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 #include "ntp_leapsec.h" 17 #include "refidsmear.h" 18 #include "lib_strbuf.h" 19 20 #include <stdio.h> 21 #ifdef HAVE_LIBSCF_H 22 #include <libscf.h> 23 #endif 24 #ifdef HAVE_UNISTD_H 25 #include <unistd.h> 26 #endif 27 28 /* [Bug 3031] define automatic broadcastdelay cutoff preset */ 29 #ifndef BDELAY_DEFAULT 30 # define BDELAY_DEFAULT (-0.050) 31 #endif 32 33 /* 34 * This macro defines the authentication state. If x is 1 authentication 35 * is required; othewise it is optional. 36 */ 37 #define AUTH(x, y) ((x) ? (y) == AUTH_OK \ 38 : (y) == AUTH_OK || (y) == AUTH_NONE) 39 40 #define AUTH_NONE 0 /* authentication not required */ 41 #define AUTH_OK 1 /* authentication OK */ 42 #define AUTH_ERROR 2 /* authentication error */ 43 #define AUTH_CRYPTO 3 /* crypto_NAK */ 44 45 /* 46 * Set up Kiss Code values 47 */ 48 49 enum kiss_codes { 50 NOKISS, /* No Kiss Code */ 51 RATEKISS, /* Rate limit Kiss Code */ 52 DENYKISS, /* Deny Kiss */ 53 RSTRKISS, /* Restricted Kiss */ 54 XKISS, /* Experimental Kiss */ 55 UNKNOWNKISS /* Unknown Kiss Code */ 56 }; 57 58 enum nak_error_codes { 59 NONAK, /* No NAK seen */ 60 INVALIDNAK, /* NAK cannot be used */ 61 VALIDNAK /* NAK is valid */ 62 }; 63 64 /* 65 * traffic shaping parameters 66 */ 67 #define NTP_IBURST 6 /* packets in iburst */ 68 #define RESP_DELAY 1 /* refclock burst delay (s) */ 69 70 /* 71 * pool soliciting restriction duration (s) 72 */ 73 #define POOL_SOLICIT_WINDOW 8 74 75 /* 76 * peer_select groups statistics for a peer used by clock_select() and 77 * clock_cluster(). 78 */ 79 typedef struct peer_select_tag { 80 struct peer * peer; 81 double synch; /* sync distance */ 82 double error; /* jitter */ 83 double seljit; /* selection jitter */ 84 } peer_select; 85 86 /* 87 * System variables are declared here. Unless specified otherwise, all 88 * times are in seconds. 89 */ 90 u_char sys_leap; /* system leap indicator, use set_sys_leap() to change this */ 91 u_char xmt_leap; /* leap indicator sent in client requests, set up by set_sys_leap() */ 92 u_char sys_stratum; /* system stratum */ 93 s_char sys_precision; /* local clock precision (log2 s) */ 94 double sys_rootdelay; /* roundtrip delay to primary source */ 95 double sys_rootdisp; /* dispersion to primary source */ 96 u_int32 sys_refid; /* reference id (network byte order) */ 97 l_fp sys_reftime; /* last update time */ 98 struct peer *sys_peer; /* current peer */ 99 100 #ifdef LEAP_SMEAR 101 struct leap_smear_info leap_smear; 102 #endif 103 int leap_sec_in_progress; 104 105 /* 106 * Rate controls. Leaky buckets are used to throttle the packet 107 * transmission rates in order to protect busy servers such as at NIST 108 * and USNO. There is a counter for each association and another for KoD 109 * packets. The association counter decrements each second, but not 110 * below zero. Each time a packet is sent the counter is incremented by 111 * a configurable value representing the average interval between 112 * packets. A packet is delayed as long as the counter is greater than 113 * zero. Note this does not affect the time value computations. 114 */ 115 /* 116 * Nonspecified system state variables 117 */ 118 int sys_bclient; /* broadcast client enable */ 119 double sys_bdelay; /* broadcast client default delay */ 120 int sys_authenticate; /* requre authentication for config */ 121 l_fp sys_authdelay; /* authentication delay */ 122 double sys_offset; /* current local clock offset */ 123 double sys_mindisp = MINDISPERSE; /* minimum distance (s) */ 124 double sys_maxdist = MAXDISTANCE; /* selection threshold */ 125 double sys_jitter; /* system jitter */ 126 u_long sys_epoch; /* last clock update time */ 127 static double sys_clockhop; /* clockhop threshold */ 128 static int leap_vote_ins; /* leap consensus for insert */ 129 static int leap_vote_del; /* leap consensus for delete */ 130 keyid_t sys_private; /* private value for session seed */ 131 int sys_manycastserver; /* respond to manycast client pkts */ 132 int ntp_mode7; /* respond to ntpdc (mode7) */ 133 int peer_ntpdate; /* active peers in ntpdate mode */ 134 int sys_survivors; /* truest of the truechimers */ 135 char *sys_ident = NULL; /* identity scheme */ 136 137 /* 138 * TOS and multicast mapping stuff 139 */ 140 int sys_floor = 0; /* cluster stratum floor */ 141 u_char sys_bcpollbstep = 0; /* Broadcast Poll backstep gate */ 142 int sys_ceiling = STRATUM_UNSPEC - 1; /* cluster stratum ceiling */ 143 int sys_minsane = 1; /* minimum candidates */ 144 int sys_minclock = NTP_MINCLOCK; /* minimum candidates */ 145 int sys_maxclock = NTP_MAXCLOCK; /* maximum candidates */ 146 int sys_cohort = 0; /* cohort switch */ 147 int sys_orphan = STRATUM_UNSPEC + 1; /* orphan stratum */ 148 int sys_orphwait = NTP_ORPHWAIT; /* orphan wait */ 149 int sys_beacon = BEACON; /* manycast beacon interval */ 150 int sys_ttlmax; /* max ttl mapping vector index */ 151 u_char sys_ttl[MAX_TTL]; /* ttl mapping vector */ 152 153 /* 154 * Statistics counters - first the good, then the bad 155 */ 156 u_long sys_stattime; /* elapsed time */ 157 u_long sys_received; /* packets received */ 158 u_long sys_processed; /* packets for this host */ 159 u_long sys_newversion; /* current version */ 160 u_long sys_oldversion; /* old version */ 161 u_long sys_restricted; /* access denied */ 162 u_long sys_badlength; /* bad length or format */ 163 u_long sys_badauth; /* bad authentication */ 164 u_long sys_declined; /* declined */ 165 u_long sys_limitrejected; /* rate exceeded */ 166 u_long sys_kodsent; /* KoD sent */ 167 168 /* 169 * Mechanism knobs: how soon do we peer_clear() or unpeer()? 170 * 171 * The default way is "on-receipt". If this was a packet from a 172 * well-behaved source, on-receipt will offer the fastest recovery. 173 * If this was from a DoS attack, the default way makes it easier 174 * for a bad-guy to DoS us. So look and see what bites you harder 175 * and choose according to your environment. 176 */ 177 int peer_clear_digest_early = 1; /* bad digest (TEST5) and Autokey */ 178 int unpeer_crypto_early = 1; /* bad crypto (TEST9) */ 179 int unpeer_crypto_nak_early = 1; /* crypto_NAK (TEST5) */ 180 int unpeer_digest_early = 1; /* bad digest (TEST5) */ 181 182 int dynamic_interleave = DYNAMIC_INTERLEAVE; /* Bug 2978 mitigation */ 183 184 int kiss_code_check(u_char hisleap, u_char hisstratum, u_char hismode, u_int32 refid); 185 enum nak_error_codes valid_NAK(struct peer *peer, struct recvbuf *rbufp, u_char hismode); 186 static double root_distance (struct peer *); 187 static void clock_combine (peer_select *, int, int); 188 static void peer_xmit (struct peer *); 189 static void fast_xmit (struct recvbuf *, int, keyid_t, int); 190 static void pool_xmit (struct peer *); 191 static void clock_update (struct peer *); 192 static void measure_precision(void); 193 static double measure_tick_fuzz(void); 194 static int local_refid (struct peer *); 195 static int peer_unfit (struct peer *); 196 #ifdef AUTOKEY 197 static int group_test (char *, char *); 198 #endif /* AUTOKEY */ 199 #ifdef WORKER 200 void pool_name_resolved (int, int, void *, const char *, 201 const char *, const struct addrinfo *, 202 const struct addrinfo *); 203 #endif /* WORKER */ 204 205 const char * amtoa (int am); 206 207 208 void 209 set_sys_leap( 210 u_char new_sys_leap 211 ) 212 { 213 sys_leap = new_sys_leap; 214 xmt_leap = sys_leap; 215 216 /* 217 * Under certain conditions we send faked leap bits to clients, so 218 * eventually change xmt_leap below, but never change LEAP_NOTINSYNC. 219 */ 220 if (xmt_leap != LEAP_NOTINSYNC) { 221 if (leap_sec_in_progress) { 222 /* always send "not sync" */ 223 xmt_leap = LEAP_NOTINSYNC; 224 } 225 #ifdef LEAP_SMEAR 226 else { 227 /* 228 * If leap smear is enabled in general we must 229 * never send a leap second warning to clients, 230 * so make sure we only send "in sync". 231 */ 232 if (leap_smear.enabled) 233 xmt_leap = LEAP_NOWARNING; 234 } 235 #endif /* LEAP_SMEAR */ 236 } 237 } 238 239 240 /* 241 * Kiss Code check 242 */ 243 int 244 kiss_code_check( 245 u_char hisleap, 246 u_char hisstratum, 247 u_char hismode, 248 u_int32 refid 249 ) 250 { 251 252 if ( hismode == MODE_SERVER 253 && hisleap == LEAP_NOTINSYNC 254 && hisstratum == STRATUM_UNSPEC) { 255 if(memcmp(&refid,"RATE", 4) == 0) { 256 return (RATEKISS); 257 } else if(memcmp(&refid,"DENY", 4) == 0) { 258 return (DENYKISS); 259 } else if(memcmp(&refid,"RSTR", 4) == 0) { 260 return (RSTRKISS); 261 } else if(memcmp(&refid,"X", 1) == 0) { 262 return (XKISS); 263 } else { 264 return (UNKNOWNKISS); 265 } 266 } else { 267 return (NOKISS); 268 } 269 } 270 271 272 /* 273 * Check that NAK is valid 274 */ 275 enum nak_error_codes 276 valid_NAK( 277 struct peer *peer, 278 struct recvbuf *rbufp, 279 u_char hismode 280 ) 281 { 282 int base_packet_length = MIN_V4_PKT_LEN; 283 int remainder_size; 284 struct pkt * rpkt; 285 int keyid; 286 l_fp p_org; /* origin timestamp */ 287 const l_fp * myorg; /* selected peer origin */ 288 289 /* 290 * Check to see if there is something beyond the basic packet 291 */ 292 if (rbufp->recv_length == base_packet_length) { 293 return NONAK; 294 } 295 296 remainder_size = rbufp->recv_length - base_packet_length; 297 /* 298 * Is this a potential NAK? 299 */ 300 if (remainder_size != 4) { 301 return NONAK; 302 } 303 304 /* 305 * Only server responses can contain NAK's 306 */ 307 308 if (hismode != MODE_SERVER && 309 hismode != MODE_ACTIVE && 310 hismode != MODE_PASSIVE 311 ) { 312 return INVALIDNAK; 313 } 314 315 /* 316 * Make sure that the extra field in the packet is all zeros 317 */ 318 rpkt = &rbufp->recv_pkt; 319 keyid = ntohl(((u_int32 *)rpkt)[base_packet_length / 4]); 320 if (keyid != 0) { 321 return INVALIDNAK; 322 } 323 324 /* 325 * Only valid if peer uses a key 326 */ 327 if (!peer || !peer->keyid || !(peer->flags & FLAG_SKEY)) { 328 return INVALIDNAK; 329 } 330 331 /* 332 * The ORIGIN must match, or this cannot be a valid NAK, either. 333 */ 334 NTOHL_FP(&rpkt->org, &p_org); 335 if (peer->flip > 0) 336 myorg = &peer->borg; 337 else 338 myorg = &peer->aorg; 339 340 if (L_ISZERO(&p_org) || 341 L_ISZERO( myorg) || 342 !L_ISEQU(&p_org, myorg)) { 343 return INVALIDNAK; 344 } 345 346 /* If we ever passed all that checks, we should be safe. Well, 347 * as safe as we can ever be with an unauthenticated crypto-nak. 348 */ 349 return VALIDNAK; 350 } 351 352 353 /* 354 * transmit - transmit procedure called by poll timeout 355 */ 356 void 357 transmit( 358 struct peer *peer /* peer structure pointer */ 359 ) 360 { 361 u_char hpoll; 362 363 /* 364 * The polling state machine. There are two kinds of machines, 365 * those that never expect a reply (broadcast and manycast 366 * server modes) and those that do (all other modes). The dance 367 * is intricate... 368 */ 369 hpoll = peer->hpoll; 370 371 /* 372 * In broadcast mode the poll interval is never changed from 373 * minpoll. 374 */ 375 if (peer->cast_flags & (MDF_BCAST | MDF_MCAST)) { 376 peer->outdate = current_time; 377 if (sys_leap != LEAP_NOTINSYNC) 378 peer_xmit(peer); 379 poll_update(peer, hpoll); 380 return; 381 } 382 383 /* 384 * In manycast mode we start with unity ttl. The ttl is 385 * increased by one for each poll until either sys_maxclock 386 * servers have been found or the maximum ttl is reached. When 387 * sys_maxclock servers are found we stop polling until one or 388 * more servers have timed out or until less than sys_minclock 389 * associations turn up. In this case additional better servers 390 * are dragged in and preempt the existing ones. Once every 391 * sys_beacon seconds we are to transmit unconditionally, but 392 * this code is not quite right -- peer->unreach counts polls 393 * and is being compared with sys_beacon, so the beacons happen 394 * every sys_beacon polls. 395 */ 396 if (peer->cast_flags & MDF_ACAST) { 397 peer->outdate = current_time; 398 if (peer->unreach > sys_beacon) { 399 peer->unreach = 0; 400 peer->ttl = 0; 401 peer_xmit(peer); 402 } else if ( sys_survivors < sys_minclock 403 || peer_associations < sys_maxclock) { 404 if (peer->ttl < (u_int32)sys_ttlmax) 405 peer->ttl++; 406 peer_xmit(peer); 407 } 408 peer->unreach++; 409 poll_update(peer, hpoll); 410 return; 411 } 412 413 /* 414 * Pool associations transmit unicast solicitations when there 415 * are less than a hard limit of 2 * sys_maxclock associations, 416 * and either less than sys_minclock survivors or less than 417 * sys_maxclock associations. The hard limit prevents unbounded 418 * growth in associations if the system clock or network quality 419 * result in survivor count dipping below sys_minclock often. 420 * This was observed testing with pool, where sys_maxclock == 12 421 * resulted in 60 associations without the hard limit. A 422 * similar hard limit on manycastclient ephemeral associations 423 * may be appropriate. 424 */ 425 if (peer->cast_flags & MDF_POOL) { 426 peer->outdate = current_time; 427 if ( (peer_associations <= 2 * sys_maxclock) 428 && ( peer_associations < sys_maxclock 429 || sys_survivors < sys_minclock)) 430 pool_xmit(peer); 431 poll_update(peer, hpoll); 432 return; 433 } 434 435 /* 436 * In unicast modes the dance is much more intricate. It is 437 * designed to back off whenever possible to minimize network 438 * traffic. 439 */ 440 if (peer->burst == 0) { 441 u_char oreach; 442 443 /* 444 * Update the reachability status. If not heard for 445 * three consecutive polls, stuff infinity in the clock 446 * filter. 447 */ 448 oreach = peer->reach; 449 peer->outdate = current_time; 450 peer->unreach++; 451 peer->reach <<= 1; 452 if (!peer->reach) { 453 454 /* 455 * Here the peer is unreachable. If it was 456 * previously reachable raise a trap. Send a 457 * burst if enabled. 458 */ 459 clock_filter(peer, 0., 0., MAXDISPERSE); 460 if (oreach) { 461 peer_unfit(peer); 462 report_event(PEVNT_UNREACH, peer, NULL); 463 } 464 if ( (peer->flags & FLAG_IBURST) 465 && peer->retry == 0) 466 peer->retry = NTP_RETRY; 467 } else { 468 469 /* 470 * Here the peer is reachable. Send a burst if 471 * enabled and the peer is fit. Reset unreach 472 * for persistent and ephemeral associations. 473 * Unreach is also reset for survivors in 474 * clock_select(). 475 */ 476 hpoll = sys_poll; 477 if (!(peer->flags & FLAG_PREEMPT)) 478 peer->unreach = 0; 479 if ( (peer->flags & FLAG_BURST) 480 && peer->retry == 0 481 && !peer_unfit(peer)) 482 peer->retry = NTP_RETRY; 483 } 484 485 /* 486 * Watch for timeout. If ephemeral, toss the rascal; 487 * otherwise, bump the poll interval. Note the 488 * poll_update() routine will clamp it to maxpoll. 489 * If preemptible and we have more peers than maxclock, 490 * and this peer has the minimum score of preemptibles, 491 * demobilize. 492 */ 493 if (peer->unreach >= NTP_UNREACH) { 494 hpoll++; 495 /* ephemeral: no FLAG_CONFIG nor FLAG_PREEMPT */ 496 if (!(peer->flags & (FLAG_CONFIG | FLAG_PREEMPT))) { 497 report_event(PEVNT_RESTART, peer, "timeout"); 498 peer_clear(peer, "TIME"); 499 unpeer(peer); 500 return; 501 } 502 if ( (peer->flags & FLAG_PREEMPT) 503 && (peer_associations > sys_maxclock) 504 && score_all(peer)) { 505 report_event(PEVNT_RESTART, peer, "timeout"); 506 peer_clear(peer, "TIME"); 507 unpeer(peer); 508 return; 509 } 510 } 511 } else { 512 peer->burst--; 513 if (peer->burst == 0) { 514 515 /* 516 * If ntpdate mode and the clock has not been 517 * set and all peers have completed the burst, 518 * we declare a successful failure. 519 */ 520 if (mode_ntpdate) { 521 peer_ntpdate--; 522 if (peer_ntpdate == 0) { 523 msyslog(LOG_NOTICE, 524 "ntpd: no servers found"); 525 if (!msyslog_term) 526 printf( 527 "ntpd: no servers found\n"); 528 exit (0); 529 } 530 } 531 } 532 } 533 if (peer->retry > 0) 534 peer->retry--; 535 536 /* 537 * Do not transmit if in broadcast client mode. 538 */ 539 if (peer->hmode != MODE_BCLIENT) 540 peer_xmit(peer); 541 poll_update(peer, hpoll); 542 543 return; 544 } 545 546 547 const char * 548 amtoa( 549 int am 550 ) 551 { 552 char *bp; 553 554 switch(am) { 555 case AM_ERR: return "AM_ERR"; 556 case AM_NOMATCH: return "AM_NOMATCH"; 557 case AM_PROCPKT: return "AM_PROCPKT"; 558 case AM_BCST: return "AM_BCST"; 559 case AM_FXMIT: return "AM_FXMIT"; 560 case AM_MANYCAST: return "AM_MANYCAST"; 561 case AM_NEWPASS: return "AM_NEWPASS"; 562 case AM_NEWBCL: return "AM_NEWBCL"; 563 case AM_POSSBCL: return "AM_POSSBCL"; 564 default: 565 LIB_GETBUF(bp); 566 snprintf(bp, LIB_BUFLENGTH, "AM_#%d", am); 567 return bp; 568 } 569 } 570 571 572 /* 573 * receive - receive procedure called for each packet received 574 */ 575 void 576 receive( 577 struct recvbuf *rbufp 578 ) 579 { 580 register struct peer *peer; /* peer structure pointer */ 581 register struct pkt *pkt; /* receive packet pointer */ 582 u_char hisversion; /* packet version */ 583 u_char hisleap; /* packet leap indicator */ 584 u_char hismode; /* packet mode */ 585 u_char hisstratum; /* packet stratum */ 586 u_short restrict_mask; /* restrict bits */ 587 const char *hm_str; /* hismode string */ 588 const char *am_str; /* association match string */ 589 int kissCode = NOKISS; /* Kiss Code */ 590 int has_mac; /* length of MAC field */ 591 int authlen; /* offset of MAC field */ 592 int is_authentic = AUTH_NONE; /* cryptosum ok */ 593 int crypto_nak_test; /* result of crypto-NAK check */ 594 int retcode = AM_NOMATCH; /* match code */ 595 keyid_t skeyid = 0; /* key IDs */ 596 u_int32 opcode = 0; /* extension field opcode */ 597 sockaddr_u *dstadr_sin; /* active runway */ 598 struct peer *peer2; /* aux peer structure pointer */ 599 endpt *match_ep; /* newpeer() local address */ 600 l_fp p_org; /* origin timestamp */ 601 l_fp p_rec; /* receive timestamp */ 602 l_fp p_xmt; /* transmit timestamp */ 603 #ifdef AUTOKEY 604 char hostname[NTP_MAXSTRLEN + 1]; 605 char *groupname = NULL; 606 struct autokey *ap; /* autokey structure pointer */ 607 int rval; /* cookie snatcher */ 608 keyid_t pkeyid = 0, tkeyid = 0; /* key IDs */ 609 #endif /* AUTOKEY */ 610 #ifdef HAVE_NTP_SIGND 611 static unsigned char zero_key[16]; 612 #endif /* HAVE_NTP_SIGND */ 613 614 /* 615 * Monitor the packet and get restrictions. Note that the packet 616 * length for control and private mode packets must be checked 617 * by the service routines. Some restrictions have to be handled 618 * later in order to generate a kiss-o'-death packet. 619 */ 620 /* 621 * Bogus port check is before anything, since it probably 622 * reveals a clogging attack. 623 */ 624 sys_received++; 625 if (0 == SRCPORT(&rbufp->recv_srcadr)) { 626 sys_badlength++; 627 return; /* bogus port */ 628 } 629 restrict_mask = restrictions(&rbufp->recv_srcadr); 630 pkt = &rbufp->recv_pkt; 631 DPRINTF(2, ("receive: at %ld %s<-%s flags %x restrict %03x org %#010x.%08x xmt %#010x.%08x\n", 632 current_time, stoa(&rbufp->dstadr->sin), 633 stoa(&rbufp->recv_srcadr), rbufp->dstadr->flags, 634 restrict_mask, ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf), 635 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf))); 636 hisversion = PKT_VERSION(pkt->li_vn_mode); 637 hisleap = PKT_LEAP(pkt->li_vn_mode); 638 hismode = (int)PKT_MODE(pkt->li_vn_mode); 639 hisstratum = PKT_TO_STRATUM(pkt->stratum); 640 INSIST(0 != hisstratum); 641 642 if (restrict_mask & RES_IGNORE) { 643 sys_restricted++; 644 return; /* ignore everything */ 645 } 646 if (hismode == MODE_PRIVATE) { 647 if (!ntp_mode7 || (restrict_mask & RES_NOQUERY)) { 648 sys_restricted++; 649 return; /* no query private */ 650 } 651 process_private(rbufp, ((restrict_mask & 652 RES_NOMODIFY) == 0)); 653 return; 654 } 655 if (hismode == MODE_CONTROL) { 656 if (restrict_mask & RES_NOQUERY) { 657 sys_restricted++; 658 return; /* no query control */ 659 } 660 process_control(rbufp, restrict_mask); 661 return; 662 } 663 if (restrict_mask & RES_DONTSERVE) { 664 sys_restricted++; 665 return; /* no time serve */ 666 } 667 668 /* 669 * This is for testing. If restricted drop ten percent of 670 * surviving packets. 671 */ 672 if (restrict_mask & RES_FLAKE) { 673 if ((double)ntp_random() / 0x7fffffff < .1) { 674 sys_restricted++; 675 return; /* no flakeway */ 676 } 677 } 678 679 /* 680 * Version check must be after the query packets, since they 681 * intentionally use an early version. 682 */ 683 if (hisversion == NTP_VERSION) { 684 sys_newversion++; /* new version */ 685 } else if ( !(restrict_mask & RES_VERSION) 686 && hisversion >= NTP_OLDVERSION) { 687 sys_oldversion++; /* previous version */ 688 } else { 689 sys_badlength++; 690 return; /* old version */ 691 } 692 693 /* 694 * Figure out his mode and validate the packet. This has some 695 * legacy raunch that probably should be removed. In very early 696 * NTP versions mode 0 was equivalent to what later versions 697 * would interpret as client mode. 698 */ 699 if (hismode == MODE_UNSPEC) { 700 if (hisversion == NTP_OLDVERSION) { 701 hismode = MODE_CLIENT; 702 } else { 703 sys_badlength++; 704 return; /* invalid mode */ 705 } 706 } 707 708 /* 709 * Parse the extension field if present. We figure out whether 710 * an extension field is present by measuring the MAC size. If 711 * the number of words following the packet header is 0, no MAC 712 * is present and the packet is not authenticated. If 1, the 713 * packet is a crypto-NAK; if 3, the packet is authenticated 714 * with DES; if 5, the packet is authenticated with MD5; if 6, 715 * the packet is authenticated with SHA. If 2 or * 4, the packet 716 * is a runt and discarded forthwith. If greater than 6, an 717 * extension field is present, so we subtract the length of the 718 * field and go around again. 719 */ 720 721 authlen = LEN_PKT_NOMAC; 722 has_mac = rbufp->recv_length - authlen; 723 while (has_mac > 0) { 724 u_int32 len; 725 #ifdef AUTOKEY 726 u_int32 hostlen; 727 struct exten *ep; 728 #endif /*AUTOKEY */ 729 730 if (has_mac % 4 != 0 || has_mac < (int)MIN_MAC_LEN) { 731 sys_badlength++; 732 return; /* bad length */ 733 } 734 if (has_mac <= (int)MAX_MAC_LEN) { 735 skeyid = ntohl(((u_int32 *)pkt)[authlen / 4]); 736 break; 737 738 } else { 739 opcode = ntohl(((u_int32 *)pkt)[authlen / 4]); 740 len = opcode & 0xffff; 741 if ( len % 4 != 0 742 || len < 4 743 || (int)len + authlen > rbufp->recv_length) { 744 sys_badlength++; 745 return; /* bad length */ 746 } 747 #ifdef AUTOKEY 748 /* 749 * Extract calling group name for later. If 750 * sys_groupname is non-NULL, there must be 751 * a group name provided to elicit a response. 752 */ 753 if ( (opcode & 0x3fff0000) == CRYPTO_ASSOC 754 && sys_groupname != NULL) { 755 ep = (struct exten *)&((u_int32 *)pkt)[authlen / 4]; 756 hostlen = ntohl(ep->vallen); 757 if ( hostlen >= sizeof(hostname) 758 || hostlen > len - 759 offsetof(struct exten, pkt)) { 760 sys_badlength++; 761 return; /* bad length */ 762 } 763 memcpy(hostname, &ep->pkt, hostlen); 764 hostname[hostlen] = '\0'; 765 groupname = strchr(hostname, '@'); 766 if (groupname == NULL) { 767 sys_declined++; 768 return; 769 } 770 groupname++; 771 } 772 #endif /* AUTOKEY */ 773 authlen += len; 774 has_mac -= len; 775 } 776 } 777 778 /* 779 * If has_mac is < 0 we had a malformed packet. 780 */ 781 if (has_mac < 0) { 782 sys_badlength++; 783 return; /* bad length */ 784 } 785 786 /* 787 * If authentication required, a MAC must be present. 788 */ 789 if (restrict_mask & RES_DONTTRUST && has_mac == 0) { 790 sys_restricted++; 791 return; /* access denied */ 792 } 793 794 /* 795 * Update the MRU list and finger the cloggers. It can be a 796 * little expensive, so turn it off for production use. 797 * RES_LIMITED and RES_KOD will be cleared in the returned 798 * restrict_mask unless one or both actions are warranted. 799 */ 800 restrict_mask = ntp_monitor(rbufp, restrict_mask); 801 if (restrict_mask & RES_LIMITED) { 802 sys_limitrejected++; 803 if ( !(restrict_mask & RES_KOD) 804 || MODE_BROADCAST == hismode 805 || MODE_SERVER == hismode) { 806 if (MODE_SERVER == hismode) 807 DPRINTF(1, ("Possibly self-induced rate limiting of MODE_SERVER from %s\n", 808 stoa(&rbufp->recv_srcadr))); 809 return; /* rate exceeded */ 810 } 811 if (hismode == MODE_CLIENT) 812 fast_xmit(rbufp, MODE_SERVER, skeyid, 813 restrict_mask); 814 else 815 fast_xmit(rbufp, MODE_ACTIVE, skeyid, 816 restrict_mask); 817 return; /* rate exceeded */ 818 } 819 restrict_mask &= ~RES_KOD; 820 821 /* 822 * We have tossed out as many buggy packets as possible early in 823 * the game to reduce the exposure to a clogging attack. Now we 824 * have to burn some cycles to find the association and 825 * authenticate the packet if required. Note that we burn only 826 * digest cycles, again to reduce exposure. There may be no 827 * matching association and that's okay. 828 * 829 * More on the autokey mambo. Normally the local interface is 830 * found when the association was mobilized with respect to a 831 * designated remote address. We assume packets arriving from 832 * the remote address arrive via this interface and the local 833 * address used to construct the autokey is the unicast address 834 * of the interface. However, if the sender is a broadcaster, 835 * the interface broadcast address is used instead. 836 * Notwithstanding this technobabble, if the sender is a 837 * multicaster, the broadcast address is null, so we use the 838 * unicast address anyway. Don't ask. 839 */ 840 peer = findpeer(rbufp, hismode, &retcode); 841 dstadr_sin = &rbufp->dstadr->sin; 842 NTOHL_FP(&pkt->org, &p_org); 843 NTOHL_FP(&pkt->rec, &p_rec); 844 NTOHL_FP(&pkt->xmt, &p_xmt); 845 hm_str = modetoa(hismode); 846 am_str = amtoa(retcode); 847 848 /* 849 * Authentication is conditioned by three switches: 850 * 851 * NOPEER (RES_NOPEER) do not mobilize an association unless 852 * authenticated 853 * NOTRUST (RES_DONTTRUST) do not allow access unless 854 * authenticated (implies NOPEER) 855 * enable (sys_authenticate) master NOPEER switch, by default 856 * on 857 * 858 * The NOPEER and NOTRUST can be specified on a per-client basis 859 * using the restrict command. The enable switch if on implies 860 * NOPEER for all clients. There are four outcomes: 861 * 862 * NONE The packet has no MAC. 863 * OK the packet has a MAC and authentication succeeds 864 * ERROR the packet has a MAC and authentication fails 865 * CRYPTO crypto-NAK. The MAC has four octets only. 866 * 867 * Note: The AUTH(x, y) macro is used to filter outcomes. If x 868 * is zero, acceptable outcomes of y are NONE and OK. If x is 869 * one, the only acceptable outcome of y is OK. 870 */ 871 crypto_nak_test = valid_NAK(peer, rbufp, hismode); 872 873 /* 874 * Drop any invalid crypto-NAKs 875 */ 876 if (crypto_nak_test == INVALIDNAK) { 877 report_event(PEVNT_AUTH, peer, "Invalid_NAK"); 878 if (0 != peer) { 879 peer->badNAK++; 880 } 881 msyslog(LOG_ERR, "Invalid-NAK error at %ld %s<-%s", 882 current_time, stoa(dstadr_sin), stoa(&rbufp->recv_srcadr)); 883 return; 884 } 885 886 if (has_mac == 0) { 887 restrict_mask &= ~RES_MSSNTP; 888 is_authentic = AUTH_NONE; /* not required */ 889 DPRINTF(2, ("receive: at %ld %s<-%s mode %d/%s:%s len %d org %#010x.%08x xmt %#010x.%08x NOMAC\n", 890 current_time, stoa(dstadr_sin), 891 stoa(&rbufp->recv_srcadr), hismode, hm_str, am_str, 892 authlen, 893 ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf), 894 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf))); 895 } else if (crypto_nak_test == VALIDNAK) { 896 restrict_mask &= ~RES_MSSNTP; 897 is_authentic = AUTH_CRYPTO; /* crypto-NAK */ 898 DPRINTF(2, ("receive: at %ld %s<-%s mode %d/%s:%s keyid %08x len %d auth %d org %#010x.%08x xmt %#010x.%08x MAC4\n", 899 current_time, stoa(dstadr_sin), 900 stoa(&rbufp->recv_srcadr), hismode, hm_str, am_str, 901 skeyid, authlen + has_mac, is_authentic, 902 ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf), 903 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf))); 904 905 #ifdef HAVE_NTP_SIGND 906 /* 907 * If the signature is 20 bytes long, the last 16 of 908 * which are zero, then this is a Microsoft client 909 * wanting AD-style authentication of the server's 910 * reply. 911 * 912 * This is described in Microsoft's WSPP docs, in MS-SNTP: 913 * http://msdn.microsoft.com/en-us/library/cc212930.aspx 914 */ 915 } else if ( has_mac == MAX_MD5_LEN 916 && (restrict_mask & RES_MSSNTP) 917 && (retcode == AM_FXMIT || retcode == AM_NEWPASS) 918 && (memcmp(zero_key, (char *)pkt + authlen + 4, 919 MAX_MD5_LEN - 4) == 0)) { 920 is_authentic = AUTH_NONE; 921 #endif /* HAVE_NTP_SIGND */ 922 923 } else { 924 restrict_mask &= ~RES_MSSNTP; 925 #ifdef AUTOKEY 926 /* 927 * For autokey modes, generate the session key 928 * and install in the key cache. Use the socket 929 * broadcast or unicast address as appropriate. 930 */ 931 if (crypto_flags && skeyid > NTP_MAXKEY) { 932 933 /* 934 * More on the autokey dance (AKD). A cookie is 935 * constructed from public and private values. 936 * For broadcast packets, the cookie is public 937 * (zero). For packets that match no 938 * association, the cookie is hashed from the 939 * addresses and private value. For server 940 * packets, the cookie was previously obtained 941 * from the server. For symmetric modes, the 942 * cookie was previously constructed using an 943 * agreement protocol; however, should PKI be 944 * unavailable, we construct a fake agreement as 945 * the EXOR of the peer and host cookies. 946 * 947 * hismode ephemeral persistent 948 * ======================================= 949 * active 0 cookie# 950 * passive 0% cookie# 951 * client sys cookie 0% 952 * server 0% sys cookie 953 * broadcast 0 0 954 * 955 * # if unsync, 0 956 * % can't happen 957 */ 958 if (has_mac < (int)MAX_MD5_LEN) { 959 sys_badauth++; 960 return; 961 } 962 if (hismode == MODE_BROADCAST) { 963 964 /* 965 * For broadcaster, use the interface 966 * broadcast address when available; 967 * otherwise, use the unicast address 968 * found when the association was 969 * mobilized. However, if this is from 970 * the wildcard interface, game over. 971 */ 972 if ( crypto_flags 973 && rbufp->dstadr == 974 ANY_INTERFACE_CHOOSE(&rbufp->recv_srcadr)) { 975 sys_restricted++; 976 return; /* no wildcard */ 977 } 978 pkeyid = 0; 979 if (!SOCK_UNSPEC(&rbufp->dstadr->bcast)) 980 dstadr_sin = 981 &rbufp->dstadr->bcast; 982 } else if (peer == NULL) { 983 pkeyid = session_key( 984 &rbufp->recv_srcadr, dstadr_sin, 0, 985 sys_private, 0); 986 } else { 987 pkeyid = peer->pcookie; 988 } 989 990 /* 991 * The session key includes both the public 992 * values and cookie. In case of an extension 993 * field, the cookie used for authentication 994 * purposes is zero. Note the hash is saved for 995 * use later in the autokey mambo. 996 */ 997 if (authlen > (int)LEN_PKT_NOMAC && pkeyid != 0) { 998 session_key(&rbufp->recv_srcadr, 999 dstadr_sin, skeyid, 0, 2); 1000 tkeyid = session_key( 1001 &rbufp->recv_srcadr, dstadr_sin, 1002 skeyid, pkeyid, 0); 1003 } else { 1004 tkeyid = session_key( 1005 &rbufp->recv_srcadr, dstadr_sin, 1006 skeyid, pkeyid, 2); 1007 } 1008 1009 } 1010 #endif /* AUTOKEY */ 1011 1012 /* 1013 * Compute the cryptosum. Note a clogging attack may 1014 * succeed in bloating the key cache. If an autokey, 1015 * purge it immediately, since we won't be needing it 1016 * again. If the packet is authentic, it can mobilize an 1017 * association. Note that there is no key zero. 1018 */ 1019 if (!authdecrypt(skeyid, (u_int32 *)pkt, authlen, 1020 has_mac)) 1021 is_authentic = AUTH_ERROR; 1022 else 1023 is_authentic = AUTH_OK; 1024 #ifdef AUTOKEY 1025 if (crypto_flags && skeyid > NTP_MAXKEY) 1026 authtrust(skeyid, 0); 1027 #endif /* AUTOKEY */ 1028 DPRINTF(2, ("receive: at %ld %s<-%s mode %d/%s:%s keyid %08x len %d auth %d org %#010x.%08x xmt %#010x.%08x\n", 1029 current_time, stoa(dstadr_sin), 1030 stoa(&rbufp->recv_srcadr), hismode, hm_str, am_str, 1031 skeyid, authlen + has_mac, is_authentic, 1032 ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf), 1033 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf))); 1034 } 1035 1036 /* 1037 * The association matching rules are implemented by a set of 1038 * routines and an association table. A packet matching an 1039 * association is processed by the peer process for that 1040 * association. If there are no errors, an ephemeral association 1041 * is mobilized: a broadcast packet mobilizes a broadcast client 1042 * aassociation; a manycast server packet mobilizes a manycast 1043 * client association; a symmetric active packet mobilizes a 1044 * symmetric passive association. 1045 */ 1046 switch (retcode) { 1047 1048 /* 1049 * This is a client mode packet not matching any association. If 1050 * an ordinary client, simply toss a server mode packet back 1051 * over the fence. If a manycast client, we have to work a 1052 * little harder. 1053 */ 1054 case AM_FXMIT: 1055 1056 /* 1057 * If authentication OK, send a server reply; otherwise, 1058 * send a crypto-NAK. 1059 */ 1060 if (!(rbufp->dstadr->flags & INT_MCASTOPEN)) { 1061 if (AUTH(restrict_mask & RES_DONTTRUST, 1062 is_authentic)) { 1063 fast_xmit(rbufp, MODE_SERVER, skeyid, 1064 restrict_mask); 1065 } else if (is_authentic == AUTH_ERROR) { 1066 fast_xmit(rbufp, MODE_SERVER, 0, 1067 restrict_mask); 1068 sys_badauth++; 1069 } else { 1070 sys_restricted++; 1071 } 1072 return; /* hooray */ 1073 } 1074 1075 /* 1076 * This must be manycast. Do not respond if not 1077 * configured as a manycast server. 1078 */ 1079 if (!sys_manycastserver) { 1080 sys_restricted++; 1081 return; /* not enabled */ 1082 } 1083 1084 #ifdef AUTOKEY 1085 /* 1086 * Do not respond if not the same group. 1087 */ 1088 if (group_test(groupname, NULL)) { 1089 sys_declined++; 1090 return; 1091 } 1092 #endif /* AUTOKEY */ 1093 1094 /* 1095 * Do not respond if we are not synchronized or our 1096 * stratum is greater than the manycaster or the 1097 * manycaster has already synchronized to us. 1098 */ 1099 if ( sys_leap == LEAP_NOTINSYNC 1100 || sys_stratum >= hisstratum 1101 || (!sys_cohort && sys_stratum == hisstratum + 1) 1102 || rbufp->dstadr->addr_refid == pkt->refid) { 1103 sys_declined++; 1104 return; /* no help */ 1105 } 1106 1107 /* 1108 * Respond only if authentication succeeds. Don't do a 1109 * crypto-NAK, as that would not be useful. 1110 */ 1111 if (AUTH(restrict_mask & RES_DONTTRUST, is_authentic)) 1112 fast_xmit(rbufp, MODE_SERVER, skeyid, 1113 restrict_mask); 1114 return; /* hooray */ 1115 1116 /* 1117 * This is a server mode packet returned in response to a client 1118 * mode packet sent to a multicast group address (for 1119 * manycastclient) or to a unicast address (for pool). The 1120 * origin timestamp is a good nonce to reliably associate the 1121 * reply with what was sent. If there is no match, that's 1122 * curious and could be an intruder attempting to clog, so we 1123 * just ignore it. 1124 * 1125 * If the packet is authentic and the manycastclient or pool 1126 * association is found, we mobilize a client association and 1127 * copy pertinent variables from the manycastclient or pool 1128 * association to the new client association. If not, just 1129 * ignore the packet. 1130 * 1131 * There is an implosion hazard at the manycast client, since 1132 * the manycast servers send the server packet immediately. If 1133 * the guy is already here, don't fire up a duplicate. 1134 */ 1135 case AM_MANYCAST: 1136 1137 #ifdef AUTOKEY 1138 /* 1139 * Do not respond if not the same group. 1140 */ 1141 if (group_test(groupname, NULL)) { 1142 sys_declined++; 1143 return; 1144 } 1145 #endif /* AUTOKEY */ 1146 if ((peer2 = findmanycastpeer(rbufp)) == NULL) { 1147 sys_restricted++; 1148 return; /* not enabled */ 1149 } 1150 if (!AUTH( (!(peer2->cast_flags & MDF_POOL) 1151 && sys_authenticate) 1152 || (restrict_mask & (RES_NOPEER | 1153 RES_DONTTRUST)), is_authentic)) { 1154 sys_restricted++; 1155 return; /* access denied */ 1156 } 1157 1158 /* 1159 * Do not respond if unsynchronized or stratum is below 1160 * the floor or at or above the ceiling. 1161 */ 1162 if ( hisleap == LEAP_NOTINSYNC 1163 || hisstratum < sys_floor 1164 || hisstratum >= sys_ceiling) { 1165 sys_declined++; 1166 return; /* no help */ 1167 } 1168 peer = newpeer(&rbufp->recv_srcadr, NULL, rbufp->dstadr, 1169 MODE_CLIENT, hisversion, peer2->minpoll, 1170 peer2->maxpoll, FLAG_PREEMPT | 1171 (FLAG_IBURST & peer2->flags), MDF_UCAST | 1172 MDF_UCLNT, 0, skeyid, sys_ident); 1173 if (NULL == peer) { 1174 sys_declined++; 1175 return; /* ignore duplicate */ 1176 } 1177 1178 /* 1179 * After each ephemeral pool association is spun, 1180 * accelerate the next poll for the pool solicitor so 1181 * the pool will fill promptly. 1182 */ 1183 if (peer2->cast_flags & MDF_POOL) 1184 peer2->nextdate = current_time + 1; 1185 1186 /* 1187 * Further processing of the solicitation response would 1188 * simply detect its origin timestamp as bogus for the 1189 * brand-new association (it matches the prototype 1190 * association) and tinker with peer->nextdate delaying 1191 * first sync. 1192 */ 1193 return; /* solicitation response handled */ 1194 1195 /* 1196 * This is the first packet received from a broadcast server. If 1197 * the packet is authentic and we are enabled as broadcast 1198 * client, mobilize a broadcast client association. We don't 1199 * kiss any frogs here. 1200 */ 1201 case AM_NEWBCL: 1202 1203 #ifdef AUTOKEY 1204 /* 1205 * Do not respond if not the same group. 1206 */ 1207 if (group_test(groupname, sys_ident)) { 1208 sys_declined++; 1209 return; 1210 } 1211 #endif /* AUTOKEY */ 1212 if (sys_bclient == 0) { 1213 sys_restricted++; 1214 return; /* not enabled */ 1215 } 1216 if (!AUTH(sys_authenticate | (restrict_mask & 1217 (RES_NOPEER | RES_DONTTRUST)), is_authentic)) { 1218 sys_restricted++; 1219 return; /* access denied */ 1220 } 1221 1222 /* 1223 * Do not respond if unsynchronized or stratum is below 1224 * the floor or at or above the ceiling. 1225 */ 1226 if ( hisleap == LEAP_NOTINSYNC 1227 || hisstratum < sys_floor 1228 || hisstratum >= sys_ceiling) { 1229 sys_declined++; 1230 return; /* no help */ 1231 } 1232 1233 #ifdef AUTOKEY 1234 /* 1235 * Do not respond if Autokey and the opcode is not a 1236 * CRYPTO_ASSOC response with association ID. 1237 */ 1238 if ( crypto_flags && skeyid > NTP_MAXKEY 1239 && (opcode & 0xffff0000) != (CRYPTO_ASSOC | CRYPTO_RESP)) { 1240 sys_declined++; 1241 return; /* protocol error */ 1242 } 1243 #endif /* AUTOKEY */ 1244 1245 /* 1246 * Broadcasts received via a multicast address may 1247 * arrive after a unicast volley has begun 1248 * with the same remote address. newpeer() will not 1249 * find duplicate associations on other local endpoints 1250 * if a non-NULL endpoint is supplied. multicastclient 1251 * ephemeral associations are unique across all local 1252 * endpoints. 1253 */ 1254 if (!(INT_MCASTOPEN & rbufp->dstadr->flags)) 1255 match_ep = rbufp->dstadr; 1256 else 1257 match_ep = NULL; 1258 1259 /* 1260 * Determine whether to execute the initial volley. 1261 */ 1262 if (sys_bdelay > 0.0) { 1263 #ifdef AUTOKEY 1264 /* 1265 * If a two-way exchange is not possible, 1266 * neither is Autokey. 1267 */ 1268 if (crypto_flags && skeyid > NTP_MAXKEY) { 1269 sys_restricted++; 1270 return; /* no autokey */ 1271 } 1272 #endif /* AUTOKEY */ 1273 1274 /* 1275 * Do not execute the volley. Start out in 1276 * broadcast client mode. 1277 */ 1278 peer = newpeer(&rbufp->recv_srcadr, NULL, 1279 match_ep, MODE_BCLIENT, hisversion, 1280 pkt->ppoll, pkt->ppoll, FLAG_PREEMPT, 1281 MDF_BCLNT, 0, skeyid, sys_ident); 1282 if (NULL == peer) { 1283 sys_restricted++; 1284 return; /* ignore duplicate */ 1285 1286 } else { 1287 peer->delay = sys_bdelay; 1288 peer->bxmt = p_xmt; 1289 } 1290 break; 1291 } 1292 1293 /* 1294 * Execute the initial volley in order to calibrate the 1295 * propagation delay and run the Autokey protocol. 1296 * 1297 * Note that the minpoll is taken from the broadcast 1298 * packet, normally 6 (64 s) and that the poll interval 1299 * is fixed at this value. 1300 */ 1301 peer = newpeer(&rbufp->recv_srcadr, NULL, match_ep, 1302 MODE_CLIENT, hisversion, pkt->ppoll, pkt->ppoll, 1303 FLAG_BC_VOL | FLAG_IBURST | FLAG_PREEMPT, MDF_BCLNT, 1304 0, skeyid, sys_ident); 1305 if (NULL == peer) { 1306 sys_restricted++; 1307 return; /* ignore duplicate */ 1308 } 1309 peer->bxmt = p_xmt; 1310 #ifdef AUTOKEY 1311 if (skeyid > NTP_MAXKEY) 1312 crypto_recv(peer, rbufp); 1313 #endif /* AUTOKEY */ 1314 1315 return; /* hooray */ 1316 1317 /* 1318 * This is the first packet received from a symmetric active 1319 * peer. If the packet is authentic and the first he sent, 1320 * mobilize a passive association. If not, kiss the frog. 1321 */ 1322 case AM_NEWPASS: 1323 1324 #ifdef AUTOKEY 1325 /* 1326 * Do not respond if not the same group. 1327 */ 1328 if (group_test(groupname, sys_ident)) { 1329 sys_declined++; 1330 return; 1331 } 1332 #endif /* AUTOKEY */ 1333 if (!AUTH(sys_authenticate | (restrict_mask & 1334 (RES_NOPEER | RES_DONTTRUST)), is_authentic)) { 1335 1336 /* 1337 * If authenticated but cannot mobilize an 1338 * association, send a symmetric passive 1339 * response without mobilizing an association. 1340 * This is for drat broken Windows clients. See 1341 * Microsoft KB 875424 for preferred workaround. 1342 */ 1343 if (AUTH(restrict_mask & RES_DONTTRUST, 1344 is_authentic)) { 1345 fast_xmit(rbufp, MODE_PASSIVE, skeyid, 1346 restrict_mask); 1347 return; /* hooray */ 1348 } 1349 if (is_authentic == AUTH_ERROR) { 1350 fast_xmit(rbufp, MODE_ACTIVE, 0, 1351 restrict_mask); 1352 sys_restricted++; 1353 return; 1354 } 1355 /* [Bug 2941] 1356 * If we got here, the packet isn't part of an 1357 * existing association, it isn't correctly 1358 * authenticated, and it didn't meet either of 1359 * the previous two special cases so we should 1360 * just drop it on the floor. For example, 1361 * crypto-NAKs (is_authentic == AUTH_CRYPTO) 1362 * will make it this far. This is just 1363 * debug-printed and not logged to avoid log 1364 * flooding. 1365 */ 1366 DPRINTF(2, ("receive: at %ld refusing to mobilize passive association" 1367 " with unknown peer %s mode %d/%s:%s keyid %08x len %d auth %d\n", 1368 current_time, stoa(&rbufp->recv_srcadr), 1369 hismode, hm_str, am_str, skeyid, 1370 (authlen + has_mac), is_authentic)); 1371 sys_declined++; 1372 return; 1373 } 1374 1375 /* 1376 * Do not respond if synchronized and if stratum is 1377 * below the floor or at or above the ceiling. Note, 1378 * this allows an unsynchronized peer to synchronize to 1379 * us. It would be very strange if he did and then was 1380 * nipped, but that could only happen if we were 1381 * operating at the top end of the range. It also means 1382 * we will spin an ephemeral association in response to 1383 * MODE_ACTIVE KoDs, which will time out eventually. 1384 */ 1385 if ( hisleap != LEAP_NOTINSYNC 1386 && (hisstratum < sys_floor || hisstratum >= sys_ceiling)) { 1387 sys_declined++; 1388 return; /* no help */ 1389 } 1390 1391 /* 1392 * The message is correctly authenticated and allowed. 1393 * Mobilize a symmetric passive association. 1394 */ 1395 if ((peer = newpeer(&rbufp->recv_srcadr, NULL, 1396 rbufp->dstadr, MODE_PASSIVE, hisversion, pkt->ppoll, 1397 NTP_MAXDPOLL, 0, MDF_UCAST, 0, skeyid, 1398 sys_ident)) == NULL) { 1399 sys_declined++; 1400 return; /* ignore duplicate */ 1401 } 1402 break; 1403 1404 1405 /* 1406 * Process regular packet. Nothing special. 1407 */ 1408 case AM_PROCPKT: 1409 1410 #ifdef AUTOKEY 1411 /* 1412 * Do not respond if not the same group. 1413 */ 1414 if (group_test(groupname, peer->ident)) { 1415 sys_declined++; 1416 return; 1417 } 1418 #endif /* AUTOKEY */ 1419 1420 if (MODE_BROADCAST == hismode) { 1421 int bail = 0; 1422 l_fp tdiff; 1423 u_long deadband; 1424 1425 DPRINTF(2, ("receive: PROCPKT/BROADCAST: prev pkt %ld seconds ago, ppoll: %d, %d secs\n", 1426 (current_time - peer->timelastrec), 1427 peer->ppoll, (1 << peer->ppoll) 1428 )); 1429 /* Things we can check: 1430 * 1431 * Did the poll interval change? 1432 * Is the poll interval in the packet in-range? 1433 * Did this packet arrive too soon? 1434 * Is the timestamp in this packet monotonic 1435 * with respect to the previous packet? 1436 */ 1437 1438 /* This is noteworthy, not error-worthy */ 1439 if (pkt->ppoll != peer->ppoll) { 1440 msyslog(LOG_INFO, "receive: broadcast poll from %s changed from %ud to %ud", 1441 stoa(&rbufp->recv_srcadr), 1442 peer->ppoll, pkt->ppoll); 1443 } 1444 1445 /* This is error-worthy */ 1446 if (pkt->ppoll < peer->minpoll || 1447 pkt->ppoll > peer->maxpoll ) { 1448 msyslog(LOG_INFO, "receive: broadcast poll of %ud from %s is out-of-range (%d to %d)!", 1449 pkt->ppoll, stoa(&rbufp->recv_srcadr), 1450 peer->minpoll, peer->maxpoll); 1451 ++bail; 1452 } 1453 1454 /* too early? worth an error, too! 1455 * 1456 * [Bug 3113] Ensure that at least one poll 1457 * interval has elapsed since the last **clean** 1458 * packet was received. We limit the check to 1459 * **clean** packets to prevent replayed packets 1460 * and incorrectly authenticated packets, which 1461 * we'll discard, from being used to create a 1462 * denial of service condition. 1463 */ 1464 deadband = (1u << pkt->ppoll); 1465 if (FLAG_BC_VOL & peer->flags) 1466 deadband -= 3; /* allow greater fuzz after volley */ 1467 if ((current_time - peer->timereceived) < deadband) { 1468 msyslog(LOG_INFO, "receive: broadcast packet from %s arrived after %lu, not %lu seconds!", 1469 stoa(&rbufp->recv_srcadr), 1470 (current_time - peer->timereceived), 1471 deadband); 1472 ++bail; 1473 } 1474 1475 /* Alert if time from the server is non-monotonic. 1476 * 1477 * [Bug 3114] is about Broadcast mode replay DoS. 1478 * 1479 * Broadcast mode *assumes* a trusted network. 1480 * Even so, it's nice to be robust in the face 1481 * of attacks. 1482 * 1483 * If we get an authenticated broadcast packet 1484 * with an "earlier" timestamp, it means one of 1485 * two things: 1486 * 1487 * - the broadcast server had a backward step. 1488 * 1489 * - somebody is trying a replay attack. 1490 * 1491 * deadband: By default, we assume the broadcast 1492 * network is trustable, so we take our accepted 1493 * broadcast packets as we receive them. But 1494 * some folks might want to take additional poll 1495 * delays before believing a backward step. 1496 */ 1497 if (sys_bcpollbstep) { 1498 /* pkt->ppoll or peer->ppoll ? */ 1499 deadband = (1u << pkt->ppoll) 1500 * sys_bcpollbstep + 2; 1501 } else { 1502 deadband = 0; 1503 } 1504 1505 if (L_ISZERO(&peer->bxmt)) { 1506 tdiff.l_ui = tdiff.l_uf = 0; 1507 } else { 1508 tdiff = p_xmt; 1509 L_SUB(&tdiff, &peer->bxmt); 1510 } 1511 if (tdiff.l_i < 0 && 1512 (current_time - peer->timereceived) < deadband) 1513 { 1514 msyslog(LOG_INFO, "receive: broadcast packet from %s contains non-monotonic timestamp: %#010x.%08x -> %#010x.%08x", 1515 stoa(&rbufp->recv_srcadr), 1516 peer->bxmt.l_ui, peer->bxmt.l_uf, 1517 p_xmt.l_ui, p_xmt.l_uf 1518 ); 1519 ++bail; 1520 } 1521 1522 if (bail) { 1523 peer->timelastrec = current_time; 1524 sys_declined++; 1525 return; 1526 } 1527 } 1528 1529 break; 1530 1531 /* 1532 * A passive packet matches a passive association. This is 1533 * usually the result of reconfiguring a client on the fly. As 1534 * this association might be legitimate and this packet an 1535 * attempt to deny service, just ignore it. 1536 */ 1537 case AM_ERR: 1538 sys_declined++; 1539 return; 1540 1541 /* 1542 * For everything else there is the bit bucket. 1543 */ 1544 default: 1545 sys_declined++; 1546 return; 1547 } 1548 1549 #ifdef AUTOKEY 1550 /* 1551 * If the association is configured for Autokey, the packet must 1552 * have a public key ID; if not, the packet must have a 1553 * symmetric key ID. 1554 */ 1555 if ( is_authentic != AUTH_CRYPTO 1556 && ( ((peer->flags & FLAG_SKEY) && skeyid <= NTP_MAXKEY) 1557 || (!(peer->flags & FLAG_SKEY) && skeyid > NTP_MAXKEY))) { 1558 sys_badauth++; 1559 return; 1560 } 1561 #endif /* AUTOKEY */ 1562 1563 peer->received++; 1564 peer->flash &= ~PKT_TEST_MASK; 1565 if (peer->flags & FLAG_XBOGUS) { 1566 peer->flags &= ~FLAG_XBOGUS; 1567 peer->flash |= TEST3; 1568 } 1569 1570 /* 1571 * Next comes a rigorous schedule of timestamp checking. If the 1572 * transmit timestamp is zero, the server has not initialized in 1573 * interleaved modes or is horribly broken. 1574 * 1575 * A KoD packet we pay attention to cannot have a 0 transmit 1576 * timestamp. 1577 */ 1578 if (L_ISZERO(&p_xmt)) { 1579 peer->flash |= TEST3; /* unsynch */ 1580 if (STRATUM_UNSPEC == hisstratum) { /* KoD packet */ 1581 peer->bogusorg++; /* for TEST2 or TEST3 */ 1582 msyslog(LOG_INFO, 1583 "receive: Unexpected zero transmit timestamp in KoD from %s", 1584 ntoa(&peer->srcadr)); 1585 return; 1586 } 1587 1588 /* 1589 * If the transmit timestamp duplicates our previous one, the 1590 * packet is a replay. This prevents the bad guys from replaying 1591 * the most recent packet, authenticated or not. 1592 */ 1593 } else if (L_ISEQU(&peer->xmt, &p_xmt)) { 1594 peer->flash |= TEST1; /* duplicate */ 1595 peer->oldpkt++; 1596 return; 1597 1598 /* 1599 * If this is a broadcast mode packet, make sure hisstratum 1600 * is appropriate. Don't do anything else here - we wait to 1601 * see if this is an interleave broadcast packet until after 1602 * we've validated the MAC that SHOULD be provided. 1603 * 1604 * hisstratum should never be 0. 1605 * If hisstratum is 15, then we'll advertise as UNSPEC but 1606 * at least we'll be able to sync with the broadcast server. 1607 */ 1608 } else if (hismode == MODE_BROADCAST) { 1609 if ( 0 == hisstratum 1610 || STRATUM_UNSPEC <= hisstratum) { 1611 /* Is this a ++sys_declined or ??? */ 1612 msyslog(LOG_INFO, 1613 "receive: Unexpected stratum (%d) in broadcast from %s", 1614 hisstratum, ntoa(&peer->srcadr)); 1615 return; 1616 } 1617 1618 /* 1619 * Basic KoD validation checking: 1620 * 1621 * KoD packets are a mixed-blessing. Forged KoD packets 1622 * are DoS attacks. There are rare situations where we might 1623 * get a valid KoD response, though. Since KoD packets are 1624 * a special case that complicate the checks we do next, we 1625 * handle the basic KoD checks here. 1626 * 1627 * Note that we expect the incoming KoD packet to have its 1628 * (nonzero) org, rec, and xmt timestamps set to the xmt timestamp 1629 * that we have previously sent out. Watch interleave mode. 1630 */ 1631 } else if (STRATUM_UNSPEC == hisstratum) { 1632 DEBUG_INSIST(!L_ISZERO(&p_xmt)); 1633 if ( L_ISZERO(&p_org) /* We checked p_xmt above */ 1634 || L_ISZERO(&p_rec)) { 1635 peer->bogusorg++; 1636 msyslog(LOG_INFO, 1637 "receive: KoD packet from %s has a zero org or rec timestamp. Ignoring.", 1638 ntoa(&peer->srcadr)); 1639 return; 1640 } 1641 1642 if ( !L_ISEQU(&p_xmt, &p_org) 1643 || !L_ISEQU(&p_xmt, &p_rec)) { 1644 peer->bogusorg++; 1645 msyslog(LOG_INFO, 1646 "receive: KoD packet from %s has inconsistent xmt/org/rec timestamps. Ignoring.", 1647 ntoa(&peer->srcadr)); 1648 return; 1649 } 1650 1651 /* Be conservative */ 1652 if (peer->flip == 0 && !L_ISEQU(&p_org, &peer->aorg)) { 1653 peer->bogusorg++; 1654 msyslog(LOG_INFO, 1655 "receive: flip 0 KoD origin timestamp %#010x.%08x from %s does not match %#010x.%08x - ignoring.", 1656 p_org.l_ui, p_org.l_uf, 1657 ntoa(&peer->srcadr), 1658 peer->aorg.l_ui, peer->aorg.l_uf); 1659 return; 1660 } else if (peer->flip == 1 && !L_ISEQU(&p_org, &peer->borg)) { 1661 peer->bogusorg++; 1662 msyslog(LOG_INFO, 1663 "receive: flip 1 KoD origin timestamp %#010x.%08x from %s does not match interleave %#010x.%08x - ignoring.", 1664 p_org.l_ui, p_org.l_uf, 1665 ntoa(&peer->srcadr), 1666 peer->borg.l_ui, peer->borg.l_uf); 1667 return; 1668 } 1669 1670 /* 1671 * Basic mode checks: 1672 * 1673 * If there is no origin timestamp, it's either an initial packet 1674 * or we've already received a response to our query. Of course, 1675 * should 'aorg' be all-zero because this really was the original 1676 * transmit timestamp, we'll ignore this reply. There is a window 1677 * of one nanosecond once every 136 years' time where this is 1678 * possible. We currently ignore this situation. 1679 * 1680 * Otherwise, check for bogus packet in basic mode. 1681 * If it is bogus, switch to interleaved mode and resynchronize, 1682 * but only after confirming the packet is not bogus in 1683 * symmetric interleaved mode. 1684 * 1685 * This could also mean somebody is forging packets claiming to 1686 * be from us, attempting to cause our server to KoD us. 1687 */ 1688 } else if (peer->flip == 0) { 1689 INSIST(0 != hisstratum); 1690 INSIST(STRATUM_UNSPEC != hisstratum); 1691 1692 if (0) { 1693 } else if (L_ISZERO(&p_org)) { 1694 char *action; 1695 1696 L_CLR(&peer->aorg); 1697 /**/ 1698 switch (hismode) { 1699 /* We allow 0org for: */ 1700 case UCHAR_MAX: 1701 action = "Allow"; 1702 break; 1703 /* We disallow 0org for: */ 1704 case MODE_UNSPEC: 1705 case MODE_ACTIVE: 1706 case MODE_PASSIVE: 1707 case MODE_CLIENT: 1708 case MODE_SERVER: 1709 case MODE_BROADCAST: 1710 action = "Drop"; 1711 peer->bogusorg++; 1712 peer->flash |= TEST2; /* bogus */ 1713 break; 1714 default: 1715 INSIST(!"receive(): impossible hismode"); 1716 break; 1717 } 1718 /**/ 1719 msyslog(LOG_INFO, 1720 "receive: %s 0 origin timestamp from %s@%s xmt %#010x.%08x", 1721 action, hm_str, ntoa(&peer->srcadr), 1722 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf)); 1723 } else if (!L_ISEQU(&p_org, &peer->aorg)) { 1724 /* are there cases here where we should bail? */ 1725 /* Should we set TEST2 if we decide to try xleave? */ 1726 peer->bogusorg++; 1727 peer->flash |= TEST2; /* bogus */ 1728 msyslog(LOG_INFO, 1729 "receive: Unexpected origin timestamp %#010x.%08x does not match aorg %#010x.%08x from %s@%s xmt %#010x.%08x", 1730 ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf), 1731 peer->aorg.l_ui, peer->aorg.l_uf, 1732 hm_str, ntoa(&peer->srcadr), 1733 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf)); 1734 if ( !L_ISZERO(&peer->dst) 1735 && L_ISEQU(&p_org, &peer->dst)) { 1736 /* Might be the start of an interleave */ 1737 if (dynamic_interleave) { 1738 peer->flip = 1; 1739 report_event(PEVNT_XLEAVE, peer, NULL); 1740 } else { 1741 msyslog(LOG_INFO, 1742 "receive: Dynamic interleave from %s@%s denied", 1743 hm_str, ntoa(&peer->srcadr)); 1744 } 1745 } 1746 } else { 1747 L_CLR(&peer->aorg); 1748 } 1749 1750 /* 1751 * Check for valid nonzero timestamp fields. 1752 */ 1753 } else if ( L_ISZERO(&p_org) 1754 || L_ISZERO(&p_rec) 1755 || L_ISZERO(&peer->dst)) { 1756 peer->flash |= TEST3; /* unsynch */ 1757 1758 /* 1759 * Check for bogus packet in interleaved symmetric mode. This 1760 * can happen if a packet is lost, duplicated or crossed. If 1761 * found, flip and resynchronize. 1762 */ 1763 } else if ( !L_ISZERO(&peer->dst) 1764 && !L_ISEQU(&p_org, &peer->dst)) { 1765 peer->bogusorg++; 1766 peer->flags |= FLAG_XBOGUS; 1767 peer->flash |= TEST2; /* bogus */ 1768 return; /* Bogus packet, we are done */ 1769 } 1770 1771 /**/ 1772 1773 /* 1774 * If this is a crypto_NAK, the server cannot authenticate a 1775 * client packet. The server might have just changed keys. Clear 1776 * the association and restart the protocol. 1777 */ 1778 if (crypto_nak_test == VALIDNAK) { 1779 report_event(PEVNT_AUTH, peer, "crypto_NAK"); 1780 peer->flash |= TEST5; /* bad auth */ 1781 peer->badauth++; 1782 if (peer->flags & FLAG_PREEMPT) { 1783 if (unpeer_crypto_nak_early) { 1784 unpeer(peer); 1785 } 1786 return; 1787 } 1788 #ifdef AUTOKEY 1789 if (peer->crypto) { 1790 peer_clear(peer, "AUTH"); 1791 } 1792 #endif /* AUTOKEY */ 1793 return; 1794 1795 /* 1796 * If the digest fails or it's missing for authenticated 1797 * associations, the client cannot authenticate a server 1798 * reply to a client packet previously sent. The loopback check 1799 * is designed to avoid a bait-and-switch attack, which was 1800 * possible in past versions. If symmetric modes, return a 1801 * crypto-NAK. The peer should restart the protocol. 1802 */ 1803 } else if (!AUTH(peer->keyid || has_mac || 1804 (restrict_mask & RES_DONTTRUST), is_authentic)) { 1805 1806 if (peer->flash & PKT_TEST_MASK) { 1807 msyslog(LOG_INFO, 1808 "receive: Bad auth in packet with bad timestamps from %s denied - spoof?", 1809 ntoa(&peer->srcadr)); 1810 return; 1811 } 1812 1813 report_event(PEVNT_AUTH, peer, "digest"); 1814 peer->flash |= TEST5; /* bad auth */ 1815 peer->badauth++; 1816 if ( has_mac 1817 && ( hismode == MODE_ACTIVE 1818 || hismode == MODE_PASSIVE)) 1819 fast_xmit(rbufp, MODE_ACTIVE, 0, restrict_mask); 1820 if (peer->flags & FLAG_PREEMPT) { 1821 if (unpeer_digest_early) { 1822 unpeer(peer); 1823 } 1824 } 1825 #ifdef AUTOKEY 1826 else if (peer_clear_digest_early && peer->crypto) { 1827 peer_clear(peer, "AUTH"); 1828 } 1829 #endif /* AUTOKEY */ 1830 return; 1831 } 1832 1833 /* 1834 * For broadcast packets: 1835 * 1836 * HMS: This next line never made much sense to me, even 1837 * when it was up higher: 1838 * If an initial volley, bail out now and let the 1839 * client do its stuff. 1840 * 1841 * If the packet has not failed authentication, then 1842 * - if the origin timestamp is nonzero this is an 1843 * interleaved broadcast, so restart the protocol. 1844 * - else, this is not an interleaved broadcast packet. 1845 */ 1846 if (hismode == MODE_BROADCAST) { 1847 if ( is_authentic == AUTH_OK 1848 || is_authentic == AUTH_NONE) { 1849 if (!L_ISZERO(&p_org)) { 1850 if (!(peer->flags & FLAG_XB)) { 1851 msyslog(LOG_INFO, 1852 "receive: Broadcast server at %s is in interleave mode", 1853 ntoa(&peer->srcadr)); 1854 peer->flags |= FLAG_XB; 1855 peer->aorg = p_xmt; 1856 peer->borg = rbufp->recv_time; 1857 report_event(PEVNT_XLEAVE, peer, NULL); 1858 return; 1859 } 1860 } else if (peer->flags & FLAG_XB) { 1861 msyslog(LOG_INFO, 1862 "receive: Broadcast server at %s is no longer in interleave mode", 1863 ntoa(&peer->srcadr)); 1864 peer->flags &= ~FLAG_XB; 1865 } 1866 } else { 1867 msyslog(LOG_INFO, 1868 "receive: Bad broadcast auth (%d) from %s", 1869 is_authentic, ntoa(&peer->srcadr)); 1870 } 1871 1872 /* 1873 * Now that we know the packet is correctly authenticated, 1874 * update peer->bxmt. 1875 */ 1876 peer->bxmt = p_xmt; 1877 } 1878 1879 1880 /* 1881 ** Update the state variables. 1882 */ 1883 if (peer->flip == 0) { 1884 if (hismode != MODE_BROADCAST) 1885 peer->rec = p_xmt; 1886 peer->dst = rbufp->recv_time; 1887 } 1888 peer->xmt = p_xmt; 1889 1890 /* 1891 * Set the peer ppoll to the maximum of the packet ppoll and the 1892 * peer minpoll. If a kiss-o'-death, set the peer minpoll to 1893 * this maximum and advance the headway to give the sender some 1894 * headroom. Very intricate. 1895 */ 1896 1897 /* 1898 * Check for any kiss codes. Note this is only used when a server 1899 * responds to a packet request 1900 */ 1901 1902 kissCode = kiss_code_check(hisleap, hisstratum, hismode, pkt->refid); 1903 1904 /* 1905 * Check to see if this is a RATE Kiss Code 1906 * Currently this kiss code will accept whatever poll 1907 * rate that the server sends 1908 */ 1909 peer->ppoll = max(peer->minpoll, pkt->ppoll); 1910 if (kissCode == RATEKISS) { 1911 peer->selbroken++; /* Increment the KoD count */ 1912 report_event(PEVNT_RATE, peer, NULL); 1913 if (pkt->ppoll > peer->minpoll) 1914 peer->minpoll = peer->ppoll; 1915 peer->burst = peer->retry = 0; 1916 peer->throttle = (NTP_SHIFT + 1) * (1 << peer->minpoll); 1917 poll_update(peer, pkt->ppoll); 1918 return; /* kiss-o'-death */ 1919 } 1920 if (kissCode != NOKISS) { 1921 peer->selbroken++; /* Increment the KoD count */ 1922 return; /* Drop any other kiss code packets */ 1923 } 1924 1925 1926 /* 1927 * XXX 1928 */ 1929 1930 1931 /* 1932 * If: 1933 * - this is a *cast (uni-, broad-, or m-) server packet 1934 * - and it's symmetric-key authenticated 1935 * then see if the sender's IP is trusted for this keyid. 1936 * If it is, great - nothing special to do here. 1937 * Otherwise, we should report and bail. 1938 * 1939 * Autokey-authenticated packets are accepted. 1940 */ 1941 1942 switch (hismode) { 1943 case MODE_SERVER: /* server mode */ 1944 case MODE_BROADCAST: /* broadcast mode */ 1945 case MODE_ACTIVE: /* symmetric active mode */ 1946 case MODE_PASSIVE: /* symmetric passive mode */ 1947 if ( is_authentic == AUTH_OK 1948 && skeyid 1949 && skeyid <= NTP_MAXKEY 1950 && !authistrustedip(skeyid, &peer->srcadr)) { 1951 report_event(PEVNT_AUTH, peer, "authIP"); 1952 peer->badauth++; 1953 return; 1954 } 1955 break; 1956 1957 case MODE_CLIENT: /* client mode */ 1958 #if 0 /* At this point, MODE_CONTROL is overloaded by MODE_BCLIENT */ 1959 case MODE_CONTROL: /* control mode */ 1960 #endif 1961 case MODE_PRIVATE: /* private mode */ 1962 case MODE_BCLIENT: /* broadcast client mode */ 1963 break; 1964 1965 case MODE_UNSPEC: /* unspecified (old version) */ 1966 default: 1967 msyslog(LOG_INFO, 1968 "receive: Unexpected mode (%d) in packet from %s", 1969 hismode, ntoa(&peer->srcadr)); 1970 break; 1971 } 1972 1973 1974 /* 1975 * That was hard and I am sweaty, but the packet is squeaky 1976 * clean. Get on with real work. 1977 */ 1978 peer->timereceived = current_time; 1979 peer->timelastrec = current_time; 1980 if (is_authentic == AUTH_OK) 1981 peer->flags |= FLAG_AUTHENTIC; 1982 else 1983 peer->flags &= ~FLAG_AUTHENTIC; 1984 1985 #ifdef AUTOKEY 1986 /* 1987 * More autokey dance. The rules of the cha-cha are as follows: 1988 * 1989 * 1. If there is no key or the key is not auto, do nothing. 1990 * 1991 * 2. If this packet is in response to the one just previously 1992 * sent or from a broadcast server, do the extension fields. 1993 * Otherwise, assume bogosity and bail out. 1994 * 1995 * 3. If an extension field contains a verified signature, it is 1996 * self-authenticated and we sit the dance. 1997 * 1998 * 4. If this is a server reply, check only to see that the 1999 * transmitted key ID matches the received key ID. 2000 * 2001 * 5. Check to see that one or more hashes of the current key ID 2002 * matches the previous key ID or ultimate original key ID 2003 * obtained from the broadcaster or symmetric peer. If no 2004 * match, sit the dance and call for new autokey values. 2005 * 2006 * In case of crypto error, fire the orchestra, stop dancing and 2007 * restart the protocol. 2008 */ 2009 if (peer->flags & FLAG_SKEY) { 2010 /* 2011 * Decrement remaining autokey hashes. This isn't 2012 * perfect if a packet is lost, but results in no harm. 2013 */ 2014 ap = (struct autokey *)peer->recval.ptr; 2015 if (ap != NULL) { 2016 if (ap->seq > 0) 2017 ap->seq--; 2018 } 2019 peer->flash |= TEST8; 2020 rval = crypto_recv(peer, rbufp); 2021 if (rval == XEVNT_OK) { 2022 peer->unreach = 0; 2023 } else { 2024 if (rval == XEVNT_ERR) { 2025 report_event(PEVNT_RESTART, peer, 2026 "crypto error"); 2027 peer_clear(peer, "CRYP"); 2028 peer->flash |= TEST9; /* bad crypt */ 2029 if (peer->flags & FLAG_PREEMPT) { 2030 if (unpeer_crypto_early) { 2031 unpeer(peer); 2032 } 2033 } 2034 } 2035 return; 2036 } 2037 2038 /* 2039 * If server mode, verify the receive key ID matches 2040 * the transmit key ID. 2041 */ 2042 if (hismode == MODE_SERVER) { 2043 if (skeyid == peer->keyid) 2044 peer->flash &= ~TEST8; 2045 2046 /* 2047 * If an extension field is present, verify only that it 2048 * has been correctly signed. We don't need a sequence 2049 * check here, but the sequence continues. 2050 */ 2051 } else if (!(peer->flash & TEST8)) { 2052 peer->pkeyid = skeyid; 2053 2054 /* 2055 * Now the fun part. Here, skeyid is the current ID in 2056 * the packet, pkeyid is the ID in the last packet and 2057 * tkeyid is the hash of skeyid. If the autokey values 2058 * have not been received, this is an automatic error. 2059 * If so, check that the tkeyid matches pkeyid. If not, 2060 * hash tkeyid and try again. If the number of hashes 2061 * exceeds the number remaining in the sequence, declare 2062 * a successful failure and refresh the autokey values. 2063 */ 2064 } else if (ap != NULL) { 2065 int i; 2066 2067 for (i = 0; ; i++) { 2068 if ( tkeyid == peer->pkeyid 2069 || tkeyid == ap->key) { 2070 peer->flash &= ~TEST8; 2071 peer->pkeyid = skeyid; 2072 ap->seq -= i; 2073 break; 2074 } 2075 if (i > ap->seq) { 2076 peer->crypto &= 2077 ~CRYPTO_FLAG_AUTO; 2078 break; 2079 } 2080 tkeyid = session_key( 2081 &rbufp->recv_srcadr, dstadr_sin, 2082 tkeyid, pkeyid, 0); 2083 } 2084 if (peer->flash & TEST8) 2085 report_event(PEVNT_AUTH, peer, "keylist"); 2086 } 2087 if (!(peer->crypto & CRYPTO_FLAG_PROV)) /* test 9 */ 2088 peer->flash |= TEST8; /* bad autokey */ 2089 2090 /* 2091 * The maximum lifetime of the protocol is about one 2092 * week before restarting the Autokey protocol to 2093 * refresh certificates and leapseconds values. 2094 */ 2095 if (current_time > peer->refresh) { 2096 report_event(PEVNT_RESTART, peer, 2097 "crypto refresh"); 2098 peer_clear(peer, "TIME"); 2099 return; 2100 } 2101 } 2102 #endif /* AUTOKEY */ 2103 2104 /* 2105 * The dance is complete and the flash bits have been lit. Toss 2106 * the packet over the fence for processing, which may light up 2107 * more flashers. 2108 */ 2109 process_packet(peer, pkt, rbufp->recv_length); 2110 2111 /* 2112 * In interleaved mode update the state variables. Also adjust the 2113 * transmit phase to avoid crossover. 2114 */ 2115 if (peer->flip != 0) { 2116 peer->rec = p_rec; 2117 peer->dst = rbufp->recv_time; 2118 if (peer->nextdate - current_time < (1U << min(peer->ppoll, 2119 peer->hpoll)) / 2) 2120 peer->nextdate++; 2121 else 2122 peer->nextdate--; 2123 } 2124 } 2125 2126 2127 /* 2128 * process_packet - Packet Procedure, a la Section 3.4.4 of RFC-1305 2129 * Or almost, at least. If we're in here we have a reasonable 2130 * expectation that we will be having a long term 2131 * relationship with this host. 2132 */ 2133 void 2134 process_packet( 2135 register struct peer *peer, 2136 register struct pkt *pkt, 2137 u_int len 2138 ) 2139 { 2140 double t34, t21; 2141 double p_offset, p_del, p_disp; 2142 l_fp p_rec, p_xmt, p_org, p_reftime, ci; 2143 u_char pmode, pleap, pversion, pstratum; 2144 char statstr[NTP_MAXSTRLEN]; 2145 #ifdef ASSYM 2146 int itemp; 2147 double etemp, ftemp, td; 2148 #endif /* ASSYM */ 2149 2150 #if 0 2151 sys_processed++; 2152 peer->processed++; 2153 #endif 2154 p_del = FPTOD(NTOHS_FP(pkt->rootdelay)); 2155 p_offset = 0; 2156 p_disp = FPTOD(NTOHS_FP(pkt->rootdisp)); 2157 NTOHL_FP(&pkt->reftime, &p_reftime); 2158 NTOHL_FP(&pkt->org, &p_org); 2159 NTOHL_FP(&pkt->rec, &p_rec); 2160 NTOHL_FP(&pkt->xmt, &p_xmt); 2161 pmode = PKT_MODE(pkt->li_vn_mode); 2162 pleap = PKT_LEAP(pkt->li_vn_mode); 2163 pversion = PKT_VERSION(pkt->li_vn_mode); 2164 pstratum = PKT_TO_STRATUM(pkt->stratum); 2165 2166 /**/ 2167 2168 /**/ 2169 2170 /* 2171 * Verify the server is synchronized; that is, the leap bits, 2172 * stratum and root distance are valid. 2173 */ 2174 if ( pleap == LEAP_NOTINSYNC /* test 6 */ 2175 || pstratum < sys_floor || pstratum >= sys_ceiling) 2176 peer->flash |= TEST6; /* bad synch or strat */ 2177 if (p_del / 2 + p_disp >= MAXDISPERSE) /* test 7 */ 2178 peer->flash |= TEST7; /* bad header */ 2179 2180 /* 2181 * If any tests fail at this point, the packet is discarded. 2182 * Note that some flashers may have already been set in the 2183 * receive() routine. 2184 */ 2185 if (peer->flash & PKT_TEST_MASK) { 2186 peer->seldisptoolarge++; 2187 DPRINTF(1, ("packet: flash header %04x\n", 2188 peer->flash)); 2189 return; 2190 } 2191 2192 /**/ 2193 2194 #if 1 2195 sys_processed++; 2196 peer->processed++; 2197 #endif 2198 2199 /* 2200 * Capture the header values in the client/peer association.. 2201 */ 2202 record_raw_stats(&peer->srcadr, peer->dstadr ? 2203 &peer->dstadr->sin : NULL, 2204 &p_org, &p_rec, &p_xmt, &peer->dst, 2205 pleap, pversion, pmode, pstratum, pkt->ppoll, pkt->precision, 2206 p_del, p_disp, pkt->refid); 2207 peer->leap = pleap; 2208 peer->stratum = min(pstratum, STRATUM_UNSPEC); 2209 peer->pmode = pmode; 2210 peer->precision = pkt->precision; 2211 peer->rootdelay = p_del; 2212 peer->rootdisp = p_disp; 2213 peer->refid = pkt->refid; /* network byte order */ 2214 peer->reftime = p_reftime; 2215 2216 /* 2217 * First, if either burst mode is armed, enable the burst. 2218 * Compute the headway for the next packet and delay if 2219 * necessary to avoid exceeding the threshold. 2220 */ 2221 if (peer->retry > 0) { 2222 peer->retry = 0; 2223 if (peer->reach) 2224 peer->burst = min(1 << (peer->hpoll - 2225 peer->minpoll), NTP_SHIFT) - 1; 2226 else 2227 peer->burst = NTP_IBURST - 1; 2228 if (peer->burst > 0) 2229 peer->nextdate = current_time; 2230 } 2231 poll_update(peer, peer->hpoll); 2232 2233 /**/ 2234 2235 /* 2236 * If the peer was previously unreachable, raise a trap. In any 2237 * case, mark it reachable. 2238 */ 2239 if (!peer->reach) { 2240 report_event(PEVNT_REACH, peer, NULL); 2241 peer->timereachable = current_time; 2242 } 2243 peer->reach |= 1; 2244 2245 /* 2246 * For a client/server association, calculate the clock offset, 2247 * roundtrip delay and dispersion. The equations are reordered 2248 * from the spec for more efficient use of temporaries. For a 2249 * broadcast association, offset the last measurement by the 2250 * computed delay during the client/server volley. Note the 2251 * computation of dispersion includes the system precision plus 2252 * that due to the frequency error since the origin time. 2253 * 2254 * It is very important to respect the hazards of overflow. The 2255 * only permitted operation on raw timestamps is subtraction, 2256 * where the result is a signed quantity spanning from 68 years 2257 * in the past to 68 years in the future. To avoid loss of 2258 * precision, these calculations are done using 64-bit integer 2259 * arithmetic. However, the offset and delay calculations are 2260 * sums and differences of these first-order differences, which 2261 * if done using 64-bit integer arithmetic, would be valid over 2262 * only half that span. Since the typical first-order 2263 * differences are usually very small, they are converted to 64- 2264 * bit doubles and all remaining calculations done in floating- 2265 * double arithmetic. This preserves the accuracy while 2266 * retaining the 68-year span. 2267 * 2268 * There are three interleaving schemes, basic, interleaved 2269 * symmetric and interleaved broadcast. The timestamps are 2270 * idioscyncratically different. See the onwire briefing/white 2271 * paper at www.eecis.udel.edu/~mills for details. 2272 * 2273 * Interleaved symmetric mode 2274 * t1 = peer->aorg/borg, t2 = peer->rec, t3 = p_xmt, 2275 * t4 = peer->dst 2276 */ 2277 if (peer->flip != 0) { 2278 ci = p_xmt; /* t3 - t4 */ 2279 L_SUB(&ci, &peer->dst); 2280 LFPTOD(&ci, t34); 2281 ci = p_rec; /* t2 - t1 */ 2282 if (peer->flip > 0) 2283 L_SUB(&ci, &peer->borg); 2284 else 2285 L_SUB(&ci, &peer->aorg); 2286 LFPTOD(&ci, t21); 2287 p_del = t21 - t34; 2288 p_offset = (t21 + t34) / 2.; 2289 if (p_del < 0 || p_del > 1.) { 2290 snprintf(statstr, sizeof(statstr), 2291 "t21 %.6f t34 %.6f", t21, t34); 2292 report_event(PEVNT_XERR, peer, statstr); 2293 return; 2294 } 2295 2296 /* 2297 * Broadcast modes 2298 */ 2299 } else if (peer->pmode == MODE_BROADCAST) { 2300 2301 /* 2302 * Interleaved broadcast mode. Use interleaved timestamps. 2303 * t1 = peer->borg, t2 = p_org, t3 = p_org, t4 = aorg 2304 */ 2305 if (peer->flags & FLAG_XB) { 2306 ci = p_org; /* delay */ 2307 L_SUB(&ci, &peer->aorg); 2308 LFPTOD(&ci, t34); 2309 ci = p_org; /* t2 - t1 */ 2310 L_SUB(&ci, &peer->borg); 2311 LFPTOD(&ci, t21); 2312 peer->aorg = p_xmt; 2313 peer->borg = peer->dst; 2314 if (t34 < 0 || t34 > 1.) { 2315 /* drop all if in the initial volley */ 2316 if (FLAG_BC_VOL & peer->flags) 2317 goto bcc_init_volley_fail; 2318 snprintf(statstr, sizeof(statstr), 2319 "offset %.6f delay %.6f", t21, t34); 2320 report_event(PEVNT_XERR, peer, statstr); 2321 return; 2322 } 2323 p_offset = t21; 2324 peer->xleave = t34; 2325 2326 /* 2327 * Basic broadcast - use direct timestamps. 2328 * t3 = p_xmt, t4 = peer->dst 2329 */ 2330 } else { 2331 ci = p_xmt; /* t3 - t4 */ 2332 L_SUB(&ci, &peer->dst); 2333 LFPTOD(&ci, t34); 2334 p_offset = t34; 2335 } 2336 2337 /* 2338 * When calibration is complete and the clock is 2339 * synchronized, the bias is calculated as the difference 2340 * between the unicast timestamp and the broadcast 2341 * timestamp. This works for both basic and interleaved 2342 * modes. 2343 * [Bug 3031] Don't keep this peer when the delay 2344 * calculation gives reason to suspect clock steps. 2345 * This is assumed for delays > 50ms. 2346 */ 2347 if (FLAG_BC_VOL & peer->flags) { 2348 peer->flags &= ~FLAG_BC_VOL; 2349 peer->delay = fabs(peer->offset - p_offset) * 2; 2350 DPRINTF(2, ("broadcast volley: initial delay=%.6f\n", 2351 peer->delay)); 2352 if (peer->delay > fabs(sys_bdelay)) { 2353 bcc_init_volley_fail: 2354 DPRINTF(2, ("%s", "broadcast volley: initial delay exceeds limit\n")); 2355 unpeer(peer); 2356 return; 2357 } 2358 } 2359 peer->nextdate = current_time + (1u << peer->ppoll) - 2u; 2360 p_del = peer->delay; 2361 p_offset += p_del / 2; 2362 2363 2364 /* 2365 * Basic mode, otherwise known as the old fashioned way. 2366 * 2367 * t1 = p_org, t2 = p_rec, t3 = p_xmt, t4 = peer->dst 2368 */ 2369 } else { 2370 ci = p_xmt; /* t3 - t4 */ 2371 L_SUB(&ci, &peer->dst); 2372 LFPTOD(&ci, t34); 2373 ci = p_rec; /* t2 - t1 */ 2374 L_SUB(&ci, &p_org); 2375 LFPTOD(&ci, t21); 2376 p_del = fabs(t21 - t34); 2377 p_offset = (t21 + t34) / 2.; 2378 } 2379 p_del = max(p_del, LOGTOD(sys_precision)); 2380 p_disp = LOGTOD(sys_precision) + LOGTOD(peer->precision) + 2381 clock_phi * p_del; 2382 2383 #if ASSYM 2384 /* 2385 * This code calculates the outbound and inbound data rates by 2386 * measuring the differences between timestamps at different 2387 * packet lengths. This is helpful in cases of large asymmetric 2388 * delays commonly experienced on deep space communication 2389 * links. 2390 */ 2391 if (peer->t21_last > 0 && peer->t34_bytes > 0) { 2392 itemp = peer->t21_bytes - peer->t21_last; 2393 if (itemp > 25) { 2394 etemp = t21 - peer->t21; 2395 if (fabs(etemp) > 1e-6) { 2396 ftemp = itemp / etemp; 2397 if (ftemp > 1000.) 2398 peer->r21 = ftemp; 2399 } 2400 } 2401 itemp = len - peer->t34_bytes; 2402 if (itemp > 25) { 2403 etemp = -t34 - peer->t34; 2404 if (fabs(etemp) > 1e-6) { 2405 ftemp = itemp / etemp; 2406 if (ftemp > 1000.) 2407 peer->r34 = ftemp; 2408 } 2409 } 2410 } 2411 2412 /* 2413 * The following section compensates for different data rates on 2414 * the outbound (d21) and inbound (t34) directions. To do this, 2415 * it finds t such that r21 * t - r34 * (d - t) = 0, where d is 2416 * the roundtrip delay. Then it calculates the correction as a 2417 * fraction of d. 2418 */ 2419 peer->t21 = t21; 2420 peer->t21_last = peer->t21_bytes; 2421 peer->t34 = -t34; 2422 peer->t34_bytes = len; 2423 DPRINTF(2, ("packet: t21 %.9lf %d t34 %.9lf %d\n", peer->t21, 2424 peer->t21_bytes, peer->t34, peer->t34_bytes)); 2425 if (peer->r21 > 0 && peer->r34 > 0 && p_del > 0) { 2426 if (peer->pmode != MODE_BROADCAST) 2427 td = (peer->r34 / (peer->r21 + peer->r34) - 2428 .5) * p_del; 2429 else 2430 td = 0; 2431 2432 /* 2433 * Unfortunately, in many cases the errors are 2434 * unacceptable, so for the present the rates are not 2435 * used. In future, we might find conditions where the 2436 * calculations are useful, so this should be considered 2437 * a work in progress. 2438 */ 2439 t21 -= td; 2440 t34 -= td; 2441 DPRINTF(2, ("packet: del %.6lf r21 %.1lf r34 %.1lf %.6lf\n", 2442 p_del, peer->r21 / 1e3, peer->r34 / 1e3, 2443 td)); 2444 } 2445 #endif /* ASSYM */ 2446 2447 /* 2448 * That was awesome. Now hand off to the clock filter. 2449 */ 2450 clock_filter(peer, p_offset + peer->bias, p_del, p_disp); 2451 2452 /* 2453 * If we are in broadcast calibrate mode, return to broadcast 2454 * client mode when the client is fit and the autokey dance is 2455 * complete. 2456 */ 2457 if ( (FLAG_BC_VOL & peer->flags) 2458 && MODE_CLIENT == peer->hmode 2459 && !(TEST11 & peer_unfit(peer))) { /* distance exceeded */ 2460 #ifdef AUTOKEY 2461 if (peer->flags & FLAG_SKEY) { 2462 if (!(~peer->crypto & CRYPTO_FLAG_ALL)) 2463 peer->hmode = MODE_BCLIENT; 2464 } else { 2465 peer->hmode = MODE_BCLIENT; 2466 } 2467 #else /* !AUTOKEY follows */ 2468 peer->hmode = MODE_BCLIENT; 2469 #endif /* !AUTOKEY */ 2470 } 2471 } 2472 2473 2474 /* 2475 * clock_update - Called at system process update intervals. 2476 */ 2477 static void 2478 clock_update( 2479 struct peer *peer /* peer structure pointer */ 2480 ) 2481 { 2482 double dtemp; 2483 l_fp now; 2484 #ifdef HAVE_LIBSCF_H 2485 char *fmri; 2486 #endif /* HAVE_LIBSCF_H */ 2487 2488 /* 2489 * Update the system state variables. We do this very carefully, 2490 * as the poll interval might need to be clamped differently. 2491 */ 2492 sys_peer = peer; 2493 sys_epoch = peer->epoch; 2494 if (sys_poll < peer->minpoll) 2495 sys_poll = peer->minpoll; 2496 if (sys_poll > peer->maxpoll) 2497 sys_poll = peer->maxpoll; 2498 poll_update(peer, sys_poll); 2499 sys_stratum = min(peer->stratum + 1, STRATUM_UNSPEC); 2500 if ( peer->stratum == STRATUM_REFCLOCK 2501 || peer->stratum == STRATUM_UNSPEC) 2502 sys_refid = peer->refid; 2503 else 2504 sys_refid = addr2refid(&peer->srcadr); 2505 /* 2506 * Root Dispersion (E) is defined (in RFC 5905) as: 2507 * 2508 * E = p.epsilon_r + p.epsilon + p.psi + PHI*(s.t - p.t) + |THETA| 2509 * 2510 * where: 2511 * p.epsilon_r is the PollProc's root dispersion 2512 * p.epsilon is the PollProc's dispersion 2513 * p.psi is the PollProc's jitter 2514 * THETA is the combined offset 2515 * 2516 * NB: Think Hard about where these numbers come from and 2517 * what they mean. When did peer->update happen? Has anything 2518 * interesting happened since then? What values are the most 2519 * defensible? Why? 2520 * 2521 * DLM thinks this equation is probably the best of all worse choices. 2522 */ 2523 dtemp = peer->rootdisp 2524 + peer->disp 2525 + sys_jitter 2526 + clock_phi * (current_time - peer->update) 2527 + fabs(sys_offset); 2528 2529 if (dtemp > sys_mindisp) 2530 sys_rootdisp = dtemp; 2531 else 2532 sys_rootdisp = sys_mindisp; 2533 sys_rootdelay = peer->delay + peer->rootdelay; 2534 sys_reftime = peer->dst; 2535 2536 DPRINTF(1, ("clock_update: at %lu sample %lu associd %d\n", 2537 current_time, peer->epoch, peer->associd)); 2538 2539 /* 2540 * Comes now the moment of truth. Crank the clock discipline and 2541 * see what comes out. 2542 */ 2543 switch (local_clock(peer, sys_offset)) { 2544 2545 /* 2546 * Clock exceeds panic threshold. Life as we know it ends. 2547 */ 2548 case -1: 2549 #ifdef HAVE_LIBSCF_H 2550 /* 2551 * For Solaris enter the maintenance mode. 2552 */ 2553 if ((fmri = getenv("SMF_FMRI")) != NULL) { 2554 if (smf_maintain_instance(fmri, 0) < 0) { 2555 printf("smf_maintain_instance: %s\n", 2556 scf_strerror(scf_error())); 2557 exit(1); 2558 } 2559 /* 2560 * Sleep until SMF kills us. 2561 */ 2562 for (;;) 2563 pause(); 2564 } 2565 #endif /* HAVE_LIBSCF_H */ 2566 exit (-1); 2567 /* not reached */ 2568 2569 /* 2570 * Clock was stepped. Flush all time values of all peers. 2571 */ 2572 case 2: 2573 clear_all(); 2574 set_sys_leap(LEAP_NOTINSYNC); 2575 sys_stratum = STRATUM_UNSPEC; 2576 memcpy(&sys_refid, "STEP", 4); 2577 sys_rootdelay = 0; 2578 sys_rootdisp = 0; 2579 L_CLR(&sys_reftime); 2580 sys_jitter = LOGTOD(sys_precision); 2581 leapsec_reset_frame(); 2582 break; 2583 2584 /* 2585 * Clock was slewed. Handle the leapsecond stuff. 2586 */ 2587 case 1: 2588 2589 /* 2590 * If this is the first time the clock is set, reset the 2591 * leap bits. If crypto, the timer will goose the setup 2592 * process. 2593 */ 2594 if (sys_leap == LEAP_NOTINSYNC) { 2595 set_sys_leap(LEAP_NOWARNING); 2596 #ifdef AUTOKEY 2597 if (crypto_flags) 2598 crypto_update(); 2599 #endif /* AUTOKEY */ 2600 /* 2601 * If our parent process is waiting for the 2602 * first clock sync, send them home satisfied. 2603 */ 2604 #ifdef HAVE_WORKING_FORK 2605 if (waitsync_fd_to_close != -1) { 2606 close(waitsync_fd_to_close); 2607 waitsync_fd_to_close = -1; 2608 DPRINTF(1, ("notified parent --wait-sync is done\n")); 2609 } 2610 #endif /* HAVE_WORKING_FORK */ 2611 2612 } 2613 2614 /* 2615 * If there is no leap second pending and the number of 2616 * survivor leap bits is greater than half the number of 2617 * survivors, try to schedule a leap for the end of the 2618 * current month. (This only works if no leap second for 2619 * that range is in the table, so doing this more than 2620 * once is mostly harmless.) 2621 */ 2622 if (leapsec == LSPROX_NOWARN) { 2623 if ( leap_vote_ins > leap_vote_del 2624 && leap_vote_ins > sys_survivors / 2) { 2625 get_systime(&now); 2626 leapsec_add_dyn(TRUE, now.l_ui, NULL); 2627 } 2628 if ( leap_vote_del > leap_vote_ins 2629 && leap_vote_del > sys_survivors / 2) { 2630 get_systime(&now); 2631 leapsec_add_dyn(FALSE, now.l_ui, NULL); 2632 } 2633 } 2634 break; 2635 2636 /* 2637 * Popcorn spike or step threshold exceeded. Pretend it never 2638 * happened. 2639 */ 2640 default: 2641 break; 2642 } 2643 } 2644 2645 2646 /* 2647 * poll_update - update peer poll interval 2648 */ 2649 void 2650 poll_update( 2651 struct peer *peer, /* peer structure pointer */ 2652 u_char mpoll 2653 ) 2654 { 2655 u_long next, utemp; 2656 u_char hpoll; 2657 2658 /* 2659 * This routine figures out when the next poll should be sent. 2660 * That turns out to be wickedly complicated. One problem is 2661 * that sometimes the time for the next poll is in the past when 2662 * the poll interval is reduced. We watch out for races here 2663 * between the receive process and the poll process. 2664 * 2665 * Clamp the poll interval between minpoll and maxpoll. 2666 */ 2667 hpoll = max(min(peer->maxpoll, mpoll), peer->minpoll); 2668 2669 #ifdef AUTOKEY 2670 /* 2671 * If during the crypto protocol the poll interval has changed, 2672 * the lifetimes in the key list are probably bogus. Purge the 2673 * the key list and regenerate it later. 2674 */ 2675 if ((peer->flags & FLAG_SKEY) && hpoll != peer->hpoll) 2676 key_expire(peer); 2677 #endif /* AUTOKEY */ 2678 peer->hpoll = hpoll; 2679 2680 /* 2681 * There are three variables important for poll scheduling, the 2682 * current time (current_time), next scheduled time (nextdate) 2683 * and the earliest time (utemp). The earliest time is 2 s 2684 * seconds, but could be more due to rate management. When 2685 * sending in a burst, use the earliest time. When not in a 2686 * burst but with a reply pending, send at the earliest time 2687 * unless the next scheduled time has not advanced. This can 2688 * only happen if multiple replies are pending in the same 2689 * response interval. Otherwise, send at the later of the next 2690 * scheduled time and the earliest time. 2691 * 2692 * Now we figure out if there is an override. If a burst is in 2693 * progress and we get called from the receive process, just 2694 * slink away. If called from the poll process, delay 1 s for a 2695 * reference clock, otherwise 2 s. 2696 */ 2697 utemp = current_time + max(peer->throttle - (NTP_SHIFT - 1) * 2698 (1 << peer->minpoll), ntp_minpkt); 2699 if (peer->burst > 0) { 2700 if (peer->nextdate > current_time) 2701 return; 2702 #ifdef REFCLOCK 2703 else if (peer->flags & FLAG_REFCLOCK) 2704 peer->nextdate = current_time + RESP_DELAY; 2705 #endif /* REFCLOCK */ 2706 else 2707 peer->nextdate = utemp; 2708 2709 #ifdef AUTOKEY 2710 /* 2711 * If a burst is not in progress and a crypto response message 2712 * is pending, delay 2 s, but only if this is a new interval. 2713 */ 2714 } else if (peer->cmmd != NULL) { 2715 if (peer->nextdate > current_time) { 2716 if (peer->nextdate + ntp_minpkt != utemp) 2717 peer->nextdate = utemp; 2718 } else { 2719 peer->nextdate = utemp; 2720 } 2721 #endif /* AUTOKEY */ 2722 2723 /* 2724 * The ordinary case. If a retry, use minpoll; if unreachable, 2725 * use host poll; otherwise, use the minimum of host and peer 2726 * polls; In other words, oversampling is okay but 2727 * understampling is evil. Use the maximum of this value and the 2728 * headway. If the average headway is greater than the headway 2729 * threshold, increase the headway by the minimum interval. 2730 */ 2731 } else { 2732 if (peer->retry > 0) 2733 hpoll = peer->minpoll; 2734 else if (!(peer->reach)) 2735 hpoll = peer->hpoll; 2736 else 2737 hpoll = min(peer->ppoll, peer->hpoll); 2738 #ifdef REFCLOCK 2739 if (peer->flags & FLAG_REFCLOCK) 2740 next = 1 << hpoll; 2741 else 2742 #endif /* REFCLOCK */ 2743 next = ((0x1000UL | (ntp_random() & 0x0ff)) << 2744 hpoll) >> 12; 2745 next += peer->outdate; 2746 if (next > utemp) 2747 peer->nextdate = next; 2748 else 2749 peer->nextdate = utemp; 2750 if (peer->throttle > (1 << peer->minpoll)) 2751 peer->nextdate += ntp_minpkt; 2752 } 2753 DPRINTF(2, ("poll_update: at %lu %s poll %d burst %d retry %d head %d early %lu next %lu\n", 2754 current_time, ntoa(&peer->srcadr), peer->hpoll, 2755 peer->burst, peer->retry, peer->throttle, 2756 utemp - current_time, peer->nextdate - 2757 current_time)); 2758 } 2759 2760 2761 /* 2762 * peer_clear - clear peer filter registers. See Section 3.4.8 of the 2763 * spec. 2764 */ 2765 void 2766 peer_clear( 2767 struct peer *peer, /* peer structure */ 2768 const char *ident /* tally lights */ 2769 ) 2770 { 2771 u_char u; 2772 l_fp bxmt = peer->bxmt; /* bcast clients retain this! */ 2773 2774 #ifdef AUTOKEY 2775 /* 2776 * If cryptographic credentials have been acquired, toss them to 2777 * Valhalla. Note that autokeys are ephemeral, in that they are 2778 * tossed immediately upon use. Therefore, the keylist can be 2779 * purged anytime without needing to preserve random keys. Note 2780 * that, if the peer is purged, the cryptographic variables are 2781 * purged, too. This makes it much harder to sneak in some 2782 * unauthenticated data in the clock filter. 2783 */ 2784 key_expire(peer); 2785 if (peer->iffval != NULL) 2786 BN_free(peer->iffval); 2787 value_free(&peer->cookval); 2788 value_free(&peer->recval); 2789 value_free(&peer->encrypt); 2790 value_free(&peer->sndval); 2791 if (peer->cmmd != NULL) 2792 free(peer->cmmd); 2793 if (peer->subject != NULL) 2794 free(peer->subject); 2795 if (peer->issuer != NULL) 2796 free(peer->issuer); 2797 #endif /* AUTOKEY */ 2798 2799 /* 2800 * Clear all values, including the optional crypto values above. 2801 */ 2802 memset(CLEAR_TO_ZERO(peer), 0, LEN_CLEAR_TO_ZERO(peer)); 2803 peer->ppoll = peer->maxpoll; 2804 peer->hpoll = peer->minpoll; 2805 peer->disp = MAXDISPERSE; 2806 peer->flash = peer_unfit(peer); 2807 peer->jitter = LOGTOD(sys_precision); 2808 2809 /* Don't throw away our broadcast replay protection */ 2810 if (peer->hmode == MODE_BCLIENT) 2811 peer->bxmt = bxmt; 2812 2813 /* 2814 * If interleave mode, initialize the alternate origin switch. 2815 */ 2816 if (peer->flags & FLAG_XLEAVE) 2817 peer->flip = 1; 2818 for (u = 0; u < NTP_SHIFT; u++) { 2819 peer->filter_order[u] = u; 2820 peer->filter_disp[u] = MAXDISPERSE; 2821 } 2822 #ifdef REFCLOCK 2823 if (!(peer->flags & FLAG_REFCLOCK)) { 2824 #endif 2825 peer->leap = LEAP_NOTINSYNC; 2826 peer->stratum = STRATUM_UNSPEC; 2827 memcpy(&peer->refid, ident, 4); 2828 #ifdef REFCLOCK 2829 } 2830 #endif 2831 2832 /* 2833 * During initialization use the association count to spread out 2834 * the polls at one-second intervals. Passive associations' 2835 * first poll is delayed by the "discard minimum" to avoid rate 2836 * limiting. Other post-startup new or cleared associations 2837 * randomize the first poll over the minimum poll interval to 2838 * avoid implosion. 2839 */ 2840 peer->nextdate = peer->update = peer->outdate = current_time; 2841 if (initializing) { 2842 peer->nextdate += peer_associations; 2843 } else if (MODE_PASSIVE == peer->hmode) { 2844 peer->nextdate += ntp_minpkt; 2845 } else { 2846 peer->nextdate += ntp_random() % peer->minpoll; 2847 } 2848 #ifdef AUTOKEY 2849 peer->refresh = current_time + (1 << NTP_REFRESH); 2850 #endif /* AUTOKEY */ 2851 DPRINTF(1, ("peer_clear: at %ld next %ld associd %d refid %s\n", 2852 current_time, peer->nextdate, peer->associd, 2853 ident)); 2854 } 2855 2856 2857 /* 2858 * clock_filter - add incoming clock sample to filter register and run 2859 * the filter procedure to find the best sample. 2860 */ 2861 void 2862 clock_filter( 2863 struct peer *peer, /* peer structure pointer */ 2864 double sample_offset, /* clock offset */ 2865 double sample_delay, /* roundtrip delay */ 2866 double sample_disp /* dispersion */ 2867 ) 2868 { 2869 double dst[NTP_SHIFT]; /* distance vector */ 2870 int ord[NTP_SHIFT]; /* index vector */ 2871 int i, j, k, m; 2872 double dtemp, etemp; 2873 char tbuf[80]; 2874 2875 /* 2876 * A sample consists of the offset, delay, dispersion and epoch 2877 * of arrival. The offset and delay are determined by the on- 2878 * wire protocol. The dispersion grows from the last outbound 2879 * packet to the arrival of this one increased by the sum of the 2880 * peer precision and the system precision as required by the 2881 * error budget. First, shift the new arrival into the shift 2882 * register discarding the oldest one. 2883 */ 2884 j = peer->filter_nextpt; 2885 peer->filter_offset[j] = sample_offset; 2886 peer->filter_delay[j] = sample_delay; 2887 peer->filter_disp[j] = sample_disp; 2888 peer->filter_epoch[j] = current_time; 2889 j = (j + 1) % NTP_SHIFT; 2890 peer->filter_nextpt = j; 2891 2892 /* 2893 * Update dispersions since the last update and at the same 2894 * time initialize the distance and index lists. Since samples 2895 * become increasingly uncorrelated beyond the Allan intercept, 2896 * only under exceptional cases will an older sample be used. 2897 * Therefore, the distance list uses a compound metric. If the 2898 * dispersion is greater than the maximum dispersion, clamp the 2899 * distance at that value. If the time since the last update is 2900 * less than the Allan intercept use the delay; otherwise, use 2901 * the sum of the delay and dispersion. 2902 */ 2903 dtemp = clock_phi * (current_time - peer->update); 2904 peer->update = current_time; 2905 for (i = NTP_SHIFT - 1; i >= 0; i--) { 2906 if (i != 0) 2907 peer->filter_disp[j] += dtemp; 2908 if (peer->filter_disp[j] >= MAXDISPERSE) { 2909 peer->filter_disp[j] = MAXDISPERSE; 2910 dst[i] = MAXDISPERSE; 2911 } else if (peer->update - peer->filter_epoch[j] > 2912 (u_long)ULOGTOD(allan_xpt)) { 2913 dst[i] = peer->filter_delay[j] + 2914 peer->filter_disp[j]; 2915 } else { 2916 dst[i] = peer->filter_delay[j]; 2917 } 2918 ord[i] = j; 2919 j = (j + 1) % NTP_SHIFT; 2920 } 2921 2922 /* 2923 * If the clock has stabilized, sort the samples by distance. 2924 */ 2925 if (freq_cnt == 0) { 2926 for (i = 1; i < NTP_SHIFT; i++) { 2927 for (j = 0; j < i; j++) { 2928 if (dst[j] > dst[i]) { 2929 k = ord[j]; 2930 ord[j] = ord[i]; 2931 ord[i] = k; 2932 etemp = dst[j]; 2933 dst[j] = dst[i]; 2934 dst[i] = etemp; 2935 } 2936 } 2937 } 2938 } 2939 2940 /* 2941 * Copy the index list to the association structure so ntpq 2942 * can see it later. Prune the distance list to leave only 2943 * samples less than the maximum dispersion, which disfavors 2944 * uncorrelated samples older than the Allan intercept. To 2945 * further improve the jitter estimate, of the remainder leave 2946 * only samples less than the maximum distance, but keep at 2947 * least two samples for jitter calculation. 2948 */ 2949 m = 0; 2950 for (i = 0; i < NTP_SHIFT; i++) { 2951 peer->filter_order[i] = (u_char) ord[i]; 2952 if ( dst[i] >= MAXDISPERSE 2953 || (m >= 2 && dst[i] >= sys_maxdist)) 2954 continue; 2955 m++; 2956 } 2957 2958 /* 2959 * Compute the dispersion and jitter. The dispersion is weighted 2960 * exponentially by NTP_FWEIGHT (0.5) so it is normalized close 2961 * to 1.0. The jitter is the RMS differences relative to the 2962 * lowest delay sample. 2963 */ 2964 peer->disp = peer->jitter = 0; 2965 k = ord[0]; 2966 for (i = NTP_SHIFT - 1; i >= 0; i--) { 2967 j = ord[i]; 2968 peer->disp = NTP_FWEIGHT * (peer->disp + 2969 peer->filter_disp[j]); 2970 if (i < m) 2971 peer->jitter += DIFF(peer->filter_offset[j], 2972 peer->filter_offset[k]); 2973 } 2974 2975 /* 2976 * If no acceptable samples remain in the shift register, 2977 * quietly tiptoe home leaving only the dispersion. Otherwise, 2978 * save the offset, delay and jitter. Note the jitter must not 2979 * be less than the precision. 2980 */ 2981 if (m == 0) { 2982 clock_select(); 2983 return; 2984 } 2985 etemp = fabs(peer->offset - peer->filter_offset[k]); 2986 peer->offset = peer->filter_offset[k]; 2987 peer->delay = peer->filter_delay[k]; 2988 if (m > 1) 2989 peer->jitter /= m - 1; 2990 peer->jitter = max(SQRT(peer->jitter), LOGTOD(sys_precision)); 2991 2992 /* 2993 * If the the new sample and the current sample are both valid 2994 * and the difference between their offsets exceeds CLOCK_SGATE 2995 * (3) times the jitter and the interval between them is less 2996 * than twice the host poll interval, consider the new sample 2997 * a popcorn spike and ignore it. 2998 */ 2999 if ( peer->disp < sys_maxdist 3000 && peer->filter_disp[k] < sys_maxdist 3001 && etemp > CLOCK_SGATE * peer->jitter 3002 && peer->filter_epoch[k] - peer->epoch 3003 < 2. * ULOGTOD(peer->hpoll)) { 3004 snprintf(tbuf, sizeof(tbuf), "%.6f s", etemp); 3005 report_event(PEVNT_POPCORN, peer, tbuf); 3006 return; 3007 } 3008 3009 /* 3010 * A new minimum sample is useful only if it is later than the 3011 * last one used. In this design the maximum lifetime of any 3012 * sample is not greater than eight times the poll interval, so 3013 * the maximum interval between minimum samples is eight 3014 * packets. 3015 */ 3016 if (peer->filter_epoch[k] <= peer->epoch) { 3017 DPRINTF(2, ("clock_filter: old sample %lu\n", current_time - 3018 peer->filter_epoch[k])); 3019 return; 3020 } 3021 peer->epoch = peer->filter_epoch[k]; 3022 3023 /* 3024 * The mitigated sample statistics are saved for later 3025 * processing. If not synchronized or not in a burst, tickle the 3026 * clock select algorithm. 3027 */ 3028 record_peer_stats(&peer->srcadr, ctlpeerstatus(peer), 3029 peer->offset, peer->delay, peer->disp, peer->jitter); 3030 DPRINTF(1, ("clock_filter: n %d off %.6f del %.6f dsp %.6f jit %.6f\n", 3031 m, peer->offset, peer->delay, peer->disp, 3032 peer->jitter)); 3033 if (peer->burst == 0 || sys_leap == LEAP_NOTINSYNC) 3034 clock_select(); 3035 } 3036 3037 3038 /* 3039 * clock_select - find the pick-of-the-litter clock 3040 * 3041 * LOCKCLOCK: (1) If the local clock is the prefer peer, it will always 3042 * be enabled, even if declared falseticker, (2) only the prefer peer 3043 * can be selected as the system peer, (3) if the external source is 3044 * down, the system leap bits are set to 11 and the stratum set to 3045 * infinity. 3046 */ 3047 void 3048 clock_select(void) 3049 { 3050 struct peer *peer; 3051 int i, j, k, n; 3052 int nlist, nl2; 3053 int allow; 3054 int speer; 3055 double d, e, f, g; 3056 double high, low; 3057 double speermet; 3058 double orphmet = 2.0 * U_INT32_MAX; /* 2x is greater than */ 3059 struct endpoint endp; 3060 struct peer *osys_peer; 3061 struct peer *sys_prefer = NULL; /* prefer peer */ 3062 struct peer *typesystem = NULL; 3063 struct peer *typeorphan = NULL; 3064 #ifdef REFCLOCK 3065 struct peer *typeacts = NULL; 3066 struct peer *typelocal = NULL; 3067 struct peer *typepps = NULL; 3068 #endif /* REFCLOCK */ 3069 static struct endpoint *endpoint = NULL; 3070 static int *indx = NULL; 3071 static peer_select *peers = NULL; 3072 static u_int endpoint_size = 0; 3073 static u_int peers_size = 0; 3074 static u_int indx_size = 0; 3075 size_t octets; 3076 3077 /* 3078 * Initialize and create endpoint, index and peer lists big 3079 * enough to handle all associations. 3080 */ 3081 osys_peer = sys_peer; 3082 sys_survivors = 0; 3083 #ifdef LOCKCLOCK 3084 set_sys_leap(LEAP_NOTINSYNC); 3085 sys_stratum = STRATUM_UNSPEC; 3086 memcpy(&sys_refid, "DOWN", 4); 3087 #endif /* LOCKCLOCK */ 3088 3089 /* 3090 * Allocate dynamic space depending on the number of 3091 * associations. 3092 */ 3093 nlist = 1; 3094 for (peer = peer_list; peer != NULL; peer = peer->p_link) 3095 nlist++; 3096 endpoint_size = ALIGNED_SIZE(nlist * 2 * sizeof(*endpoint)); 3097 peers_size = ALIGNED_SIZE(nlist * sizeof(*peers)); 3098 indx_size = ALIGNED_SIZE(nlist * 2 * sizeof(*indx)); 3099 octets = endpoint_size + peers_size + indx_size; 3100 endpoint = erealloc(endpoint, octets); 3101 peers = INC_ALIGNED_PTR(endpoint, endpoint_size); 3102 indx = INC_ALIGNED_PTR(peers, peers_size); 3103 3104 /* 3105 * Initially, we populate the island with all the rifraff peers 3106 * that happen to be lying around. Those with seriously 3107 * defective clocks are immediately booted off the island. Then, 3108 * the falsetickers are culled and put to sea. The truechimers 3109 * remaining are subject to repeated rounds where the most 3110 * unpopular at each round is kicked off. When the population 3111 * has dwindled to sys_minclock, the survivors split a million 3112 * bucks and collectively crank the chimes. 3113 */ 3114 nlist = nl2 = 0; /* none yet */ 3115 for (peer = peer_list; peer != NULL; peer = peer->p_link) { 3116 peer->new_status = CTL_PST_SEL_REJECT; 3117 3118 /* 3119 * Leave the island immediately if the peer is 3120 * unfit to synchronize. 3121 */ 3122 if (peer_unfit(peer)) { 3123 continue; 3124 } 3125 3126 /* 3127 * If this peer is an orphan parent, elect the 3128 * one with the lowest metric defined as the 3129 * IPv4 address or the first 64 bits of the 3130 * hashed IPv6 address. To ensure convergence 3131 * on the same selected orphan, consider as 3132 * well that this system may have the lowest 3133 * metric and be the orphan parent. If this 3134 * system wins, sys_peer will be NULL to trigger 3135 * orphan mode in timer(). 3136 */ 3137 if (peer->stratum == sys_orphan) { 3138 u_int32 localmet; 3139 u_int32 peermet; 3140 3141 if (peer->dstadr != NULL) 3142 localmet = ntohl(peer->dstadr->addr_refid); 3143 else 3144 localmet = U_INT32_MAX; 3145 peermet = ntohl(addr2refid(&peer->srcadr)); 3146 if (peermet < localmet && peermet < orphmet) { 3147 typeorphan = peer; 3148 orphmet = peermet; 3149 } 3150 continue; 3151 } 3152 3153 /* 3154 * If this peer could have the orphan parent 3155 * as a synchronization ancestor, exclude it 3156 * from selection to avoid forming a 3157 * synchronization loop within the orphan mesh, 3158 * triggering stratum climb to infinity 3159 * instability. Peers at stratum higher than 3160 * the orphan stratum could have the orphan 3161 * parent in ancestry so are excluded. 3162 * See http://bugs.ntp.org/2050 3163 */ 3164 if (peer->stratum > sys_orphan) { 3165 continue; 3166 } 3167 #ifdef REFCLOCK 3168 /* 3169 * The following are special cases. We deal 3170 * with them later. 3171 */ 3172 if (!(peer->flags & FLAG_PREFER)) { 3173 switch (peer->refclktype) { 3174 case REFCLK_LOCALCLOCK: 3175 if ( current_time > orphwait 3176 && typelocal == NULL) 3177 typelocal = peer; 3178 continue; 3179 3180 case REFCLK_ACTS: 3181 if ( current_time > orphwait 3182 && typeacts == NULL) 3183 typeacts = peer; 3184 continue; 3185 } 3186 } 3187 #endif /* REFCLOCK */ 3188 3189 /* 3190 * If we get this far, the peer can stay on the 3191 * island, but does not yet have the immunity 3192 * idol. 3193 */ 3194 peer->new_status = CTL_PST_SEL_SANE; 3195 f = root_distance(peer); 3196 peers[nlist].peer = peer; 3197 peers[nlist].error = peer->jitter; 3198 peers[nlist].synch = f; 3199 nlist++; 3200 3201 /* 3202 * Insert each interval endpoint on the unsorted 3203 * endpoint[] list. 3204 */ 3205 e = peer->offset; 3206 endpoint[nl2].type = -1; /* lower end */ 3207 endpoint[nl2].val = e - f; 3208 nl2++; 3209 endpoint[nl2].type = 1; /* upper end */ 3210 endpoint[nl2].val = e + f; 3211 nl2++; 3212 } 3213 /* 3214 * Construct sorted indx[] of endpoint[] indexes ordered by 3215 * offset. 3216 */ 3217 for (i = 0; i < nl2; i++) 3218 indx[i] = i; 3219 for (i = 0; i < nl2; i++) { 3220 endp = endpoint[indx[i]]; 3221 e = endp.val; 3222 k = i; 3223 for (j = i + 1; j < nl2; j++) { 3224 endp = endpoint[indx[j]]; 3225 if (endp.val < e) { 3226 e = endp.val; 3227 k = j; 3228 } 3229 } 3230 if (k != i) { 3231 j = indx[k]; 3232 indx[k] = indx[i]; 3233 indx[i] = j; 3234 } 3235 } 3236 for (i = 0; i < nl2; i++) 3237 DPRINTF(3, ("select: endpoint %2d %.6f\n", 3238 endpoint[indx[i]].type, endpoint[indx[i]].val)); 3239 3240 /* 3241 * This is the actual algorithm that cleaves the truechimers 3242 * from the falsetickers. The original algorithm was described 3243 * in Keith Marzullo's dissertation, but has been modified for 3244 * better accuracy. 3245 * 3246 * Briefly put, we first assume there are no falsetickers, then 3247 * scan the candidate list first from the low end upwards and 3248 * then from the high end downwards. The scans stop when the 3249 * number of intersections equals the number of candidates less 3250 * the number of falsetickers. If this doesn't happen for a 3251 * given number of falsetickers, we bump the number of 3252 * falsetickers and try again. If the number of falsetickers 3253 * becomes equal to or greater than half the number of 3254 * candidates, the Albanians have won the Byzantine wars and 3255 * correct synchronization is not possible. 3256 * 3257 * Here, nlist is the number of candidates and allow is the 3258 * number of falsetickers. Upon exit, the truechimers are the 3259 * survivors with offsets not less than low and not greater than 3260 * high. There may be none of them. 3261 */ 3262 low = 1e9; 3263 high = -1e9; 3264 for (allow = 0; 2 * allow < nlist; allow++) { 3265 3266 /* 3267 * Bound the interval (low, high) as the smallest 3268 * interval containing points from the most sources. 3269 */ 3270 n = 0; 3271 for (i = 0; i < nl2; i++) { 3272 low = endpoint[indx[i]].val; 3273 n -= endpoint[indx[i]].type; 3274 if (n >= nlist - allow) 3275 break; 3276 } 3277 n = 0; 3278 for (j = nl2 - 1; j >= 0; j--) { 3279 high = endpoint[indx[j]].val; 3280 n += endpoint[indx[j]].type; 3281 if (n >= nlist - allow) 3282 break; 3283 } 3284 3285 /* 3286 * If an interval containing truechimers is found, stop. 3287 * If not, increase the number of falsetickers and go 3288 * around again. 3289 */ 3290 if (high > low) 3291 break; 3292 } 3293 3294 /* 3295 * Clustering algorithm. Whittle candidate list of falsetickers, 3296 * who leave the island immediately. The TRUE peer is always a 3297 * truechimer. We must leave at least one peer to collect the 3298 * million bucks. 3299 * 3300 * We assert the correct time is contained in the interval, but 3301 * the best offset estimate for the interval might not be 3302 * contained in the interval. For this purpose, a truechimer is 3303 * defined as the midpoint of an interval that overlaps the 3304 * intersection interval. 3305 */ 3306 j = 0; 3307 for (i = 0; i < nlist; i++) { 3308 double h; 3309 3310 peer = peers[i].peer; 3311 h = peers[i].synch; 3312 if (( high <= low 3313 || peer->offset + h < low 3314 || peer->offset - h > high 3315 ) && !(peer->flags & FLAG_TRUE)) 3316 continue; 3317 3318 #ifdef REFCLOCK 3319 /* 3320 * Eligible PPS peers must survive the intersection 3321 * algorithm. Use the first one found, but don't 3322 * include any of them in the cluster population. 3323 */ 3324 if (peer->flags & FLAG_PPS) { 3325 if (typepps == NULL) 3326 typepps = peer; 3327 if (!(peer->flags & FLAG_TSTAMP_PPS)) 3328 continue; 3329 } 3330 #endif /* REFCLOCK */ 3331 3332 if (j != i) 3333 peers[j] = peers[i]; 3334 j++; 3335 } 3336 nlist = j; 3337 3338 /* 3339 * If no survivors remain at this point, check if the modem 3340 * driver, local driver or orphan parent in that order. If so, 3341 * nominate the first one found as the only survivor. 3342 * Otherwise, give up and leave the island to the rats. 3343 */ 3344 if (nlist == 0) { 3345 peers[0].error = 0; 3346 peers[0].synch = sys_mindisp; 3347 #ifdef REFCLOCK 3348 if (typeacts != NULL) { 3349 peers[0].peer = typeacts; 3350 nlist = 1; 3351 } else if (typelocal != NULL) { 3352 peers[0].peer = typelocal; 3353 nlist = 1; 3354 } else 3355 #endif /* REFCLOCK */ 3356 if (typeorphan != NULL) { 3357 peers[0].peer = typeorphan; 3358 nlist = 1; 3359 } 3360 } 3361 3362 /* 3363 * Mark the candidates at this point as truechimers. 3364 */ 3365 for (i = 0; i < nlist; i++) { 3366 peers[i].peer->new_status = CTL_PST_SEL_SELCAND; 3367 DPRINTF(2, ("select: survivor %s %f\n", 3368 stoa(&peers[i].peer->srcadr), peers[i].synch)); 3369 } 3370 3371 /* 3372 * Now, vote outliers off the island by select jitter weighted 3373 * by root distance. Continue voting as long as there are more 3374 * than sys_minclock survivors and the select jitter of the peer 3375 * with the worst metric is greater than the minimum peer 3376 * jitter. Stop if we are about to discard a TRUE or PREFER 3377 * peer, who of course have the immunity idol. 3378 */ 3379 while (1) { 3380 d = 1e9; 3381 e = -1e9; 3382 g = 0; 3383 k = 0; 3384 for (i = 0; i < nlist; i++) { 3385 if (peers[i].error < d) 3386 d = peers[i].error; 3387 peers[i].seljit = 0; 3388 if (nlist > 1) { 3389 f = 0; 3390 for (j = 0; j < nlist; j++) 3391 f += DIFF(peers[j].peer->offset, 3392 peers[i].peer->offset); 3393 peers[i].seljit = SQRT(f / (nlist - 1)); 3394 } 3395 if (peers[i].seljit * peers[i].synch > e) { 3396 g = peers[i].seljit; 3397 e = peers[i].seljit * peers[i].synch; 3398 k = i; 3399 } 3400 } 3401 g = max(g, LOGTOD(sys_precision)); 3402 if ( nlist <= max(1, sys_minclock) 3403 || g <= d 3404 || ((FLAG_TRUE | FLAG_PREFER) & peers[k].peer->flags)) 3405 break; 3406 3407 DPRINTF(3, ("select: drop %s seljit %.6f jit %.6f\n", 3408 ntoa(&peers[k].peer->srcadr), g, d)); 3409 if (nlist > sys_maxclock) 3410 peers[k].peer->new_status = CTL_PST_SEL_EXCESS; 3411 for (j = k + 1; j < nlist; j++) 3412 peers[j - 1] = peers[j]; 3413 nlist--; 3414 } 3415 3416 /* 3417 * What remains is a list usually not greater than sys_minclock 3418 * peers. Note that unsynchronized peers cannot survive this 3419 * far. Count and mark these survivors. 3420 * 3421 * While at it, count the number of leap warning bits found. 3422 * This will be used later to vote the system leap warning bit. 3423 * If a leap warning bit is found on a reference clock, the vote 3424 * is always won. 3425 * 3426 * Choose the system peer using a hybrid metric composed of the 3427 * selection jitter scaled by the root distance augmented by 3428 * stratum scaled by sys_mindisp (.001 by default). The goal of 3429 * the small stratum factor is to avoid clockhop between a 3430 * reference clock and a network peer which has a refclock and 3431 * is using an older ntpd, which does not floor sys_rootdisp at 3432 * sys_mindisp. 3433 * 3434 * In contrast, ntpd 4.2.6 and earlier used stratum primarily 3435 * in selecting the system peer, using a weight of 1 second of 3436 * additional root distance per stratum. This heavy bias is no 3437 * longer appropriate, as the scaled root distance provides a 3438 * more rational metric carrying the cumulative error budget. 3439 */ 3440 e = 1e9; 3441 speer = 0; 3442 leap_vote_ins = 0; 3443 leap_vote_del = 0; 3444 for (i = 0; i < nlist; i++) { 3445 peer = peers[i].peer; 3446 peer->unreach = 0; 3447 peer->new_status = CTL_PST_SEL_SYNCCAND; 3448 sys_survivors++; 3449 if (peer->leap == LEAP_ADDSECOND) { 3450 if (peer->flags & FLAG_REFCLOCK) 3451 leap_vote_ins = nlist; 3452 else if (leap_vote_ins < nlist) 3453 leap_vote_ins++; 3454 } 3455 if (peer->leap == LEAP_DELSECOND) { 3456 if (peer->flags & FLAG_REFCLOCK) 3457 leap_vote_del = nlist; 3458 else if (leap_vote_del < nlist) 3459 leap_vote_del++; 3460 } 3461 if (peer->flags & FLAG_PREFER) 3462 sys_prefer = peer; 3463 speermet = peers[i].seljit * peers[i].synch + 3464 peer->stratum * sys_mindisp; 3465 if (speermet < e) { 3466 e = speermet; 3467 speer = i; 3468 } 3469 } 3470 3471 /* 3472 * Unless there are at least sys_misane survivors, leave the 3473 * building dark. Otherwise, do a clockhop dance. Ordinarily, 3474 * use the selected survivor speer. However, if the current 3475 * system peer is not speer, stay with the current system peer 3476 * as long as it doesn't get too old or too ugly. 3477 */ 3478 if (nlist > 0 && nlist >= sys_minsane) { 3479 double x; 3480 3481 typesystem = peers[speer].peer; 3482 if (osys_peer == NULL || osys_peer == typesystem) { 3483 sys_clockhop = 0; 3484 } else if ((x = fabs(typesystem->offset - 3485 osys_peer->offset)) < sys_mindisp) { 3486 if (sys_clockhop == 0) 3487 sys_clockhop = sys_mindisp; 3488 else 3489 sys_clockhop *= .5; 3490 DPRINTF(1, ("select: clockhop %d %.6f %.6f\n", 3491 j, x, sys_clockhop)); 3492 if (fabs(x) < sys_clockhop) 3493 typesystem = osys_peer; 3494 else 3495 sys_clockhop = 0; 3496 } else { 3497 sys_clockhop = 0; 3498 } 3499 } 3500 3501 /* 3502 * Mitigation rules of the game. We have the pick of the 3503 * litter in typesystem if any survivors are left. If 3504 * there is a prefer peer, use its offset and jitter. 3505 * Otherwise, use the combined offset and jitter of all kitters. 3506 */ 3507 if (typesystem != NULL) { 3508 if (sys_prefer == NULL) { 3509 typesystem->new_status = CTL_PST_SEL_SYSPEER; 3510 clock_combine(peers, sys_survivors, speer); 3511 } else { 3512 typesystem = sys_prefer; 3513 sys_clockhop = 0; 3514 typesystem->new_status = CTL_PST_SEL_SYSPEER; 3515 sys_offset = typesystem->offset; 3516 sys_jitter = typesystem->jitter; 3517 } 3518 DPRINTF(1, ("select: combine offset %.9f jitter %.9f\n", 3519 sys_offset, sys_jitter)); 3520 } 3521 #ifdef REFCLOCK 3522 /* 3523 * If a PPS driver is lit and the combined offset is less than 3524 * 0.4 s, select the driver as the PPS peer and use its offset 3525 * and jitter. However, if this is the atom driver, use it only 3526 * if there is a prefer peer or there are no survivors and none 3527 * are required. 3528 */ 3529 if ( typepps != NULL 3530 && fabs(sys_offset) < 0.4 3531 && ( typepps->refclktype != REFCLK_ATOM_PPS 3532 || ( typepps->refclktype == REFCLK_ATOM_PPS 3533 && ( sys_prefer != NULL 3534 || (typesystem == NULL && sys_minsane == 0))))) { 3535 typesystem = typepps; 3536 sys_clockhop = 0; 3537 typesystem->new_status = CTL_PST_SEL_PPS; 3538 sys_offset = typesystem->offset; 3539 sys_jitter = typesystem->jitter; 3540 DPRINTF(1, ("select: pps offset %.9f jitter %.9f\n", 3541 sys_offset, sys_jitter)); 3542 } 3543 #endif /* REFCLOCK */ 3544 3545 /* 3546 * If there are no survivors at this point, there is no 3547 * system peer. If so and this is an old update, keep the 3548 * current statistics, but do not update the clock. 3549 */ 3550 if (typesystem == NULL) { 3551 if (osys_peer != NULL) { 3552 if (sys_orphwait > 0) 3553 orphwait = current_time + sys_orphwait; 3554 report_event(EVNT_NOPEER, NULL, NULL); 3555 } 3556 sys_peer = NULL; 3557 for (peer = peer_list; peer != NULL; peer = peer->p_link) 3558 peer->status = peer->new_status; 3559 return; 3560 } 3561 3562 /* 3563 * Do not use old data, as this may mess up the clock discipline 3564 * stability. 3565 */ 3566 if (typesystem->epoch <= sys_epoch) 3567 return; 3568 3569 /* 3570 * We have found the alpha male. Wind the clock. 3571 */ 3572 if (osys_peer != typesystem) 3573 report_event(PEVNT_NEWPEER, typesystem, NULL); 3574 for (peer = peer_list; peer != NULL; peer = peer->p_link) 3575 peer->status = peer->new_status; 3576 clock_update(typesystem); 3577 } 3578 3579 3580 static void 3581 clock_combine( 3582 peer_select * peers, /* survivor list */ 3583 int npeers, /* number of survivors */ 3584 int syspeer /* index of sys.peer */ 3585 ) 3586 { 3587 int i; 3588 double x, y, z, w; 3589 3590 y = z = w = 0; 3591 for (i = 0; i < npeers; i++) { 3592 x = 1. / peers[i].synch; 3593 y += x; 3594 z += x * peers[i].peer->offset; 3595 w += x * DIFF(peers[i].peer->offset, 3596 peers[syspeer].peer->offset); 3597 } 3598 sys_offset = z / y; 3599 sys_jitter = SQRT(w / y + SQUARE(peers[syspeer].seljit)); 3600 } 3601 3602 3603 /* 3604 * root_distance - compute synchronization distance from peer to root 3605 */ 3606 static double 3607 root_distance( 3608 struct peer *peer /* peer structure pointer */ 3609 ) 3610 { 3611 double dtemp; 3612 3613 /* 3614 * Root Distance (LAMBDA) is defined as: 3615 * (delta + DELTA)/2 + epsilon + EPSILON + D 3616 * 3617 * where: 3618 * delta is the round-trip delay 3619 * DELTA is the root delay 3620 * epsilon is the peer dispersion 3621 * + (15 usec each second) 3622 * EPSILON is the root dispersion 3623 * D is sys_jitter 3624 * 3625 * NB: Think hard about why we are using these values, and what 3626 * the alternatives are, and the various pros/cons. 3627 * 3628 * DLM thinks these are probably the best choices from any of the 3629 * other worse choices. 3630 */ 3631 dtemp = (peer->delay + peer->rootdelay) / 2 3632 + peer->disp 3633 + clock_phi * (current_time - peer->update) 3634 + peer->rootdisp 3635 + peer->jitter; 3636 /* 3637 * Careful squeak here. The value returned must be greater than 3638 * the minimum root dispersion in order to avoid clockhop with 3639 * highly precise reference clocks. Note that the root distance 3640 * cannot exceed the sys_maxdist, as this is the cutoff by the 3641 * selection algorithm. 3642 */ 3643 if (dtemp < sys_mindisp) 3644 dtemp = sys_mindisp; 3645 return (dtemp); 3646 } 3647 3648 3649 /* 3650 * peer_xmit - send packet for persistent association. 3651 */ 3652 static void 3653 peer_xmit( 3654 struct peer *peer /* peer structure pointer */ 3655 ) 3656 { 3657 struct pkt xpkt; /* transmit packet */ 3658 size_t sendlen, authlen; 3659 keyid_t xkeyid = 0; /* transmit key ID */ 3660 l_fp xmt_tx, xmt_ty; 3661 3662 if (!peer->dstadr) /* drop peers without interface */ 3663 return; 3664 3665 xpkt.li_vn_mode = PKT_LI_VN_MODE(sys_leap, peer->version, 3666 peer->hmode); 3667 xpkt.stratum = STRATUM_TO_PKT(sys_stratum); 3668 xpkt.ppoll = peer->hpoll; 3669 xpkt.precision = sys_precision; 3670 xpkt.refid = sys_refid; 3671 xpkt.rootdelay = HTONS_FP(DTOFP(sys_rootdelay)); 3672 xpkt.rootdisp = HTONS_FP(DTOUFP(sys_rootdisp)); 3673 HTONL_FP(&sys_reftime, &xpkt.reftime); 3674 HTONL_FP(&peer->rec, &xpkt.org); 3675 HTONL_FP(&peer->dst, &xpkt.rec); 3676 3677 /* 3678 * If the received packet contains a MAC, the transmitted packet 3679 * is authenticated and contains a MAC. If not, the transmitted 3680 * packet is not authenticated. 3681 * 3682 * It is most important when autokey is in use that the local 3683 * interface IP address be known before the first packet is 3684 * sent. Otherwise, it is not possible to compute a correct MAC 3685 * the recipient will accept. Thus, the I/O semantics have to do 3686 * a little more work. In particular, the wildcard interface 3687 * might not be usable. 3688 */ 3689 sendlen = LEN_PKT_NOMAC; 3690 if ( 3691 #ifdef AUTOKEY 3692 !(peer->flags & FLAG_SKEY) && 3693 #endif /* !AUTOKEY */ 3694 peer->keyid == 0) { 3695 3696 /* 3697 * Transmit a-priori timestamps 3698 */ 3699 get_systime(&xmt_tx); 3700 if (peer->flip == 0) { /* basic mode */ 3701 peer->aorg = xmt_tx; 3702 HTONL_FP(&xmt_tx, &xpkt.xmt); 3703 } else { /* interleaved modes */ 3704 if (peer->hmode == MODE_BROADCAST) { /* bcst */ 3705 HTONL_FP(&xmt_tx, &xpkt.xmt); 3706 if (peer->flip > 0) 3707 HTONL_FP(&peer->borg, 3708 &xpkt.org); 3709 else 3710 HTONL_FP(&peer->aorg, 3711 &xpkt.org); 3712 } else { /* symmetric */ 3713 if (peer->flip > 0) 3714 HTONL_FP(&peer->borg, 3715 &xpkt.xmt); 3716 else 3717 HTONL_FP(&peer->aorg, 3718 &xpkt.xmt); 3719 } 3720 } 3721 peer->t21_bytes = sendlen; 3722 sendpkt(&peer->srcadr, peer->dstadr, sys_ttl[peer->ttl], 3723 &xpkt, sendlen); 3724 peer->sent++; 3725 peer->throttle += (1 << peer->minpoll) - 2; 3726 3727 /* 3728 * Capture a-posteriori timestamps 3729 */ 3730 get_systime(&xmt_ty); 3731 if (peer->flip != 0) { /* interleaved modes */ 3732 if (peer->flip > 0) 3733 peer->aorg = xmt_ty; 3734 else 3735 peer->borg = xmt_ty; 3736 peer->flip = -peer->flip; 3737 } 3738 L_SUB(&xmt_ty, &xmt_tx); 3739 LFPTOD(&xmt_ty, peer->xleave); 3740 DPRINTF(1, ("peer_xmit: at %ld %s->%s mode %d len %zu xmt %#010x.%08x\n", 3741 current_time, 3742 peer->dstadr ? stoa(&peer->dstadr->sin) : "-", 3743 stoa(&peer->srcadr), peer->hmode, sendlen, 3744 xmt_tx.l_ui, xmt_tx.l_uf)); 3745 return; 3746 } 3747 3748 /* 3749 * Authentication is enabled, so the transmitted packet must be 3750 * authenticated. If autokey is enabled, fuss with the various 3751 * modes; otherwise, symmetric key cryptography is used. 3752 */ 3753 #ifdef AUTOKEY 3754 if (peer->flags & FLAG_SKEY) { 3755 struct exten *exten; /* extension field */ 3756 3757 /* 3758 * The Public Key Dance (PKD): Cryptographic credentials 3759 * are contained in extension fields, each including a 3760 * 4-octet length/code word followed by a 4-octet 3761 * association ID and optional additional data. Optional 3762 * data includes a 4-octet data length field followed by 3763 * the data itself. Request messages are sent from a 3764 * configured association; response messages can be sent 3765 * from a configured association or can take the fast 3766 * path without ever matching an association. Response 3767 * messages have the same code as the request, but have 3768 * a response bit and possibly an error bit set. In this 3769 * implementation, a message may contain no more than 3770 * one command and one or more responses. 3771 * 3772 * Cryptographic session keys include both a public and 3773 * a private componet. Request and response messages 3774 * using extension fields are always sent with the 3775 * private component set to zero. Packets without 3776 * extension fields indlude the private component when 3777 * the session key is generated. 3778 */ 3779 while (1) { 3780 3781 /* 3782 * Allocate and initialize a keylist if not 3783 * already done. Then, use the list in inverse 3784 * order, discarding keys once used. Keep the 3785 * latest key around until the next one, so 3786 * clients can use client/server packets to 3787 * compute propagation delay. 3788 * 3789 * Note that once a key is used from the list, 3790 * it is retained in the key cache until the 3791 * next key is used. This is to allow a client 3792 * to retrieve the encrypted session key 3793 * identifier to verify authenticity. 3794 * 3795 * If for some reason a key is no longer in the 3796 * key cache, a birthday has happened or the key 3797 * has expired, so the pseudo-random sequence is 3798 * broken. In that case, purge the keylist and 3799 * regenerate it. 3800 */ 3801 if (peer->keynumber == 0) 3802 make_keylist(peer, peer->dstadr); 3803 else 3804 peer->keynumber--; 3805 xkeyid = peer->keylist[peer->keynumber]; 3806 if (authistrusted(xkeyid)) 3807 break; 3808 else 3809 key_expire(peer); 3810 } 3811 peer->keyid = xkeyid; 3812 exten = NULL; 3813 switch (peer->hmode) { 3814 3815 /* 3816 * In broadcast server mode the autokey values are 3817 * required by the broadcast clients. Push them when a 3818 * new keylist is generated; otherwise, push the 3819 * association message so the client can request them at 3820 * other times. 3821 */ 3822 case MODE_BROADCAST: 3823 if (peer->flags & FLAG_ASSOC) 3824 exten = crypto_args(peer, CRYPTO_AUTO | 3825 CRYPTO_RESP, peer->associd, NULL); 3826 else 3827 exten = crypto_args(peer, CRYPTO_ASSOC | 3828 CRYPTO_RESP, peer->associd, NULL); 3829 break; 3830 3831 /* 3832 * In symmetric modes the parameter, certificate, 3833 * identity, cookie and autokey exchanges are 3834 * required. The leapsecond exchange is optional. But, a 3835 * peer will not believe the other peer until the other 3836 * peer has synchronized, so the certificate exchange 3837 * might loop until then. If a peer finds a broken 3838 * autokey sequence, it uses the autokey exchange to 3839 * retrieve the autokey values. In any case, if a new 3840 * keylist is generated, the autokey values are pushed. 3841 */ 3842 case MODE_ACTIVE: 3843 case MODE_PASSIVE: 3844 3845 /* 3846 * Parameter, certificate and identity. 3847 */ 3848 if (!peer->crypto) 3849 exten = crypto_args(peer, CRYPTO_ASSOC, 3850 peer->associd, hostval.ptr); 3851 else if (!(peer->crypto & CRYPTO_FLAG_CERT)) 3852 exten = crypto_args(peer, CRYPTO_CERT, 3853 peer->associd, peer->issuer); 3854 else if (!(peer->crypto & CRYPTO_FLAG_VRFY)) 3855 exten = crypto_args(peer, 3856 crypto_ident(peer), peer->associd, 3857 NULL); 3858 3859 /* 3860 * Cookie and autokey. We request the cookie 3861 * only when the this peer and the other peer 3862 * are synchronized. But, this peer needs the 3863 * autokey values when the cookie is zero. Any 3864 * time we regenerate the key list, we offer the 3865 * autokey values without being asked. If for 3866 * some reason either peer finds a broken 3867 * autokey sequence, the autokey exchange is 3868 * used to retrieve the autokey values. 3869 */ 3870 else if ( sys_leap != LEAP_NOTINSYNC 3871 && peer->leap != LEAP_NOTINSYNC 3872 && !(peer->crypto & CRYPTO_FLAG_COOK)) 3873 exten = crypto_args(peer, CRYPTO_COOK, 3874 peer->associd, NULL); 3875 else if (!(peer->crypto & CRYPTO_FLAG_AUTO)) 3876 exten = crypto_args(peer, CRYPTO_AUTO, 3877 peer->associd, NULL); 3878 else if ( peer->flags & FLAG_ASSOC 3879 && peer->crypto & CRYPTO_FLAG_SIGN) 3880 exten = crypto_args(peer, CRYPTO_AUTO | 3881 CRYPTO_RESP, peer->assoc, NULL); 3882 3883 /* 3884 * Wait for clock sync, then sign the 3885 * certificate and retrieve the leapsecond 3886 * values. 3887 */ 3888 else if (sys_leap == LEAP_NOTINSYNC) 3889 break; 3890 3891 else if (!(peer->crypto & CRYPTO_FLAG_SIGN)) 3892 exten = crypto_args(peer, CRYPTO_SIGN, 3893 peer->associd, hostval.ptr); 3894 else if (!(peer->crypto & CRYPTO_FLAG_LEAP)) 3895 exten = crypto_args(peer, CRYPTO_LEAP, 3896 peer->associd, NULL); 3897 break; 3898 3899 /* 3900 * In client mode the parameter, certificate, identity, 3901 * cookie and sign exchanges are required. The 3902 * leapsecond exchange is optional. If broadcast client 3903 * mode the same exchanges are required, except that the 3904 * autokey exchange is substitutes for the cookie 3905 * exchange, since the cookie is always zero. If the 3906 * broadcast client finds a broken autokey sequence, it 3907 * uses the autokey exchange to retrieve the autokey 3908 * values. 3909 */ 3910 case MODE_CLIENT: 3911 3912 /* 3913 * Parameter, certificate and identity. 3914 */ 3915 if (!peer->crypto) 3916 exten = crypto_args(peer, CRYPTO_ASSOC, 3917 peer->associd, hostval.ptr); 3918 else if (!(peer->crypto & CRYPTO_FLAG_CERT)) 3919 exten = crypto_args(peer, CRYPTO_CERT, 3920 peer->associd, peer->issuer); 3921 else if (!(peer->crypto & CRYPTO_FLAG_VRFY)) 3922 exten = crypto_args(peer, 3923 crypto_ident(peer), peer->associd, 3924 NULL); 3925 3926 /* 3927 * Cookie and autokey. These are requests, but 3928 * we use the peer association ID with autokey 3929 * rather than our own. 3930 */ 3931 else if (!(peer->crypto & CRYPTO_FLAG_COOK)) 3932 exten = crypto_args(peer, CRYPTO_COOK, 3933 peer->associd, NULL); 3934 else if (!(peer->crypto & CRYPTO_FLAG_AUTO)) 3935 exten = crypto_args(peer, CRYPTO_AUTO, 3936 peer->assoc, NULL); 3937 3938 /* 3939 * Wait for clock sync, then sign the 3940 * certificate and retrieve the leapsecond 3941 * values. 3942 */ 3943 else if (sys_leap == LEAP_NOTINSYNC) 3944 break; 3945 3946 else if (!(peer->crypto & CRYPTO_FLAG_SIGN)) 3947 exten = crypto_args(peer, CRYPTO_SIGN, 3948 peer->associd, hostval.ptr); 3949 else if (!(peer->crypto & CRYPTO_FLAG_LEAP)) 3950 exten = crypto_args(peer, CRYPTO_LEAP, 3951 peer->associd, NULL); 3952 break; 3953 } 3954 3955 /* 3956 * Add a queued extension field if present. This is 3957 * always a request message, so the reply ID is already 3958 * in the message. If an error occurs, the error bit is 3959 * lit in the response. 3960 */ 3961 if (peer->cmmd != NULL) { 3962 u_int32 temp32; 3963 3964 temp32 = CRYPTO_RESP; 3965 peer->cmmd->opcode |= htonl(temp32); 3966 sendlen += crypto_xmit(peer, &xpkt, NULL, 3967 sendlen, peer->cmmd, 0); 3968 free(peer->cmmd); 3969 peer->cmmd = NULL; 3970 } 3971 3972 /* 3973 * Add an extension field created above. All but the 3974 * autokey response message are request messages. 3975 */ 3976 if (exten != NULL) { 3977 if (exten->opcode != 0) 3978 sendlen += crypto_xmit(peer, &xpkt, 3979 NULL, sendlen, exten, 0); 3980 free(exten); 3981 } 3982 3983 /* 3984 * Calculate the next session key. Since extension 3985 * fields are present, the cookie value is zero. 3986 */ 3987 if (sendlen > (int)LEN_PKT_NOMAC) { 3988 session_key(&peer->dstadr->sin, &peer->srcadr, 3989 xkeyid, 0, 2); 3990 } 3991 } 3992 #endif /* AUTOKEY */ 3993 3994 /* 3995 * Transmit a-priori timestamps 3996 */ 3997 get_systime(&xmt_tx); 3998 if (peer->flip == 0) { /* basic mode */ 3999 peer->aorg = xmt_tx; 4000 HTONL_FP(&xmt_tx, &xpkt.xmt); 4001 } else { /* interleaved modes */ 4002 if (peer->hmode == MODE_BROADCAST) { /* bcst */ 4003 HTONL_FP(&xmt_tx, &xpkt.xmt); 4004 if (peer->flip > 0) 4005 HTONL_FP(&peer->borg, &xpkt.org); 4006 else 4007 HTONL_FP(&peer->aorg, &xpkt.org); 4008 } else { /* symmetric */ 4009 if (peer->flip > 0) 4010 HTONL_FP(&peer->borg, &xpkt.xmt); 4011 else 4012 HTONL_FP(&peer->aorg, &xpkt.xmt); 4013 } 4014 } 4015 xkeyid = peer->keyid; 4016 authlen = authencrypt(xkeyid, (u_int32 *)&xpkt, sendlen); 4017 if (authlen == 0) { 4018 report_event(PEVNT_AUTH, peer, "no key"); 4019 peer->flash |= TEST5; /* auth error */ 4020 peer->badauth++; 4021 return; 4022 } 4023 sendlen += authlen; 4024 #ifdef AUTOKEY 4025 if (xkeyid > NTP_MAXKEY) 4026 authtrust(xkeyid, 0); 4027 #endif /* AUTOKEY */ 4028 if (sendlen > sizeof(xpkt)) { 4029 msyslog(LOG_ERR, "peer_xmit: buffer overflow %zu", sendlen); 4030 exit (-1); 4031 } 4032 peer->t21_bytes = sendlen; 4033 sendpkt(&peer->srcadr, peer->dstadr, sys_ttl[peer->ttl], &xpkt, 4034 sendlen); 4035 peer->sent++; 4036 peer->throttle += (1 << peer->minpoll) - 2; 4037 4038 /* 4039 * Capture a-posteriori timestamps 4040 */ 4041 get_systime(&xmt_ty); 4042 if (peer->flip != 0) { /* interleaved modes */ 4043 if (peer->flip > 0) 4044 peer->aorg = xmt_ty; 4045 else 4046 peer->borg = xmt_ty; 4047 peer->flip = -peer->flip; 4048 } 4049 L_SUB(&xmt_ty, &xmt_tx); 4050 LFPTOD(&xmt_ty, peer->xleave); 4051 #ifdef AUTOKEY 4052 DPRINTF(1, ("peer_xmit: at %ld %s->%s mode %d keyid %08x len %zu index %d\n", 4053 current_time, latoa(peer->dstadr), 4054 ntoa(&peer->srcadr), peer->hmode, xkeyid, sendlen, 4055 peer->keynumber)); 4056 #else /* !AUTOKEY follows */ 4057 DPRINTF(1, ("peer_xmit: at %ld %s->%s mode %d keyid %08x len %d\n", 4058 current_time, peer->dstadr ? 4059 ntoa(&peer->dstadr->sin) : "-", 4060 ntoa(&peer->srcadr), peer->hmode, xkeyid, sendlen)); 4061 #endif /* !AUTOKEY */ 4062 4063 return; 4064 } 4065 4066 4067 #ifdef LEAP_SMEAR 4068 4069 static void 4070 leap_smear_add_offs( 4071 l_fp *t, 4072 l_fp *t_recv 4073 ) 4074 { 4075 4076 L_ADD(t, &leap_smear.offset); 4077 4078 /* 4079 ** XXX: Should the smear be added to the root dispersion? 4080 */ 4081 4082 return; 4083 } 4084 4085 #endif /* LEAP_SMEAR */ 4086 4087 4088 /* 4089 * fast_xmit - Send packet for nonpersistent association. Note that 4090 * neither the source or destination can be a broadcast address. 4091 */ 4092 static void 4093 fast_xmit( 4094 struct recvbuf *rbufp, /* receive packet pointer */ 4095 int xmode, /* receive mode */ 4096 keyid_t xkeyid, /* transmit key ID */ 4097 int flags /* restrict mask */ 4098 ) 4099 { 4100 struct pkt xpkt; /* transmit packet structure */ 4101 struct pkt *rpkt; /* receive packet structure */ 4102 l_fp xmt_tx, xmt_ty; 4103 size_t sendlen; 4104 #ifdef AUTOKEY 4105 u_int32 temp32; 4106 #endif 4107 4108 /* 4109 * Initialize transmit packet header fields from the receive 4110 * buffer provided. We leave the fields intact as received, but 4111 * set the peer poll at the maximum of the receive peer poll and 4112 * the system minimum poll (ntp_minpoll). This is for KoD rate 4113 * control and not strictly specification compliant, but doesn't 4114 * break anything. 4115 * 4116 * If the gazinta was from a multicast address, the gazoutta 4117 * must go out another way. 4118 */ 4119 rpkt = &rbufp->recv_pkt; 4120 if (rbufp->dstadr->flags & INT_MCASTOPEN) 4121 rbufp->dstadr = findinterface(&rbufp->recv_srcadr); 4122 4123 /* 4124 * If this is a kiss-o'-death (KoD) packet, show leap 4125 * unsynchronized, stratum zero, reference ID the four-character 4126 * kiss code and system root delay. Note we don't reveal the 4127 * local time, so these packets can't be used for 4128 * synchronization. 4129 */ 4130 if (flags & RES_KOD) { 4131 sys_kodsent++; 4132 xpkt.li_vn_mode = PKT_LI_VN_MODE(LEAP_NOTINSYNC, 4133 PKT_VERSION(rpkt->li_vn_mode), xmode); 4134 xpkt.stratum = STRATUM_PKT_UNSPEC; 4135 xpkt.ppoll = max(rpkt->ppoll, ntp_minpoll); 4136 xpkt.precision = rpkt->precision; 4137 memcpy(&xpkt.refid, "RATE", 4); 4138 xpkt.rootdelay = rpkt->rootdelay; 4139 xpkt.rootdisp = rpkt->rootdisp; 4140 xpkt.reftime = rpkt->reftime; 4141 xpkt.org = rpkt->xmt; 4142 xpkt.rec = rpkt->xmt; 4143 xpkt.xmt = rpkt->xmt; 4144 4145 /* 4146 * This is a normal packet. Use the system variables. 4147 */ 4148 } else { 4149 #ifdef LEAP_SMEAR 4150 /* 4151 * Make copies of the variables which can be affected by smearing. 4152 */ 4153 l_fp this_ref_time; 4154 l_fp this_recv_time; 4155 #endif 4156 4157 /* 4158 * If we are inside the leap smear interval we add the current smear offset to 4159 * the packet receive time, to the packet transmit time, and eventually to the 4160 * reftime to make sure the reftime isn't later than the transmit/receive times. 4161 */ 4162 xpkt.li_vn_mode = PKT_LI_VN_MODE(xmt_leap, 4163 PKT_VERSION(rpkt->li_vn_mode), xmode); 4164 4165 xpkt.stratum = STRATUM_TO_PKT(sys_stratum); 4166 xpkt.ppoll = max(rpkt->ppoll, ntp_minpoll); 4167 xpkt.precision = sys_precision; 4168 xpkt.refid = sys_refid; 4169 xpkt.rootdelay = HTONS_FP(DTOFP(sys_rootdelay)); 4170 xpkt.rootdisp = HTONS_FP(DTOUFP(sys_rootdisp)); 4171 4172 #ifdef LEAP_SMEAR 4173 this_ref_time = sys_reftime; 4174 if (leap_smear.in_progress) { 4175 leap_smear_add_offs(&this_ref_time, NULL); 4176 xpkt.refid = convertLFPToRefID(leap_smear.offset); 4177 DPRINTF(2, ("fast_xmit: leap_smear.in_progress: refid %8x, smear %s\n", 4178 ntohl(xpkt.refid), 4179 lfptoa(&leap_smear.offset, 8) 4180 )); 4181 } 4182 HTONL_FP(&this_ref_time, &xpkt.reftime); 4183 #else 4184 HTONL_FP(&sys_reftime, &xpkt.reftime); 4185 #endif 4186 4187 xpkt.org = rpkt->xmt; 4188 4189 #ifdef LEAP_SMEAR 4190 this_recv_time = rbufp->recv_time; 4191 if (leap_smear.in_progress) 4192 leap_smear_add_offs(&this_recv_time, NULL); 4193 HTONL_FP(&this_recv_time, &xpkt.rec); 4194 #else 4195 HTONL_FP(&rbufp->recv_time, &xpkt.rec); 4196 #endif 4197 4198 get_systime(&xmt_tx); 4199 #ifdef LEAP_SMEAR 4200 if (leap_smear.in_progress) 4201 leap_smear_add_offs(&xmt_tx, &this_recv_time); 4202 #endif 4203 HTONL_FP(&xmt_tx, &xpkt.xmt); 4204 } 4205 4206 #ifdef HAVE_NTP_SIGND 4207 if (flags & RES_MSSNTP) { 4208 send_via_ntp_signd(rbufp, xmode, xkeyid, flags, &xpkt); 4209 return; 4210 } 4211 #endif /* HAVE_NTP_SIGND */ 4212 4213 /* 4214 * If the received packet contains a MAC, the transmitted packet 4215 * is authenticated and contains a MAC. If not, the transmitted 4216 * packet is not authenticated. 4217 */ 4218 sendlen = LEN_PKT_NOMAC; 4219 if (rbufp->recv_length == sendlen) { 4220 sendpkt(&rbufp->recv_srcadr, rbufp->dstadr, 0, &xpkt, 4221 sendlen); 4222 DPRINTF(1, ("fast_xmit: at %ld %s->%s mode %d len %lu\n", 4223 current_time, stoa(&rbufp->dstadr->sin), 4224 stoa(&rbufp->recv_srcadr), xmode, 4225 (u_long)sendlen)); 4226 return; 4227 } 4228 4229 /* 4230 * The received packet contains a MAC, so the transmitted packet 4231 * must be authenticated. For symmetric key cryptography, use 4232 * the predefined and trusted symmetric keys to generate the 4233 * cryptosum. For autokey cryptography, use the server private 4234 * value to generate the cookie, which is unique for every 4235 * source-destination-key ID combination. 4236 */ 4237 #ifdef AUTOKEY 4238 if (xkeyid > NTP_MAXKEY) { 4239 keyid_t cookie; 4240 4241 /* 4242 * The only way to get here is a reply to a legitimate 4243 * client request message, so the mode must be 4244 * MODE_SERVER. If an extension field is present, there 4245 * can be only one and that must be a command. Do what 4246 * needs, but with private value of zero so the poor 4247 * jerk can decode it. If no extension field is present, 4248 * use the cookie to generate the session key. 4249 */ 4250 cookie = session_key(&rbufp->recv_srcadr, 4251 &rbufp->dstadr->sin, 0, sys_private, 0); 4252 if ((size_t)rbufp->recv_length > sendlen + MAX_MAC_LEN) { 4253 session_key(&rbufp->dstadr->sin, 4254 &rbufp->recv_srcadr, xkeyid, 0, 2); 4255 temp32 = CRYPTO_RESP; 4256 rpkt->exten[0] |= htonl(temp32); 4257 sendlen += crypto_xmit(NULL, &xpkt, rbufp, 4258 sendlen, (struct exten *)rpkt->exten, 4259 cookie); 4260 } else { 4261 session_key(&rbufp->dstadr->sin, 4262 &rbufp->recv_srcadr, xkeyid, cookie, 2); 4263 } 4264 } 4265 #endif /* AUTOKEY */ 4266 get_systime(&xmt_tx); 4267 sendlen += authencrypt(xkeyid, (u_int32 *)&xpkt, sendlen); 4268 #ifdef AUTOKEY 4269 if (xkeyid > NTP_MAXKEY) 4270 authtrust(xkeyid, 0); 4271 #endif /* AUTOKEY */ 4272 sendpkt(&rbufp->recv_srcadr, rbufp->dstadr, 0, &xpkt, sendlen); 4273 get_systime(&xmt_ty); 4274 L_SUB(&xmt_ty, &xmt_tx); 4275 sys_authdelay = xmt_ty; 4276 DPRINTF(1, ("fast_xmit: at %ld %s->%s mode %d keyid %08x len %lu\n", 4277 current_time, ntoa(&rbufp->dstadr->sin), 4278 ntoa(&rbufp->recv_srcadr), xmode, xkeyid, 4279 (u_long)sendlen)); 4280 } 4281 4282 4283 /* 4284 * pool_xmit - resolve hostname or send unicast solicitation for pool. 4285 */ 4286 static void 4287 pool_xmit( 4288 struct peer *pool /* pool solicitor association */ 4289 ) 4290 { 4291 #ifdef WORKER 4292 struct pkt xpkt; /* transmit packet structure */ 4293 struct addrinfo hints; 4294 int rc; 4295 struct interface * lcladr; 4296 sockaddr_u * rmtadr; 4297 int restrict_mask; 4298 struct peer * p; 4299 l_fp xmt_tx; 4300 4301 if (NULL == pool->ai) { 4302 if (pool->addrs != NULL) { 4303 /* free() is used with copy_addrinfo_list() */ 4304 free(pool->addrs); 4305 pool->addrs = NULL; 4306 } 4307 ZERO(hints); 4308 hints.ai_family = AF(&pool->srcadr); 4309 hints.ai_socktype = SOCK_DGRAM; 4310 hints.ai_protocol = IPPROTO_UDP; 4311 /* ignore getaddrinfo_sometime() errors, we will retry */ 4312 rc = getaddrinfo_sometime( 4313 pool->hostname, 4314 "ntp", 4315 &hints, 4316 0, /* no retry */ 4317 &pool_name_resolved, 4318 (void *)(intptr_t)pool->associd); 4319 if (!rc) 4320 DPRINTF(1, ("pool DNS lookup %s started\n", 4321 pool->hostname)); 4322 else 4323 msyslog(LOG_ERR, 4324 "unable to start pool DNS %s: %m", 4325 pool->hostname); 4326 return; 4327 } 4328 4329 do { 4330 /* copy_addrinfo_list ai_addr points to a sockaddr_u */ 4331 rmtadr = (sockaddr_u *)(void *)pool->ai->ai_addr; 4332 pool->ai = pool->ai->ai_next; 4333 p = findexistingpeer(rmtadr, NULL, NULL, MODE_CLIENT, 0); 4334 } while (p != NULL && pool->ai != NULL); 4335 if (p != NULL) 4336 return; /* out of addresses, re-query DNS next poll */ 4337 restrict_mask = restrictions(rmtadr); 4338 if (RES_FLAGS & restrict_mask) 4339 restrict_source(rmtadr, 0, 4340 current_time + POOL_SOLICIT_WINDOW + 1); 4341 lcladr = findinterface(rmtadr); 4342 memset(&xpkt, 0, sizeof(xpkt)); 4343 xpkt.li_vn_mode = PKT_LI_VN_MODE(sys_leap, pool->version, 4344 MODE_CLIENT); 4345 xpkt.stratum = STRATUM_TO_PKT(sys_stratum); 4346 xpkt.ppoll = pool->hpoll; 4347 xpkt.precision = sys_precision; 4348 xpkt.refid = sys_refid; 4349 xpkt.rootdelay = HTONS_FP(DTOFP(sys_rootdelay)); 4350 xpkt.rootdisp = HTONS_FP(DTOUFP(sys_rootdisp)); 4351 HTONL_FP(&sys_reftime, &xpkt.reftime); 4352 get_systime(&xmt_tx); 4353 pool->aorg = xmt_tx; 4354 HTONL_FP(&xmt_tx, &xpkt.xmt); 4355 sendpkt(rmtadr, lcladr, sys_ttl[pool->ttl], &xpkt, 4356 LEN_PKT_NOMAC); 4357 pool->sent++; 4358 pool->throttle += (1 << pool->minpoll) - 2; 4359 DPRINTF(1, ("pool_xmit: at %ld %s->%s pool\n", 4360 current_time, latoa(lcladr), stoa(rmtadr))); 4361 msyslog(LOG_INFO, "Soliciting pool server %s", stoa(rmtadr)); 4362 #endif /* WORKER */ 4363 } 4364 4365 4366 #ifdef AUTOKEY 4367 /* 4368 * group_test - test if this is the same group 4369 * 4370 * host assoc return action 4371 * none none 0 mobilize * 4372 * none group 0 mobilize * 4373 * group none 0 mobilize * 4374 * group group 1 mobilize 4375 * group different 1 ignore 4376 * * ignore if notrust 4377 */ 4378 int 4379 group_test( 4380 char *grp, 4381 char *ident 4382 ) 4383 { 4384 if (grp == NULL) 4385 return (0); 4386 4387 if (strcmp(grp, sys_groupname) == 0) 4388 return (0); 4389 4390 if (ident == NULL) 4391 return (1); 4392 4393 if (strcmp(grp, ident) == 0) 4394 return (0); 4395 4396 return (1); 4397 } 4398 #endif /* AUTOKEY */ 4399 4400 4401 #ifdef WORKER 4402 void 4403 pool_name_resolved( 4404 int rescode, 4405 int gai_errno, 4406 void * context, 4407 const char * name, 4408 const char * service, 4409 const struct addrinfo * hints, 4410 const struct addrinfo * res 4411 ) 4412 { 4413 struct peer * pool; /* pool solicitor association */ 4414 associd_t assoc; 4415 4416 if (rescode) { 4417 msyslog(LOG_ERR, 4418 "error resolving pool %s: %s (%d)", 4419 name, gai_strerror(rescode), rescode); 4420 return; 4421 } 4422 4423 assoc = (associd_t)(intptr_t)context; 4424 pool = findpeerbyassoc(assoc); 4425 if (NULL == pool) { 4426 msyslog(LOG_ERR, 4427 "Could not find assoc %u for pool DNS %s", 4428 assoc, name); 4429 return; 4430 } 4431 DPRINTF(1, ("pool DNS %s completed\n", name)); 4432 pool->addrs = copy_addrinfo_list(res); 4433 pool->ai = pool->addrs; 4434 pool_xmit(pool); 4435 4436 } 4437 #endif /* WORKER */ 4438 4439 4440 #ifdef AUTOKEY 4441 /* 4442 * key_expire - purge the key list 4443 */ 4444 void 4445 key_expire( 4446 struct peer *peer /* peer structure pointer */ 4447 ) 4448 { 4449 int i; 4450 4451 if (peer->keylist != NULL) { 4452 for (i = 0; i <= peer->keynumber; i++) 4453 authtrust(peer->keylist[i], 0); 4454 free(peer->keylist); 4455 peer->keylist = NULL; 4456 } 4457 value_free(&peer->sndval); 4458 peer->keynumber = 0; 4459 peer->flags &= ~FLAG_ASSOC; 4460 DPRINTF(1, ("key_expire: at %lu associd %d\n", current_time, 4461 peer->associd)); 4462 } 4463 #endif /* AUTOKEY */ 4464 4465 4466 /* 4467 * local_refid(peer) - check peer refid to avoid selecting peers 4468 * currently synced to this ntpd. 4469 */ 4470 static int 4471 local_refid( 4472 struct peer * p 4473 ) 4474 { 4475 endpt * unicast_ep; 4476 4477 if (p->dstadr != NULL && !(INT_MCASTIF & p->dstadr->flags)) 4478 unicast_ep = p->dstadr; 4479 else 4480 unicast_ep = findinterface(&p->srcadr); 4481 4482 if (unicast_ep != NULL && p->refid == unicast_ep->addr_refid) 4483 return TRUE; 4484 else 4485 return FALSE; 4486 } 4487 4488 4489 /* 4490 * Determine if the peer is unfit for synchronization 4491 * 4492 * A peer is unfit for synchronization if 4493 * > TEST10 bad leap or stratum below floor or at or above ceiling 4494 * > TEST11 root distance exceeded for remote peer 4495 * > TEST12 a direct or indirect synchronization loop would form 4496 * > TEST13 unreachable or noselect 4497 */ 4498 int /* FALSE if fit, TRUE if unfit */ 4499 peer_unfit( 4500 struct peer *peer /* peer structure pointer */ 4501 ) 4502 { 4503 int rval = 0; 4504 4505 /* 4506 * A stratum error occurs if (1) the server has never been 4507 * synchronized, (2) the server stratum is below the floor or 4508 * greater than or equal to the ceiling. 4509 */ 4510 if ( peer->leap == LEAP_NOTINSYNC 4511 || peer->stratum < sys_floor 4512 || peer->stratum >= sys_ceiling) { 4513 rval |= TEST10; /* bad synch or stratum */ 4514 } 4515 4516 /* 4517 * A distance error for a remote peer occurs if the root 4518 * distance is greater than or equal to the distance threshold 4519 * plus the increment due to one host poll interval. 4520 */ 4521 if ( !(peer->flags & FLAG_REFCLOCK) 4522 && root_distance(peer) >= sys_maxdist 4523 + clock_phi * ULOGTOD(peer->hpoll)) { 4524 rval |= TEST11; /* distance exceeded */ 4525 } 4526 4527 /* 4528 * A loop error occurs if the remote peer is synchronized to the 4529 * local peer or if the remote peer is synchronized to the same 4530 * server as the local peer but only if the remote peer is 4531 * neither a reference clock nor an orphan. 4532 */ 4533 if (peer->stratum > 1 && local_refid(peer)) { 4534 rval |= TEST12; /* synchronization loop */ 4535 } 4536 4537 /* 4538 * An unreachable error occurs if the server is unreachable or 4539 * the noselect bit is set. 4540 */ 4541 if (!peer->reach || (peer->flags & FLAG_NOSELECT)) { 4542 rval |= TEST13; /* unreachable */ 4543 } 4544 4545 peer->flash &= ~PEER_TEST_MASK; 4546 peer->flash |= rval; 4547 return (rval); 4548 } 4549 4550 4551 /* 4552 * Find the precision of this particular machine 4553 */ 4554 #define MINSTEP 20e-9 /* minimum clock increment (s) */ 4555 #define MAXSTEP 1 /* maximum clock increment (s) */ 4556 #define MINCHANGES 12 /* minimum number of step samples */ 4557 #define MAXLOOPS ((int)(1. / MINSTEP)) /* avoid infinite loop */ 4558 4559 /* 4560 * This routine measures the system precision defined as the minimum of 4561 * a sequence of differences between successive readings of the system 4562 * clock. However, if a difference is less than MINSTEP, the clock has 4563 * been read more than once during a clock tick and the difference is 4564 * ignored. We set MINSTEP greater than zero in case something happens 4565 * like a cache miss, and to tolerate underlying system clocks which 4566 * ensure each reading is strictly greater than prior readings while 4567 * using an underlying stepping (not interpolated) clock. 4568 * 4569 * sys_tick and sys_precision represent the time to read the clock for 4570 * systems with high-precision clocks, and the tick interval or step 4571 * size for lower-precision stepping clocks. 4572 * 4573 * This routine also measures the time to read the clock on stepping 4574 * system clocks by counting the number of readings between changes of 4575 * the underlying clock. With either type of clock, the minimum time 4576 * to read the clock is saved as sys_fuzz, and used to ensure the 4577 * get_systime() readings always increase and are fuzzed below sys_fuzz. 4578 */ 4579 void 4580 measure_precision(void) 4581 { 4582 /* 4583 * With sys_fuzz set to zero, get_systime() fuzzing of low bits 4584 * is effectively disabled. trunc_os_clock is FALSE to disable 4585 * get_ostime() simulation of a low-precision system clock. 4586 */ 4587 set_sys_fuzz(0.); 4588 trunc_os_clock = FALSE; 4589 measured_tick = measure_tick_fuzz(); 4590 set_sys_tick_precision(measured_tick); 4591 msyslog(LOG_INFO, "proto: precision = %.3f usec (%d)", 4592 sys_tick * 1e6, sys_precision); 4593 if (sys_fuzz < sys_tick) { 4594 msyslog(LOG_NOTICE, "proto: fuzz beneath %.3f usec", 4595 sys_fuzz * 1e6); 4596 } 4597 } 4598 4599 4600 /* 4601 * measure_tick_fuzz() 4602 * 4603 * measures the minimum time to read the clock (stored in sys_fuzz) 4604 * and returns the tick, the larger of the minimum increment observed 4605 * between successive clock readings and the time to read the clock. 4606 */ 4607 double 4608 measure_tick_fuzz(void) 4609 { 4610 l_fp minstep; /* MINSTEP as l_fp */ 4611 l_fp val; /* current seconds fraction */ 4612 l_fp last; /* last seconds fraction */ 4613 l_fp ldiff; /* val - last */ 4614 double tick; /* computed tick value */ 4615 double diff; 4616 long repeats; 4617 long max_repeats; 4618 int changes; 4619 int i; /* log2 precision */ 4620 4621 tick = MAXSTEP; 4622 max_repeats = 0; 4623 repeats = 0; 4624 changes = 0; 4625 DTOLFP(MINSTEP, &minstep); 4626 get_systime(&last); 4627 for (i = 0; i < MAXLOOPS && changes < MINCHANGES; i++) { 4628 get_systime(&val); 4629 ldiff = val; 4630 L_SUB(&ldiff, &last); 4631 last = val; 4632 if (L_ISGT(&ldiff, &minstep)) { 4633 max_repeats = max(repeats, max_repeats); 4634 repeats = 0; 4635 changes++; 4636 LFPTOD(&ldiff, diff); 4637 tick = min(diff, tick); 4638 } else { 4639 repeats++; 4640 } 4641 } 4642 if (changes < MINCHANGES) { 4643 msyslog(LOG_ERR, "Fatal error: precision could not be measured (MINSTEP too large?)"); 4644 exit(1); 4645 } 4646 4647 if (0 == max_repeats) { 4648 set_sys_fuzz(tick); 4649 } else { 4650 set_sys_fuzz(tick / max_repeats); 4651 } 4652 4653 return tick; 4654 } 4655 4656 4657 void 4658 set_sys_tick_precision( 4659 double tick 4660 ) 4661 { 4662 int i; 4663 4664 if (tick > 1.) { 4665 msyslog(LOG_ERR, 4666 "unsupported tick %.3f > 1s ignored", tick); 4667 return; 4668 } 4669 if (tick < measured_tick) { 4670 msyslog(LOG_ERR, 4671 "proto: tick %.3f less than measured tick %.3f, ignored", 4672 tick, measured_tick); 4673 return; 4674 } else if (tick > measured_tick) { 4675 trunc_os_clock = TRUE; 4676 msyslog(LOG_NOTICE, 4677 "proto: truncating system clock to multiples of %.9f", 4678 tick); 4679 } 4680 sys_tick = tick; 4681 4682 /* 4683 * Find the nearest power of two. 4684 */ 4685 for (i = 0; tick <= 1; i--) 4686 tick *= 2; 4687 if (tick - 1 > 1 - tick / 2) 4688 i++; 4689 4690 sys_precision = (s_char)i; 4691 } 4692 4693 4694 /* 4695 * init_proto - initialize the protocol module's data 4696 */ 4697 void 4698 init_proto(void) 4699 { 4700 l_fp dummy; 4701 int i; 4702 4703 /* 4704 * Fill in the sys_* stuff. Default is don't listen to 4705 * broadcasting, require authentication. 4706 */ 4707 set_sys_leap(LEAP_NOTINSYNC); 4708 sys_stratum = STRATUM_UNSPEC; 4709 memcpy(&sys_refid, "INIT", 4); 4710 sys_peer = NULL; 4711 sys_rootdelay = 0; 4712 sys_rootdisp = 0; 4713 L_CLR(&sys_reftime); 4714 sys_jitter = 0; 4715 measure_precision(); 4716 get_systime(&dummy); 4717 sys_survivors = 0; 4718 sys_manycastserver = 0; 4719 sys_bclient = 0; 4720 sys_bdelay = BDELAY_DEFAULT; /*[Bug 3031] delay cutoff */ 4721 sys_authenticate = 1; 4722 sys_stattime = current_time; 4723 orphwait = current_time + sys_orphwait; 4724 proto_clr_stats(); 4725 for (i = 0; i < MAX_TTL; i++) { 4726 sys_ttl[i] = (u_char)((i * 256) / MAX_TTL); 4727 sys_ttlmax = i; 4728 } 4729 hardpps_enable = 0; 4730 stats_control = 1; 4731 } 4732 4733 4734 /* 4735 * proto_config - configure the protocol module 4736 */ 4737 void 4738 proto_config( 4739 int item, 4740 u_long value, 4741 double dvalue, 4742 sockaddr_u *svalue 4743 ) 4744 { 4745 /* 4746 * Figure out what he wants to change, then do it 4747 */ 4748 DPRINTF(2, ("proto_config: code %d value %lu dvalue %lf\n", 4749 item, value, dvalue)); 4750 4751 switch (item) { 4752 4753 /* 4754 * enable and disable commands - arguments are Boolean. 4755 */ 4756 case PROTO_AUTHENTICATE: /* authentication (auth) */ 4757 sys_authenticate = value; 4758 break; 4759 4760 case PROTO_BROADCLIENT: /* broadcast client (bclient) */ 4761 sys_bclient = (int)value; 4762 if (sys_bclient == 0) 4763 io_unsetbclient(); 4764 else 4765 io_setbclient(); 4766 break; 4767 4768 #ifdef REFCLOCK 4769 case PROTO_CAL: /* refclock calibrate (calibrate) */ 4770 cal_enable = value; 4771 break; 4772 #endif /* REFCLOCK */ 4773 4774 case PROTO_KERNEL: /* kernel discipline (kernel) */ 4775 select_loop(value); 4776 break; 4777 4778 case PROTO_MONITOR: /* monitoring (monitor) */ 4779 if (value) 4780 mon_start(MON_ON); 4781 else { 4782 mon_stop(MON_ON); 4783 if (mon_enabled) 4784 msyslog(LOG_WARNING, 4785 "restrict: 'monitor' cannot be disabled while 'limited' is enabled"); 4786 } 4787 break; 4788 4789 case PROTO_NTP: /* NTP discipline (ntp) */ 4790 ntp_enable = value; 4791 break; 4792 4793 case PROTO_MODE7: /* mode7 management (ntpdc) */ 4794 ntp_mode7 = value; 4795 break; 4796 4797 case PROTO_PPS: /* PPS discipline (pps) */ 4798 hardpps_enable = value; 4799 break; 4800 4801 case PROTO_FILEGEN: /* statistics (stats) */ 4802 stats_control = value; 4803 break; 4804 4805 /* 4806 * tos command - arguments are double, sometimes cast to int 4807 */ 4808 4809 case PROTO_BCPOLLBSTEP: /* Broadcast Poll Backstep gate (bcpollbstep) */ 4810 sys_bcpollbstep = (u_char)dvalue; 4811 break; 4812 4813 case PROTO_BEACON: /* manycast beacon (beacon) */ 4814 sys_beacon = (int)dvalue; 4815 break; 4816 4817 case PROTO_BROADDELAY: /* default broadcast delay (bdelay) */ 4818 sys_bdelay = (dvalue ? dvalue : BDELAY_DEFAULT); 4819 break; 4820 4821 case PROTO_CEILING: /* stratum ceiling (ceiling) */ 4822 sys_ceiling = (int)dvalue; 4823 break; 4824 4825 case PROTO_COHORT: /* cohort switch (cohort) */ 4826 sys_cohort = (int)dvalue; 4827 break; 4828 4829 case PROTO_FLOOR: /* stratum floor (floor) */ 4830 sys_floor = (int)dvalue; 4831 break; 4832 4833 case PROTO_MAXCLOCK: /* maximum candidates (maxclock) */ 4834 sys_maxclock = (int)dvalue; 4835 break; 4836 4837 case PROTO_MAXDIST: /* select threshold (maxdist) */ 4838 sys_maxdist = dvalue; 4839 break; 4840 4841 case PROTO_CALLDELAY: /* modem call delay (mdelay) */ 4842 break; /* NOT USED */ 4843 4844 case PROTO_MINCLOCK: /* minimum candidates (minclock) */ 4845 sys_minclock = (int)dvalue; 4846 break; 4847 4848 case PROTO_MINDISP: /* minimum distance (mindist) */ 4849 sys_mindisp = dvalue; 4850 break; 4851 4852 case PROTO_MINSANE: /* minimum survivors (minsane) */ 4853 sys_minsane = (int)dvalue; 4854 break; 4855 4856 case PROTO_ORPHAN: /* orphan stratum (orphan) */ 4857 sys_orphan = (int)dvalue; 4858 break; 4859 4860 case PROTO_ORPHWAIT: /* orphan wait (orphwait) */ 4861 orphwait -= sys_orphwait; 4862 sys_orphwait = (int)dvalue; 4863 orphwait += sys_orphwait; 4864 break; 4865 4866 /* 4867 * Miscellaneous commands 4868 */ 4869 case PROTO_MULTICAST_ADD: /* add group address */ 4870 if (svalue != NULL) 4871 io_multicast_add(svalue); 4872 sys_bclient = 1; 4873 break; 4874 4875 case PROTO_MULTICAST_DEL: /* delete group address */ 4876 if (svalue != NULL) 4877 io_multicast_del(svalue); 4878 break; 4879 4880 /* 4881 * Peer_clear Early policy choices 4882 */ 4883 4884 case PROTO_PCEDIGEST: /* Digest */ 4885 peer_clear_digest_early = value; 4886 break; 4887 4888 /* 4889 * Unpeer Early policy choices 4890 */ 4891 4892 case PROTO_UECRYPTO: /* Crypto */ 4893 unpeer_crypto_early = value; 4894 break; 4895 4896 case PROTO_UECRYPTONAK: /* Crypto_NAK */ 4897 unpeer_crypto_nak_early = value; 4898 break; 4899 4900 case PROTO_UEDIGEST: /* Digest */ 4901 unpeer_digest_early = value; 4902 break; 4903 4904 default: 4905 msyslog(LOG_NOTICE, 4906 "proto: unsupported option %d", item); 4907 } 4908 } 4909 4910 4911 /* 4912 * proto_clr_stats - clear protocol stat counters 4913 */ 4914 void 4915 proto_clr_stats(void) 4916 { 4917 sys_stattime = current_time; 4918 sys_received = 0; 4919 sys_processed = 0; 4920 sys_newversion = 0; 4921 sys_oldversion = 0; 4922 sys_declined = 0; 4923 sys_restricted = 0; 4924 sys_badlength = 0; 4925 sys_badauth = 0; 4926 sys_limitrejected = 0; 4927 sys_kodsent = 0; 4928 } 4929