.
3600 */
3601 peer->new_status = CTL_PST_SEL_SANE;
3602 f = root_distance(peer);
3603 peers[nlist].peer = peer;
3604 peers[nlist].error = peer->jitter;
3605 peers[nlist].synch = f;
3606 nlist++;
3607
3608 /*
3609 * Insert each interval endpoint on the unsorted
3610 * endpoint[] list.
3611 */
3612 e = peer->offset;
3613 endpoint[nl2].type = -1; /* lower end */
3614 endpoint[nl2].val = e - f;
3615 nl2++;
3616 endpoint[nl2].type = 1; /* upper end */
3617 endpoint[nl2].val = e + f;
3618 nl2++;
3619 }
3620 /*
3621 * Construct sorted indx[] of endpoint[] indexes ordered by
3622 * offset.
3623 */
3624 for (i = 0; i < nl2; i++)
3625 indx[i] = i;
3626 for (i = 0; i < nl2; i++) {
3627 endp = endpoint[indx[i]];
3628 e = endp.val;
3629 k = i;
3630 for (j = i + 1; j < nl2; j++) {
3631 endp = endpoint[indx[j]];
3632 if (endp.val < e) {
3633 e = endp.val;
3634 k = j;
3635 }
3636 }
3637 if (k != i) {
3638 j = indx[k];
3639 indx[k] = indx[i];
3640 indx[i] = j;
3641 }
3642 }
3643 for (i = 0; i < nl2; i++)
3644 DPRINTF(3, ("select: endpoint %2d %.6f\n",
3645 endpoint[indx[i]].type, endpoint[indx[i]].val));
3646
3647 /*
3648 * This is the actual algorithm that cleaves the truechimers
3649 * from the falsetickers. The original algorithm was described
3650 * in Keith Marzullo's dissertation, but has been modified for
3651 * better accuracy.
3652 *
3653 * Briefly put, we first assume there are no falsetickers, then
3654 * scan the candidate list first from the low end upwards and
3655 * then from the high end downwards. The scans stop when the
3656 * number of intersections equals the number of candidates less
3657 * the number of falsetickers. If this doesn't happen for a
3658 * given number of falsetickers, we bump the number of
3659 * falsetickers and try again. If the number of falsetickers
3660 * becomes equal to or greater than half the number of
3661 * candidates, the Albanians have won the Byzantine wars and
3662 * correct synchronization is not possible.
3663 *
3664 * Here, nlist is the number of candidates and allow is the
3665 * number of falsetickers. Upon exit, the truechimers are the
3666 * survivors with offsets not less than low and not greater than
3667 * high. There may be none of them.
3668 */
3669 low = 1e9;
3670 high = -1e9;
3671 for (allow = 0; 2 * allow < nlist; allow++) {
3672
3673 /*
3674 * Bound the interval (low, high) as the smallest
3675 * interval containing points from the most sources.
3676 */
3677 n = 0;
3678 for (i = 0; i < nl2; i++) {
3679 low = endpoint[indx[i]].val;
3680 n -= endpoint[indx[i]].type;
3681 if (n >= nlist - allow)
3682 break;
3683 }
3684 n = 0;
3685 for (j = nl2 - 1; j >= 0; j--) {
3686 high = endpoint[indx[j]].val;
3687 n += endpoint[indx[j]].type;
3688 if (n >= nlist - allow)
3689 break;
3690 }
3691
3692 /*
3693 * If an interval containing truechimers is found, stop.
3694 * If not, increase the number of falsetickers and go
3695 * around again.
3696 */
3697 if (high > low)
3698 break;
3699 }
3700
3701 /*
3702 * Clustering algorithm. Whittle candidate list of falsetickers,
3703 * who leave the island immediately. The TRUE peer is always a
3704 * truechimer. We must leave at least one peer to collect the
3705 * million bucks.
3706 *
3707 * We assert the correct time is contained in the interval, but
3708 * the best offset estimate for the interval might not be
3709 * contained in the interval. For this purpose, a truechimer is
3710 * defined as the midpoint of an interval that overlaps the
3711 * intersection interval.
3712 */
3713 j = 0;
3714 for (i = 0; i < nlist; i++) {
3715 double h;
3716
3717 peer = peers[i].peer;
3718 h = peers[i].synch;
3719 if (( high <= low
3720 || peer->offset + h < low
3721 || peer->offset - h > high
3722 ) && !(peer->flags & FLAG_TRUE))
3723 continue;
3724
3725 #ifdef REFCLOCK
3726 /*
3727 * Eligible PPS peers must survive the intersection
3728 * algorithm. Use the first one found, but don't
3729 * include any of them in the cluster population.
3730 */
3731 if (peer->flags & FLAG_PPS) {
3732 if (typepps == NULL)
3733 typepps = peer;
3734 if (!(peer->flags & FLAG_TSTAMP_PPS))
3735 continue;
3736 }
3737 #endif /* REFCLOCK */
3738
3739 if (j != i)
3740 peers[j] = peers[i];
3741 j++;
3742 }
3743 nlist = j;
3744
3745 /*
3746 * If no survivors remain at this point, check if the modem
3747 * driver, local driver or orphan parent in that order. If so,
3748 * nominate the first one found as the only survivor.
3749 * Otherwise, give up and leave the island to the rats.
3750 */
3751 if (nlist == 0) {
3752 peers[0].error = 0;
3753 peers[0].synch = sys_mindisp;
3754 #ifdef REFCLOCK
3755 if (typeacts != NULL) {
3756 peers[0].peer = typeacts;
3757 nlist = 1;
3758 } else if (typelocal != NULL) {
3759 peers[0].peer = typelocal;
3760 nlist = 1;
3761 } else
3762 #endif /* REFCLOCK */
3763 if (typeorphan != NULL) {
3764 peers[0].peer = typeorphan;
3765 nlist = 1;
3766 } else if (typelastresort != NULL) {
3767 peers[0].peer = typelastresort;
3768 nlist = 1;
3769 }
3770 }
3771
3772 /*
3773 * Mark the candidates at this point as truechimers.
3774 */
3775 for (i = 0; i < nlist; i++) {
3776 peers[i].peer->new_status = CTL_PST_SEL_SELCAND;
3777 DPRINTF(2, ("select: survivor %s %f\n",
3778 stoa(&peers[i].peer->srcadr), peers[i].synch));
3779 }
3780
3781 /*
3782 * Now, vote outliers off the island by select jitter weighted
3783 * by root distance. Continue voting as long as there are more
3784 * than sys_minclock survivors and the select jitter of the peer
3785 * with the worst metric is greater than the minimum peer
3786 * jitter. Stop if we are about to discard a TRUE or PREFER
3787 * peer, who of course have the immunity idol.
3788 */
3789 while (1) {
3790 d = 1e9;
3791 e = -1e9;
3792 g = 0;
3793 k = 0;
3794 for (i = 0; i < nlist; i++) {
3795 if (peers[i].error < d)
3796 d = peers[i].error;
3797 peers[i].seljit = 0;
3798 if (nlist > 1) {
3799 f = 0;
3800 for (j = 0; j < nlist; j++)
3801 f += DIFF(peers[j].peer->offset,
3802 peers[i].peer->offset);
3803 peers[i].seljit = SQRT(f / (nlist - 1));
3804 }
3805 if (peers[i].seljit * peers[i].synch > e) {
3806 g = peers[i].seljit;
3807 e = peers[i].seljit * peers[i].synch;
3808 k = i;
3809 }
3810 }
3811 g = max(g, LOGTOD(sys_precision));
3812 if ( nlist <= max(1, sys_minclock)
3813 || g <= d
3814 || ((FLAG_TRUE | FLAG_PREFER) & peers[k].peer->flags))
3815 break;
3816
3817 DPRINTF(3, ("select: drop %s seljit %.6f jit %.6f\n",
3818 ntoa(&peers[k].peer->srcadr), g, d));
3819 if (nlist > sys_maxclock)
3820 peers[k].peer->new_status = CTL_PST_SEL_EXCESS;
3821 for (j = k + 1; j < nlist; j++)
3822 peers[j - 1] = peers[j];
3823 nlist--;
3824 }
3825
3826 /*
3827 * What remains is a list usually not greater than sys_minclock
3828 * peers. Note that unsynchronized peers cannot survive this
3829 * far. Count and mark these survivors.
3830 *
3831 * While at it, count the number of leap warning bits found.
3832 * This will be used later to vote the system leap warning bit.
3833 * If a leap warning bit is found on a reference clock, the vote
3834 * is always won.
3835 *
3836 * Choose the system peer using a hybrid metric composed of the
3837 * selection jitter scaled by the root distance augmented by
3838 * stratum scaled by sys_mindisp (.001 by default). The goal of
3839 * the small stratum factor is to avoid clockhop between a
3840 * reference clock and a network peer which has a refclock and
3841 * is using an older ntpd, which does not floor sys_rootdisp at
3842 * sys_mindisp.
3843 *
3844 * In contrast, ntpd 4.2.6 and earlier used stratum primarily
3845 * in selecting the system peer, using a weight of 1 second of
3846 * additional root distance per stratum. This heavy bias is no
3847 * longer appropriate, as the scaled root distance provides a
3848 * more rational metric carrying the cumulative error budget.
3849 */
3850 e = 1e9;
3851 speer = 0;
3852 leap_vote_ins = 0;
3853 leap_vote_del = 0;
3854 for (i = 0; i < nlist; i++) {
3855 peer = peers[i].peer;
3856 peer->unreach = 0;
3857 peer->new_status = CTL_PST_SEL_SYNCCAND;
3858 sys_survivors++;
3859 if (peer->leap == LEAP_ADDSECOND) {
3860 if (peer->flags & FLAG_REFCLOCK)
3861 leap_vote_ins = nlist;
3862 else if (leap_vote_ins < nlist)
3863 leap_vote_ins++;
3864 }
3865 if (peer->leap == LEAP_DELSECOND) {
3866 if (peer->flags & FLAG_REFCLOCK)
3867 leap_vote_del = nlist;
3868 else if (leap_vote_del < nlist)
3869 leap_vote_del++;
3870 }
3871 if (peer->flags & FLAG_PREFER)
3872 sys_prefer = peer;
3873 speermet = peers[i].seljit * peers[i].synch +
3874 peer->stratum * sys_mindisp;
3875 if (speermet < e) {
3876 e = speermet;
3877 speer = i;
3878 }
3879 }
3880
3881 /*
3882 * Unless there are at least sys_misane survivors, leave the
3883 * building dark. Otherwise, do a clockhop dance. Ordinarily,
3884 * use the selected survivor speer. However, if the current
3885 * system peer is not speer, stay with the current system peer
3886 * as long as it doesn't get too old or too ugly.
3887 */
3888 if (nlist > 0 && nlist >= sys_minsane) {
3889 double x;
3890
3891 typesystem = peers[speer].peer;
3892 if (osys_peer == NULL || osys_peer == typesystem) {
3893 sys_clockhop = 0;
3894 } else if ((x = fabs(typesystem->offset -
3895 osys_peer->offset)) < sys_mindisp) {
3896 if (sys_clockhop == 0)
3897 sys_clockhop = sys_mindisp;
3898 else
3899 sys_clockhop *= .5;
3900 DPRINTF(1, ("select: clockhop %d %.6f %.6f\n",
3901 j, x, sys_clockhop));
3902 if (fabs(x) < sys_clockhop)
3903 typesystem = osys_peer;
3904 else
3905 sys_clockhop = 0;
3906 } else {
3907 sys_clockhop = 0;
3908 }
3909 }
3910
3911 /*
3912 * Mitigation rules of the game. We have the pick of the
3913 * litter in typesystem if any survivors are left. If
3914 * there is a prefer peer, use its offset and jitter.
3915 * Otherwise, use the combined offset and jitter of all kitters.
3916 */
3917 if (typesystem != NULL) {
3918 if (sys_prefer == NULL) {
3919 typesystem->new_status = CTL_PST_SEL_SYSPEER;
3920 clock_combine(peers, sys_survivors, speer);
3921 } else {
3922 typesystem = sys_prefer;
3923 sys_clockhop = 0;
3924 typesystem->new_status = CTL_PST_SEL_SYSPEER;
3925 sys_offset = typesystem->offset;
3926 sys_jitter = typesystem->jitter;
3927 }
3928 DPRINTF(1, ("select: combine offset %.9f jitter %.9f\n",
3929 sys_offset, sys_jitter));
3930 }
3931 #ifdef REFCLOCK
3932 /*
3933 * If a PPS driver is lit and the combined offset is less than
3934 * 0.4 s, select the driver as the PPS peer and use its offset
3935 * and jitter. However, if this is the atom driver, use it only
3936 * if there is a prefer peer or there are no survivors and none
3937 * are required.
3938 */
3939 if ( typepps != NULL
3940 && fabs(sys_offset) < 0.4
3941 && ( typepps->refclktype != REFCLK_ATOM_PPS
3942 || ( typepps->refclktype == REFCLK_ATOM_PPS
3943 && ( sys_prefer != NULL
3944 || (typesystem == NULL && sys_minsane == 0))))) {
3945 typesystem = typepps;
3946 sys_clockhop = 0;
3947 typesystem->new_status = CTL_PST_SEL_PPS;
3948 sys_offset = typesystem->offset;
3949 sys_jitter = typesystem->jitter;
3950 DPRINTF(1, ("select: pps offset %.9f jitter %.9f\n",
3951 sys_offset, sys_jitter));
3952 }
3953 #endif /* REFCLOCK */
3954
3955 /*
3956 * If there are no survivors at this point, there is no
3957 * system peer. If so and this is an old update, keep the
3958 * current statistics, but do not update the clock.
3959 */
3960 if (typesystem == NULL) {
3961 if (osys_peer != NULL) {
3962 orphwait = current_time + sys_orphwait;
3963 report_event(EVNT_NOPEER, NULL, NULL);
3964 }
3965 sys_peer = NULL;
3966 for (peer = peer_list; peer != NULL; peer = peer->p_link)
3967 peer->status = peer->new_status;
3968 return;
3969 }
3970
3971 /*
3972 * Do not use old data, as this may mess up the clock discipline
3973 * stability.
3974 */
3975 if (typesystem->epoch <= sys_epoch)
3976 return;
3977
3978 /*
3979 * We have found the alpha male. Wind the clock.
3980 */
3981 if (osys_peer != typesystem)
3982 report_event(PEVNT_NEWPEER, typesystem, NULL);
3983 for (peer = peer_list; peer != NULL; peer = peer->p_link)
3984 peer->status = peer->new_status;
3985 clock_update(typesystem);
3986 }
3987
3988
3989 static void
clock_combine(peer_select * peers,int npeers,int syspeer)3990 clock_combine(
3991 peer_select * peers, /* survivor list */
3992 int npeers, /* number of survivors */
3993 int syspeer /* index of sys.peer */
3994 )
3995 {
3996 int i;
3997 double x, y, z, w;
3998
3999 y = z = w = 0;
4000 for (i = 0; i < npeers; i++) {
4001 x = 1. / peers[i].synch;
4002 y += x;
4003 z += x * peers[i].peer->offset;
4004 w += x * DIFF(peers[i].peer->offset,
4005 peers[syspeer].peer->offset);
4006 }
4007 sys_offset = z / y;
4008 sys_jitter = SQRT(w / y + SQUARE(peers[syspeer].seljit));
4009 }
4010
4011
4012 /*
4013 * root_distance - compute synchronization distance from peer to root
4014 */
4015 static double
root_distance(struct peer * peer)4016 root_distance(
4017 struct peer *peer /* peer structure pointer */
4018 )
4019 {
4020 double dtemp;
4021
4022 /*
4023 * Root Distance (LAMBDA) is defined as:
4024 * (delta + DELTA)/2 + epsilon + EPSILON + D
4025 *
4026 * where:
4027 * delta is the round-trip delay
4028 * DELTA is the root delay
4029 * epsilon is the peer dispersion
4030 * + (15 usec each second)
4031 * EPSILON is the root dispersion
4032 * D is sys_jitter
4033 *
4034 * NB: Think hard about why we are using these values, and what
4035 * the alternatives are, and the various pros/cons.
4036 *
4037 * DLM thinks these are probably the best choices from any of the
4038 * other worse choices.
4039 */
4040 dtemp = (peer->delay + peer->rootdelay) / 2
4041 + peer->disp
4042 + clock_phi * (current_time - peer->update)
4043 + peer->rootdisp
4044 + peer->jitter;
4045 /*
4046 * Careful squeak here. The value returned must be greater than
4047 * the minimum root dispersion in order to avoid clockhop with
4048 * highly precise reference clocks. Note that the root distance
4049 * cannot exceed the sys_maxdist, as this is the cutoff by the
4050 * selection algorithm.
4051 */
4052 if (dtemp < sys_mindisp)
4053 dtemp = sys_mindisp;
4054 return (dtemp);
4055 }
4056
4057
4058 /*
4059 * peer_xmit - send packet for persistent association.
4060 */
4061 static void
peer_xmit(struct peer * peer)4062 peer_xmit(
4063 struct peer *peer /* peer structure pointer */
4064 )
4065 {
4066 struct pkt xpkt; /* transmit packet */
4067 size_t sendlen, authlen;
4068 keyid_t xkeyid = 0; /* transmit key ID */
4069 l_fp xmt_tx, xmt_ty;
4070
4071 if (!peer->dstadr) /* drop peers without interface */
4072 return;
4073
4074 xpkt.li_vn_mode = PKT_LI_VN_MODE(sys_leap, peer->version,
4075 peer->hmode);
4076 xpkt.stratum = STRATUM_TO_PKT(sys_stratum);
4077 xpkt.ppoll = peer->hpoll;
4078 xpkt.precision = sys_precision;
4079 xpkt.refid = sys_refid;
4080 xpkt.rootdelay = HTONS_FP(DTOFP(sys_rootdelay));
4081 xpkt.rootdisp = HTONS_FP(DTOUFP(sys_rootdisp));
4082 /* Use sys_reftime for peer exchanges */
4083 HTONL_FP(&sys_reftime, &xpkt.reftime);
4084 HTONL_FP(&peer->rec, &xpkt.org);
4085 HTONL_FP(&peer->dst, &xpkt.rec);
4086
4087 /*
4088 * If the received packet contains a MAC, the transmitted packet
4089 * is authenticated and contains a MAC. If not, the transmitted
4090 * packet is not authenticated.
4091 *
4092 * It is most important when autokey is in use that the local
4093 * interface IP address be known before the first packet is
4094 * sent. Otherwise, it is not possible to compute a correct MAC
4095 * the recipient will accept. Thus, the I/O semantics have to do
4096 * a little more work. In particular, the wildcard interface
4097 * might not be usable.
4098 */
4099 sendlen = LEN_PKT_NOMAC;
4100 if (
4101 #ifdef AUTOKEY
4102 !(peer->flags & FLAG_SKEY) &&
4103 #endif /* !AUTOKEY */
4104 peer->keyid == 0) {
4105
4106 /*
4107 * Transmit a-priori timestamps
4108 */
4109 get_systime(&xmt_tx);
4110 if (peer->flip == 0) { /* basic mode */
4111 peer->aorg = xmt_tx;
4112 HTONL_FP(&xmt_tx, &xpkt.xmt);
4113 } else { /* interleaved modes */
4114 if (peer->hmode == MODE_BROADCAST) { /* bcst */
4115 HTONL_FP(&xmt_tx, &xpkt.xmt);
4116 if (peer->flip > 0)
4117 HTONL_FP(&peer->borg,
4118 &xpkt.org);
4119 else
4120 HTONL_FP(&peer->aorg,
4121 &xpkt.org);
4122 } else { /* symmetric */
4123 if (peer->flip > 0)
4124 HTONL_FP(&peer->borg,
4125 &xpkt.xmt);
4126 else
4127 HTONL_FP(&peer->aorg,
4128 &xpkt.xmt);
4129 }
4130 }
4131 peer->t21_bytes = sendlen;
4132 sendpkt(&peer->srcadr, peer->dstadr,
4133 sys_ttl[(peer->ttl >= sys_ttlmax) ? sys_ttlmax : peer->ttl],
4134 &xpkt, sendlen);
4135 peer->sent++;
4136 peer->throttle += (1 << peer->minpoll) - 2;
4137
4138 /*
4139 * Capture a-posteriori timestamps
4140 */
4141 get_systime(&xmt_ty);
4142 if (peer->flip != 0) { /* interleaved modes */
4143 if (peer->flip > 0)
4144 peer->aorg = xmt_ty;
4145 else
4146 peer->borg = xmt_ty;
4147 peer->flip = -peer->flip;
4148 }
4149 L_SUB(&xmt_ty, &xmt_tx);
4150 LFPTOD(&xmt_ty, peer->xleave);
4151 DPRINTF(1, ("peer_xmit: at %ld %s->%s mode %d len %zu xmt %#010x.%08x\n",
4152 current_time,
4153 peer->dstadr ? stoa(&peer->dstadr->sin) : "-",
4154 stoa(&peer->srcadr), peer->hmode, sendlen,
4155 xmt_tx.l_ui, xmt_tx.l_uf));
4156 return;
4157 }
4158
4159 /*
4160 * Authentication is enabled, so the transmitted packet must be
4161 * authenticated. If autokey is enabled, fuss with the various
4162 * modes; otherwise, symmetric key cryptography is used.
4163 */
4164 #ifdef AUTOKEY
4165 if (peer->flags & FLAG_SKEY) {
4166 struct exten *exten; /* extension field */
4167
4168 /*
4169 * The Public Key Dance (PKD): Cryptographic credentials
4170 * are contained in extension fields, each including a
4171 * 4-octet length/code word followed by a 4-octet
4172 * association ID and optional additional data. Optional
4173 * data includes a 4-octet data length field followed by
4174 * the data itself. Request messages are sent from a
4175 * configured association; response messages can be sent
4176 * from a configured association or can take the fast
4177 * path without ever matching an association. Response
4178 * messages have the same code as the request, but have
4179 * a response bit and possibly an error bit set. In this
4180 * implementation, a message may contain no more than
4181 * one command and one or more responses.
4182 *
4183 * Cryptographic session keys include both a public and
4184 * a private componet. Request and response messages
4185 * using extension fields are always sent with the
4186 * private component set to zero. Packets without
4187 * extension fields indlude the private component when
4188 * the session key is generated.
4189 */
4190 while (1) {
4191
4192 /*
4193 * Allocate and initialize a keylist if not
4194 * already done. Then, use the list in inverse
4195 * order, discarding keys once used. Keep the
4196 * latest key around until the next one, so
4197 * clients can use client/server packets to
4198 * compute propagation delay.
4199 *
4200 * Note that once a key is used from the list,
4201 * it is retained in the key cache until the
4202 * next key is used. This is to allow a client
4203 * to retrieve the encrypted session key
4204 * identifier to verify authenticity.
4205 *
4206 * If for some reason a key is no longer in the
4207 * key cache, a birthday has happened or the key
4208 * has expired, so the pseudo-random sequence is
4209 * broken. In that case, purge the keylist and
4210 * regenerate it.
4211 */
4212 if (peer->keynumber == 0)
4213 make_keylist(peer, peer->dstadr);
4214 else
4215 peer->keynumber--;
4216 xkeyid = peer->keylist[peer->keynumber];
4217 if (authistrusted(xkeyid))
4218 break;
4219 else
4220 key_expire(peer);
4221 }
4222 peer->keyid = xkeyid;
4223 exten = NULL;
4224 switch (peer->hmode) {
4225
4226 /*
4227 * In broadcast server mode the autokey values are
4228 * required by the broadcast clients. Push them when a
4229 * new keylist is generated; otherwise, push the
4230 * association message so the client can request them at
4231 * other times.
4232 */
4233 case MODE_BROADCAST:
4234 if (peer->flags & FLAG_ASSOC)
4235 exten = crypto_args(peer, CRYPTO_AUTO |
4236 CRYPTO_RESP, peer->associd, NULL);
4237 else
4238 exten = crypto_args(peer, CRYPTO_ASSOC |
4239 CRYPTO_RESP, peer->associd, NULL);
4240 break;
4241
4242 /*
4243 * In symmetric modes the parameter, certificate,
4244 * identity, cookie and autokey exchanges are
4245 * required. The leapsecond exchange is optional. But, a
4246 * peer will not believe the other peer until the other
4247 * peer has synchronized, so the certificate exchange
4248 * might loop until then. If a peer finds a broken
4249 * autokey sequence, it uses the autokey exchange to
4250 * retrieve the autokey values. In any case, if a new
4251 * keylist is generated, the autokey values are pushed.
4252 */
4253 case MODE_ACTIVE:
4254 case MODE_PASSIVE:
4255
4256 /*
4257 * Parameter, certificate and identity.
4258 */
4259 if (!peer->crypto)
4260 exten = crypto_args(peer, CRYPTO_ASSOC,
4261 peer->associd, hostval.ptr);
4262 else if (!(peer->crypto & CRYPTO_FLAG_CERT))
4263 exten = crypto_args(peer, CRYPTO_CERT,
4264 peer->associd, peer->issuer);
4265 else if (!(peer->crypto & CRYPTO_FLAG_VRFY))
4266 exten = crypto_args(peer,
4267 crypto_ident(peer), peer->associd,
4268 NULL);
4269
4270 /*
4271 * Cookie and autokey. We request the cookie
4272 * only when the this peer and the other peer
4273 * are synchronized. But, this peer needs the
4274 * autokey values when the cookie is zero. Any
4275 * time we regenerate the key list, we offer the
4276 * autokey values without being asked. If for
4277 * some reason either peer finds a broken
4278 * autokey sequence, the autokey exchange is
4279 * used to retrieve the autokey values.
4280 */
4281 else if ( sys_leap != LEAP_NOTINSYNC
4282 && peer->leap != LEAP_NOTINSYNC
4283 && !(peer->crypto & CRYPTO_FLAG_COOK))
4284 exten = crypto_args(peer, CRYPTO_COOK,
4285 peer->associd, NULL);
4286 else if (!(peer->crypto & CRYPTO_FLAG_AUTO))
4287 exten = crypto_args(peer, CRYPTO_AUTO,
4288 peer->associd, NULL);
4289 else if ( peer->flags & FLAG_ASSOC
4290 && peer->crypto & CRYPTO_FLAG_SIGN)
4291 exten = crypto_args(peer, CRYPTO_AUTO |
4292 CRYPTO_RESP, peer->assoc, NULL);
4293
4294 /*
4295 * Wait for clock sync, then sign the
4296 * certificate and retrieve the leapsecond
4297 * values.
4298 */
4299 else if (sys_leap == LEAP_NOTINSYNC)
4300 break;
4301
4302 else if (!(peer->crypto & CRYPTO_FLAG_SIGN))
4303 exten = crypto_args(peer, CRYPTO_SIGN,
4304 peer->associd, hostval.ptr);
4305 else if (!(peer->crypto & CRYPTO_FLAG_LEAP))
4306 exten = crypto_args(peer, CRYPTO_LEAP,
4307 peer->associd, NULL);
4308 break;
4309
4310 /*
4311 * In client mode the parameter, certificate, identity,
4312 * cookie and sign exchanges are required. The
4313 * leapsecond exchange is optional. If broadcast client
4314 * mode the same exchanges are required, except that the
4315 * autokey exchange is substitutes for the cookie
4316 * exchange, since the cookie is always zero. If the
4317 * broadcast client finds a broken autokey sequence, it
4318 * uses the autokey exchange to retrieve the autokey
4319 * values.
4320 */
4321 case MODE_CLIENT:
4322
4323 /*
4324 * Parameter, certificate and identity.
4325 */
4326 if (!peer->crypto)
4327 exten = crypto_args(peer, CRYPTO_ASSOC,
4328 peer->associd, hostval.ptr);
4329 else if (!(peer->crypto & CRYPTO_FLAG_CERT))
4330 exten = crypto_args(peer, CRYPTO_CERT,
4331 peer->associd, peer->issuer);
4332 else if (!(peer->crypto & CRYPTO_FLAG_VRFY))
4333 exten = crypto_args(peer,
4334 crypto_ident(peer), peer->associd,
4335 NULL);
4336
4337 /*
4338 * Cookie and autokey. These are requests, but
4339 * we use the peer association ID with autokey
4340 * rather than our own.
4341 */
4342 else if (!(peer->crypto & CRYPTO_FLAG_COOK))
4343 exten = crypto_args(peer, CRYPTO_COOK,
4344 peer->associd, NULL);
4345 else if (!(peer->crypto & CRYPTO_FLAG_AUTO))
4346 exten = crypto_args(peer, CRYPTO_AUTO,
4347 peer->assoc, NULL);
4348
4349 /*
4350 * Wait for clock sync, then sign the
4351 * certificate and retrieve the leapsecond
4352 * values.
4353 */
4354 else if (sys_leap == LEAP_NOTINSYNC)
4355 break;
4356
4357 else if (!(peer->crypto & CRYPTO_FLAG_SIGN))
4358 exten = crypto_args(peer, CRYPTO_SIGN,
4359 peer->associd, hostval.ptr);
4360 else if (!(peer->crypto & CRYPTO_FLAG_LEAP))
4361 exten = crypto_args(peer, CRYPTO_LEAP,
4362 peer->associd, NULL);
4363 break;
4364 }
4365
4366 /*
4367 * Add a queued extension field if present. This is
4368 * always a request message, so the reply ID is already
4369 * in the message. If an error occurs, the error bit is
4370 * lit in the response.
4371 */
4372 if (peer->cmmd != NULL) {
4373 u_int32 temp32;
4374
4375 temp32 = CRYPTO_RESP;
4376 peer->cmmd->opcode |= htonl(temp32);
4377 sendlen += crypto_xmit(peer, &xpkt, NULL,
4378 sendlen, peer->cmmd, 0);
4379 free(peer->cmmd);
4380 peer->cmmd = NULL;
4381 }
4382
4383 /*
4384 * Add an extension field created above. All but the
4385 * autokey response message are request messages.
4386 */
4387 if (exten != NULL) {
4388 if (exten->opcode != 0)
4389 sendlen += crypto_xmit(peer, &xpkt,
4390 NULL, sendlen, exten, 0);
4391 free(exten);
4392 }
4393
4394 /*
4395 * Calculate the next session key. Since extension
4396 * fields are present, the cookie value is zero.
4397 */
4398 if (sendlen > (int)LEN_PKT_NOMAC) {
4399 session_key(&peer->dstadr->sin, &peer->srcadr,
4400 xkeyid, 0, 2);
4401 }
4402 }
4403 #endif /* AUTOKEY */
4404
4405 /*
4406 * Transmit a-priori timestamps
4407 */
4408 get_systime(&xmt_tx);
4409 if (peer->flip == 0) { /* basic mode */
4410 peer->aorg = xmt_tx;
4411 HTONL_FP(&xmt_tx, &xpkt.xmt);
4412 } else { /* interleaved modes */
4413 if (peer->hmode == MODE_BROADCAST) { /* bcst */
4414 HTONL_FP(&xmt_tx, &xpkt.xmt);
4415 if (peer->flip > 0)
4416 HTONL_FP(&peer->borg, &xpkt.org);
4417 else
4418 HTONL_FP(&peer->aorg, &xpkt.org);
4419 } else { /* symmetric */
4420 if (peer->flip > 0)
4421 HTONL_FP(&peer->borg, &xpkt.xmt);
4422 else
4423 HTONL_FP(&peer->aorg, &xpkt.xmt);
4424 }
4425 }
4426 xkeyid = peer->keyid;
4427 authlen = authencrypt(xkeyid, (u_int32 *)&xpkt, sendlen);
4428 if (authlen == 0) {
4429 report_event(PEVNT_AUTH, peer, "no key");
4430 peer->flash |= TEST5; /* auth error */
4431 peer->badauth++;
4432 return;
4433 }
4434 sendlen += authlen;
4435 #ifdef AUTOKEY
4436 if (xkeyid > NTP_MAXKEY)
4437 authtrust(xkeyid, 0);
4438 #endif /* AUTOKEY */
4439 if (sendlen > sizeof(xpkt)) {
4440 msyslog(LOG_ERR, "peer_xmit: buffer overflow %zu", sendlen);
4441 exit (-1);
4442 }
4443 peer->t21_bytes = sendlen;
4444 sendpkt(&peer->srcadr, peer->dstadr,
4445 sys_ttl[(peer->ttl >= sys_ttlmax) ? sys_ttlmax : peer->ttl],
4446 &xpkt, sendlen);
4447 peer->sent++;
4448 peer->throttle += (1 << peer->minpoll) - 2;
4449
4450 /*
4451 * Capture a-posteriori timestamps
4452 */
4453 get_systime(&xmt_ty);
4454 if (peer->flip != 0) { /* interleaved modes */
4455 if (peer->flip > 0)
4456 peer->aorg = xmt_ty;
4457 else
4458 peer->borg = xmt_ty;
4459 peer->flip = -peer->flip;
4460 }
4461 L_SUB(&xmt_ty, &xmt_tx);
4462 LFPTOD(&xmt_ty, peer->xleave);
4463 #ifdef AUTOKEY
4464 DPRINTF(1, ("peer_xmit: at %ld %s->%s mode %d keyid %08x len %zu index %d\n",
4465 current_time, latoa(peer->dstadr),
4466 ntoa(&peer->srcadr), peer->hmode, xkeyid, sendlen,
4467 peer->keynumber));
4468 #else /* !AUTOKEY follows */
4469 DPRINTF(1, ("peer_xmit: at %ld %s->%s mode %d keyid %08x len %zu\n",
4470 current_time, peer->dstadr ?
4471 ntoa(&peer->dstadr->sin) : "-",
4472 ntoa(&peer->srcadr), peer->hmode, xkeyid, sendlen));
4473 #endif /* !AUTOKEY */
4474
4475 return;
4476 }
4477
4478
4479 #ifdef LEAP_SMEAR
4480
4481 static void
leap_smear_add_offs(l_fp * t,l_fp * t_recv)4482 leap_smear_add_offs(
4483 l_fp *t,
4484 l_fp *t_recv
4485 )
4486 {
4487
4488 L_ADD(t, &leap_smear.offset);
4489
4490 /*
4491 ** XXX: Should the smear be added to the root dispersion?
4492 */
4493
4494 return;
4495 }
4496
4497 #endif /* LEAP_SMEAR */
4498
4499
4500 /*
4501 * fast_xmit - Send packet for nonpersistent association. Note that
4502 * neither the source or destination can be a broadcast address.
4503 */
4504 static void
fast_xmit(struct recvbuf * rbufp,int xmode,keyid_t xkeyid,int flags)4505 fast_xmit(
4506 struct recvbuf *rbufp, /* receive packet pointer */
4507 int xmode, /* receive mode */ /* XXX: HMS: really? */
4508 keyid_t xkeyid, /* transmit key ID */
4509 int flags /* restrict mask */
4510 )
4511 {
4512 struct pkt xpkt; /* transmit packet structure */
4513 struct pkt *rpkt; /* receive packet structure */
4514 l_fp xmt_tx, xmt_ty;
4515 size_t sendlen;
4516 #ifdef AUTOKEY
4517 u_int32 temp32;
4518 #endif
4519
4520 /*
4521 * Initialize transmit packet header fields from the receive
4522 * buffer provided. We leave the fields intact as received, but
4523 * set the peer poll at the maximum of the receive peer poll and
4524 * the system minimum poll (ntp_minpoll). This is for KoD rate
4525 * control and not strictly specification compliant, but doesn't
4526 * break anything.
4527 *
4528 * If the gazinta was from a multicast address, the gazoutta
4529 * must go out another way.
4530 */
4531 rpkt = &rbufp->recv_pkt;
4532 if (rbufp->dstadr->flags & INT_MCASTOPEN)
4533 rbufp->dstadr = findinterface(&rbufp->recv_srcadr);
4534
4535 /*
4536 * If this is a kiss-o'-death (KoD) packet, show leap
4537 * unsynchronized, stratum zero, reference ID the four-character
4538 * kiss code and (???) system root delay. Note we don't reveal
4539 * the local time, so these packets can't be used for
4540 * synchronization.
4541 */
4542 if (flags & RES_KOD) {
4543 sys_kodsent++;
4544 xpkt.li_vn_mode = PKT_LI_VN_MODE(LEAP_NOTINSYNC,
4545 PKT_VERSION(rpkt->li_vn_mode), xmode);
4546 xpkt.stratum = STRATUM_PKT_UNSPEC;
4547 xpkt.ppoll = max(rpkt->ppoll, ntp_minpoll);
4548 xpkt.precision = rpkt->precision;
4549 memcpy(&xpkt.refid, "RATE", 4);
4550 xpkt.rootdelay = rpkt->rootdelay;
4551 xpkt.rootdisp = rpkt->rootdisp;
4552 xpkt.reftime = rpkt->reftime;
4553 xpkt.org = rpkt->xmt;
4554 xpkt.rec = rpkt->xmt;
4555 xpkt.xmt = rpkt->xmt;
4556
4557 /*
4558 * This is a normal packet. Use the system variables.
4559 */
4560 } else {
4561 double this_rootdisp;
4562 l_fp this_ref_time;
4563
4564 #ifdef LEAP_SMEAR
4565 /*
4566 * Make copies of the variables which can be affected by smearing.
4567 */
4568 l_fp this_recv_time;
4569 #endif
4570
4571 /*
4572 * If we are inside the leap smear interval we add
4573 * the current smear offset to:
4574 * - the packet receive time,
4575 * - the packet transmit time,
4576 * - and eventually to the reftime to make sure the
4577 * reftime isn't later than the transmit/receive times.
4578 */
4579 xpkt.li_vn_mode = PKT_LI_VN_MODE(xmt_leap,
4580 PKT_VERSION(rpkt->li_vn_mode), xmode);
4581
4582 xpkt.stratum = STRATUM_TO_PKT(sys_stratum);
4583 xpkt.ppoll = max(rpkt->ppoll, ntp_minpoll);
4584 xpkt.precision = sys_precision;
4585 xpkt.refid = sys_refid;
4586 xpkt.rootdelay = HTONS_FP(DTOFP(sys_rootdelay));
4587
4588 /*
4589 ** Server Response Fuzzing
4590 **
4591 ** Which values do we want to use for reftime and rootdisp?
4592 */
4593
4594 if ( MODE_SERVER == xmode
4595 && RES_SRVRSPFUZ & flags) {
4596 if (current_time < p2_time) {
4597 this_ref_time = p2_reftime;
4598 this_rootdisp = p2_rootdisp;
4599 } else if (current_time < prev_time) {
4600 this_ref_time = prev_reftime;
4601 this_rootdisp = prev_rootdisp;
4602 } else {
4603 this_ref_time = sys_reftime;
4604 this_rootdisp = sys_rootdisp;
4605 }
4606
4607 SRVRSP_FUZZ(this_ref_time);
4608 } else {
4609 this_ref_time = sys_reftime;
4610 this_rootdisp = sys_rootdisp;
4611 }
4612
4613 /*
4614 ** ROOT DISPERSION
4615 */
4616
4617 xpkt.rootdisp = HTONS_FP(DTOUFP(this_rootdisp));
4618
4619 /*
4620 ** REFTIME
4621 */
4622
4623 #ifdef LEAP_SMEAR
4624 if (leap_smear.in_progress) {
4625 /* adjust the reftime by the same amount as the
4626 * leap smear, as we don't want to risk the
4627 * reftime being later than the transmit time.
4628 */
4629 leap_smear_add_offs(&this_ref_time, NULL);
4630 }
4631 #endif
4632
4633 HTONL_FP(&this_ref_time, &xpkt.reftime);
4634
4635 /*
4636 ** REFID
4637 */
4638
4639 #ifdef LEAP_SMEAR
4640 if (leap_smear.in_progress) {
4641 xpkt.refid = convertLFPToRefID(leap_smear.offset);
4642 DPRINTF(2, ("fast_xmit: leap_smear.in_progress: refid %8x, smear %s\n",
4643 ntohl(xpkt.refid),
4644 lfptoa(&leap_smear.offset, 8)
4645 ));
4646 }
4647 #endif
4648
4649 /*
4650 ** ORIGIN
4651 */
4652
4653 xpkt.org = rpkt->xmt;
4654
4655 /*
4656 ** RECEIVE
4657 */
4658 #ifdef LEAP_SMEAR
4659 this_recv_time = rbufp->recv_time;
4660 if (leap_smear.in_progress)
4661 leap_smear_add_offs(&this_recv_time, NULL);
4662 HTONL_FP(&this_recv_time, &xpkt.rec);
4663 #else
4664 HTONL_FP(&rbufp->recv_time, &xpkt.rec);
4665 #endif
4666
4667 /*
4668 ** TRANSMIT
4669 */
4670
4671 get_systime(&xmt_tx);
4672 #ifdef LEAP_SMEAR
4673 if (leap_smear.in_progress)
4674 leap_smear_add_offs(&xmt_tx, &this_recv_time);
4675 #endif
4676 HTONL_FP(&xmt_tx, &xpkt.xmt);
4677 }
4678
4679 #ifdef HAVE_NTP_SIGND
4680 if (flags & RES_MSSNTP) {
4681 send_via_ntp_signd(rbufp, xmode, xkeyid, flags, &xpkt);
4682 return;
4683 }
4684 #endif /* HAVE_NTP_SIGND */
4685
4686 /*
4687 * If the received packet contains a MAC, the transmitted packet
4688 * is authenticated and contains a MAC. If not, the transmitted
4689 * packet is not authenticated.
4690 */
4691 sendlen = LEN_PKT_NOMAC;
4692 if ((size_t)rbufp->recv_length == sendlen) {
4693 sendpkt(&rbufp->recv_srcadr, rbufp->dstadr, 0, &xpkt,
4694 sendlen);
4695 DPRINTF(1, ("fast_xmit: at %ld %s->%s mode %d len %lu\n",
4696 current_time, stoa(&rbufp->dstadr->sin),
4697 stoa(&rbufp->recv_srcadr), xmode,
4698 (u_long)sendlen));
4699 return;
4700 }
4701
4702 /*
4703 * The received packet contains a MAC, so the transmitted packet
4704 * must be authenticated. For symmetric key cryptography, use
4705 * the predefined and trusted symmetric keys to generate the
4706 * cryptosum. For autokey cryptography, use the server private
4707 * value to generate the cookie, which is unique for every
4708 * source-destination-key ID combination.
4709 */
4710 #ifdef AUTOKEY
4711 if (xkeyid > NTP_MAXKEY) {
4712 keyid_t cookie;
4713
4714 /*
4715 * The only way to get here is a reply to a legitimate
4716 * client request message, so the mode must be
4717 * MODE_SERVER. If an extension field is present, there
4718 * can be only one and that must be a command. Do what
4719 * needs, but with private value of zero so the poor
4720 * jerk can decode it. If no extension field is present,
4721 * use the cookie to generate the session key.
4722 */
4723 cookie = session_key(&rbufp->recv_srcadr,
4724 &rbufp->dstadr->sin, 0, sys_private, 0);
4725 if ((size_t)rbufp->recv_length > sendlen + MAX_MAC_LEN) {
4726 session_key(&rbufp->dstadr->sin,
4727 &rbufp->recv_srcadr, xkeyid, 0, 2);
4728 temp32 = CRYPTO_RESP;
4729 rpkt->exten[0] |= htonl(temp32);
4730 sendlen += crypto_xmit(NULL, &xpkt, rbufp,
4731 sendlen, (struct exten *)rpkt->exten,
4732 cookie);
4733 } else {
4734 session_key(&rbufp->dstadr->sin,
4735 &rbufp->recv_srcadr, xkeyid, cookie, 2);
4736 }
4737 }
4738 #endif /* AUTOKEY */
4739 get_systime(&xmt_tx);
4740 sendlen += authencrypt(xkeyid, (u_int32 *)&xpkt, sendlen);
4741 #ifdef AUTOKEY
4742 if (xkeyid > NTP_MAXKEY)
4743 authtrust(xkeyid, 0);
4744 #endif /* AUTOKEY */
4745 sendpkt(&rbufp->recv_srcadr, rbufp->dstadr, 0, &xpkt, sendlen);
4746 get_systime(&xmt_ty);
4747 L_SUB(&xmt_ty, &xmt_tx);
4748 sys_authdelay = xmt_ty;
4749 DPRINTF(1, ("fast_xmit: at %ld %s->%s mode %d keyid %08x len %lu\n",
4750 current_time, ntoa(&rbufp->dstadr->sin),
4751 ntoa(&rbufp->recv_srcadr), xmode, xkeyid,
4752 (u_long)sendlen));
4753 }
4754
4755
4756 /*
4757 * pool_xmit - resolve hostname or send unicast solicitation for pool.
4758 */
4759 static void
pool_xmit(struct peer * pool)4760 pool_xmit(
4761 struct peer *pool /* pool solicitor association */
4762 )
4763 {
4764 #ifdef WORKER
4765 struct pkt xpkt; /* transmit packet structure */
4766 struct addrinfo hints;
4767 int rc;
4768 struct interface * lcladr;
4769 sockaddr_u * rmtadr;
4770 r4addr r4a;
4771 u_short restrict_mask;
4772 struct peer * p;
4773 l_fp xmt_tx;
4774
4775 DEBUG_REQUIRE(pool);
4776 if (NULL == pool->ai) {
4777 if (pool->addrs != NULL) {
4778 /* free() is used with copy_addrinfo_list() */
4779 free(pool->addrs);
4780 pool->addrs = NULL;
4781 }
4782 ZERO(hints);
4783 hints.ai_family = AF(&pool->srcadr);
4784 hints.ai_socktype = SOCK_DGRAM;
4785 hints.ai_protocol = IPPROTO_UDP;
4786 /* ignore getaddrinfo_sometime() errors, we will retry */
4787 rc = getaddrinfo_sometime(
4788 pool->hostname,
4789 "ntp",
4790 &hints,
4791 0, /* no retry */
4792 &pool_name_resolved,
4793 (void *)(intptr_t)pool->associd);
4794 if (!rc)
4795 DPRINTF(1, ("pool DNS lookup %s started\n",
4796 pool->hostname));
4797 else
4798 msyslog(LOG_ERR,
4799 "unable to start pool DNS %s: %m",
4800 pool->hostname);
4801 return;
4802 }
4803
4804 do {
4805 /* copy_addrinfo_list ai_addr points to a sockaddr_u */
4806 rmtadr = (sockaddr_u *)(void *)pool->ai->ai_addr;
4807 pool->ai = pool->ai->ai_next;
4808 p = findexistingpeer(rmtadr, NULL, NULL, MODE_CLIENT, 0, NULL);
4809 } while (p != NULL && pool->ai != NULL);
4810 if (p != NULL)
4811 return; /* out of addresses, re-query DNS next poll */
4812 restrictions(rmtadr, &r4a);
4813 restrict_mask = r4a.rflags;
4814 if (RES_FLAGS & restrict_mask)
4815 restrict_source(rmtadr, 0,
4816 current_time + POOL_SOLICIT_WINDOW + 1);
4817 lcladr = findinterface(rmtadr);
4818 memset(&xpkt, 0, sizeof(xpkt));
4819 xpkt.li_vn_mode = PKT_LI_VN_MODE(sys_leap, pool->version,
4820 MODE_CLIENT);
4821 xpkt.stratum = STRATUM_TO_PKT(sys_stratum);
4822 xpkt.ppoll = pool->hpoll;
4823 xpkt.precision = sys_precision;
4824 xpkt.refid = sys_refid;
4825 xpkt.rootdelay = HTONS_FP(DTOFP(sys_rootdelay));
4826 xpkt.rootdisp = HTONS_FP(DTOUFP(sys_rootdisp));
4827 /* Bug 3596: What are the pros/cons of using sys_reftime here? */
4828 HTONL_FP(&sys_reftime, &xpkt.reftime);
4829
4830 /* HMS: the following is better done after the ntp_random() calls */
4831 get_systime(&xmt_tx);
4832 pool->aorg = xmt_tx;
4833
4834 if (FLAG_LOOPNONCE & pool->flags) {
4835 l_fp nonce;
4836
4837 do {
4838 nonce.l_ui = ntp_random();
4839 } while (0 == nonce.l_ui);
4840 do {
4841 nonce.l_uf = ntp_random();
4842 } while (0 == nonce.l_uf);
4843 pool->nonce = nonce;
4844 HTONL_FP(&nonce, &xpkt.xmt);
4845 } else {
4846 L_CLR(&pool->nonce);
4847 HTONL_FP(&xmt_tx, &xpkt.xmt);
4848 }
4849 sendpkt(rmtadr, lcladr,
4850 sys_ttl[(pool->ttl >= sys_ttlmax) ? sys_ttlmax : pool->ttl],
4851 &xpkt, LEN_PKT_NOMAC);
4852 pool->sent++;
4853 pool->throttle += (1 << pool->minpoll) - 2;
4854 DPRINTF(1, ("pool_xmit: at %ld %s->%s pool\n",
4855 current_time, latoa(lcladr), stoa(rmtadr)));
4856 msyslog(LOG_INFO, "Soliciting pool server %s", stoa(rmtadr));
4857 #endif /* WORKER */
4858 }
4859
4860
4861 #ifdef AUTOKEY
4862 /*
4863 * group_test - test if this is the same group
4864 *
4865 * host assoc return action
4866 * none none 0 mobilize *
4867 * none group 0 mobilize *
4868 * group none 0 mobilize *
4869 * group group 1 mobilize
4870 * group different 1 ignore
4871 * * ignore if notrust
4872 */
4873 int
group_test(char * grp,char * ident)4874 group_test(
4875 char *grp,
4876 char *ident
4877 )
4878 {
4879 if (grp == NULL)
4880 return (0);
4881
4882 if (strcmp(grp, sys_groupname) == 0)
4883 return (0);
4884
4885 if (ident == NULL)
4886 return (1);
4887
4888 if (strcmp(grp, ident) == 0)
4889 return (0);
4890
4891 return (1);
4892 }
4893 #endif /* AUTOKEY */
4894
4895
4896 #ifdef WORKER
4897 void
pool_name_resolved(int rescode,int gai_errno,void * context,const char * name,const char * service,const struct addrinfo * hints,const struct addrinfo * res)4898 pool_name_resolved(
4899 int rescode,
4900 int gai_errno,
4901 void * context,
4902 const char * name,
4903 const char * service,
4904 const struct addrinfo * hints,
4905 const struct addrinfo * res
4906 )
4907 {
4908 struct peer * pool; /* pool solicitor association */
4909 associd_t assoc;
4910
4911 if (rescode) {
4912 msyslog(LOG_ERR,
4913 "error resolving pool %s: %s (%d)",
4914 name, gai_strerror(rescode), rescode);
4915 return;
4916 }
4917
4918 assoc = (associd_t)(intptr_t)context;
4919 pool = findpeerbyassoc(assoc);
4920 if (NULL == pool) {
4921 msyslog(LOG_ERR,
4922 "Could not find assoc %u for pool DNS %s",
4923 assoc, name);
4924 return;
4925 }
4926 DPRINTF(1, ("pool DNS %s completed\n", name));
4927 pool->addrs = copy_addrinfo_list(res);
4928 pool->ai = pool->addrs;
4929 pool_xmit(pool);
4930
4931 }
4932 #endif /* WORKER */
4933
4934
4935 #ifdef AUTOKEY
4936 /*
4937 * key_expire - purge the key list
4938 */
4939 void
key_expire(struct peer * peer)4940 key_expire(
4941 struct peer *peer /* peer structure pointer */
4942 )
4943 {
4944 int i;
4945
4946 if (peer->keylist != NULL) {
4947 for (i = 0; i <= peer->keynumber; i++)
4948 authtrust(peer->keylist[i], 0);
4949 free(peer->keylist);
4950 peer->keylist = NULL;
4951 }
4952 value_free(&peer->sndval);
4953 peer->keynumber = 0;
4954 peer->flags &= ~FLAG_ASSOC;
4955 DPRINTF(1, ("key_expire: at %lu associd %d\n", current_time,
4956 peer->associd));
4957 }
4958 #endif /* AUTOKEY */
4959
4960
4961 /*
4962 * local_refid(peer) - check peer refid to avoid selecting peers
4963 * currently synced to this ntpd.
4964 */
4965 static int
local_refid(struct peer * p)4966 local_refid(
4967 struct peer * p
4968 )
4969 {
4970 endpt * unicast_ep;
4971
4972 if (p->dstadr != NULL && !(INT_MCASTIF & p->dstadr->flags))
4973 unicast_ep = p->dstadr;
4974 else
4975 unicast_ep = findinterface(&p->srcadr);
4976
4977 if (unicast_ep != NULL && p->refid == unicast_ep->addr_refid)
4978 return TRUE;
4979 else
4980 return FALSE;
4981 }
4982
4983
4984 /*
4985 * Determine if the peer is unfit for synchronization
4986 *
4987 * A peer is unfit for synchronization if
4988 * > TEST10 bad leap or stratum below floor or at or above ceiling
4989 * > TEST11 root distance exceeded for remote peer
4990 * > TEST12 a direct or indirect synchronization loop would form
4991 * > TEST13 unreachable or noselect
4992 */
4993 int /* FALSE if fit, TRUE if unfit */
peer_unfit(struct peer * peer)4994 peer_unfit(
4995 struct peer *peer /* peer structure pointer */
4996 )
4997 {
4998 int rval = 0;
4999
5000 /*
5001 * A stratum error occurs if (1) the server has never been
5002 * synchronized, (2) the server stratum is below the floor or
5003 * greater than or equal to the ceiling.
5004 */
5005 if ( peer->leap == LEAP_NOTINSYNC
5006 || peer->stratum < sys_floor
5007 || peer->stratum >= sys_ceiling) {
5008 rval |= TEST10; /* bad synch or stratum */
5009 }
5010
5011 /*
5012 * A distance error for a remote peer occurs if the root
5013 * distance is greater than or equal to the distance threshold
5014 * plus the increment due to one host poll interval.
5015 */
5016 if ( !(peer->flags & FLAG_REFCLOCK)
5017 && root_distance(peer) >= sys_maxdist
5018 + clock_phi * ULOGTOD(peer->hpoll)) {
5019 rval |= TEST11; /* distance exceeded */
5020 }
5021
5022 /*
5023 * A loop error occurs if the remote peer is synchronized to the
5024 * local peer or if the remote peer is synchronized to the same
5025 * server as the local peer but only if the remote peer is
5026 * neither a reference clock nor an orphan.
5027 */
5028 if (peer->stratum > 1 && local_refid(peer)) {
5029 rval |= TEST12; /* synchronization loop */
5030 }
5031
5032 /*
5033 * An unreachable error occurs if the server is unreachable or
5034 * the noselect bit is set.
5035 */
5036 if (!peer->reach || (peer->flags & FLAG_NOSELECT)) {
5037 rval |= TEST13; /* unreachable */
5038 }
5039
5040 peer->flash &= ~PEER_TEST_MASK;
5041 peer->flash |= rval;
5042 return (rval);
5043 }
5044
5045
5046 /*
5047 * Find the precision of this particular machine
5048 */
5049 #define MINSTEP 20e-9 /* minimum clock increment (s) */
5050 #define MAXSTEP 1 /* maximum clock increment (s) */
5051 #define MINCHANGES 12 /* minimum number of step samples */
5052 #define MAXLOOPS ((int)(1. / MINSTEP)) /* avoid infinite loop */
5053
5054 /*
5055 * This routine measures the system precision defined as the minimum of
5056 * a sequence of differences between successive readings of the system
5057 * clock. However, if a difference is less than MINSTEP, the clock has
5058 * been read more than once during a clock tick and the difference is
5059 * ignored. We set MINSTEP greater than zero in case something happens
5060 * like a cache miss, and to tolerate underlying system clocks which
5061 * ensure each reading is strictly greater than prior readings while
5062 * using an underlying stepping (not interpolated) clock.
5063 *
5064 * sys_tick and sys_precision represent the time to read the clock for
5065 * systems with high-precision clocks, and the tick interval or step
5066 * size for lower-precision stepping clocks.
5067 *
5068 * This routine also measures the time to read the clock on stepping
5069 * system clocks by counting the number of readings between changes of
5070 * the underlying clock. With either type of clock, the minimum time
5071 * to read the clock is saved as sys_fuzz, and used to ensure the
5072 * get_systime() readings always increase and are fuzzed below sys_fuzz.
5073 */
5074 void
measure_precision(void)5075 measure_precision(void)
5076 {
5077 /*
5078 * With sys_fuzz set to zero, get_systime() fuzzing of low bits
5079 * is effectively disabled. trunc_os_clock is FALSE to disable
5080 * get_ostime() simulation of a low-precision system clock.
5081 */
5082 set_sys_fuzz(0.);
5083 trunc_os_clock = FALSE;
5084 measured_tick = measure_tick_fuzz();
5085 set_sys_tick_precision(measured_tick);
5086 msyslog(LOG_INFO, "proto: precision = %.3f usec (%d)",
5087 sys_tick * 1e6, sys_precision);
5088 if (sys_fuzz < sys_tick) {
5089 msyslog(LOG_NOTICE, "proto: fuzz beneath %.3f usec",
5090 sys_fuzz * 1e6);
5091 }
5092 }
5093
5094
5095 /*
5096 * measure_tick_fuzz()
5097 *
5098 * measures the minimum time to read the clock (stored in sys_fuzz)
5099 * and returns the tick, the larger of the minimum increment observed
5100 * between successive clock readings and the time to read the clock.
5101 */
5102 double
measure_tick_fuzz(void)5103 measure_tick_fuzz(void)
5104 {
5105 l_fp minstep; /* MINSTEP as l_fp */
5106 l_fp val; /* current seconds fraction */
5107 l_fp last; /* last seconds fraction */
5108 l_fp ldiff; /* val - last */
5109 double tick; /* computed tick value */
5110 double diff;
5111 long repeats;
5112 long max_repeats;
5113 int changes;
5114 int i; /* log2 precision */
5115
5116 tick = MAXSTEP;
5117 max_repeats = 0;
5118 repeats = 0;
5119 changes = 0;
5120 DTOLFP(MINSTEP, &minstep);
5121 get_systime(&last);
5122 for (i = 0; i < MAXLOOPS && changes < MINCHANGES; i++) {
5123 get_systime(&val);
5124 ldiff = val;
5125 L_SUB(&ldiff, &last);
5126 last = val;
5127 if (L_ISGT(&ldiff, &minstep)) {
5128 max_repeats = max(repeats, max_repeats);
5129 repeats = 0;
5130 changes++;
5131 LFPTOD(&ldiff, diff);
5132 tick = min(diff, tick);
5133 } else {
5134 repeats++;
5135 }
5136 }
5137 if (changes < MINCHANGES) {
5138 msyslog(LOG_ERR, "Fatal error: precision could not be measured (MINSTEP too large?)");
5139 exit(1);
5140 }
5141
5142 if (0 == max_repeats) {
5143 set_sys_fuzz(tick);
5144 } else {
5145 set_sys_fuzz(tick / max_repeats);
5146 }
5147
5148 return tick;
5149 }
5150
5151
5152 void
set_sys_tick_precision(double tick)5153 set_sys_tick_precision(
5154 double tick
5155 )
5156 {
5157 int i;
5158
5159 if (tick > 1.) {
5160 msyslog(LOG_ERR,
5161 "unsupported tick %.3f > 1s ignored", tick);
5162 return;
5163 }
5164 if (tick < measured_tick) {
5165 msyslog(LOG_ERR,
5166 "proto: tick %.3f less than measured tick %.3f, ignored",
5167 tick, measured_tick);
5168 return;
5169 } else if (tick > measured_tick) {
5170 trunc_os_clock = TRUE;
5171 msyslog(LOG_NOTICE,
5172 "proto: truncating system clock to multiples of %.9f",
5173 tick);
5174 }
5175 sys_tick = tick;
5176
5177 /*
5178 * Find the nearest power of two.
5179 */
5180 for (i = 0; tick <= 1; i--)
5181 tick *= 2;
5182 if (tick - 1 > 1 - tick / 2)
5183 i++;
5184
5185 sys_precision = (s_char)i;
5186 }
5187
5188
5189 /*
5190 * init_proto - initialize the protocol module's data
5191 */
5192 void
init_proto(void)5193 init_proto(void)
5194 {
5195 l_fp dummy;
5196 int i;
5197
5198 /*
5199 * Fill in the sys_* stuff. Default is don't listen to
5200 * broadcasting, require authentication.
5201 */
5202 set_sys_leap(LEAP_NOTINSYNC);
5203 sys_stratum = STRATUM_UNSPEC;
5204 memcpy(&sys_refid, "INIT", 4);
5205 sys_peer = NULL;
5206 sys_rootdelay = 0;
5207 sys_rootdisp = 0;
5208 L_CLR(&sys_reftime);
5209 sys_jitter = 0;
5210 measure_precision();
5211 get_systime(&dummy);
5212 sys_survivors = 0;
5213 sys_manycastserver = 0;
5214 sys_bclient = 0;
5215 sys_bdelay = BDELAY_DEFAULT; /*[Bug 3031] delay cutoff */
5216 sys_authenticate = 1;
5217 sys_stattime = current_time;
5218 orphwait = current_time + sys_orphwait;
5219 proto_clr_stats();
5220 for (i = 0; i < MAX_TTL; ++i)
5221 sys_ttl[i] = (u_char)((i * 256) / MAX_TTL);
5222 sys_ttlmax = (MAX_TTL - 1);
5223 hardpps_enable = 0;
5224 stats_control = 1;
5225 }
5226
5227
5228 /*
5229 * proto_config - configure the protocol module
5230 */
5231 void
proto_config(int item,u_long value,double dvalue,sockaddr_u * svalue)5232 proto_config(
5233 int item,
5234 u_long value,
5235 double dvalue,
5236 sockaddr_u *svalue
5237 )
5238 {
5239 /*
5240 * Figure out what he wants to change, then do it
5241 */
5242 DPRINTF(2, ("proto_config: code %d value %lu dvalue %lf\n",
5243 item, value, dvalue));
5244
5245 switch (item) {
5246
5247 /*
5248 * enable and disable commands - arguments are Boolean.
5249 */
5250 case PROTO_AUTHENTICATE: /* authentication (auth) */
5251 sys_authenticate = value;
5252 break;
5253
5254 case PROTO_BROADCLIENT: /* broadcast client (bclient) */
5255 sys_bclient = (int)value;
5256 if (sys_bclient == 0)
5257 io_unsetbclient();
5258 else
5259 io_setbclient();
5260 break;
5261
5262 #ifdef REFCLOCK
5263 case PROTO_CAL: /* refclock calibrate (calibrate) */
5264 cal_enable = value;
5265 break;
5266 #endif /* REFCLOCK */
5267
5268 case PROTO_KERNEL: /* kernel discipline (kernel) */
5269 select_loop(value);
5270 break;
5271
5272 case PROTO_MONITOR: /* monitoring (monitor) */
5273 if (value)
5274 mon_start(MON_ON);
5275 else {
5276 mon_stop(MON_ON);
5277 if (mon_enabled)
5278 msyslog(LOG_WARNING,
5279 "restrict: 'monitor' cannot be disabled while 'limited' is enabled");
5280 }
5281 break;
5282
5283 case PROTO_NTP: /* NTP discipline (ntp) */
5284 ntp_enable = value;
5285 break;
5286
5287 case PROTO_MODE7: /* mode7 management (ntpdc) */
5288 ntp_mode7 = value;
5289 break;
5290
5291 case PROTO_PPS: /* PPS discipline (pps) */
5292 hardpps_enable = value;
5293 break;
5294
5295 case PROTO_FILEGEN: /* statistics (stats) */
5296 stats_control = value;
5297 break;
5298
5299 /*
5300 * tos command - arguments are double, sometimes cast to int
5301 */
5302
5303 case PROTO_BCPOLLBSTEP: /* Broadcast Poll Backstep gate (bcpollbstep) */
5304 sys_bcpollbstep = (u_char)dvalue;
5305 break;
5306
5307 case PROTO_BEACON: /* manycast beacon (beacon) */
5308 sys_beacon = (int)dvalue;
5309 break;
5310
5311 case PROTO_BROADDELAY: /* default broadcast delay (bdelay) */
5312 sys_bdelay = (dvalue ? dvalue : BDELAY_DEFAULT);
5313 break;
5314
5315 case PROTO_CEILING: /* stratum ceiling (ceiling) */
5316 sys_ceiling = (int)dvalue;
5317 break;
5318
5319 case PROTO_COHORT: /* cohort switch (cohort) */
5320 sys_cohort = (int)dvalue;
5321 break;
5322
5323 case PROTO_FLOOR: /* stratum floor (floor) */
5324 sys_floor = (int)dvalue;
5325 break;
5326
5327 case PROTO_MAXCLOCK: /* maximum candidates (maxclock) */
5328 sys_maxclock = (int)dvalue;
5329 break;
5330
5331 case PROTO_MAXDIST: /* select threshold (maxdist) */
5332 sys_maxdist = dvalue;
5333 break;
5334
5335 case PROTO_CALLDELAY: /* modem call delay (mdelay) */
5336 break; /* NOT USED */
5337
5338 case PROTO_MINCLOCK: /* minimum candidates (minclock) */
5339 sys_minclock = (int)dvalue;
5340 break;
5341
5342 case PROTO_MINDISP: /* minimum distance (mindist) */
5343 sys_mindisp = dvalue;
5344 break;
5345
5346 case PROTO_MINSANE: /* minimum survivors (minsane) */
5347 sys_minsane = (int)dvalue;
5348 break;
5349
5350 case PROTO_ORPHAN: /* orphan stratum (orphan) */
5351 sys_orphan = (int)dvalue;
5352 break;
5353
5354 case PROTO_ORPHWAIT: /* orphan wait (orphwait) */
5355 orphwait -= sys_orphwait;
5356 sys_orphwait = (dvalue >= 1) ? (int)dvalue : NTP_ORPHWAIT;
5357 orphwait += sys_orphwait;
5358 break;
5359
5360 /*
5361 * Miscellaneous commands
5362 */
5363 case PROTO_MULTICAST_ADD: /* add group address */
5364 if (svalue != NULL)
5365 io_multicast_add(svalue);
5366 sys_bclient = 1;
5367 break;
5368
5369 case PROTO_MULTICAST_DEL: /* delete group address */
5370 if (svalue != NULL)
5371 io_multicast_del(svalue);
5372 break;
5373
5374 /*
5375 * Peer_clear Early policy choices
5376 */
5377
5378 case PROTO_PCEDIGEST: /* Digest */
5379 peer_clear_digest_early = value;
5380 break;
5381
5382 /*
5383 * Unpeer Early policy choices
5384 */
5385
5386 case PROTO_UECRYPTO: /* Crypto */
5387 unpeer_crypto_early = value;
5388 break;
5389
5390 case PROTO_UECRYPTONAK: /* Crypto_NAK */
5391 unpeer_crypto_nak_early = value;
5392 break;
5393
5394 case PROTO_UEDIGEST: /* Digest */
5395 unpeer_digest_early = value;
5396 break;
5397
5398 default:
5399 msyslog(LOG_NOTICE,
5400 "proto: unsupported option %d", item);
5401 }
5402 }
5403
5404
5405 /*
5406 * proto_clr_stats - clear protocol stat counters
5407 */
5408 void
proto_clr_stats(void)5409 proto_clr_stats(void)
5410 {
5411 sys_stattime = current_time;
5412 sys_received = 0;
5413 sys_processed = 0;
5414 sys_newversion = 0;
5415 sys_oldversion = 0;
5416 sys_declined = 0;
5417 sys_restricted = 0;
5418 sys_badlength = 0;
5419 sys_badauth = 0;
5420 sys_limitrejected = 0;
5421 sys_kodsent = 0;
5422 sys_lamport = 0;
5423 sys_tsrounding = 0;
5424 }
5425