1: /*
2: * ntp_proto.c - NTP version 4 protocol machinery
3: *
4: * ATTENTION: Get approval from Dave Mills on all changes to this file!
5: *
6: */
7: #ifdef HAVE_CONFIG_H
8: #include <config.h>
9: #endif
10:
11: #include "ntpd.h"
12: #include "ntp_stdlib.h"
13: #include "ntp_unixtime.h"
14: #include "ntp_control.h"
15: #include "ntp_string.h"
16:
17: #include <stdio.h>
18: #ifdef HAVE_LIBSCF_H
19: #include <libscf.h>
20: #include <unistd.h>
21: #endif /* HAVE_LIBSCF_H */
22:
23:
24: #if defined(VMS) && defined(VMS_LOCALUNIT) /*wjm*/
25: #include "ntp_refclock.h"
26: #endif
27:
28: /*
29: * This macro defines the authentication state. If x is 1 authentication
30: * is required; othewise it is optional.
31: */
32: #define AUTH(x, y) ((x) ? (y) == AUTH_OK : (y) == AUTH_OK || \
33: (y) == AUTH_NONE)
34:
35: #define AUTH_NONE 0 /* authentication not required */
36: #define AUTH_OK 1 /* authentication OK */
37: #define AUTH_ERROR 2 /* authentication error */
38: #define AUTH_CRYPTO 3 /* crypto_NAK */
39:
40: /*
41: * traffic shaping parameters
42: */
43: #define NTP_IBURST 6 /* packets in iburst */
44: #define RESP_DELAY 1 /* refclock burst delay (s) */
45:
46: /*
47: * System variables are declared here. Unless specified otherwise, all
48: * times are in seconds.
49: */
50: u_char sys_leap; /* system leap indicator */
51: u_char sys_stratum; /* system stratum */
52: s_char sys_precision; /* local clock precision (log2 s) */
53: double sys_rootdelay; /* roundtrip delay to primary source */
54: double sys_rootdisp; /* dispersion to primary source */
55: u_int32 sys_refid; /* reference id (network byte order) */
56: l_fp sys_reftime; /* last update time */
57: struct peer *sys_peer; /* current peer */
58:
59: /*
60: * Rate controls. Leaky buckets are used to throttle the packet
61: * transmission rates in order to protect busy servers such as at NIST
62: * and USNO. There is a counter for each association and another for KoD
63: * packets. The association counter decrements each second, but not
64: * below zero. Each time a packet is sent the counter is incremented by
65: * a configurable value representing the average interval between
66: * packets. A packet is delayed as long as the counter is greater than
67: * zero. Note this does not affect the time value computations.
68: */
69: /*
70: * Nonspecified system state variables
71: */
72: int sys_bclient; /* broadcast client enable */
73: double sys_bdelay; /* broadcast client default delay */
74: int sys_authenticate; /* requre authentication for config */
75: l_fp sys_authdelay; /* authentication delay */
76: double sys_offset; /* current local clock offset */
77: double sys_mindisp = MINDISPERSE; /* minimum distance (s) */
78: double sys_maxdist = MAXDISTANCE; /* selection threshold */
79: double sys_jitter; /* system jitter */
80: u_long sys_epoch; /* last clock update time */
81: static double sys_clockhop; /* clockhop threshold */
82: int leap_tai; /* TAI at next next leap */
83: u_long leap_sec; /* next scheduled leap from file */
84: u_long leap_peers; /* next scheduled leap from peers */
85: u_long leap_expire; /* leap information expiration */
86: static int leap_vote; /* leap consensus */
87: keyid_t sys_private; /* private value for session seed */
88: int sys_manycastserver; /* respond to manycast client pkts */
89: int peer_ntpdate; /* active peers in ntpdate mode */
90: int sys_survivors; /* truest of the truechimers */
91:
92: /*
93: * TOS and multicast mapping stuff
94: */
95: int sys_floor = 0; /* cluster stratum floor */
96: int sys_ceiling = STRATUM_UNSPEC; /* cluster stratum ceiling */
97: int sys_minsane = 1; /* minimum candidates */
98: int sys_minclock = NTP_MINCLOCK; /* minimum candidates */
99: int sys_maxclock = NTP_MAXCLOCK; /* maximum candidates */
100: int sys_cohort = 0; /* cohort switch */
101: int sys_orphan = STRATUM_UNSPEC + 1; /* orphan stratum */
102: int sys_beacon = BEACON; /* manycast beacon interval */
103: int sys_ttlmax; /* max ttl mapping vector index */
104: u_char sys_ttl[MAX_TTL]; /* ttl mapping vector */
105:
106: /*
107: * Statistics counters - first the good, then the bad
108: */
109: u_long sys_stattime; /* elapsed time */
110: u_long sys_received; /* packets received */
111: u_long sys_processed; /* packets for this host */
112: u_long sys_newversion; /* current version */
113: u_long sys_oldversion; /* old version */
114: u_long sys_restricted; /* access denied */
115: u_long sys_badlength; /* bad length or format */
116: u_long sys_badauth; /* bad authentication */
117: u_long sys_declined; /* declined */
118: u_long sys_limitrejected; /* rate exceeded */
119: u_long sys_kodsent; /* KoD sent */
120:
121: static double root_distance (struct peer *);
122: static void clock_combine (struct peer **, int);
123: static void peer_xmit (struct peer *);
124: static void fast_xmit (struct recvbuf *, int, keyid_t,
125: int);
126: static void clock_update (struct peer *);
127: static int default_get_precision (void);
128: static int local_refid (struct peer *);
129: static int peer_unfit (struct peer *);
130:
131:
132: /*
133: * transmit - transmit procedure called by poll timeout
134: */
135: void
136: transmit(
137: struct peer *peer /* peer structure pointer */
138: )
139: {
140: int hpoll;
141:
142: /*
143: * The polling state machine. There are two kinds of machines,
144: * those that never expect a reply (broadcast and manycast
145: * server modes) and those that do (all other modes). The dance
146: * is intricate...
147: */
148: hpoll = peer->hpoll;
149:
150: /*
151: * In broadcast mode the poll interval is never changed from
152: * minpoll.
153: */
154: if (peer->cast_flags & (MDF_BCAST | MDF_MCAST)) {
155: peer->outdate = current_time;
156: if (sys_leap != LEAP_NOTINSYNC)
157: peer_xmit(peer);
158: poll_update(peer, hpoll);
159: return;
160: }
161:
162: /*
163: * In manycast mode we start with unity ttl. The ttl is
164: * increased by one for each poll until either sys_maxclock
165: * servers have been found or the maximum ttl is reached. When
166: * sys_maxclock servers are found we stop polling until one or
167: * more servers have timed out or until less than minpoll
168: * associations turn up. In this case additional better servers
169: * are dragged in and preempt the existing ones.
170: */
171: if (peer->cast_flags & MDF_ACAST) {
172: peer->outdate = current_time;
173: if (peer->unreach > sys_beacon) {
174: peer->unreach = 0;
175: peer->ttl = 0;
176: peer_xmit(peer);
177: } else if (sys_survivors < sys_minclock ||
178: peer_associations < sys_maxclock) {
179: if (peer->ttl < sys_ttlmax)
180: peer->ttl++;
181: peer_xmit(peer);
182: }
183: peer->unreach++;
184: poll_update(peer, hpoll);
185: return;
186: }
187:
188: /*
189: * In unicast modes the dance is much more intricate. It is
190: * desigmed to back off whenever possible to minimize network
191: * traffic.
192: */
193: if (peer->burst == 0) {
194: u_char oreach;
195:
196: /*
197: * Update the reachability status. If not heard for
198: * three consecutive polls, stuff infinity in the clock
199: * filter.
200: */
201: oreach = peer->reach;
202: peer->outdate = current_time;
203: peer->unreach++;
204: peer->reach <<= 1;
205: if (!(peer->reach & 0x0f))
206: clock_filter(peer, 0., 0., MAXDISPERSE);
207: if (!peer->reach) {
208:
209: /*
210: * Here the peer is unreachable. If it was
211: * previously reachable raise a trap. Send a
212: * burst if enabled.
213: */
214: if (oreach)
215: report_event(PEVNT_UNREACH, peer, NULL);
216: if ((peer->flags & FLAG_IBURST) &&
217: peer->retry == 0)
218: peer->retry = NTP_RETRY;
219: } else {
220:
221: /*
222: * Here the peer is reachable. Send a burst if
223: * enabled and the peer is fit.
224: */
225: hpoll = sys_poll;
226: if (!(peer->flags & FLAG_PREEMPT &&
227: peer->hmode == MODE_CLIENT))
228: peer->unreach = 0;
229: if ((peer->flags & FLAG_BURST) && peer->retry ==
230: 0 && !peer_unfit(peer))
231: peer->retry = NTP_RETRY;
232: }
233:
234: /*
235: * Watch for timeout. If preemptable, toss the rascal;
236: * otherwise, bump the poll interval. Note the
237: * poll_update() routine will clamp it to maxpoll.
238: */
239: if (peer->unreach >= NTP_UNREACH) {
240: hpoll++;
241: if (peer->flags & FLAG_PREEMPT) {
242: report_event(PEVNT_RESTART, peer,
243: "timeout");
244: if (peer->hmode != MODE_CLIENT) {
245: peer_clear(peer, "TIME");
246: unpeer(peer);
247: return;
248: }
249: if (peer_associations > sys_maxclock &&
250: score_all(peer)) {
251: peer_clear(peer, "TIME");
252: unpeer(peer);
253: return;
254: }
255: }
256: }
257: } else {
258: peer->burst--;
259: if (peer->burst == 0) {
260:
261: /*
262: * If ntpdate mode and the clock has not been
263: * set and all peers have completed the burst,
264: * we declare a successful failure.
265: */
266: if (mode_ntpdate) {
267: peer_ntpdate--;
268: if (peer_ntpdate == 0) {
269: msyslog(LOG_NOTICE,
270: "ntpd: no servers found");
271: printf(
272: "ntpd: no servers found\n");
273: exit (0);
274: }
275: }
276: }
277: }
278: if (peer->retry > 0)
279: peer->retry--;
280:
281: /*
282: * Do not transmit if in broadcast client mode.
283: */
284: if (peer->hmode != MODE_BCLIENT)
285: peer_xmit(peer);
286: poll_update(peer, hpoll);
287: }
288:
289:
290: /*
291: * receive - receive procedure called for each packet received
292: */
293: void
294: receive(
295: struct recvbuf *rbufp
296: )
297: {
298: register struct peer *peer; /* peer structure pointer */
299: register struct pkt *pkt; /* receive packet pointer */
300: int hisversion; /* packet version */
301: int hisleap; /* packet leap indicator */
302: int hismode; /* packet mode */
303: int hisstratum; /* packet stratum */
304: int restrict_mask; /* restrict bits */
305: int has_mac; /* length of MAC field */
306: int authlen; /* offset of MAC field */
307: int is_authentic = 0; /* cryptosum ok */
308: int retcode = AM_NOMATCH; /* match code */
309: keyid_t skeyid = 0; /* key IDs */
310: u_int32 opcode = 0; /* extension field opcode */
311: sockaddr_u *dstadr_sin; /* active runway */
312: struct peer *peer2; /* aux peer structure pointer */
313: endpt * match_ep; /* newpeer() local address */
314: l_fp p_org; /* origin timestamp */
315: l_fp p_rec; /* receive timestamp */
316: l_fp p_xmt; /* transmit timestamp */
317: #ifdef OPENSSL
318: struct autokey *ap; /* autokey structure pointer */
319: int rval; /* cookie snatcher */
320: keyid_t pkeyid = 0, tkeyid = 0; /* key IDs */
321: #endif /* OPENSSL */
322: #ifdef HAVE_NTP_SIGND
323: static unsigned char zero_key[16];
324: #endif /* HAVE_NTP_SIGND */
325:
326: /*
327: * Monitor the packet and get restrictions. Note that the packet
328: * length for control and private mode packets must be checked
329: * by the service routines. Some restrictions have to be handled
330: * later in order to generate a kiss-o'-death packet.
331: */
332: /*
333: * Bogus port check is before anything, since it probably
334: * reveals a clogging attack.
335: */
336: sys_received++;
337: if (SRCPORT(&rbufp->recv_srcadr) < NTP_PORT) {
338: sys_badlength++;
339: return; /* bogus port */
340: }
341: restrict_mask = restrictions(&rbufp->recv_srcadr);
342: #ifdef DEBUG
343: if (debug > 1)
344: printf("receive: at %ld %s<-%s flags %x restrict %03x\n",
345: current_time, stoa(&rbufp->dstadr->sin),
346: stoa(&rbufp->recv_srcadr),
347: rbufp->dstadr->flags, restrict_mask);
348: #endif
349: pkt = &rbufp->recv_pkt;
350: hisversion = PKT_VERSION(pkt->li_vn_mode);
351: hisleap = PKT_LEAP(pkt->li_vn_mode);
352: hismode = (int)PKT_MODE(pkt->li_vn_mode);
353: hisstratum = PKT_TO_STRATUM(pkt->stratum);
354: if (restrict_mask & RES_IGNORE) {
355: sys_restricted++;
356: return; /* ignore everything */
357: }
358: if (hismode == MODE_PRIVATE) {
359: if (restrict_mask & RES_NOQUERY) {
360: sys_restricted++;
361: return; /* no query private */
362: }
363: process_private(rbufp, ((restrict_mask &
364: RES_NOMODIFY) == 0));
365: return;
366: }
367: if (hismode == MODE_CONTROL) {
368: if (restrict_mask & RES_NOQUERY) {
369: sys_restricted++;
370: return; /* no query control */
371: }
372: process_control(rbufp, restrict_mask);
373: return;
374: }
375: if (restrict_mask & RES_DONTSERVE) {
376: sys_restricted++;
377: return; /* no time serve */
378: }
379:
380: /*
381: * This is for testing. If restricted drop ten percent of
382: * surviving packets.
383: */
384: if (restrict_mask & RES_TIMEOUT) {
385: if ((double)ntp_random() / 0x7fffffff < .1) {
386: sys_restricted++;
387: return; /* no flakeway */
388: }
389: }
390:
391: /*
392: * Version check must be after the query packets, since they
393: * intentionally use an early version.
394: */
395: if (hisversion == NTP_VERSION) {
396: sys_newversion++; /* new version */
397: } else if (!(restrict_mask & RES_VERSION) && hisversion >=
398: NTP_OLDVERSION) {
399: sys_oldversion++; /* previous version */
400: } else {
401: sys_badlength++;
402: return; /* old version */
403: }
404:
405: /*
406: * Figure out his mode and validate the packet. This has some
407: * legacy raunch that probably should be removed. In very early
408: * NTP versions mode 0 was equivalent to what later versions
409: * would interpret as client mode.
410: */
411: if (hismode == MODE_UNSPEC) {
412: if (hisversion == NTP_OLDVERSION) {
413: hismode = MODE_CLIENT;
414: } else {
415: sys_badlength++;
416: return; /* invalid mode */
417: }
418: }
419:
420: /*
421: * Parse the extension field if present. We figure out whether
422: * an extension field is present by measuring the MAC size. If
423: * the number of words following the packet header is 0, no MAC
424: * is present and the packet is not authenticated. If 1, the
425: * packet is a crypto-NAK; if 3, the packet is authenticated
426: * with DES; if 5, the packet is authenticated with MD5; if 6,
427: * the packet is authenticated with SHA. If 2 or * 4, the packet
428: * is a runt and discarded forthwith. If greater than 6, an
429: * extension field is present, so we subtract the length of the
430: * field and go around again.
431: */
432: authlen = LEN_PKT_NOMAC;
433: has_mac = rbufp->recv_length - authlen;
434: while (has_mac != 0) {
435: u_int32 len;
436:
437: if (has_mac % 4 != 0 || has_mac < MIN_MAC_LEN) {
438: sys_badlength++;
439: return; /* bad length */
440: }
441: if (has_mac <= MAX_MAC_LEN) {
442: skeyid = ntohl(((u_int32 *)pkt)[authlen / 4]);
443: break;
444:
445: } else {
446: opcode = ntohl(((u_int32 *)pkt)[authlen / 4]);
447: len = opcode & 0xffff;
448: if (len % 4 != 0 || len < 4 || len + authlen >
449: rbufp->recv_length) {
450: sys_badlength++;
451: return; /* bad length */
452: }
453: authlen += len;
454: has_mac -= len;
455: }
456: }
457:
458: /*
459: * If authentication required, a MAC must be present.
460: */
461: if (restrict_mask & RES_DONTTRUST && has_mac == 0) {
462: sys_restricted++;
463: return; /* access denied */
464: }
465:
466: /*
467: * Update the MRU list and finger the cloggers. It can be a
468: * little expensive, so turn it off for production use.
469: */
470: restrict_mask = ntp_monitor(rbufp, restrict_mask);
471: if (restrict_mask & RES_LIMITED) {
472: sys_limitrejected++;
473: if (!(restrict_mask & RES_KOD) || MODE_BROADCAST ==
474: hismode || MODE_SERVER == hismode)
475: return; /* rate exceeded */
476:
477: if (hismode == MODE_CLIENT)
478: fast_xmit(rbufp, MODE_SERVER, skeyid,
479: restrict_mask);
480: else
481: fast_xmit(rbufp, MODE_ACTIVE, skeyid,
482: restrict_mask);
483: return; /* rate exceeded */
484: }
485: restrict_mask &= ~RES_KOD;
486:
487: /*
488: * We have tossed out as many buggy packets as possible early in
489: * the game to reduce the exposure to a clogging attack. now we
490: * have to burn some cycles to find the association and
491: * authenticate the packet if required. Note that we burn only
492: * MD5 cycles, again to reduce exposure. There may be no
493: * matching association and that's okay.
494: *
495: * More on the autokey mambo. Normally the local interface is
496: * found when the association was mobilized with respect to a
497: * designated remote address. We assume packets arriving from
498: * the remote address arrive via this interface and the local
499: * address used to construct the autokey is the unicast address
500: * of the interface. However, if the sender is a broadcaster,
501: * the interface broadcast address is used instead.
502: * Notwithstanding this technobabble, if the sender is a
503: * multicaster, the broadcast address is null, so we use the
504: * unicast address anyway. Don't ask.
505: */
506: peer = findpeer(rbufp, hismode, &retcode);
507: dstadr_sin = &rbufp->dstadr->sin;
508: NTOHL_FP(&pkt->org, &p_org);
509: NTOHL_FP(&pkt->rec, &p_rec);
510: NTOHL_FP(&pkt->xmt, &p_xmt);
511:
512: /*
513: * Authentication is conditioned by three switches:
514: *
515: * NOPEER (RES_NOPEER) do not mobilize an association unless
516: * authenticated
517: * NOTRUST (RES_DONTTRUST) do not allow access unless
518: * authenticated (implies NOPEER)
519: * enable (sys_authenticate) master NOPEER switch, by default
520: * on
521: *
522: * The NOPEER and NOTRUST can be specified on a per-client basis
523: * using the restrict command. The enable switch if on implies
524: * NOPEER for all clients. There are four outcomes:
525: *
526: * NONE The packet has no MAC.
527: * OK the packet has a MAC and authentication succeeds
528: * ERROR the packet has a MAC and authentication fails
529: * CRYPTO crypto-NAK. The MAC has four octets only.
530: *
531: * Note: The AUTH(x, y) macro is used to filter outcomes. If x
532: * is zero, acceptable outcomes of y are NONE and OK. If x is
533: * one, the only acceptable outcome of y is OK.
534: */
535:
536: if (has_mac == 0) {
537: restrict_mask &= ~RES_MSSNTP;
538: is_authentic = AUTH_NONE; /* not required */
539: #ifdef DEBUG
540: if (debug)
541: printf(
542: "receive: at %ld %s<-%s mode %d len %d\n",
543: current_time, stoa(dstadr_sin),
544: stoa(&rbufp->recv_srcadr), hismode,
545: authlen);
546: #endif
547: } else if (has_mac == 4) {
548: restrict_mask &= ~RES_MSSNTP;
549: is_authentic = AUTH_CRYPTO; /* crypto-NAK */
550: #ifdef DEBUG
551: if (debug)
552: printf(
553: "receive: at %ld %s<-%s mode %d keyid %08x len %d auth %d\n",
554: current_time, stoa(dstadr_sin),
555: stoa(&rbufp->recv_srcadr), hismode, skeyid,
556: authlen + has_mac, is_authentic);
557: #endif
558:
559: #ifdef HAVE_NTP_SIGND
560: /*
561: * If the signature is 20 bytes long, the last 16 of
562: * which are zero, then this is a Microsoft client
563: * wanting AD-style authentication of the server's
564: * reply.
565: *
566: * This is described in Microsoft's WSPP docs, in MS-SNTP:
567: * http://msdn.microsoft.com/en-us/library/cc212930.aspx
568: */
569: } else if (has_mac == MAX_MD5_LEN && (restrict_mask & RES_MSSNTP) &&
570: (retcode == AM_FXMIT || retcode == AM_NEWPASS) &&
571: (memcmp(zero_key, (char *)pkt + authlen + 4, MAX_MD5_LEN - 4) ==
572: 0)) {
573: is_authentic = AUTH_NONE;
574: #endif /* HAVE_NTP_SIGND */
575:
576: } else {
577: restrict_mask &= ~RES_MSSNTP;
578: #ifdef OPENSSL
579: /*
580: * For autokey modes, generate the session key
581: * and install in the key cache. Use the socket
582: * broadcast or unicast address as appropriate.
583: */
584: if (crypto_flags && skeyid > NTP_MAXKEY) {
585:
586: /*
587: * More on the autokey dance (AKD). A cookie is
588: * constructed from public and private values.
589: * For broadcast packets, the cookie is public
590: * (zero). For packets that match no
591: * association, the cookie is hashed from the
592: * addresses and private value. For server
593: * packets, the cookie was previously obtained
594: * from the server. For symmetric modes, the
595: * cookie was previously constructed using an
596: * agreement protocol; however, should PKI be
597: * unavailable, we construct a fake agreement as
598: * the EXOR of the peer and host cookies.
599: *
600: * hismode ephemeral persistent
601: * =======================================
602: * active 0 cookie#
603: * passive 0% cookie#
604: * client sys cookie 0%
605: * server 0% sys cookie
606: * broadcast 0 0
607: *
608: * # if unsync, 0
609: * % can't happen
610: */
611: if (has_mac < MAX_MD5_LEN) {
612: sys_badauth++;
613: return;
614: }
615: if (hismode == MODE_BROADCAST) {
616:
617: /*
618: * For broadcaster, use the interface
619: * broadcast address when available;
620: * otherwise, use the unicast address
621: * found when the association was
622: * mobilized. However, if this is from
623: * the wildcard interface, game over.
624: */
625: if (crypto_flags && rbufp->dstadr ==
626: any_interface) {
627: sys_restricted++;
628: return; /* no wildcard */
629: }
630: pkeyid = 0;
631: if (!SOCK_UNSPEC(&rbufp->dstadr->bcast))
632: dstadr_sin =
633: &rbufp->dstadr->bcast;
634: } else if (peer == NULL) {
635: pkeyid = session_key(
636: &rbufp->recv_srcadr, dstadr_sin, 0,
637: sys_private, 0);
638: } else {
639: pkeyid = peer->pcookie;
640: }
641:
642: /*
643: * The session key includes both the public
644: * values and cookie. In case of an extension
645: * field, the cookie used for authentication
646: * purposes is zero. Note the hash is saved for
647: * use later in the autokey mambo.
648: */
649: if (authlen > LEN_PKT_NOMAC && pkeyid != 0) {
650: session_key(&rbufp->recv_srcadr,
651: dstadr_sin, skeyid, 0, 2);
652: tkeyid = session_key(
653: &rbufp->recv_srcadr, dstadr_sin,
654: skeyid, pkeyid, 0);
655: } else {
656: tkeyid = session_key(
657: &rbufp->recv_srcadr, dstadr_sin,
658: skeyid, pkeyid, 2);
659: }
660:
661: }
662: #endif /* OPENSSL */
663:
664: /*
665: * Compute the cryptosum. Note a clogging attack may
666: * succeed in bloating the key cache. If an autokey,
667: * purge it immediately, since we won't be needing it
668: * again. If the packet is authentic, it can mobilize an
669: * association. Note that there is no key zero.
670: */
671: if (!authdecrypt(skeyid, (u_int32 *)pkt, authlen,
672: has_mac))
673: is_authentic = AUTH_ERROR;
674: else
675: is_authentic = AUTH_OK;
676: #ifdef OPENSSL
677: if (crypto_flags && skeyid > NTP_MAXKEY)
678: authtrust(skeyid, 0);
679: #endif /* OPENSSL */
680: #ifdef DEBUG
681: if (debug)
682: printf(
683: "receive: at %ld %s<-%s mode %d keyid %08x len %d auth %d\n",
684: current_time, stoa(dstadr_sin),
685: stoa(&rbufp->recv_srcadr), hismode, skeyid,
686: authlen + has_mac, is_authentic);
687: #endif
688: }
689:
690: /*
691: * The association matching rules are implemented by a set of
692: * routines and an association table. A packet matching an
693: * association is processed by the peer process for that
694: * association. If there are no errors, an ephemeral association
695: * is mobilized: a broadcast packet mobilizes a broadcast client
696: * aassociation; a manycast server packet mobilizes a manycast
697: * client association; a symmetric active packet mobilizes a
698: * symmetric passive association.
699: */
700: switch (retcode) {
701:
702: /*
703: * This is a client mode packet not matching any association. If
704: * an ordinary client, simply toss a server mode packet back
705: * over the fence. If a manycast client, we have to work a
706: * little harder.
707: */
708: case AM_FXMIT:
709:
710: /*
711: * If authentication OK, send a server reply; otherwise,
712: * send a crypto-NAK.
713: */
714: if (!(rbufp->dstadr->flags & INT_MCASTOPEN)) {
715: if (AUTH(restrict_mask & RES_DONTTRUST,
716: is_authentic)) {
717: fast_xmit(rbufp, MODE_SERVER, skeyid,
718: restrict_mask);
719: } else if (is_authentic == AUTH_ERROR) {
720: fast_xmit(rbufp, MODE_SERVER, 0,
721: restrict_mask);
722: sys_badauth++;
723: } else {
724: sys_restricted++;
725: }
726: return; /* hooray */
727: }
728:
729: /*
730: * This must be manycast. Do not respond if not
731: * configured as a manycast server.
732: */
733: if (!sys_manycastserver) {
734: sys_restricted++;
735: return; /* not enabled */
736: }
737:
738: /*
739: * Do not respond if we are not synchronized or our
740: * stratum is greater than the manycaster or the
741: * manycaster has already synchronized to us.
742: */
743: if (sys_leap == LEAP_NOTINSYNC || sys_stratum >=
744: hisstratum || (!sys_cohort && sys_stratum ==
745: hisstratum + 1) || rbufp->dstadr->addr_refid ==
746: pkt->refid) {
747: sys_declined++;
748: return; /* no help */
749: }
750:
751: /*
752: * Respond only if authentication succeeds. Don't do a
753: * crypto-NAK, as that would not be useful.
754: */
755: if (AUTH(restrict_mask & RES_DONTTRUST, is_authentic))
756: fast_xmit(rbufp, MODE_SERVER, skeyid,
757: restrict_mask);
758: return; /* hooray */
759:
760: /*
761: * This is a server mode packet returned in response to a client
762: * mode packet sent to a multicast group address. The origin
763: * timestamp is a good nonce to reliably associate the reply
764: * with what was sent. If there is no match, that's curious and
765: * could be an intruder attempting to clog, so we just ignore
766: * it.
767: *
768: * If the packet is authentic and the manycast association is
769: * found, we mobilize a client association and copy pertinent
770: * variables from the manycast association to the new client
771: * association. If not, just ignore the packet.
772: *
773: * There is an implosion hazard at the manycast client, since
774: * the manycast servers send the server packet immediately. If
775: * the guy is already here, don't fire up a duplicate.
776: */
777: case AM_MANYCAST:
778: if (!AUTH(sys_authenticate | (restrict_mask &
779: (RES_NOPEER | RES_DONTTRUST)), is_authentic)) {
780: sys_restricted++;
781: return; /* access denied */
782: }
783:
784: /*
785: * Do not respond if unsynchronized or stratum is below
786: * the floor or at or above the ceiling.
787: */
788: if (hisleap == LEAP_NOTINSYNC || hisstratum <
789: sys_floor || hisstratum >= sys_ceiling) {
790: sys_declined++;
791: return; /* no help */
792: }
793: if ((peer2 = findmanycastpeer(rbufp)) == NULL) {
794: sys_restricted++;
795: return; /* not enabled */
796: }
797: if ((peer = newpeer(&rbufp->recv_srcadr, rbufp->dstadr,
798: MODE_CLIENT, hisversion, NTP_MINDPOLL, NTP_MAXDPOLL,
799: FLAG_PREEMPT, MDF_UCAST | MDF_ACLNT, 0, skeyid)) ==
800: NULL) {
801: sys_declined++;
802: return; /* ignore duplicate */
803: }
804:
805: /*
806: * We don't need these, but it warms the billboards.
807: */
808: if (peer2->flags & FLAG_IBURST)
809: peer->flags |= FLAG_IBURST;
810: peer->minpoll = peer2->minpoll;
811: peer->maxpoll = peer2->maxpoll;
812: break;
813:
814: /*
815: * This is the first packet received from a broadcast server. If
816: * the packet is authentic and we are enabled as broadcast
817: * client, mobilize a broadcast client association. We don't
818: * kiss any frogs here.
819: */
820: case AM_NEWBCL:
821: if (sys_bclient == 0) {
822: sys_restricted++;
823: return; /* not enabled */
824: }
825: if (!AUTH(sys_authenticate | (restrict_mask &
826: (RES_NOPEER | RES_DONTTRUST)), is_authentic)) {
827: sys_restricted++;
828: return; /* access denied */
829: }
830:
831: /*
832: * Do not respond if unsynchronized or stratum is below
833: * the floor or at or above the ceiling.
834: */
835: if (hisleap == LEAP_NOTINSYNC || hisstratum <
836: sys_floor || hisstratum >= sys_ceiling) {
837: sys_declined++;
838: return; /* no help */
839: }
840:
841: #ifdef OPENSSL
842: /*
843: * Do not respond if Autokey and the opcode is not a
844: * CRYPTO_ASSOC response with associationn ID.
845: */
846: if (crypto_flags && skeyid > NTP_MAXKEY && (opcode &
847: 0xffff0000) != (CRYPTO_ASSOC | CRYPTO_RESP)) {
848: sys_declined++;
849: return; /* protocol error */
850: }
851: #endif /* OPENSSL */
852:
853: /*
854: * Broadcasts received via a multicast address may
855: * arrive after a unicast volley has begun
856: * with the same remote address. newpeer() will not
857: * find duplicate associations on other local endpoints
858: * if a non-NULL endpoint is supplied. multicastclient
859: * ephemeral associations are unique across all local
860: * endpoints.
861: */
862: if (!(INT_MCASTOPEN & rbufp->dstadr->flags))
863: match_ep = rbufp->dstadr;
864: else
865: match_ep = NULL;
866:
867: /*
868: * Determine whether to execute the initial volley.
869: */
870: if (sys_bdelay != 0) {
871: #ifdef OPENSSL
872: /*
873: * If a two-way exchange is not possible,
874: * neither is Autokey.
875: */
876: if (crypto_flags && skeyid > NTP_MAXKEY) {
877: sys_restricted++;
878: return; /* no autokey */
879: }
880: #endif /* OPENSSL */
881:
882: /*
883: * Do not execute the volley. Start out in
884: * broadcast client mode.
885: */
886: peer = newpeer(&rbufp->recv_srcadr, match_ep,
887: MODE_BCLIENT, hisversion, pkt->ppoll,
888: pkt->ppoll, FLAG_PREEMPT, MDF_BCLNT, 0,
889: skeyid);
890: if (NULL == peer) {
891: sys_restricted++;
892: return; /* ignore duplicate */
893:
894: } else {
895: peer->delay = sys_bdelay;
896: peer->bias = -sys_bdelay / 2.;
897: }
898: break;
899: }
900:
901: /*
902: * Execute the initial volley in order to calibrate the
903: * propagation delay and run the Autokey protocol.
904: *
905: * Note that the minpoll is taken from the broadcast
906: * packet, normally 6 (64 s) and that the poll interval
907: * is fixed at this value.
908: */
909: peer = newpeer(&rbufp->recv_srcadr, match_ep,
910: MODE_CLIENT, hisversion, pkt->ppoll, pkt->ppoll,
911: FLAG_BC_VOL | FLAG_IBURST | FLAG_PREEMPT, MDF_BCLNT,
912: 0, skeyid);
913: if (NULL == peer) {
914: sys_restricted++;
915: return; /* ignore duplicate */
916: }
917: #ifdef OPENSSL
918: if (skeyid > NTP_MAXKEY)
919: crypto_recv(peer, rbufp);
920: #endif /* OPENSSL */
921:
922: return; /* hooray */
923:
924: /*
925: * This is the first packet received from a symmetric active
926: * peer. If the packet is authentic and the first he sent,
927: * mobilize a passive association. If not, kiss the frog.
928: */
929: case AM_NEWPASS:
930: if (!AUTH(sys_authenticate | (restrict_mask &
931: (RES_NOPEER | RES_DONTTRUST)), is_authentic)) {
932:
933: /*
934: * If authenticated but cannot mobilize an
935: * association, send a symmetric passive
936: * response without mobilizing an association.
937: * This is for drat broken Windows clients. See
938: * Microsoft KB 875424 for preferred workaround.
939: */
940: if (AUTH(restrict_mask & RES_DONTTRUST,
941: is_authentic)) {
942: fast_xmit(rbufp, MODE_PASSIVE, skeyid,
943: restrict_mask);
944: return; /* hooray */
945: }
946: if (is_authentic == AUTH_ERROR) {
947: fast_xmit(rbufp, MODE_ACTIVE, 0,
948: restrict_mask);
949: sys_restricted++;
950: }
951: }
952:
953: /*
954: * Do not respond if synchronized and stratum is either
955: * below the floor or at or above the ceiling. Note,
956: * this allows an unsynchronized peer to synchronize to
957: * us. It would be very strange if he did and then was
958: * nipped, but that could only happen if we were
959: * operating at the top end of the range.
960: */
961: if (hisleap != LEAP_NOTINSYNC && (hisstratum <
962: sys_floor || hisstratum >= sys_ceiling)) {
963: sys_declined++;
964: return; /* no help */
965: }
966:
967: /*
968: * The message is correctly authenticated and
969: * allowed. Mobiliae a symmetric passive association.
970: */
971: if ((peer = newpeer(&rbufp->recv_srcadr,
972: rbufp->dstadr, MODE_PASSIVE, hisversion, pkt->ppoll,
973: NTP_MAXDPOLL, FLAG_PREEMPT, MDF_UCAST, 0,
974: skeyid)) == NULL) {
975: sys_declined++;
976: return; /* ignore duplicate */
977: }
978: break;
979:
980:
981: /*
982: * Process regular packet. Nothing special.
983: */
984: case AM_PROCPKT:
985: break;
986:
987: /*
988: * A passive packet matches a passive association. This is
989: * usually the result of reconfiguring a client on the fly. As
990: * this association might be legitamate and this packet an
991: * attempt to deny service, just ignore it.
992: */
993: case AM_ERR:
994: sys_declined++;
995: return;
996:
997: /*
998: * For everything else there is the bit bucket.
999: */
1000: default:
1001: sys_declined++;
1002: return;
1003: }
1004:
1005: #ifdef OPENSSL
1006: /*
1007: * If the association is configured for Autokey, the packet must
1008: * have a public key ID; if not, the packet must have a
1009: * symmetric key ID.
1010: */
1011: if (is_authentic != AUTH_CRYPTO && (((peer->flags &
1012: FLAG_SKEY) && skeyid <= NTP_MAXKEY) || (!(peer->flags &
1013: FLAG_SKEY) && skeyid > NTP_MAXKEY))) {
1014: sys_badauth++;
1015: return;
1016: }
1017: #endif /* OPENSSL */
1018: peer->received++;
1019: peer->flash &= ~PKT_TEST_MASK;
1020: if (peer->flags & FLAG_XBOGUS) {
1021: peer->flags &= ~FLAG_XBOGUS;
1022: peer->flash |= TEST3;
1023: }
1024:
1025: /*
1026: * Next comes a rigorous schedule of timestamp checking. If the
1027: * transmit timestamp is zero, the server has not initialized in
1028: * interleaved modes or is horribly broken.
1029: */
1030: if (L_ISZERO(&p_xmt)) {
1031: peer->flash |= TEST3; /* unsynch */
1032:
1033: /*
1034: * If the transmit timestamp duplicates a previous one, the
1035: * packet is a replay. This prevents the bad guys from replaying
1036: * the most recent packet, authenticated or not.
1037: */
1038: } else if (L_ISEQU(&peer->xmt, &p_xmt)) {
1039: peer->flash |= TEST1; /* duplicate */
1040: peer->oldpkt++;
1041: return;
1042:
1043: /*
1044: * If this is a broadcast mode packet, skip further checking. If
1045: * an intial volley, bail out now and let the client do its
1046: * stuff. If the origin timestamp is nonzero, this is an
1047: * interleaved broadcast. so restart the protocol.
1048: */
1049: } else if (hismode == MODE_BROADCAST) {
1050: if (!L_ISZERO(&p_org) && !(peer->flags & FLAG_XB)) {
1051: peer->flags |= FLAG_XB;
1052: peer->aorg = p_xmt;
1053: peer->borg = rbufp->recv_time;
1054: report_event(PEVNT_XLEAVE, peer, NULL);
1055: return;
1056: }
1057:
1058: /*
1059: * Check for bogus packet in basic mode. If found, switch to
1060: * interleaved mode and resynchronize, but only after confirming
1061: * the packet is not bogus in symmetric interleaved mode.
1062: */
1063: } else if (peer->flip == 0) {
1064: if (!L_ISEQU(&p_org, &peer->aorg)) {
1065: peer->bogusorg++;
1066: peer->flash |= TEST2; /* bogus */
1067: if (!L_ISZERO(&peer->dst) && L_ISEQU(&p_org,
1068: &peer->dst)) {
1069: peer->flip = 1;
1070: report_event(PEVNT_XLEAVE, peer, NULL);
1071: }
1072: } else {
1073: L_CLR(&peer->aorg);
1074: }
1075:
1076: /*
1077: * Check for valid nonzero timestamp fields.
1078: */
1079: } else if (L_ISZERO(&p_org) || L_ISZERO(&p_rec) ||
1080: L_ISZERO(&peer->dst)) {
1081: peer->flash |= TEST3; /* unsynch */
1082:
1083: /*
1084: * Check for bogus packet in interleaved symmetric mode. This
1085: * can happen if a packet is lost, duplicat or crossed. If
1086: * found, flip and resynchronize.
1087: */
1088: } else if (!L_ISZERO(&peer->dst) && !L_ISEQU(&p_org,
1089: &peer->dst)) {
1090: peer->bogusorg++;
1091: peer->flags |= FLAG_XBOGUS;
1092: peer->flash |= TEST2; /* bogus */
1093: }
1094:
1095: /*
1096: * Update the state variables.
1097: */
1098: if (peer->flip == 0) {
1099: if (hismode != MODE_BROADCAST)
1100: peer->rec = p_xmt;
1101: peer->dst = rbufp->recv_time;
1102: }
1103: peer->xmt = p_xmt;
1104:
1105: /*
1106: * If this is a crypto_NAK, the server cannot authenticate a
1107: * client packet. The server might have just changed keys. Clear
1108: * the association and restart the protocol.
1109: */
1110: if (is_authentic == AUTH_CRYPTO) {
1111: report_event(PEVNT_AUTH, peer, "crypto_NAK");
1112: peer->flash |= TEST5; /* bad auth */
1113: peer->badauth++;
1114: if (peer->flags & FLAG_PREEMPT) {
1115: unpeer(peer);
1116: return;
1117: }
1118: #ifdef OPENSSL
1119: if (peer->crypto)
1120: peer_clear(peer, "AUTH");
1121: #endif /* OPENSSL */
1122: return;
1123:
1124: /*
1125: * If the digest fails, the client cannot authenticate a server
1126: * reply to a client packet previously sent. The loopback check
1127: * is designed to avoid a bait-and-switch attack, which was
1128: * possible in past versions. If symmetric modes, return a
1129: * crypto-NAK. The peer should restart the protocol.
1130: */
1131: } else if (!AUTH(has_mac || (restrict_mask & RES_DONTTRUST),
1132: is_authentic)) {
1133: report_event(PEVNT_AUTH, peer, "digest");
1134: peer->flash |= TEST5; /* bad auth */
1135: peer->badauth++;
1136: if (hismode == MODE_ACTIVE || hismode == MODE_PASSIVE)
1137: fast_xmit(rbufp, MODE_ACTIVE, 0, restrict_mask);
1138: if (peer->flags & FLAG_PREEMPT) {
1139: unpeer(peer);
1140: return;
1141: }
1142: #ifdef OPENSSL
1143: if (peer->crypto)
1144: peer_clear(peer, "AUTH");
1145: #endif /* OPENSSL */
1146: return;
1147: }
1148:
1149: /*
1150: * Set the peer ppoll to the maximum of the packet ppoll and the
1151: * peer minpoll. If a kiss-o'-death, set the peer minpoll to
1152: * this maximumn and advance the headway to give the sender some
1153: * headroom. Very intricate.
1154: */
1155: peer->ppoll = max(peer->minpoll, pkt->ppoll);
1156: if (hismode == MODE_SERVER && hisleap == LEAP_NOTINSYNC &&
1157: hisstratum == STRATUM_UNSPEC && memcmp(&pkt->refid,
1158: "RATE", 4) == 0) {
1159: peer->selbroken++;
1160: report_event(PEVNT_RATE, peer, NULL);
1161: if (pkt->ppoll > peer->minpoll)
1162: peer->minpoll = peer->ppoll;
1163: peer->burst = peer->retry = 0;
1164: peer->throttle = (NTP_SHIFT + 1) * (1 << peer->minpoll);
1165: poll_update(peer, pkt->ppoll);
1166: return; /* kiss-o'-death */
1167: }
1168:
1169: /*
1170: * That was hard and I am sweaty, but the packet is squeaky
1171: * clean. Get on with real work.
1172: */
1173: peer->timereceived = current_time;
1174: if (is_authentic == AUTH_OK)
1175: peer->flags |= FLAG_AUTHENTIC;
1176: else
1177: peer->flags &= ~FLAG_AUTHENTIC;
1178:
1179: #ifdef OPENSSL
1180: /*
1181: * More autokey dance. The rules of the cha-cha are as follows:
1182: *
1183: * 1. If there is no key or the key is not auto, do nothing.
1184: *
1185: * 2. If this packet is in response to the one just previously
1186: * sent or from a broadcast server, do the extension fields.
1187: * Otherwise, assume bogosity and bail out.
1188: *
1189: * 3. If an extension field contains a verified signature, it is
1190: * self-authenticated and we sit the dance.
1191: *
1192: * 4. If this is a server reply, check only to see that the
1193: * transmitted key ID matches the received key ID.
1194: *
1195: * 5. Check to see that one or more hashes of the current key ID
1196: * matches the previous key ID or ultimate original key ID
1197: * obtained from the broadcaster or symmetric peer. If no
1198: * match, sit the dance and call for new autokey values.
1199: *
1200: * In case of crypto error, fire the orchestra, stop dancing and
1201: * restart the protocol.
1202: */
1203: if (peer->flags & FLAG_SKEY) {
1204: /*
1205: * Decrement remaining audokey hashes. This isn't
1206: * perfect if a packet is lost, but results in no harm.
1207: */
1208: ap = (struct autokey *)peer->recval.ptr;
1209: if (ap != NULL) {
1210: if (ap->seq > 0)
1211: ap->seq--;
1212: }
1213: peer->flash |= TEST8;
1214: rval = crypto_recv(peer, rbufp);
1215: if (rval == XEVNT_OK) {
1216: peer->unreach = 0;
1217: } else {
1218: if (rval == XEVNT_ERR) {
1219: report_event(PEVNT_RESTART, peer,
1220: "crypto error");
1221: peer_clear(peer, "CRYP");
1222: peer->flash |= TEST9; /* bad crypt */
1223: if (peer->flags & FLAG_PREEMPT)
1224: unpeer(peer);
1225: }
1226: return;
1227: }
1228:
1229: /*
1230: * If server mode, verify the receive key ID matches
1231: * the transmit key ID.
1232: */
1233: if (hismode == MODE_SERVER) {
1234: if (skeyid == peer->keyid)
1235: peer->flash &= ~TEST8;
1236:
1237: /*
1238: * If an extension field is present, verify only that it
1239: * has been correctly signed. We don't need a sequence
1240: * check here, but the sequence continues.
1241: */
1242: } else if (!(peer->flash & TEST8)) {
1243: peer->pkeyid = skeyid;
1244:
1245: /*
1246: * Now the fun part. Here, skeyid is the current ID in
1247: * the packet, pkeyid is the ID in the last packet and
1248: * tkeyid is the hash of skeyid. If the autokey values
1249: * have not been received, this is an automatic error.
1250: * If so, check that the tkeyid matches pkeyid. If not,
1251: * hash tkeyid and try again. If the number of hashes
1252: * exceeds the number remaining in the sequence, declare
1253: * a successful failure and refresh the autokey values.
1254: */
1255: } else if (ap != NULL) {
1256: int i;
1257:
1258: for (i = 0; ; i++) {
1259: if (tkeyid == peer->pkeyid ||
1260: tkeyid == ap->key) {
1261: peer->flash &= ~TEST8;
1262: peer->pkeyid = skeyid;
1263: ap->seq -= i;
1264: break;
1265: }
1266: if (i > ap->seq) {
1267: peer->crypto &=
1268: ~CRYPTO_FLAG_AUTO;
1269: break;
1270: }
1271: tkeyid = session_key(
1272: &rbufp->recv_srcadr, dstadr_sin,
1273: tkeyid, pkeyid, 0);
1274: }
1275: if (peer->flash & TEST8)
1276: report_event(PEVNT_AUTH, peer, "keylist");
1277: }
1278: if (!(peer->crypto & CRYPTO_FLAG_PROV)) /* test 9 */
1279: peer->flash |= TEST8; /* bad autokey */
1280:
1281: /*
1282: * The maximum lifetime of the protocol is about one
1283: * week before restarting the Autokey protocol to
1284: * refreshed certificates and leapseconds values.
1285: */
1286: if (current_time > peer->refresh) {
1287: report_event(PEVNT_RESTART, peer,
1288: "crypto refresh");
1289: peer_clear(peer, "TIME");
1290: return;
1291: }
1292: }
1293: #endif /* OPENSSL */
1294:
1295: /*
1296: * The dance is complete and the flash bits have been lit. Toss
1297: * the packet over the fence for processing, which may light up
1298: * more flashers.
1299: */
1300: process_packet(peer, pkt, rbufp->recv_length);
1301:
1302: /*
1303: * In interleaved mode update the state variables. Also adjust the
1304: * transmit phase to avoid crossover.
1305: */
1306: if (peer->flip != 0) {
1307: peer->rec = p_rec;
1308: peer->dst = rbufp->recv_time;
1309: if (peer->nextdate - current_time < (1 << min(peer->ppoll,
1310: peer->hpoll)) / 2)
1311: peer->nextdate++;
1312: else
1313: peer->nextdate--;
1314: }
1315: }
1316:
1317:
1318: /*
1319: * process_packet - Packet Procedure, a la Section 3.4.4 of the
1320: * specification. Or almost, at least. If we're in here we have a
1321: * reasonable expectation that we will be having a long term
1322: * relationship with this host.
1323: */
1324: void
1325: process_packet(
1326: register struct peer *peer,
1327: register struct pkt *pkt,
1328: u_int len
1329: )
1330: {
1331: double t34, t21;
1332: double p_offset, p_del, p_disp;
1333: l_fp p_rec, p_xmt, p_org, p_reftime, ci;
1334: u_char pmode, pleap, pstratum;
1335: char statstr[NTP_MAXSTRLEN];
1336: #ifdef ASSYM
1337: int itemp;
1338: double etemp, ftemp, td;
1339: #endif /* ASSYM */
1340:
1341: sys_processed++;
1342: peer->processed++;
1343: p_del = FPTOD(NTOHS_FP(pkt->rootdelay));
1344: p_offset = 0;
1345: p_disp = FPTOD(NTOHS_FP(pkt->rootdisp));
1346: NTOHL_FP(&pkt->reftime, &p_reftime);
1347: NTOHL_FP(&pkt->org, &p_org);
1348: NTOHL_FP(&pkt->rec, &p_rec);
1349: NTOHL_FP(&pkt->xmt, &p_xmt);
1350: pmode = PKT_MODE(pkt->li_vn_mode);
1351: pleap = PKT_LEAP(pkt->li_vn_mode);
1352: pstratum = PKT_TO_STRATUM(pkt->stratum);
1353:
1354: /*
1355: * Capture the header values in the client/peer association..
1356: */
1357: record_raw_stats(&peer->srcadr, peer->dstadr ?
1358: &peer->dstadr->sin : NULL, &p_org, &p_rec, &p_xmt,
1359: &peer->dst);
1360: peer->leap = pleap;
1361: peer->stratum = min(pstratum, STRATUM_UNSPEC);
1362: peer->pmode = pmode;
1363: peer->precision = pkt->precision;
1364: peer->rootdelay = p_del;
1365: peer->rootdisp = p_disp;
1366: peer->refid = pkt->refid; /* network byte order */
1367: peer->reftime = p_reftime;
1368:
1369: /*
1370: * First, if either burst mode is armed, enable the burst.
1371: * Compute the headway for the next packet and delay if
1372: * necessary to avoid exceeding the threshold.
1373: */
1374: if (peer->retry > 0) {
1375: peer->retry = 0;
1376: if (peer->reach)
1377: peer->burst = min(1 << (peer->hpoll -
1378: peer->minpoll), NTP_SHIFT) - 1;
1379: else
1380: peer->burst = NTP_IBURST - 1;
1381: if (peer->burst > 0)
1382: peer->nextdate = current_time;
1383: }
1384: poll_update(peer, peer->hpoll);
1385:
1386: /*
1387: * Verify the server is synchronized; that is, the leap bits,
1388: * stratum and root distance are valid.
1389: */
1390: if (pleap == LEAP_NOTINSYNC || /* test 6 */
1391: pstratum < sys_floor || pstratum >= sys_ceiling)
1392: peer->flash |= TEST6; /* bad synch or strat */
1393: if (p_del / 2 + p_disp >= MAXDISPERSE) /* test 7 */
1394: peer->flash |= TEST7; /* bad header */
1395:
1396: /*
1397: * If any tests fail at this point, the packet is discarded.
1398: * Note that some flashers may have already been set in the
1399: * receive() routine.
1400: */
1401: if (peer->flash & PKT_TEST_MASK) {
1402: peer->seldisptoolarge++;
1403: #ifdef DEBUG
1404: if (debug)
1405: printf("packet: flash header %04x\n",
1406: peer->flash);
1407: #endif
1408: return;
1409: }
1410:
1411: /*
1412: * If the peer was previously unreachable, raise a trap. In any
1413: * case, mark it reachable.
1414: */
1415: if (!peer->reach) {
1416: report_event(PEVNT_REACH, peer, NULL);
1417: peer->timereachable = current_time;
1418: }
1419: peer->reach |= 1;
1420:
1421: /*
1422: * For a client/server association, calculate the clock offset,
1423: * roundtrip delay and dispersion. The equations are reordered
1424: * from the spec for more efficient use of temporaries. For a
1425: * broadcast association, offset the last measurement by the
1426: * computed delay during the client/server volley. Note the
1427: * computation of dispersion includes the system precision plus
1428: * that due to the frequency error since the origin time.
1429: *
1430: * It is very important to respect the hazards of overflow. The
1431: * only permitted operation on raw timestamps is subtraction,
1432: * where the result is a signed quantity spanning from 68 years
1433: * in the past to 68 years in the future. To avoid loss of
1434: * precision, these calculations are done using 64-bit integer
1435: * arithmetic. However, the offset and delay calculations are
1436: * sums and differences of these first-order differences, which
1437: * if done using 64-bit integer arithmetic, would be valid over
1438: * only half that span. Since the typical first-order
1439: * differences are usually very small, they are converted to 64-
1440: * bit doubles and all remaining calculations done in floating-
1441: * double arithmetic. This preserves the accuracy while
1442: * retaining the 68-year span.
1443: *
1444: * There are three interleaving schemes, basic, interleaved
1445: * symmetric and interleaved broadcast. The timestamps are
1446: * idioscyncratically different. See the onwire briefing/white
1447: * paper at www.eecis.udel.edu/~mills for details.
1448: *
1449: * Interleaved symmetric mode
1450: * t1 = peer->aorg/borg, t2 = peer->rec, t3 = p_xmt,
1451: * t4 = peer->dst
1452: */
1453: if (peer->flip != 0) {
1454: ci = p_xmt; /* t3 - t4 */
1455: L_SUB(&ci, &peer->dst);
1456: LFPTOD(&ci, t34);
1457: ci = p_rec; /* t2 - t1 */
1458: if (peer->flip > 0)
1459: L_SUB(&ci, &peer->borg);
1460: else
1461: L_SUB(&ci, &peer->aorg);
1462: LFPTOD(&ci, t21);
1463: p_del = t21 - t34;
1464: p_offset = (t21 + t34) / 2.;
1465: if (p_del < 0 || p_del > 1.) {
1466: sprintf(statstr, "t21 %.6f t34 %.6f", t21, t34);
1467: report_event(PEVNT_XERR, peer, statstr);
1468: return;
1469: }
1470:
1471: /*
1472: * Broadcast modes
1473: */
1474: } else if (peer->pmode == MODE_BROADCAST) {
1475:
1476: /*
1477: * Interleaved broadcast mode. Use interleaved timestamps.
1478: * t1 = peer->borg, t2 = p_org, t3 = p_org, t4 = aorg
1479: */
1480: if (peer->flags & FLAG_XB) {
1481: ci = p_org; /* delay */
1482: L_SUB(&ci, &peer->aorg);
1483: LFPTOD(&ci, t34);
1484: ci = p_org; /* t2 - t1 */
1485: L_SUB(&ci, &peer->borg);
1486: LFPTOD(&ci, t21);
1487: peer->aorg = p_xmt;
1488: peer->borg = peer->dst;
1489: if (t34 < 0 || t34 > 1.) {
1490: sprintf(statstr,
1491: "offset %.6f delay %.6f", t21, t34);
1492: report_event(PEVNT_XERR, peer, statstr);
1493: return;
1494: }
1495: p_offset = t21;
1496: peer->xleave = t34;
1497:
1498: /*
1499: * Basic broadcast - use direct timestamps.
1500: * t3 = p_xmt, t4 = peer->dst
1501: */
1502: } else {
1503: ci = p_xmt; /* t3 - t4 */
1504: L_SUB(&ci, &peer->dst);
1505: LFPTOD(&ci, t34);
1506: p_offset = t34;
1507: }
1508:
1509: /*
1510: * When calibration is complete and the clock is
1511: * synchronized, the bias is calculated as the difference
1512: * between the unicast timestamp and the broadcast
1513: * timestamp. This works for both basic and interleaved
1514: * modes.
1515: */
1516: if (FLAG_BC_VOL & peer->flags) {
1517: peer->flags &= ~FLAG_BC_VOL;
1518: peer->delay = (peer->offset - p_offset) * 2;
1519: }
1520: p_del = peer->delay;
1521: p_offset += p_del / 2;
1522:
1523:
1524: /*
1525: * Basic mode, otherwise known as the old fashioned way.
1526: *
1527: * t1 = p_org, t2 = p_rec, t3 = p_xmt, t4 = peer->dst
1528: */
1529: } else {
1530: ci = p_xmt; /* t3 - t4 */
1531: L_SUB(&ci, &peer->dst);
1532: LFPTOD(&ci, t34);
1533: ci = p_rec; /* t2 - t1 */
1534: L_SUB(&ci, &p_org);
1535: LFPTOD(&ci, t21);
1536: p_del = fabs(t21 - t34);
1537: p_offset = (t21 + t34) / 2.;
1538: }
1539: p_offset += peer->bias;
1540: p_disp = LOGTOD(sys_precision) + LOGTOD(peer->precision) +
1541: clock_phi * p_del;
1542:
1543: #if ASSYM
1544: /*
1545: * This code calculates the outbound and inbound data rates by
1546: * measuring the differences between timestamps at different
1547: * packet lengths. This is helpful in cases of large asymmetric
1548: * delays commonly experienced on deep space communication
1549: * links.
1550: */
1551: if (peer->t21_last > 0 && peer->t34_bytes > 0) {
1552: itemp = peer->t21_bytes - peer->t21_last;
1553: if (itemp > 25) {
1554: etemp = t21 - peer->t21;
1555: if (fabs(etemp) > 1e-6) {
1556: ftemp = itemp / etemp;
1557: if (ftemp > 1000.)
1558: peer->r21 = ftemp;
1559: }
1560: }
1561: itemp = len - peer->t34_bytes;
1562: if (itemp > 25) {
1563: etemp = -t34 - peer->t34;
1564: if (fabs(etemp) > 1e-6) {
1565: ftemp = itemp / etemp;
1566: if (ftemp > 1000.)
1567: peer->r34 = ftemp;
1568: }
1569: }
1570: }
1571:
1572: /*
1573: * The following section compensates for different data rates on
1574: * the outbound (d21) and inbound (t34) directions. To do this,
1575: * it finds t such that r21 * t - r34 * (d - t) = 0, where d is
1576: * the roundtrip delay. Then it calculates the correction as a
1577: * fraction of d.
1578: */
1579: peer->t21 = t21;
1580: peer->t21_last = peer->t21_bytes;
1581: peer->t34 = -t34;
1582: peer->t34_bytes = len;
1583: #ifdef DEBUG
1584: if (debug > 1)
1585: printf("packet: t21 %.9lf %d t34 %.9lf %d\n", peer->t21,
1586: peer->t21_bytes, peer->t34, peer->t34_bytes);
1587: #endif
1588: if (peer->r21 > 0 && peer->r34 > 0 && p_del > 0) {
1589: if (peer->pmode != MODE_BROADCAST)
1590: td = (peer->r34 / (peer->r21 + peer->r34) -
1591: .5) * p_del;
1592: else
1593: td = 0;
1594:
1595: /*
1596: * Unfortunately, in many cases the errors are
1597: * unacceptable, so for the present the rates are not
1598: * used. In future, we might find conditions where the
1599: * calculations are useful, so this should be considered
1600: * a work in progress.
1601: */
1602: t21 -= td;
1603: t34 -= td;
1604: #ifdef DEBUG
1605: if (debug > 1)
1606: printf("packet: del %.6lf r21 %.1lf r34 %.1lf %.6lf\n",
1607: p_del, peer->r21 / 1e3, peer->r34 / 1e3,
1608: td);
1609: #endif
1610: }
1611: #endif /* ASSYM */
1612:
1613: /*
1614: * That was awesome. Now hand off to the clock filter.
1615: */
1616: clock_filter(peer, p_offset, p_del, p_disp);
1617:
1618: /*
1619: * If we are in broadcast calibrate mode, return to broadcast
1620: * client mode when the client is fit and the autokey dance is
1621: * complete.
1622: */
1623: if ((FLAG_BC_VOL & peer->flags) && MODE_CLIENT == peer->hmode &&
1624: !(TEST11 & peer_unfit(peer))) { /* distance exceeded */
1625: #ifdef OPENSSL
1626: if (peer->flags & FLAG_SKEY) {
1627: if (!(~peer->crypto & CRYPTO_FLAG_ALL))
1628: peer->hmode = MODE_BCLIENT;
1629: } else {
1630: peer->hmode = MODE_BCLIENT;
1631: }
1632: #else /* OPENSSL */
1633: peer->hmode = MODE_BCLIENT;
1634: #endif /* OPENSSL */
1635: }
1636: }
1637:
1638:
1639: /*
1640: * clock_update - Called at system process update intervals.
1641: */
1642: static void
1643: clock_update(
1644: struct peer *peer /* peer structure pointer */
1645: )
1646: {
1647: double dtemp;
1648: l_fp now;
1649: #ifdef HAVE_LIBSCF_H
1650: char *fmri;
1651: #endif /* HAVE_LIBSCF_H */
1652:
1653: /*
1654: * Update the system state variables. We do this very carefully,
1655: * as the poll interval might need to be clamped differently.
1656: */
1657: sys_peer = peer;
1658: sys_epoch = peer->epoch;
1659: if (sys_poll < peer->minpoll)
1660: sys_poll = peer->minpoll;
1661: if (sys_poll > peer->maxpoll)
1662: sys_poll = peer->maxpoll;
1663: poll_update(peer, sys_poll);
1664: sys_stratum = min(peer->stratum + 1, STRATUM_UNSPEC);
1665: if (peer->stratum == STRATUM_REFCLOCK ||
1666: peer->stratum == STRATUM_UNSPEC)
1667: sys_refid = peer->refid;
1668: else
1669: sys_refid = addr2refid(&peer->srcadr);
1670: dtemp = sys_jitter + fabs(sys_offset) + peer->disp +
1671: (peer->delay + peer->rootdelay) / 2 + clock_phi *
1672: (current_time - peer->update);
1673: sys_rootdisp = dtemp + peer->rootdisp;
1674: sys_rootdelay = peer->delay + peer->rootdelay;
1675: sys_reftime = peer->dst;
1676:
1677: #ifdef DEBUG
1678: if (debug)
1679: printf(
1680: "clock_update: at %lu sample %lu associd %d\n",
1681: current_time, peer->epoch, peer->associd);
1682: #endif
1683:
1684: /*
1685: * Comes now the moment of truth. Crank the clock discipline and
1686: * see what comes out.
1687: */
1688: switch (local_clock(peer, sys_offset)) {
1689:
1690: /*
1691: * Clock exceeds panic threshold. Life as we know it ends.
1692: */
1693: case -1:
1694: #ifdef HAVE_LIBSCF_H
1695: /*
1696: * For Solaris enter the maintenance mode.
1697: */
1698: if ((fmri = getenv("SMF_FMRI")) != NULL) {
1699: if (smf_maintain_instance(fmri, 0) < 0) {
1700: printf("smf_maintain_instance: %s\n",
1701: scf_strerror(scf_error()));
1702: exit(1);
1703: }
1704: /*
1705: * Sleep until SMF kills us.
1706: */
1707: for (;;)
1708: pause();
1709: }
1710: #endif /* HAVE_LIBSCF_H */
1711: exit (-1);
1712: /* not reached */
1713:
1714: /*
1715: * Clock was stepped. Flush all time values of all peers.
1716: */
1717: case 2:
1718: clear_all();
1719: sys_leap = LEAP_NOTINSYNC;
1720: sys_stratum = STRATUM_UNSPEC;
1721: memcpy(&sys_refid, "STEP", 4);
1722: sys_rootdelay = 0;
1723: sys_rootdisp = 0;
1724: L_CLR(&sys_reftime);
1725: sys_jitter = LOGTOD(sys_precision);
1726: leapsec = 0;
1727: break;
1728:
1729: /*
1730: * Clock was slewed. Handle the leapsecond stuff.
1731: */
1732: case 1:
1733:
1734: /*
1735: * If this is the first time the clock is set, reset the
1736: * leap bits. If crypto, the timer will goose the setup
1737: * process.
1738: */
1739: if (sys_leap == LEAP_NOTINSYNC) {
1740: sys_leap = LEAP_NOWARNING;
1741: #ifdef OPENSSL
1742: if (crypto_flags)
1743: crypto_update();
1744: #endif /* OPENSSL */
1745: }
1746:
1747: /*
1748: * If the leapseconds values are from file or network
1749: * and the leap is in the future, schedule a leap at the
1750: * given epoch. Otherwise, if the number of survivor
1751: * leap bits is greater than half the number of
1752: * survivors, schedule a leap for the end of the current
1753: * month.
1754: */
1755: get_systime(&now);
1756: if (leap_sec > 0) {
1757: if (leap_sec > now.l_ui) {
1758: sys_tai = leap_tai - 1;
1759: if (leapsec == 0)
1760: report_event(EVNT_ARMED, NULL,
1761: NULL);
1762: leapsec = leap_sec - now.l_ui;
1763: } else {
1764: sys_tai = leap_tai;
1765: }
1766: break;
1767:
1768: } else if (leap_vote > sys_survivors / 2) {
1769: leap_peers = now.l_ui + leap_month(now.l_ui);
1770: if (leap_peers > now.l_ui) {
1771: if (leapsec == 0)
1772: report_event(PEVNT_ARMED, peer,
1773: NULL);
1774: leapsec = leap_peers - now.l_ui;
1775: }
1776: } else if (leapsec > 0) {
1777: report_event(EVNT_DISARMED, NULL, NULL);
1778: leapsec = 0;
1779: }
1780: break;
1781:
1782: /*
1783: * Popcorn spike or step threshold exceeded. Pretend it never
1784: * happened.
1785: */
1786: default:
1787: break;
1788: }
1789: }
1790:
1791:
1792: /*
1793: * poll_update - update peer poll interval
1794: */
1795: void
1796: poll_update(
1797: struct peer *peer, /* peer structure pointer */
1798: int mpoll
1799: )
1800: {
1801: int hpoll, minpkt;
1802: u_long next, utemp;
1803:
1804: /*
1805: * This routine figures out when the next poll should be sent.
1806: * That turns out to be wickedly complicated. One problem is
1807: * that sometimes the time for the next poll is in the past when
1808: * the poll interval is reduced. We watch out for races here
1809: * between the receive process and the poll process.
1810: *
1811: * First, bracket the poll interval according to the type of
1812: * association and options. If a fixed interval is configured,
1813: * use minpoll. This primarily is for reference clocks, but
1814: * works for any association. Otherwise, clamp the poll interval
1815: * between minpoll and maxpoll.
1816: */
1817: if (peer->cast_flags & MDF_BCLNT)
1818: hpoll = peer->minpoll;
1819: else
1820: hpoll = max(min(peer->maxpoll, mpoll), peer->minpoll);
1821:
1822: #ifdef OPENSSL
1823: /*
1824: * If during the crypto protocol the poll interval has changed,
1825: * the lifetimes in the key list are probably bogus. Purge the
1826: * the key list and regenerate it later.
1827: */
1828: if ((peer->flags & FLAG_SKEY) && hpoll != peer->hpoll)
1829: key_expire(peer);
1830: #endif /* OPENSSL */
1831: peer->hpoll = hpoll;
1832:
1833: /*
1834: * There are three variables important for poll scheduling, the
1835: * current time (current_time), next scheduled time (nextdate)
1836: * and the earliest time (utemp). The earliest time is 2 s
1837: * seconds, but could be more due to rate management. When
1838: * sending in a burst, use the earliest time. When not in a
1839: * burst but with a reply pending, send at the earliest time
1840: * unless the next scheduled time has not advanced. This can
1841: * only happen if multiple replies are peinding in the same
1842: * response interval. Otherwise, send at the later of the next
1843: * scheduled time and the earliest time.
1844: *
1845: * Now we figure out if there is an override. If a burst is in
1846: * progress and we get called from the receive process, just
1847: * slink away. If called from the poll process, delay 1 s for a
1848: * reference clock, otherwise 2 s.
1849: */
1850: minpkt = 1 << ntp_minpkt;
1851: utemp = current_time + max(peer->throttle - (NTP_SHIFT - 1) *
1852: (1 << peer->minpoll), minpkt);
1853: if (peer->burst > 0) {
1854: if (peer->nextdate > current_time)
1855: return;
1856: #ifdef REFCLOCK
1857: else if (peer->flags & FLAG_REFCLOCK)
1858: peer->nextdate = current_time + RESP_DELAY;
1859: #endif /* REFCLOCK */
1860: else
1861: peer->nextdate = utemp;
1862:
1863: #ifdef OPENSSL
1864: /*
1865: * If a burst is not in progress and a crypto response message
1866: * is pending, delay 2 s, but only if this is a new interval.
1867: */
1868: } else if (peer->cmmd != NULL) {
1869: if (peer->nextdate > current_time) {
1870: if (peer->nextdate + minpkt != utemp)
1871: peer->nextdate = utemp;
1872: } else {
1873: peer->nextdate = utemp;
1874: }
1875: #endif /* OPENSSL */
1876:
1877: /*
1878: * The ordinary case. If a retry, use minpoll; if unreachable,
1879: * use host poll; otherwise, use the minimum of host and peer
1880: * polls; In other words, oversampling is okay but
1881: * understampling is evil. Use the maximum of this value and the
1882: * headway. If the average headway is greater than the headway
1883: * threshold, increase the headway by the minimum interval.
1884: */
1885: } else {
1886: if (peer->retry > 0)
1887: hpoll = peer->minpoll;
1888: else if (!(peer->reach))
1889: hpoll = peer->hpoll;
1890: else
1891: hpoll = min(peer->ppoll, peer->hpoll);
1892: #ifdef REFCLOCK
1893: if (peer->flags & FLAG_REFCLOCK)
1894: next = 1 << hpoll;
1895: else
1896: next = ((0x1000UL | (ntp_random() & 0x0ff)) <<
1897: hpoll) >> 12;
1898: #else /* REFCLOCK */
1899: next = ((0x1000UL | (ntp_random() & 0x0ff)) << hpoll) >>
1900: 12;
1901: #endif /* REFCLOCK */
1902: next += peer->outdate;
1903: if (next > utemp)
1904: peer->nextdate = next;
1905: else
1906: peer->nextdate = utemp;
1907: hpoll = peer->throttle - (1 << peer->minpoll);
1908: if (hpoll > 0)
1909: peer->nextdate += minpkt;
1910: }
1911: #ifdef DEBUG
1912: if (debug > 1)
1913: printf("poll_update: at %lu %s poll %d burst %d retry %d head %d early %lu next %lu\n",
1914: current_time, ntoa(&peer->srcadr), peer->hpoll,
1915: peer->burst, peer->retry, peer->throttle,
1916: utemp - current_time, peer->nextdate -
1917: current_time);
1918: #endif
1919: }
1920:
1921:
1922: /*
1923: * peer_clear - clear peer filter registers. See Section 3.4.8 of the
1924: * spec.
1925: */
1926: void
1927: peer_clear(
1928: struct peer *peer, /* peer structure */
1929: char *ident /* tally lights */
1930: )
1931: {
1932: int i;
1933:
1934: #ifdef OPENSSL
1935: /*
1936: * If cryptographic credentials have been acquired, toss them to
1937: * Valhalla. Note that autokeys are ephemeral, in that they are
1938: * tossed immediately upon use. Therefore, the keylist can be
1939: * purged anytime without needing to preserve random keys. Note
1940: * that, if the peer is purged, the cryptographic variables are
1941: * purged, too. This makes it much harder to sneak in some
1942: * unauthenticated data in the clock filter.
1943: */
1944: key_expire(peer);
1945: if (peer->iffval != NULL)
1946: BN_free(peer->iffval);
1947: value_free(&peer->cookval);
1948: value_free(&peer->recval);
1949: value_free(&peer->encrypt);
1950: value_free(&peer->sndval);
1951: if (peer->cmmd != NULL)
1952: free(peer->cmmd);
1953: if (peer->subject != NULL)
1954: free(peer->subject);
1955: if (peer->issuer != NULL)
1956: free(peer->issuer);
1957: #endif /* OPENSSL */
1958:
1959: /*
1960: * Clear all values, including the optional crypto values above.
1961: */
1962: memset(CLEAR_TO_ZERO(peer), 0, LEN_CLEAR_TO_ZERO);
1963: peer->ppoll = peer->maxpoll;
1964: peer->hpoll = peer->minpoll;
1965: peer->disp = MAXDISPERSE;
1966: peer->flash = peer_unfit(peer);
1967: peer->jitter = LOGTOD(sys_precision);
1968:
1969: /*
1970: * If interleave mode, initialize the alternate origin switch.
1971: */
1972: if (peer->flags & FLAG_XLEAVE)
1973: peer->flip = 1;
1974: for (i = 0; i < NTP_SHIFT; i++) {
1975: peer->filter_order[i] = i;
1976: peer->filter_disp[i] = MAXDISPERSE;
1977: }
1978: #ifdef REFCLOCK
1979: if (!(peer->flags & FLAG_REFCLOCK)) {
1980: peer->leap = LEAP_NOTINSYNC;
1981: peer->stratum = STRATUM_UNSPEC;
1982: memcpy(&peer->refid, ident, 4);
1983: }
1984: #else
1985: peer->leap = LEAP_NOTINSYNC;
1986: peer->stratum = STRATUM_UNSPEC;
1987: memcpy(&peer->refid, ident, 4);
1988: #endif /* REFCLOCK */
1989:
1990: /*
1991: * During initialization use the association count to spread out
1992: * the polls at one-second intervals. Otherwise, randomize over
1993: * the minimum poll interval in order to avoid broadcast
1994: * implosion.
1995: */
1996: peer->nextdate = peer->update = peer->outdate = current_time;
1997: if (initializing) {
1998: peer->nextdate += peer_associations;
1999: } else if (peer->hmode == MODE_PASSIVE) {
2000: peer->nextdate += 1 << ntp_minpkt;
2001: } else {
2002: peer->nextdate += ntp_random() % peer_associations;
2003: }
2004: #ifdef OPENSSL
2005: peer->refresh = current_time + (1 << NTP_REFRESH);
2006: #endif /* OPENSSL */
2007: #ifdef DEBUG
2008: if (debug)
2009: printf(
2010: "peer_clear: at %ld next %ld associd %d refid %s\n",
2011: current_time, peer->nextdate, peer->associd,
2012: ident);
2013: #endif
2014: }
2015:
2016:
2017: /*
2018: * clock_filter - add incoming clock sample to filter register and run
2019: * the filter procedure to find the best sample.
2020: */
2021: void
2022: clock_filter(
2023: struct peer *peer, /* peer structure pointer */
2024: double sample_offset, /* clock offset */
2025: double sample_delay, /* roundtrip delay */
2026: double sample_disp /* dispersion */
2027: )
2028: {
2029: double dst[NTP_SHIFT]; /* distance vector */
2030: int ord[NTP_SHIFT]; /* index vector */
2031: int i, j, k, m;
2032: double dtemp, etemp;
2033: char tbuf[80];
2034:
2035: /*
2036: * A sample consists of the offset, delay, dispersion and epoch
2037: * of arrival. The offset and delay are determined by the on-
2038: * wire protocol. The dispersion grows from the last outbound
2039: * packet to the arrival of this one increased by the sum of the
2040: * peer precision and the system precision as required by the
2041: * error budget. First, shift the new arrival into the shift
2042: * register discarding the oldest one.
2043: */
2044: j = peer->filter_nextpt;
2045: peer->filter_offset[j] = sample_offset;
2046: peer->filter_delay[j] = sample_delay;
2047: peer->filter_disp[j] = sample_disp;
2048: peer->filter_epoch[j] = current_time;
2049: j = (j + 1) % NTP_SHIFT;
2050: peer->filter_nextpt = j;
2051:
2052: /*
2053: * Update dispersions since the last update and at the same
2054: * time initialize the distance and index lists. Since samples
2055: * become increasingly uncorrelated beyond the Allan intercept,
2056: * only under exceptional cases will an older sample be used.
2057: * Therefore, the distance list uses a compound metric. If the
2058: * dispersion is greater than the maximum dispersion, clamp the
2059: * distance at that value. If the time since the last update is
2060: * less than the Allan intercept use the delay; otherwise, use
2061: * the sum of the delay and dispersion.
2062: */
2063: dtemp = clock_phi * (current_time - peer->update);
2064: peer->update = current_time;
2065: for (i = NTP_SHIFT - 1; i >= 0; i--) {
2066: if (i != 0)
2067: peer->filter_disp[j] += dtemp;
2068: if (peer->filter_disp[j] >= MAXDISPERSE) {
2069: peer->filter_disp[j] = MAXDISPERSE;
2070: dst[i] = MAXDISPERSE;
2071: } else if (peer->update - peer->filter_epoch[j] >
2072: ULOGTOD(allan_xpt)) {
2073: dst[i] = peer->filter_delay[j] +
2074: peer->filter_disp[j];
2075: } else {
2076: dst[i] = peer->filter_delay[j];
2077: }
2078: ord[i] = j;
2079: j = (j + 1) % NTP_SHIFT;
2080: }
2081:
2082: /*
2083: * If the clock discipline has stabilized, sort the samples by
2084: * distance.
2085: */
2086: if (sys_leap != LEAP_NOTINSYNC) {
2087: for (i = 1; i < NTP_SHIFT; i++) {
2088: for (j = 0; j < i; j++) {
2089: if (dst[j] > dst[i]) {
2090: k = ord[j];
2091: ord[j] = ord[i];
2092: ord[i] = k;
2093: etemp = dst[j];
2094: dst[j] = dst[i];
2095: dst[i] = etemp;
2096: }
2097: }
2098: }
2099: }
2100:
2101: /*
2102: * Copy the index list to the association structure so ntpq
2103: * can see it later. Prune the distance list to leave only
2104: * samples less than the maximum dispersion, which disfavors
2105: * uncorrelated samples older than the Allan intercept. To
2106: * further improve the jitter estimate, of the remainder leave
2107: * only samples less than the maximum distance, but keep at
2108: * least two samples for jitter calculation.
2109: */
2110: m = 0;
2111: for (i = 0; i < NTP_SHIFT; i++) {
2112: peer->filter_order[i] = (u_char) ord[i];
2113: if (dst[i] >= MAXDISPERSE || (m >= 2 && dst[i] >=
2114: sys_maxdist))
2115: continue;
2116: m++;
2117: }
2118:
2119: /*
2120: * Compute the dispersion and jitter. The dispersion is weighted
2121: * exponentially by NTP_FWEIGHT (0.5) so it is normalized close
2122: * to 1.0. The jitter is the RMS differences relative to the
2123: * lowest delay sample.
2124: */
2125: peer->disp = peer->jitter = 0;
2126: k = ord[0];
2127: for (i = NTP_SHIFT - 1; i >= 0; i--) {
2128: j = ord[i];
2129: peer->disp = NTP_FWEIGHT * (peer->disp +
2130: peer->filter_disp[j]);
2131: if (i < m)
2132: peer->jitter += DIFF(peer->filter_offset[j],
2133: peer->filter_offset[k]);
2134: }
2135:
2136: /*
2137: * If no acceptable samples remain in the shift register,
2138: * quietly tiptoe home leaving only the dispersion. Otherwise,
2139: * save the offset, delay and jitter. Note the jitter must not
2140: * be less than the precision.
2141: */
2142: if (m == 0) {
2143: clock_select();
2144: return;
2145: }
2146:
2147: etemp = fabs(peer->offset - peer->filter_offset[k]);
2148: peer->offset = peer->filter_offset[k];
2149: peer->delay = peer->filter_delay[k];
2150: if (m > 1)
2151: peer->jitter /= m - 1;
2152: peer->jitter = max(SQRT(peer->jitter), LOGTOD(sys_precision));
2153:
2154: /*
2155: * If the the new sample and the current sample are both valid
2156: * and the difference between their offsets exceeds CLOCK_SGATE
2157: * (3) times the jitter and the interval between them is less
2158: * than twice the host poll interval, consider the new sample
2159: * a popcorn spike and ignore it.
2160: */
2161: if (peer->disp < sys_maxdist && peer->filter_disp[k] <
2162: sys_maxdist && etemp > CLOCK_SGATE * peer->jitter &&
2163: peer->filter_epoch[k] - peer->epoch < 2. *
2164: ULOGTOD(peer->hpoll)) {
2165: snprintf(tbuf, sizeof(tbuf), "%.6f s", etemp);
2166: report_event(PEVNT_POPCORN, peer, tbuf);
2167: return;
2168: }
2169:
2170: /*
2171: * A new minimum sample is useful only if it is later than the
2172: * last one used. In this design the maximum lifetime of any
2173: * sample is not greater than eight times the poll interval, so
2174: * the maximum interval between minimum samples is eight
2175: * packets.
2176: */
2177: if (peer->filter_epoch[k] <= peer->epoch) {
2178: #if DEBUG
2179: if (debug)
2180: printf("clock_filter: old sample %lu\n", current_time -
2181: peer->filter_epoch[k]);
2182: #endif
2183: return;
2184: }
2185: peer->epoch = peer->filter_epoch[k];
2186:
2187: /*
2188: * The mitigated sample statistics are saved for later
2189: * processing. If not synchronized or not in a burst, tickle the
2190: * clock select algorithm.
2191: */
2192: record_peer_stats(&peer->srcadr, ctlpeerstatus(peer),
2193: peer->offset, peer->delay, peer->disp, peer->jitter);
2194: #ifdef DEBUG
2195: if (debug)
2196: printf(
2197: "clock_filter: n %d off %.6f del %.6f dsp %.6f jit %.6f\n",
2198: m, peer->offset, peer->delay, peer->disp,
2199: peer->jitter);
2200: #endif
2201: if (peer->burst == 0 || sys_leap == LEAP_NOTINSYNC)
2202: clock_select();
2203: }
2204:
2205:
2206: /*
2207: * clock_select - find the pick-of-the-litter clock
2208: *
2209: * LOCKCLOCK: (1) If the local clock is the prefer peer, it will always
2210: * be enabled, even if declared falseticker, (2) only the prefer peer
2211: * caN Be selected as the system peer, (3) if the external source is
2212: * down, the system leap bits are set to 11 and the stratum set to
2213: * infinity.
2214: */
2215: void
2216: clock_select(void)
2217: {
2218: struct peer *peer;
2219: int i, j, k, n;
2220: int nlist, nl3;
2221: int allow, osurv;
2222: double d, e, f, g;
2223: double high, low;
2224: double seljitter;
2225: double synch[NTP_MAXASSOC], error[NTP_MAXASSOC];
2226: double orphmet = 2.0 * U_INT32_MAX; /* 2x is greater than */
2227: struct peer *osys_peer = NULL;
2228: struct peer *sys_prefer = NULL; /* prefer peer */
2229: struct peer *typesystem = NULL;
2230: struct peer *typeorphan = NULL;
2231: #ifdef REFCLOCK
2232: struct peer *typeacts = NULL;
2233: struct peer *typelocal = NULL;
2234: struct peer *typepps = NULL;
2235: #endif /* REFCLOCK */
2236:
2237: static int list_alloc = 0;
2238: static struct endpoint *endpoint = NULL;
2239: static int *indx = NULL;
2240: static struct peer **peer_list = NULL;
2241: static u_int endpoint_size = 0;
2242: static u_int indx_size = 0;
2243: static u_int peer_list_size = 0;
2244:
2245: /*
2246: * Initialize and create endpoint, index and peer lists big
2247: * enough to handle all associations.
2248: */
2249: osys_peer = sys_peer;
2250: osurv = sys_survivors;
2251: sys_survivors = 0;
2252: #ifdef LOCKCLOCK
2253: sys_leap = LEAP_NOTINSYNC;
2254: sys_stratum = STRATUM_UNSPEC;
2255: memcpy(&sys_refid, "DOWN", 4);
2256: #endif /* LOCKCLOCK */
2257: nlist = 0;
2258: for (n = 0; n < NTP_HASH_SIZE; n++)
2259: nlist += peer_hash_count[n];
2260: if (nlist > list_alloc) {
2261: if (list_alloc > 0) {
2262: free(endpoint);
2263: free(indx);
2264: free(peer_list);
2265: }
2266: while (list_alloc < nlist) {
2267: list_alloc += 5;
2268: endpoint_size += 5 * 3 * sizeof(*endpoint);
2269: indx_size += 5 * 3 * sizeof(*indx);
2270: peer_list_size += 5 * sizeof(*peer_list);
2271: }
2272: endpoint = (struct endpoint *)emalloc(endpoint_size);
2273: indx = (int *)emalloc(indx_size);
2274: peer_list = (struct peer **)emalloc(peer_list_size);
2275: }
2276:
2277: /*
2278: * Initially, we populate the island with all the rifraff peers
2279: * that happen to be lying around. Those with seriously
2280: * defective clocks are immediately booted off the island. Then,
2281: * the falsetickers are culled and put to sea. The truechimers
2282: * remaining are subject to repeated rounds where the most
2283: * unpopular at each round is kicked off. When the population
2284: * has dwindled to sys_minclock, the survivors split a million
2285: * bucks and collectively crank the chimes.
2286: */
2287: nlist = nl3 = 0; /* none yet */
2288: for (n = 0; n < NTP_HASH_SIZE; n++) {
2289: for (peer = peer_hash[n]; peer != NULL; peer =
2290: peer->next) {
2291: peer->new_status = CTL_PST_SEL_REJECT;
2292:
2293: /*
2294: * Leave the island immediately if the peer is
2295: * unfit to synchronize.
2296: */
2297: if (peer_unfit(peer))
2298: continue;
2299:
2300: /*
2301: * If this peer is an orphan parent, elect the
2302: * one with the lowest metric defined as the
2303: * IPv4 address or the first 64 bits of the
2304: * hashed IPv6 address. To ensure convergence
2305: * on the same selected orphan, consider as
2306: * well that this system may have the lowest
2307: * metric and be the orphan parent. If this
2308: * system wins, sys_peer will be NULL to trigger
2309: * orphan mode in timer().
2310: */
2311: if (peer->stratum == sys_orphan) {
2312: u_int32 localmet;
2313: u_int32 peermet;
2314:
2315: if (peer->dstadr != NULL)
2316: localmet = ntohl(peer->dstadr->addr_refid);
2317: else
2318: localmet = U_INT32_MAX;
2319: peermet = ntohl(addr2refid(&peer->srcadr));
2320: if (peermet < localmet &&
2321: peermet < orphmet) {
2322: typeorphan = peer;
2323: orphmet = peermet;
2324: }
2325: continue;
2326: }
2327:
2328: /*
2329: * If this peer could have the orphan parent
2330: * as a synchronization ancestor, exclude it
2331: * from selection to avoid forming a
2332: * synchronization loop within the orphan mesh,
2333: * triggering stratum climb to infinity
2334: * instability. Peers at stratum higher than
2335: * the orphan stratum could have the orphan
2336: * parent in ancestry so are excluded.
2337: * See http://bugs.ntp.org/2050
2338: */
2339: if (peer->stratum > sys_orphan)
2340: continue;
2341: #ifdef REFCLOCK
2342: /*
2343: * The following are special cases. We deal
2344: * with them later.
2345: */
2346: if (!(peer->flags & FLAG_PREFER)) {
2347: switch (peer->refclktype) {
2348: case REFCLK_LOCALCLOCK:
2349: if (typelocal == NULL)
2350: typelocal = peer;
2351: continue;
2352:
2353: case REFCLK_ACTS:
2354: if (typeacts == NULL)
2355: typeacts = peer;
2356: continue;
2357: }
2358: }
2359: #endif /* REFCLOCK */
2360:
2361: /*
2362: * If we get this far, the peer can stay on the
2363: * island, but does not yet have the immunity
2364: * idol.
2365: */
2366: peer->new_status = CTL_PST_SEL_SANE;
2367: peer_list[nlist++] = peer;
2368:
2369: /*
2370: * Insert each interval endpoint on the sorted
2371: * list.
2372: */
2373: e = peer->offset; /* Upper end */
2374: f = root_distance(peer);
2375: e = e + f;
2376: for (i = nl3 - 1; i >= 0; i--) {
2377: if (e >= endpoint[indx[i]].val)
2378: break;
2379:
2380: indx[i + 3] = indx[i];
2381: }
2382: indx[i + 3] = nl3;
2383: endpoint[nl3].type = 1;
2384: endpoint[nl3++].val = e;
2385:
2386: e = e - f; /* Center point */
2387: for (; i >= 0; i--) {
2388: if (e >= endpoint[indx[i]].val)
2389: break;
2390:
2391: indx[i + 2] = indx[i];
2392: }
2393: indx[i + 2] = nl3;
2394: endpoint[nl3].type = 0;
2395: endpoint[nl3++].val = e;
2396:
2397: e = e - f; /* Lower end */
2398: for (; i >= 0; i--) {
2399: if (e >= endpoint[indx[i]].val)
2400: break;
2401:
2402: indx[i + 1] = indx[i];
2403: }
2404: indx[i + 1] = nl3;
2405: endpoint[nl3].type = -1;
2406: endpoint[nl3++].val = e;
2407: }
2408: }
2409: #ifdef DEBUG
2410: if (debug > 2)
2411: for (i = 0; i < nl3; i++)
2412: printf("select: endpoint %2d %.6f\n",
2413: endpoint[indx[i]].type,
2414: endpoint[indx[i]].val);
2415: #endif
2416: /*
2417: * This is the actual algorithm that cleaves the truechimers
2418: * from the falsetickers. The original algorithm was described
2419: * in Keith Marzullo's dissertation, but has been modified for
2420: * better accuracy.
2421: *
2422: * Briefly put, we first assume there are no falsetickers, then
2423: * scan the candidate list first from the low end upwards and
2424: * then from the high end downwards. The scans stop when the
2425: * number of intersections equals the number of candidates less
2426: * the number of falsetickers. If this doesn't happen for a
2427: * given number of falsetickers, we bump the number of
2428: * falsetickers and try again. If the number of falsetickers
2429: * becomes equal to or greater than half the number of
2430: * candidates, the Albanians have won the Byzantine wars and
2431: * correct synchronization is not possible.
2432: *
2433: * Here, nlist is the number of candidates and allow is the
2434: * number of falsetickers. Upon exit, the truechimers are the
2435: * survivors with offsets not less than low and not greater than
2436: * high. There may be none of them.
2437: */
2438: low = 1e9;
2439: high = -1e9;
2440: for (allow = 0; 2 * allow < nlist; allow++) {
2441: int found;
2442:
2443: /*
2444: * Bound the interval (low, high) as the largest
2445: * interval containing points from presumed truechimers.
2446: */
2447: found = 0;
2448: n = 0;
2449: for (i = 0; i < nl3; i++) {
2450: low = endpoint[indx[i]].val;
2451: n -= endpoint[indx[i]].type;
2452: if (n >= nlist - allow)
2453: break;
2454: if (endpoint[indx[i]].type == 0)
2455: found++;
2456: }
2457: n = 0;
2458: for (j = nl3 - 1; j >= 0; j--) {
2459: high = endpoint[indx[j]].val;
2460: n += endpoint[indx[j]].type;
2461: if (n >= nlist - allow)
2462: break;
2463: if (endpoint[indx[j]].type == 0)
2464: found++;
2465: }
2466:
2467: /*
2468: * If the number of candidates found outside the
2469: * interval is greater than the number of falsetickers,
2470: * then at least one truechimer is outside the interval,
2471: * so go around again. This is what makes this algorithm
2472: * different than Marzullo's.
2473: */
2474: if (found > allow)
2475: continue;
2476:
2477: /*
2478: * If an interval containing truechimers is found, stop.
2479: * If not, increase the number of falsetickers and go
2480: * around again.
2481: */
2482: if (high > low)
2483: break;
2484: }
2485:
2486: /*
2487: * Clustering algorithm. Construct candidate list in order first
2488: * by stratum then by root distance, but keep only the best
2489: * NTP_MAXASSOC of them. Scan the list to find falsetickers, who
2490: * leave the island immediately. The TRUE peer is always a
2491: * truechimer. We must leave at least one peer to collect the
2492: * million bucks.
2493: */
2494: j = 0;
2495: for (i = 0; i < nlist; i++) {
2496: peer = peer_list[i];
2497: if (nlist > 1 && (peer->offset <= low || peer->offset >=
2498: high) && !(peer->flags & FLAG_TRUE))
2499: continue;
2500:
2501: #ifdef REFCLOCK
2502: /*
2503: * Eligible PPS peers must survive the intersection
2504: * algorithm. Use the first one found, but don't
2505: * include any of them in the cluster population.
2506: */
2507: if (peer->flags & FLAG_PPS) {
2508: if (typepps == NULL)
2509: typepps = peer;
2510: continue;
2511: }
2512: #endif /* REFCLOCK */
2513:
2514: /*
2515: * The metric is the scaled root distance at the next
2516: * poll interval plus the peer stratum.
2517: */
2518: d = (root_distance(peer) + clock_phi * (peer->nextdate -
2519: current_time)) / sys_maxdist + peer->stratum;
2520: if (j >= NTP_MAXASSOC) {
2521: if (d >= synch[j - 1])
2522: continue;
2523: else
2524: j--;
2525: }
2526: for (k = j; k > 0; k--) {
2527: if (d >= synch[k - 1])
2528: break;
2529:
2530: peer_list[k] = peer_list[k - 1];
2531: error[k] = error[k - 1];
2532: synch[k] = synch[k - 1];
2533: }
2534: peer_list[k] = peer;
2535: error[k] = peer->jitter;
2536: synch[k] = d;
2537: j++;
2538: }
2539: nlist = j;
2540:
2541: /*
2542: * If no survivors remain at this point, check if the modem
2543: * driver, local driver or orphan parent in that order. If so,
2544: * nominate the first one found as the only survivor.
2545: * Otherwise, give up and leave the island to the rats.
2546: */
2547: if (nlist == 0) {
2548: error[0] = 0;
2549: synch[0] = 0;
2550: #ifdef REFCLOCK
2551: if (typeacts != NULL) {
2552: peer_list[0] = typeacts;
2553: nlist = 1;
2554: } else if (typelocal != NULL) {
2555: peer_list[0] = typelocal;
2556: nlist = 1;
2557: } else
2558: #endif /* REFCLOCK */
2559: if (typeorphan != NULL) {
2560: peer_list[0] = typeorphan;
2561: nlist = 1;
2562: }
2563: }
2564:
2565: /*
2566: * Mark the candidates at this point as truechimers.
2567: */
2568: for (i = 0; i < nlist; i++) {
2569: peer_list[i]->new_status = CTL_PST_SEL_SELCAND;
2570: #ifdef DEBUG
2571: if (debug > 1)
2572: printf("select: survivor %s %f\n",
2573: stoa(&peer_list[i]->srcadr), synch[i]);
2574: #endif
2575: }
2576:
2577: /*
2578: * Now, vote outlyers off the island by select jitter weighted
2579: * by root distance. Continue voting as long as there are more
2580: * than sys_minclock survivors and the minimum select jitter is
2581: * greater than the maximum peer jitter. Stop if we are about to
2582: * discard a TRUE or PREFER peer, who of course has the
2583: * immunity idol.
2584: */
2585: seljitter = 0;
2586: while (1) {
2587: d = 1e9;
2588: e = -1e9;
2589: f = g = 0;
2590: k = 0;
2591: for (i = 0; i < nlist; i++) {
2592: if (error[i] < d)
2593: d = error[i];
2594: f = 0;
2595: if (nlist > 1) {
2596: for (j = 0; j < nlist; j++)
2597: f += DIFF(peer_list[j]->offset,
2598: peer_list[i]->offset);
2599: f = SQRT(f / (nlist - 1));
2600: }
2601: if (f * synch[i] > e) {
2602: g = f;
2603: e = f * synch[i];
2604: k = i;
2605: }
2606: }
2607: f = max(f, LOGTOD(sys_precision));
2608: if (nlist <= sys_minsane || nlist <= sys_minclock) {
2609: break;
2610:
2611: } else if (f <= d || peer_list[k]->flags &
2612: (FLAG_TRUE | FLAG_PREFER)) {
2613: seljitter = f;
2614: break;
2615: }
2616: #ifdef DEBUG
2617: if (debug > 2)
2618: printf(
2619: "select: drop %s seljit %.6f jit %.6f\n",
2620: ntoa(&peer_list[k]->srcadr), g, d);
2621: #endif
2622: if (nlist > sys_maxclock)
2623: peer_list[k]->new_status = CTL_PST_SEL_EXCESS;
2624: for (j = k + 1; j < nlist; j++) {
2625: peer_list[j - 1] = peer_list[j];
2626: synch[j - 1] = synch[j];
2627: error[j - 1] = error[j];
2628: }
2629: nlist--;
2630: }
2631:
2632: /*
2633: * What remains is a list usually not greater than sys_minclock
2634: * peers. Note that the head of the list is the system peer at
2635: * the lowest stratum and that unsynchronized peers cannot
2636: * survive this far.
2637: *
2638: * While at it, count the number of leap warning bits found.
2639: * This will be used later to vote the system leap warning bit.
2640: * If a leap warning bit is found on a reference clock, the vote
2641: * is always won.
2642: */
2643: leap_vote = 0;
2644: for (i = 0; i < nlist; i++) {
2645: peer = peer_list[i];
2646: peer->unreach = 0;
2647: peer->new_status = CTL_PST_SEL_SYNCCAND;
2648: sys_survivors++;
2649: if (peer->leap == LEAP_ADDSECOND) {
2650: if (peer->flags & FLAG_REFCLOCK)
2651: leap_vote = nlist;
2652: else
2653: leap_vote++;
2654: }
2655: if (peer->flags & FLAG_PREFER)
2656: sys_prefer = peer;
2657: }
2658:
2659: /*
2660: * Unless there are at least sys_misane survivors, leave the
2661: * building dark. Otherwise, do a clockhop dance. Ordinarily,
2662: * use the first survivor on the survivor list. However, if the
2663: * last selection is not first on the list, use it as long as
2664: * it doesn't get too old or too ugly.
2665: */
2666: if (nlist > 0 && nlist >= sys_minsane) {
2667: double x;
2668:
2669: typesystem = peer_list[0];
2670: if (osys_peer == NULL || osys_peer == typesystem) {
2671: sys_clockhop = 0;
2672: } else if ((x = fabs(typesystem->offset -
2673: osys_peer->offset)) < sys_mindisp) {
2674: if (sys_clockhop == 0)
2675: sys_clockhop = sys_mindisp;
2676: else
2677: sys_clockhop *= .5;
2678: #ifdef DEBUG
2679: if (debug)
2680: printf("select: clockhop %d %.6f %.6f\n",
2681: j, x, sys_clockhop);
2682: #endif
2683: if (fabs(x) < sys_clockhop)
2684: typesystem = osys_peer;
2685: else
2686: sys_clockhop = 0;
2687: } else {
2688: sys_clockhop = 0;
2689: }
2690: }
2691:
2692: /*
2693: * Mitigation rules of the game. We have the pick of the
2694: * litter in typesystem if any survivors are left. If
2695: * there is a prefer peer, use its offset and jitter.
2696: * Otherwise, use the combined offset and jitter of all kitters.
2697: */
2698: if (typesystem != NULL) {
2699: if (sys_prefer == NULL) {
2700: typesystem->new_status = CTL_PST_SEL_SYSPEER;
2701: clock_combine(peer_list, sys_survivors);
2702: sys_jitter = SQRT(SQUARE(sys_jitter) +
2703: SQUARE(seljitter));
2704: } else {
2705: typesystem = sys_prefer;
2706: sys_clockhop = 0;
2707: typesystem->new_status = CTL_PST_SEL_SYSPEER;
2708: sys_offset = typesystem->offset;
2709: sys_jitter = typesystem->jitter;
2710: }
2711: #ifdef DEBUG
2712: if (debug)
2713: printf("select: combine offset %.9f jitter %.9f\n",
2714: sys_offset, sys_jitter);
2715: #endif
2716: }
2717: #ifdef REFCLOCK
2718: /*
2719: * If a PPS driver is lit and the combined offset is less than
2720: * 0.4 s, select the driver as the PPS peer and use its offset
2721: * and jitter. However, if this is the atom driver, use it only
2722: * if there is a prefer peer or there are no survivors and none
2723: * are required.
2724: */
2725: if (typepps != NULL && fabs(sys_offset) < 0.4 &&
2726: (typepps->refclktype != REFCLK_ATOM_PPS ||
2727: (typepps->refclktype == REFCLK_ATOM_PPS && (sys_prefer !=
2728: NULL || (typesystem == NULL && sys_minsane == 0))))) {
2729: typesystem = typepps;
2730: sys_clockhop = 0;
2731: typesystem->new_status = CTL_PST_SEL_PPS;
2732: sys_offset = typesystem->offset;
2733: sys_jitter = typesystem->jitter;
2734: #ifdef DEBUG
2735: if (debug)
2736: printf("select: pps offset %.9f jitter %.9f\n",
2737: sys_offset, sys_jitter);
2738: #endif
2739: }
2740: #endif /* REFCLOCK */
2741:
2742: /*
2743: * If there are no survivors at this point, there is no
2744: * system peer. If so and this is an old update, keep the
2745: * current statistics, but do not update the clock.
2746: */
2747: if (typesystem == NULL) {
2748: if (osys_peer != NULL)
2749: report_event(EVNT_NOPEER, NULL, NULL);
2750: sys_peer = NULL;
2751: for (n = 0; n < NTP_HASH_SIZE; n++)
2752: for (peer = peer_hash[n]; peer != NULL; peer =
2753: peer->next)
2754: peer->status = peer->new_status;
2755: return;
2756: }
2757:
2758: /*
2759: * Do not use old data, as this may mess up the clock discipline
2760: * stability.
2761: */
2762: if (typesystem->epoch <= sys_epoch)
2763: return;
2764:
2765: /*
2766: * We have found the alpha male. Wind the clock.
2767: */
2768: if (osys_peer != typesystem)
2769: report_event(PEVNT_NEWPEER, typesystem, NULL);
2770: for (n = 0; n < NTP_HASH_SIZE; n++)
2771: for (peer = peer_hash[n]; peer != NULL; peer =
2772: peer->next)
2773: peer->status = peer->new_status;
2774: clock_update(typesystem);
2775: }
2776:
2777:
2778: /*
2779: * clock_combine - compute system offset and jitter from selected peers
2780: */
2781: static void
2782: clock_combine(
2783: struct peer **peers, /* survivor list */
2784: int npeers /* number of survivors */
2785: )
2786: {
2787: int i;
2788: double x, y, z, w;
2789:
2790: y = z = w = 0;
2791: for (i = 0; i < npeers; i++) {
2792: x = root_distance(peers[i]);
2793: y += 1. / x;
2794: z += peers[i]->offset / x;
2795: w += SQUARE(peers[i]->offset - peers[0]->offset) / x;
2796: }
2797: sys_offset = z / y;
2798: sys_jitter = SQRT(w / y);
2799: }
2800:
2801:
2802: /*
2803: * root_distance - compute synchronization distance from peer to root
2804: */
2805: static double
2806: root_distance(
2807: struct peer *peer /* peer structure pointer */
2808: )
2809: {
2810: double dtemp;
2811:
2812: /*
2813: * Careful squeak here. The value returned must be greater than
2814: * the minimum root dispersion in order to avoid clockhop with
2815: * highly precise reference clocks. Note that the root distance
2816: * cannot exceed the sys_maxdist, as this is the cutoff by the
2817: * selection algorithm.
2818: */
2819: dtemp = (peer->delay + peer->rootdelay) / 2 + peer->disp +
2820: peer->rootdisp + clock_phi * (current_time - peer->update) +
2821: peer->jitter;
2822: if (dtemp < sys_mindisp)
2823: dtemp = sys_mindisp;
2824: return (dtemp);
2825: }
2826:
2827:
2828: /*
2829: * peer_xmit - send packet for persistent association.
2830: */
2831: static void
2832: peer_xmit(
2833: struct peer *peer /* peer structure pointer */
2834: )
2835: {
2836: struct pkt xpkt; /* transmit packet */
2837: int sendlen, authlen;
2838: keyid_t xkeyid = 0; /* transmit key ID */
2839: l_fp xmt_tx, xmt_ty;
2840:
2841: if (!peer->dstadr) /* drop peers without interface */
2842: return;
2843:
2844: xpkt.li_vn_mode = PKT_LI_VN_MODE(sys_leap, peer->version,
2845: peer->hmode);
2846: xpkt.stratum = STRATUM_TO_PKT(sys_stratum);
2847: xpkt.ppoll = peer->hpoll;
2848: xpkt.precision = sys_precision;
2849: xpkt.refid = sys_refid;
2850: xpkt.rootdelay = HTONS_FP(DTOFP(sys_rootdelay));
2851: xpkt.rootdisp = HTONS_FP(DTOUFP(sys_rootdisp));
2852: HTONL_FP(&sys_reftime, &xpkt.reftime);
2853: HTONL_FP(&peer->rec, &xpkt.org);
2854: HTONL_FP(&peer->dst, &xpkt.rec);
2855:
2856: /*
2857: * If the received packet contains a MAC, the transmitted packet
2858: * is authenticated and contains a MAC. If not, the transmitted
2859: * packet is not authenticated.
2860: *
2861: * It is most important when autokey is in use that the local
2862: * interface IP address be known before the first packet is
2863: * sent. Otherwise, it is not possible to compute a correct MAC
2864: * the recipient will accept. Thus, the I/O semantics have to do
2865: * a little more work. In particular, the wildcard interface
2866: * might not be usable.
2867: */
2868: sendlen = LEN_PKT_NOMAC;
2869: #ifdef OPENSSL
2870: if (!(peer->flags & FLAG_SKEY) && peer->keyid == 0) {
2871: #else
2872: if (peer->keyid == 0) {
2873: #endif /* OPENSSL */
2874:
2875: /*
2876: * Transmit a-priori timestamps
2877: */
2878: get_systime(&xmt_tx);
2879: if (peer->flip == 0) { /* basic mode */
2880: peer->aorg = xmt_tx;
2881: HTONL_FP(&xmt_tx, &xpkt.xmt);
2882: } else { /* interleaved modes */
2883: if (peer->hmode == MODE_BROADCAST) { /* bcst */
2884: HTONL_FP(&xmt_tx, &xpkt.xmt);
2885: if (peer->flip > 0)
2886: HTONL_FP(&peer->borg,
2887: &xpkt.org);
2888: else
2889: HTONL_FP(&peer->aorg,
2890: &xpkt.org);
2891: } else { /* symmetric */
2892: if (peer->flip > 0)
2893: HTONL_FP(&peer->borg,
2894: &xpkt.xmt);
2895: else
2896: HTONL_FP(&peer->aorg,
2897: &xpkt.xmt);
2898: }
2899: }
2900: peer->t21_bytes = sendlen;
2901: sendpkt(&peer->srcadr, peer->dstadr, sys_ttl[peer->ttl],
2902: &xpkt, sendlen);
2903: peer->sent++;
2904: peer->throttle += (1 << peer->minpoll) - 2;
2905:
2906: /*
2907: * Capture a-posteriori timestamps
2908: */
2909: get_systime(&xmt_ty);
2910: if (peer->flip != 0) { /* interleaved modes */
2911: if (peer->flip > 0)
2912: peer->aorg = xmt_ty;
2913: else
2914: peer->borg = xmt_ty;
2915: peer->flip = -peer->flip;
2916: }
2917: L_SUB(&xmt_ty, &xmt_tx);
2918: LFPTOD(&xmt_ty, peer->xleave);
2919: #ifdef DEBUG
2920: if (debug)
2921: printf("transmit: at %ld %s->%s mode %d len %d\n",
2922: current_time, peer->dstadr ?
2923: stoa(&peer->dstadr->sin) : "-",
2924: stoa(&peer->srcadr), peer->hmode, sendlen);
2925: #endif
2926: return;
2927: }
2928:
2929: /*
2930: * Authentication is enabled, so the transmitted packet must be
2931: * authenticated. If autokey is enabled, fuss with the various
2932: * modes; otherwise, symmetric key cryptography is used.
2933: */
2934: #ifdef OPENSSL
2935: if (peer->flags & FLAG_SKEY) {
2936: struct exten *exten; /* extension field */
2937:
2938: /*
2939: * The Public Key Dance (PKD): Cryptographic credentials
2940: * are contained in extension fields, each including a
2941: * 4-octet length/code word followed by a 4-octet
2942: * association ID and optional additional data. Optional
2943: * data includes a 4-octet data length field followed by
2944: * the data itself. Request messages are sent from a
2945: * configured association; response messages can be sent
2946: * from a configured association or can take the fast
2947: * path without ever matching an association. Response
2948: * messages have the same code as the request, but have
2949: * a response bit and possibly an error bit set. In this
2950: * implementation, a message may contain no more than
2951: * one command and one or more responses.
2952: *
2953: * Cryptographic session keys include both a public and
2954: * a private componet. Request and response messages
2955: * using extension fields are always sent with the
2956: * private component set to zero. Packets without
2957: * extension fields indlude the private component when
2958: * the session key is generated.
2959: */
2960: while (1) {
2961:
2962: /*
2963: * Allocate and initialize a keylist if not
2964: * already done. Then, use the list in inverse
2965: * order, discarding keys once used. Keep the
2966: * latest key around until the next one, so
2967: * clients can use client/server packets to
2968: * compute propagation delay.
2969: *
2970: * Note that once a key is used from the list,
2971: * it is retained in the key cache until the
2972: * next key is used. This is to allow a client
2973: * to retrieve the encrypted session key
2974: * identifier to verify authenticity.
2975: *
2976: * If for some reason a key is no longer in the
2977: * key cache, a birthday has happened or the key
2978: * has expired, so the pseudo-random sequence is
2979: * broken. In that case, purge the keylist and
2980: * regenerate it.
2981: */
2982: if (peer->keynumber == 0)
2983: make_keylist(peer, peer->dstadr);
2984: else
2985: peer->keynumber--;
2986: xkeyid = peer->keylist[peer->keynumber];
2987: if (authistrusted(xkeyid))
2988: break;
2989: else
2990: key_expire(peer);
2991: }
2992: peer->keyid = xkeyid;
2993: exten = NULL;
2994: switch (peer->hmode) {
2995:
2996: /*
2997: * In broadcast server mode the autokey values are
2998: * required by the broadcast clients. Push them when a
2999: * new keylist is generated; otherwise, push the
3000: * association message so the client can request them at
3001: * other times.
3002: */
3003: case MODE_BROADCAST:
3004: if (peer->flags & FLAG_ASSOC)
3005: exten = crypto_args(peer, CRYPTO_AUTO |
3006: CRYPTO_RESP, peer->associd, NULL);
3007: else
3008: exten = crypto_args(peer, CRYPTO_ASSOC |
3009: CRYPTO_RESP, peer->associd, NULL);
3010: break;
3011:
3012: /*
3013: * In symmetric modes the parameter, certificate,
3014: * identity, cookie and autokey exchanges are
3015: * required. The leapsecond exchange is optional. But, a
3016: * peer will not believe the other peer until the other
3017: * peer has synchronized, so the certificate exchange
3018: * might loop until then. If a peer finds a broken
3019: * autokey sequence, it uses the autokey exchange to
3020: * retrieve the autokey values. In any case, if a new
3021: * keylist is generated, the autokey values are pushed.
3022: */
3023: case MODE_ACTIVE:
3024: case MODE_PASSIVE:
3025:
3026: /*
3027: * Parameter, certificate and identity.
3028: */
3029: if (!peer->crypto)
3030: exten = crypto_args(peer, CRYPTO_ASSOC,
3031: peer->associd, sys_hostname);
3032: else if (!(peer->crypto & CRYPTO_FLAG_CERT))
3033: exten = crypto_args(peer, CRYPTO_CERT,
3034: peer->associd, peer->issuer);
3035: else if (!(peer->crypto & CRYPTO_FLAG_VRFY))
3036: exten = crypto_args(peer,
3037: crypto_ident(peer), peer->associd,
3038: NULL);
3039:
3040: /*
3041: * Cookie and autokey. We request the cookie
3042: * only when the this peer and the other peer
3043: * are synchronized. But, this peer needs the
3044: * autokey values when the cookie is zero. Any
3045: * time we regenerate the key list, we offer the
3046: * autokey values without being asked. If for
3047: * some reason either peer finds a broken
3048: * autokey sequence, the autokey exchange is
3049: * used to retrieve the autokey values.
3050: */
3051: else if (sys_leap != LEAP_NOTINSYNC &&
3052: peer->leap != LEAP_NOTINSYNC &&
3053: !(peer->crypto & CRYPTO_FLAG_COOK))
3054: exten = crypto_args(peer, CRYPTO_COOK,
3055: peer->associd, NULL);
3056: else if (!(peer->crypto & CRYPTO_FLAG_AUTO))
3057: exten = crypto_args(peer, CRYPTO_AUTO,
3058: peer->associd, NULL);
3059: else if (peer->flags & FLAG_ASSOC &&
3060: peer->crypto & CRYPTO_FLAG_SIGN)
3061: exten = crypto_args(peer, CRYPTO_AUTO |
3062: CRYPTO_RESP, peer->assoc, NULL);
3063:
3064: /*
3065: * Wait for clock sync, then sign the
3066: * certificate and retrieve the leapsecond
3067: * values.
3068: */
3069: else if (sys_leap == LEAP_NOTINSYNC)
3070: break;
3071:
3072: else if (!(peer->crypto & CRYPTO_FLAG_SIGN))
3073: exten = crypto_args(peer, CRYPTO_SIGN,
3074: peer->associd, sys_hostname);
3075: else if (!(peer->crypto & CRYPTO_FLAG_LEAP))
3076: exten = crypto_args(peer, CRYPTO_LEAP,
3077: peer->associd, NULL);
3078: break;
3079:
3080: /*
3081: * In client mode the parameter, certificate, identity,
3082: * cookie and sign exchanges are required. The
3083: * leapsecond exchange is optional. If broadcast client
3084: * mode the same exchanges are required, except that the
3085: * autokey exchange is substitutes for the cookie
3086: * exchange, since the cookie is always zero. If the
3087: * broadcast client finds a broken autokey sequence, it
3088: * uses the autokey exchange to retrieve the autokey
3089: * values.
3090: */
3091: case MODE_CLIENT:
3092:
3093: /*
3094: * Parameter, certificate and identity.
3095: */
3096: if (!peer->crypto)
3097: exten = crypto_args(peer, CRYPTO_ASSOC,
3098: peer->associd, sys_hostname);
3099: else if (!(peer->crypto & CRYPTO_FLAG_CERT))
3100: exten = crypto_args(peer, CRYPTO_CERT,
3101: peer->associd, peer->issuer);
3102: else if (!(peer->crypto & CRYPTO_FLAG_VRFY))
3103: exten = crypto_args(peer,
3104: crypto_ident(peer), peer->associd,
3105: NULL);
3106:
3107: /*
3108: * Cookie and autokey. These are requests, but
3109: * we use the peer association ID with autokey
3110: * rather than our own.
3111: */
3112: else if (!(peer->crypto & CRYPTO_FLAG_COOK))
3113: exten = crypto_args(peer, CRYPTO_COOK,
3114: peer->associd, NULL);
3115: else if (!(peer->crypto & CRYPTO_FLAG_AUTO))
3116: exten = crypto_args(peer, CRYPTO_AUTO,
3117: peer->assoc, NULL);
3118:
3119: /*
3120: * Wait for clock sync, then sign the
3121: * certificate and retrieve the leapsecond
3122: * values.
3123: */
3124: else if (sys_leap == LEAP_NOTINSYNC)
3125: break;
3126:
3127: else if (!(peer->crypto & CRYPTO_FLAG_SIGN))
3128: exten = crypto_args(peer, CRYPTO_SIGN,
3129: peer->associd, sys_hostname);
3130: else if (!(peer->crypto & CRYPTO_FLAG_LEAP))
3131: exten = crypto_args(peer, CRYPTO_LEAP,
3132: peer->associd, NULL);
3133: break;
3134: }
3135:
3136: /*
3137: * Add a queued extension field if present. This is
3138: * always a request message, so the reply ID is already
3139: * in the message. If an error occurs, the error bit is
3140: * lit in the response.
3141: */
3142: if (peer->cmmd != NULL) {
3143: u_int32 temp32;
3144:
3145: temp32 = CRYPTO_RESP;
3146: peer->cmmd->opcode |= htonl(temp32);
3147: sendlen += crypto_xmit(peer, &xpkt, NULL,
3148: sendlen, peer->cmmd, 0);
3149: free(peer->cmmd);
3150: peer->cmmd = NULL;
3151: }
3152:
3153: /*
3154: * Add an extension field created above. All but the
3155: * autokey response message are request messages.
3156: */
3157: if (exten != NULL) {
3158: if (exten->opcode != 0)
3159: sendlen += crypto_xmit(peer, &xpkt,
3160: NULL, sendlen, exten, 0);
3161: free(exten);
3162: }
3163:
3164: /*
3165: * Calculate the next session key. Since extension
3166: * fields are present, the cookie value is zero.
3167: */
3168: if (sendlen > LEN_PKT_NOMAC) {
3169: session_key(&peer->dstadr->sin, &peer->srcadr,
3170: xkeyid, 0, 2);
3171: }
3172: }
3173: #endif /* OPENSSL */
3174:
3175: /*
3176: * Transmit a-priori timestamps
3177: */
3178: get_systime(&xmt_tx);
3179: if (peer->flip == 0) { /* basic mode */
3180: peer->aorg = xmt_tx;
3181: HTONL_FP(&xmt_tx, &xpkt.xmt);
3182: } else { /* interleaved modes */
3183: if (peer->hmode == MODE_BROADCAST) { /* bcst */
3184: HTONL_FP(&xmt_tx, &xpkt.xmt);
3185: if (peer->flip > 0)
3186: HTONL_FP(&peer->borg, &xpkt.org);
3187: else
3188: HTONL_FP(&peer->aorg, &xpkt.org);
3189: } else { /* symmetric */
3190: if (peer->flip > 0)
3191: HTONL_FP(&peer->borg, &xpkt.xmt);
3192: else
3193: HTONL_FP(&peer->aorg, &xpkt.xmt);
3194: }
3195: }
3196: xkeyid = peer->keyid;
3197: authlen = authencrypt(xkeyid, (u_int32 *)&xpkt, sendlen);
3198: if (authlen == 0) {
3199: report_event(PEVNT_AUTH, peer, "no key");
3200: peer->flash |= TEST5; /* auth error */
3201: peer->badauth++;
3202: return;
3203: }
3204: sendlen += authlen;
3205: #ifdef OPENSSL
3206: if (xkeyid > NTP_MAXKEY)
3207: authtrust(xkeyid, 0);
3208: #endif /* OPENSSL */
3209: if (sendlen > sizeof(xpkt)) {
3210: msyslog(LOG_ERR, "proto: buffer overflow %u", sendlen);
3211: exit (-1);
3212: }
3213: peer->t21_bytes = sendlen;
3214: sendpkt(&peer->srcadr, peer->dstadr, sys_ttl[peer->ttl], &xpkt,
3215: sendlen);
3216: peer->sent++;
3217: peer->throttle += (1 << peer->minpoll) - 2;
3218:
3219: /*
3220: * Capture a-posteriori timestamps
3221: */
3222: get_systime(&xmt_ty);
3223: if (peer->flip != 0) { /* interleaved modes */
3224: if (peer->flip > 0)
3225: peer->aorg = xmt_ty;
3226: else
3227: peer->borg = xmt_ty;
3228: peer->flip = -peer->flip;
3229: }
3230: L_SUB(&xmt_ty, &xmt_tx);
3231: LFPTOD(&xmt_ty, peer->xleave);
3232: #ifdef OPENSSL
3233: #ifdef DEBUG
3234: if (debug)
3235: printf("transmit: at %ld %s->%s mode %d keyid %08x len %d index %d\n",
3236: current_time, peer->dstadr ?
3237: ntoa(&peer->dstadr->sin) : "-",
3238: ntoa(&peer->srcadr), peer->hmode, xkeyid, sendlen,
3239: peer->keynumber);
3240: #endif
3241: #else /* OPENSSL */
3242: #ifdef DEBUG
3243: if (debug)
3244: printf("transmit: at %ld %s->%s mode %d keyid %08x len %d\n",
3245: current_time, peer->dstadr ?
3246: ntoa(&peer->dstadr->sin) : "-",
3247: ntoa(&peer->srcadr), peer->hmode, xkeyid, sendlen);
3248: #endif
3249: #endif /* OPENSSL */
3250: }
3251:
3252:
3253: /*
3254: * fast_xmit - Send packet for nonpersistent association. Note that
3255: * neither the source or destination can be a broadcast address.
3256: */
3257: static void
3258: fast_xmit(
3259: struct recvbuf *rbufp, /* receive packet pointer */
3260: int xmode, /* receive mode */
3261: keyid_t xkeyid, /* transmit key ID */
3262: int flags /* restrict mask */
3263: )
3264: {
3265: struct pkt xpkt; /* transmit packet structure */
3266: struct pkt *rpkt; /* receive packet structure */
3267: l_fp xmt_tx, xmt_ty;
3268: int sendlen;
3269: #ifdef OPENSSL
3270: u_int32 temp32;
3271: #endif
3272:
3273: /*
3274: * Initialize transmit packet header fields from the receive
3275: * buffer provided. We leave the fields intact as received, but
3276: * set the peer poll at the maximum of the receive peer poll and
3277: * the system minimum poll (ntp_minpoll). This is for KoD rate
3278: * control and not strictly specification compliant, but doesn't
3279: * break anything.
3280: *
3281: * If the gazinta was from a multicast address, the gazoutta
3282: * must go out another way.
3283: */
3284: rpkt = &rbufp->recv_pkt;
3285: if (rbufp->dstadr->flags & INT_MCASTOPEN)
3286: rbufp->dstadr = findinterface(&rbufp->recv_srcadr);
3287:
3288: /*
3289: * If this is a kiss-o'-death (KoD) packet, show leap
3290: * unsynchronized, stratum zero, reference ID the four-character
3291: * kiss code and system root delay. Note we don't reveal the
3292: * local time, so these packets can't be used for
3293: * synchronization.
3294: */
3295: if (flags & RES_KOD) {
3296: sys_kodsent++;
3297: xpkt.li_vn_mode = PKT_LI_VN_MODE(LEAP_NOTINSYNC,
3298: PKT_VERSION(rpkt->li_vn_mode), xmode);
3299: xpkt.stratum = STRATUM_PKT_UNSPEC;
3300: xpkt.ppoll = max(rpkt->ppoll, ntp_minpoll);
3301: memcpy(&xpkt.refid, "RATE", 4);
3302: xpkt.org = rpkt->xmt;
3303: xpkt.rec = rpkt->xmt;
3304: xpkt.xmt = rpkt->xmt;
3305:
3306: /*
3307: * This is a normal packet. Use the system variables.
3308: */
3309: } else {
3310: xpkt.li_vn_mode = PKT_LI_VN_MODE(sys_leap,
3311: PKT_VERSION(rpkt->li_vn_mode), xmode);
3312: xpkt.stratum = STRATUM_TO_PKT(sys_stratum);
3313: xpkt.ppoll = max(rpkt->ppoll, ntp_minpoll);
3314: xpkt.precision = sys_precision;
3315: xpkt.refid = sys_refid;
3316: xpkt.rootdelay = HTONS_FP(DTOFP(sys_rootdelay));
3317: xpkt.rootdisp = HTONS_FP(DTOUFP(sys_rootdisp));
3318: HTONL_FP(&sys_reftime, &xpkt.reftime);
3319: xpkt.org = rpkt->xmt;
3320: HTONL_FP(&rbufp->recv_time, &xpkt.rec);
3321: get_systime(&xmt_tx);
3322: HTONL_FP(&xmt_tx, &xpkt.xmt);
3323: }
3324:
3325: #ifdef HAVE_NTP_SIGND
3326: if (flags & RES_MSSNTP) {
3327: send_via_ntp_signd(rbufp, xmode, xkeyid, flags, &xpkt);
3328: return;
3329: }
3330: #endif /* HAVE_NTP_SIGND */
3331:
3332: /*
3333: * If the received packet contains a MAC, the transmitted packet
3334: * is authenticated and contains a MAC. If not, the transmitted
3335: * packet is not authenticated.
3336: */
3337: sendlen = LEN_PKT_NOMAC;
3338: if (rbufp->recv_length == sendlen) {
3339: sendpkt(&rbufp->recv_srcadr, rbufp->dstadr, 0, &xpkt,
3340: sendlen);
3341: #ifdef DEBUG
3342: if (debug)
3343: printf(
3344: "transmit: at %ld %s->%s mode %d len %d\n",
3345: current_time, stoa(&rbufp->dstadr->sin),
3346: stoa(&rbufp->recv_srcadr), xmode, sendlen);
3347: #endif
3348: return;
3349: }
3350:
3351: /*
3352: * The received packet contains a MAC, so the transmitted packet
3353: * must be authenticated. For symmetric key cryptography, use
3354: * the predefined and trusted symmetric keys to generate the
3355: * cryptosum. For autokey cryptography, use the server private
3356: * value to generate the cookie, which is unique for every
3357: * source-destination-key ID combination.
3358: */
3359: #ifdef OPENSSL
3360: if (xkeyid > NTP_MAXKEY) {
3361: keyid_t cookie;
3362:
3363: /*
3364: * The only way to get here is a reply to a legitimate
3365: * client request message, so the mode must be
3366: * MODE_SERVER. If an extension field is present, there
3367: * can be only one and that must be a command. Do what
3368: * needs, but with private value of zero so the poor
3369: * jerk can decode it. If no extension field is present,
3370: * use the cookie to generate the session key.
3371: */
3372: cookie = session_key(&rbufp->recv_srcadr,
3373: &rbufp->dstadr->sin, 0, sys_private, 0);
3374: if (rbufp->recv_length > sendlen + MAX_MAC_LEN) {
3375: session_key(&rbufp->dstadr->sin,
3376: &rbufp->recv_srcadr, xkeyid, 0, 2);
3377: temp32 = CRYPTO_RESP;
3378: rpkt->exten[0] |= htonl(temp32);
3379: sendlen += crypto_xmit(NULL, &xpkt, rbufp,
3380: sendlen, (struct exten *)rpkt->exten,
3381: cookie);
3382: } else {
3383: session_key(&rbufp->dstadr->sin,
3384: &rbufp->recv_srcadr, xkeyid, cookie, 2);
3385: }
3386: }
3387: #endif /* OPENSSL */
3388: get_systime(&xmt_tx);
3389: sendlen += authencrypt(xkeyid, (u_int32 *)&xpkt, sendlen);
3390: #ifdef OPENSSL
3391: if (xkeyid > NTP_MAXKEY)
3392: authtrust(xkeyid, 0);
3393: #endif /* OPENSSL */
3394: sendpkt(&rbufp->recv_srcadr, rbufp->dstadr, 0, &xpkt, sendlen);
3395: get_systime(&xmt_ty);
3396: L_SUB(&xmt_ty, &xmt_tx);
3397: sys_authdelay = xmt_ty;
3398: #ifdef DEBUG
3399: if (debug)
3400: printf(
3401: "transmit: at %ld %s->%s mode %d keyid %08x len %d\n",
3402: current_time, ntoa(&rbufp->dstadr->sin),
3403: ntoa(&rbufp->recv_srcadr), xmode, xkeyid, sendlen);
3404: #endif
3405: }
3406:
3407:
3408: #ifdef OPENSSL
3409: /*
3410: * key_expire - purge the key list
3411: */
3412: void
3413: key_expire(
3414: struct peer *peer /* peer structure pointer */
3415: )
3416: {
3417: int i;
3418:
3419: if (peer->keylist != NULL) {
3420: for (i = 0; i <= peer->keynumber; i++)
3421: authtrust(peer->keylist[i], 0);
3422: free(peer->keylist);
3423: peer->keylist = NULL;
3424: }
3425: value_free(&peer->sndval);
3426: peer->keynumber = 0;
3427: peer->flags &= ~FLAG_ASSOC;
3428: #ifdef DEBUG
3429: if (debug)
3430: printf("key_expire: at %lu associd %d\n", current_time,
3431: peer->associd);
3432: #endif
3433: }
3434: #endif /* OPENSSL */
3435:
3436:
3437: /*
3438: * local_refid(peer) - check peer refid to avoid selecting peers
3439: * currently synced to this ntpd.
3440: */
3441: static int
3442: local_refid(
3443: struct peer * p
3444: )
3445: {
3446: endpt * unicast_ep;
3447:
3448: if (p->dstadr != NULL && !(INT_MCASTIF & p->dstadr->flags))
3449: unicast_ep = p->dstadr;
3450: else
3451: unicast_ep = findinterface(&p->srcadr);
3452:
3453: if (unicast_ep != NULL && p->refid == unicast_ep->addr_refid)
3454: return TRUE;
3455: else
3456: return FALSE;
3457: }
3458:
3459:
3460: /*
3461: * Determine if the peer is unfit for synchronization
3462: *
3463: * A peer is unfit for synchronization if
3464: * > TEST10 bad leap or stratum below floor or at or above ceiling
3465: * > TEST11 root distance exceeded for remote peer
3466: * > TEST12 a direct or indirect synchronization loop would form
3467: * > TEST13 unreachable or noselect
3468: */
3469: int /* FALSE if fit, TRUE if unfit */
3470: peer_unfit(
3471: struct peer *peer /* peer structure pointer */
3472: )
3473: {
3474: int rval = 0;
3475:
3476: /*
3477: * A stratum error occurs if (1) the server has never been
3478: * synchronized, (2) the server stratum is below the floor or
3479: * greater than or equal to the ceiling.
3480: */
3481: if (peer->leap == LEAP_NOTINSYNC || peer->stratum < sys_floor ||
3482: peer->stratum >= sys_ceiling)
3483: rval |= TEST10; /* bad synch or stratum */
3484:
3485: /*
3486: * A distance error for a remote peer occurs if the root
3487: * distance is greater than or equal to the distance threshold
3488: * plus the increment due to one host poll interval.
3489: */
3490: if (!(peer->flags & FLAG_REFCLOCK) && root_distance(peer) >=
3491: sys_maxdist + clock_phi * ULOGTOD(peer->hpoll))
3492: rval |= TEST11; /* distance exceeded */
3493:
3494: /*
3495: * A loop error occurs if the remote peer is synchronized to the
3496: * local peer or if the remote peer is synchronized to the same
3497: * server as the local peer but only if the remote peer is
3498: * neither a reference clock nor an orphan.
3499: */
3500: if (peer->stratum > 1 && local_refid(peer))
3501: rval |= TEST12; /* synchronization loop */
3502:
3503: /*
3504: * An unreachable error occurs if the server is unreachable or
3505: * the noselect bit is set.
3506: */
3507: if (!peer->reach || (peer->flags & FLAG_NOSELECT))
3508: rval |= TEST13; /* unreachable */
3509:
3510: peer->flash &= ~PEER_TEST_MASK;
3511: peer->flash |= rval;
3512: return (rval);
3513: }
3514:
3515:
3516: /*
3517: * Find the precision of this particular machine
3518: */
3519: #define MINSTEP 100e-9 /* minimum clock increment (s) */
3520: #define MAXSTEP 20e-3 /* maximum clock increment (s) */
3521: #define MINLOOPS 5 /* minimum number of step samples */
3522:
3523: /*
3524: * This routine measures the system precision defined as the minimum of
3525: * a sequence of differences between successive readings of the system
3526: * clock. However, if a difference is less than MINSTEP, the clock has
3527: * been read more than once during a clock tick and the difference is
3528: * ignored. We set MINSTEP greater than zero in case something happens
3529: * like a cache miss.
3530: */
3531: int
3532: default_get_precision(void)
3533: {
3534: l_fp val; /* current seconds fraction */
3535: l_fp last; /* last seconds fraction */
3536: l_fp diff; /* difference */
3537: double tick; /* computed tick value */
3538: double dtemp; /* scratch */
3539: int i; /* log2 precision */
3540:
3541: /*
3542: * Loop to find precision value in seconds.
3543: */
3544: tick = MAXSTEP;
3545: i = 0;
3546: get_systime(&last);
3547: while (1) {
3548: get_systime(&val);
3549: diff = val;
3550: L_SUB(&diff, &last);
3551: last = val;
3552: LFPTOD(&diff, dtemp);
3553: if (dtemp < MINSTEP)
3554: continue;
3555:
3556: if (dtemp < tick)
3557: tick = dtemp;
3558: if (++i >= MINLOOPS)
3559: break;
3560: }
3561: sys_tick = tick;
3562:
3563: /*
3564: * Find the nearest power of two.
3565: */
3566: msyslog(LOG_NOTICE, "proto: precision = %.3f usec", tick * 1e6);
3567: for (i = 0; tick <= 1; i++)
3568: tick *= 2;
3569: if (tick - 1 > 1 - tick / 2)
3570: i--;
3571: return (-i);
3572: }
3573:
3574:
3575: /*
3576: * init_proto - initialize the protocol module's data
3577: */
3578: void
3579: init_proto(void)
3580: {
3581: l_fp dummy;
3582: int i;
3583:
3584: /*
3585: * Fill in the sys_* stuff. Default is don't listen to
3586: * broadcasting, require authentication.
3587: */
3588: sys_leap = LEAP_NOTINSYNC;
3589: sys_stratum = STRATUM_UNSPEC;
3590: memcpy(&sys_refid, "INIT", 4);
3591: sys_peer = NULL;
3592: sys_rootdelay = 0;
3593: sys_rootdisp = 0;
3594: L_CLR(&sys_reftime);
3595: sys_jitter = 0;
3596: sys_precision = (s_char)default_get_precision();
3597: get_systime(&dummy);
3598: sys_survivors = 0;
3599: sys_manycastserver = 0;
3600: sys_bclient = 0;
3601: sys_bdelay = 0;
3602: sys_authenticate = 1;
3603: sys_stattime = current_time;
3604: proto_clr_stats();
3605: for (i = 0; i < MAX_TTL; i++) {
3606: sys_ttl[i] = (u_char)((i * 256) / MAX_TTL);
3607: sys_ttlmax = i;
3608: }
3609: pps_enable = 0;
3610: stats_control = 1;
3611: }
3612:
3613:
3614: /*
3615: * proto_config - configure the protocol module
3616: */
3617: void
3618: proto_config(
3619: int item,
3620: u_long value,
3621: double dvalue,
3622: sockaddr_u *svalue
3623: )
3624: {
3625: /*
3626: * Figure out what he wants to change, then do it
3627: */
3628: DPRINTF(2, ("proto_config: code %d value %lu dvalue %lf\n",
3629: item, value, dvalue));
3630:
3631: switch (item) {
3632:
3633: /*
3634: * enable and disable commands - arguments are Boolean.
3635: */
3636: case PROTO_AUTHENTICATE: /* authentication (auth) */
3637: sys_authenticate = value;
3638: break;
3639:
3640: case PROTO_BROADCLIENT: /* broadcast client (bclient) */
3641: sys_bclient = (int)value;
3642: if (sys_bclient == 0)
3643: io_unsetbclient();
3644: else
3645: io_setbclient();
3646: break;
3647:
3648: #ifdef REFCLOCK
3649: case PROTO_CAL: /* refclock calibrate (calibrate) */
3650: cal_enable = value;
3651: break;
3652: #endif /* REFCLOCK */
3653:
3654: case PROTO_KERNEL: /* kernel discipline (kernel) */
3655: kern_enable = value;
3656: break;
3657:
3658: case PROTO_MONITOR: /* monitoring (monitor) */
3659: if (value)
3660: mon_start(MON_ON);
3661: else
3662: mon_stop(MON_ON);
3663: break;
3664:
3665: case PROTO_NTP: /* NTP discipline (ntp) */
3666: ntp_enable = value;
3667: break;
3668:
3669: case PROTO_PPS: /* PPS discipline (pps) */
3670: pps_enable = value;
3671: break;
3672:
3673: case PROTO_FILEGEN: /* statistics (stats) */
3674: stats_control = value;
3675: break;
3676:
3677: /*
3678: * tos command - arguments are double, sometimes cast to int
3679: */
3680: case PROTO_BEACON: /* manycast beacon (beacon) */
3681: sys_beacon = (int)dvalue;
3682: break;
3683:
3684: case PROTO_BROADDELAY: /* default broadcast delay (bdelay) */
3685: sys_bdelay = dvalue;
3686: break;
3687:
3688: case PROTO_CEILING: /* stratum ceiling (ceiling) */
3689: sys_ceiling = (int)dvalue;
3690: break;
3691:
3692: case PROTO_COHORT: /* cohort switch (cohort) */
3693: sys_cohort = (int)dvalue;
3694: break;
3695:
3696: case PROTO_FLOOR: /* stratum floor (floor) */
3697: sys_floor = (int)dvalue;
3698: break;
3699:
3700: case PROTO_MAXCLOCK: /* maximum candidates (maxclock) */
3701: sys_maxclock = (int)dvalue;
3702: break;
3703:
3704: case PROTO_MAXDIST: /* select threshold (maxdist) */
3705: sys_maxdist = dvalue;
3706: break;
3707:
3708: case PROTO_CALLDELAY: /* modem call delay (mdelay) */
3709: break; /* NOT USED */
3710:
3711: case PROTO_MINCLOCK: /* minimum candidates (minclock) */
3712: sys_minclock = (int)dvalue;
3713: break;
3714:
3715: case PROTO_MINDISP: /* minimum distance (mindist) */
3716: sys_mindisp = dvalue;
3717: break;
3718:
3719: case PROTO_MINSANE: /* minimum survivors (minsane) */
3720: sys_minsane = (int)dvalue;
3721: break;
3722:
3723: case PROTO_ORPHAN: /* orphan stratum (orphan) */
3724: sys_orphan = (int)dvalue;
3725: break;
3726:
3727: case PROTO_ADJ: /* tick increment (tick) */
3728: sys_tick = dvalue;
3729: break;
3730:
3731: /*
3732: * Miscellaneous commands
3733: */
3734: case PROTO_MULTICAST_ADD: /* add group address */
3735: if (svalue != NULL)
3736: io_multicast_add(svalue);
3737: sys_bclient = 1;
3738: break;
3739:
3740: case PROTO_MULTICAST_DEL: /* delete group address */
3741: if (svalue != NULL)
3742: io_multicast_del(svalue);
3743: break;
3744:
3745: default:
3746: msyslog(LOG_NOTICE,
3747: "proto: unsupported option %d", item);
3748: }
3749: }
3750:
3751:
3752: /*
3753: * proto_clr_stats - clear protocol stat counters
3754: */
3755: void
3756: proto_clr_stats(void)
3757: {
3758: sys_stattime = current_time;
3759: sys_received = 0;
3760: sys_processed = 0;
3761: sys_newversion = 0;
3762: sys_oldversion = 0;
3763: sys_declined = 0;
3764: sys_restricted = 0;
3765: sys_badlength = 0;
3766: sys_badauth = 0;
3767: sys_limitrejected = 0;
3768: }
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